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On the prevalence importance and control of helminths in cattle in Colombia

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(2) 1. ON THE PREVALENCE, IMPORTANCE AND CONTROL OF HELMINTHS IN CATTLE IN COLOMBIA. by J. Guillermo Mateus Valles. .J$LIOTECA AGWOPECUAAb*. r e)LOMfiIi. 25 ENE, 1999. A thesis submitted in partial fulfillment of the requirements for the degree of. DOCTOR OF PHILOSOPHY (Veterinary Science) at the UNIVERSITY OF WISCONSIN. 1968.

(3) ji ACKNOWLEDGMENTS. The counsel and guidance of Dr. A. C. Todd of the Department of Veterinary Science, throughout this investigation are gratefully acknowledged. Acknowledgment is made to the Rockefeller Foundation and its staff in Colombia for funds and facilities to support these studies and for giving the author opportunity for advanced trairiing. The author also is indebted to Dr. Miles Agee for his time in preparing the manuscript. Acknowledgment is also made to the Instituto Colombiano Agropecuario (ICA), for supporting these studies and for giving the author opportunity for advanced studies. To my wife, Alicia thanks are specially due for carrying the major sha-re of family responsibility during the completion of these studies.. aLIciTECA ,G*CPECUARIA.

(4) iii TABLE OF CONTENTS PACE Líst of Tables .............................................ix List of Figures ............................................ix 1.. INTRODUCTION ......... . ...................................... 1. II. SURVEYS ON PREVALENCE OF PARASITES .........................4 1.. Geography of Colombia ................................... 2,. Areas of Studies .......................................4. 4. A. The Bogota Savanna.................................4 Bogota Farm 1 ......................................7 Bogota Farm 2 ......................................9 Bogota Farm. 3....................................... 11. Bogota Farin 4 ......., ..............................13 Bogota Farm 5 ......................................14 Bogota Farm 6 .....................................16 Bogota Farm 7 ......................................17 Bogota Farm 8 .......................................18 B. The Cauca Valley...................................19 C. The Sinu Basin.....................................23 III.. MATERIALS AND METHODS ......................................27 1.. General Methodology ....................................27. 2,. Records of Egg Counts in Feces .......................... 33. A.. The Bogota Savanna ........................ .......... 33. Bogota Farm 1. ........................ — ........... 33. Bogota Farm 2 ......................................34 BogotaFarm 3......................................34 Bogota Farm 4 ......................................35.

(5) iv PACE BogotaFarm5. 35. Bogota Farm 6 .......................................36 Bogota Farm 7 .......................................36 Bogota Farm 8 .......................................36 B. The Cauca Valley .......................... . ......... 36 Cauca Valley Farm 1 .................................36 Cauca Valley Farm 2 .................................. 37. Cauca Valley Farm 3 .................................37 Cauca Valley Farm 4 .................................37 Cauca Valley Farm 5 .................................37 Cauca Valley Farm 6 ................................38 Cauca Valley Farm 7 ................................38 Cauca Valley Farms 8, 9, and 10 ....................38 C. The Sinu Basin ...................................... 38 Sinu Basin Farm 1 ...................................38 Sinu Basin Farm 2 ...................................39 Sinu Basin Farm 3 ...................................39 Sinu Basin Farm 4 ...................................39 Sinu Basin Farm 5 ...................................40 3.. Animais Sacrificed ......................................40 A. The Bogota Savanna..................................40 B. The Cauca Valley ....................................43 C. The Sinu Basin .................. ...... ................. 4. Parasíte Control Programs at Demonstration Parms ....... A.. 41 41. Chemicals Used .....................................-+2.

(6) y PAGE. .................................. Cyanacethydrazide ................................... Thiabendazole ....................................... Neguvon ............................................. B. Trials Conducted .................................... Trial 1, Bogota Farm 1 .............................. Trial 2, Bogota Farm 1 .............................. Trial 3, Bogota Farm 1 .............................. Trial 4, Bogota Farin 7 .............................. RESULTS AND OBSERVATIONS .................................... 1. Surveys on Prevalence of Parasites ...................... A. The Bogota Savanna .................................. Bogota Farm 1 ....................................... Bogota Farrrt 2 ....................................... Bogota Farm 3 ....................................... Bogota Farm 4 ....................................... Bogota Farm 5 ....................................... Bogota Farm 6 ....................................... Bogota Farm 7 ....................................... BogotaFarm 8 ....................................... B. The Cauca Valley ................. ................... Cauca Valley Farra 1 ................................. Cauca Valley Farra 2 ................................. Cauca Valley Farra 3 ................................. Cauca Valley Farra 4 ................................. Diethylcarbainazine. IV.. 42 44 44a 44a 45 45 47 49 50 54 54 54 54 55 56. 58 59 60 61 62 81 81 82 83 84.

(7) vi PAGE Cauca Valley Farin 5 ..................................85 Cauca Va.11ey Farm 6 ..................................86 Cauca Valley Farm 7 ..................................87 C. The Sinu Basin....................................... 102 SinuBasinFarml .................................... 102 Sinu Basin Farm 2 ....................................104 Sinu Basin Farm 3....................................105 Sinu Basin Farm 4 ....................................106 Sinu Basin Farin 5 .....................................107 2. Parasite'Recoveries .....................................121 Bogota Farm 1 ........................................... 121 Bogota Farm 5 ............................................ 121 Cauca Valley Farms 4, 5, 8, 9, and 10 ................... 122 Sinu Basin Farm 2 .......................................124 3. Results of Control Programs at Demonstration Farms ......136 Trial 1, Bogota Farm 1..................................136 Trial 2, Bogota Farin 1 .................................. 142 Tríal 3, Bogota Farm 1 .................................. 154 Trial 4, Bogota Farm 7 ..................................170 V.. DISCUSSION ........... .................... ---- .......... 179 1.. Surveys on Prevalence of Parasites ................... A.. 179. The BogQta Savanna..................................179 Farm 1............................................. 179 Farm 2. .............................................185 Farm 3 .............. .......................... ......187.

(8) vii PACE Farra 4 .............. 189 Farra 5 .............................................• 191 Farras 6 and 7 .......................................192 Farra 8..............................................194 B•. The Cauca Valley ....................................195 Farra 1..............................................195 Farms 2, 3, 4, and 5 .................................196 Farras 6 and 7 .......................................198. C.. The Sinu Basin...................................... 199 Farra 1.............................................. 199 Farra 2 ..............................................200 Farra 3 ..............................................201 Farras 4 and 5 .......................................201. 2.' Parasíte Recoveríes .....................................202 Bogota Farras 1 and 2 ....................................202 Cauca Valley Farras 4, 5, 8, 9, and 10 ...................202 Sinu Basin Farms 1 and 2 ................................203 3. Parasite Control Prograras ...............................204 Trials 1, 2 and 3 .......................................204 Trial 4 .................................................208 VI. DICTYOCAULUS VIVIPARUS STUDIES ..............................209 1.. Incidence andBionornics .................................209. 2. Dictyocaulus viviparus control..........................220 A. Prophylactic Chemotherapy ................... . ...... .220 Results ...........• .................................221.

(9) viii PAGE Discussion. • • • .........• • ........• • • • • ................222 B. Therapeutic treatments ..................229 Results ........................,, .........229 Discussion.....................230 C. Preimmunization method. ...........................236. ResultsandDiscussion ............... ................. vii. VIII.. 240. sUuLAR.Y .......................................................251 BIBLIOGRAPIIY ................................................... /. 255.

(10) ix PAGE. LIST OF TABLES Table 1 Bogota Savanna Farins . . . . . , .................. . . . . . . . . . . . . .. 20. Cauca Valley Farms ............. . . . . . . . . . . . . . . . ............ 24. Table 2. Table 3 Sinu Basin Fartns . ...............26 Table 4 Design of trial 3..................... . . . . . ..... 51 Table 5 Design of trial 4.........................................53 Tables 6 to 21 Bogota Savanna farms .............................63-80 Tables 22 to 35 Cauca Valley farms ..............................88-101 Tables 36 to 45 Sinu Basin farms ..............................109-120 Tables 46 to 50 Parasíte recoveries ..., ......................125-129 Tables 51 to 52 Results trial 1 .............................. Tables 53 to 58 Results trial 2 .............................. Tables59to69 Resultstrial3 .............................. 157-167 Tables 70 to 75 Results trial 4 ................, , ............173-178 Tables 76 to 83 Dictyocaulus viviparus studies ............... Tables 76 to 78 • , , .....................................215-217 Table 79 ..................................................224 Table 80 ..................................................231 Tables 81 to 83 ........................................244-246 LIST OF FIGURES Figures 1 to 5 Parasites recovered ...........................131-135 Figure. 6. Figure 7 Trial 2 Figure 8. Trial 3. Trial. 1. ..............141 153. .................... ................... • . 000..s,,.s . .. . ............ 169.

(11) x PAGE Figure 9 Climatic factors Bogota Savanna 1965......... .... 0... 219 Figure 10 Prophylactic chemotherapy for D. viviparus. ........226. Figure 11 Prophylactic chemotherapy for D. viviparus. 228. Figure 12 Therapeutic treatments for D. viviparus. 233. Figure 13 Therapeutic treatments for D. viviparus ......235 Figure 14 Preinununization method in D. viviparus control....... 248. Figure 15 Preimmunization method in D. viviparus control. 250. 1.

(12) 1 1. I. INTRODUCTION. Ruminants are parasitized by countless numbers of a wide variety of parasites, at all ages and under the most diversified conditions. The parasites are as ancient as their hosts. Parasites have adapted themselves to their hosts in such a manner that according to their physiological needs they select the right níche in which to settle and complete their biotic aim. The result of parasitism in such an association is one in which the effects of the parasites become most apparent in the neglected and undernourished hosts. The remarkable capacity of parasites to uve inside an animal is sometimes so great that the parasites may destroy their host and what they have built for years. The significance of parasites to cattle has always been neglected by livestock producers, men in animal husbandry and even veterinarians. This is because, and especially in field condítions, the effects of parasites upon their hosts are not so noticeable or spectacular as the effects of many infectíous diseases of cattle. Generaily speaking parasitiasis is a common phenomenon wherever cattle are found and as a result of parasitic adaptation, age sex or breed barríers no longer exist Furthermore it takes only a little success for parasites to continua their pathogenic careers and develop from simple parasitiasis to more complicated parasitosis. This may be accomplished by increasing the numbers within the host, increasing the pathogenic capacity, from stresses exerted upon the host, or a.

(13) 2 combination of all these factors. Parasitisms in cattle generahly have been considered only when the effects of the parasites upon the host are such that the animais show loss of condition, stunting and unthriftiness. No attention has been paid when less obvious signs of parasitisms are present and the fact that parasites are perhaps the greatest source of hidden losses has always been neglected. Clinical cases of parasitisms are not difficult to diagnose be~ cause symptoms of anemia, poor growth, loss of weight, weakness, rough hair coat, loss of appetite, diarrhea, bad breath and edemas are so apparent that they are easily detected. Symptoms of parasitiasis are relatively mild and much more difficult to detect. Animais born from parasitized dams and raised in a contaminated environment wihl be badly handicapped and will not attain their genetic potential, if they survive. Man now faces a shortage of animal protein and his needs wihl be greater in the future because of population increases. Among the possible solutions to this shortage would be to increase the production of meat and milk by raising larger numbers of cattle, and by taking better care of the present animal populations. It has to be considered that increasing numbers of animais and overstocking grazing areas will produce many more problems, for as far as parasites are concerned this wihl afford them a better opportunity to survive and cause greater harm to these animais. Nematodes alone are estimated to cause $14 million a ycar loss in cattle in the U.S.. 13.

(14) 3 In Colombia this loss was figured at $12.7 million in 1966.27 Figures of parasitic 1osses however, are underestimated all over the world. The economic impact of parasitisms has to be carefully considered in all types of cattle operations, both from death losses and from the not so obvious loss caused by parasitiasis. Along with the adaptation of the parasites to the host, parasites also adapted to the host's environment. This is the reason parasites so readily adapt to geographic regions, to local climatic influences, to particular farm conditiona and even to particular management practice conditions. Field parasitisms are characterized by mixed infections, parasitiasis throughout a herd and seasonal variations. However parasitosis may appear in one or more animals within a herd and the clinical picture may be caused primarily by one species of parasite. From the preceding considerations, it is obvious that parasite control programs should be estabhished to prevent cattle from being further harmed, to reduce the losses and to niinimize their effect on the hosts. Highly developed systems for eradication of parasites could be attempted if the systems are proved prof itable. Colombiark cattle are another example of the comphicated parasitic syndrome that affects animais, denies people food and clothing and predisposes man to the same or other diseases. The primary purpose of this research was to study the existing parasite population in cattle in Colombia and to evaluate several control systems, suitable for the different conditions in Colombia..

(15) 4. II. SURVEYS ON PREVALENCE OF PARASITES. 1.. Geography of Colombia Colombia is located on the northwest comer of South Axnerica, latí-. o . o o o tude 3 south to 13 north, longitude 67 to 78 west. The total area is 1,136,153 square kilometers or approximately 1-1/2 times greater than the state of Texas. There are 4 different climatíc zones: Tropical: O to 2,400 feet Semitropical: 2,400 to 3,300 feet Temperate: 3,300 to 8,250 feet Cool: 8,250 to 17,100 feet abo ye sea level The total population (1962) was 14,768,510 persons.16 The cattle population was 17,000,000 head in 1966.27 Accórding to Guerrero. 14. Colombia is divided into 10 "Natural Regions,". 5 of which are of importance to the cattle industry. The studies reported herein were conducted in 3 of the 5 cattle regions which were selected because they represented the 3 more important cattle raising areas, because transportation was available and because the author was more familiar with these areas. Each of these 3 regions represents one of the 3 main climatic conditíons, tropical, semitropical and temperate, existing in Colombia.. 2.. Áreas of Studies A. The Bogota Savanna This savanna is located in about the center of Colombia, 8,250 feet.

(16) 5 aboye sea level. The Bogota Savanna has about 1,400 square kilometers and represents approximately 0.15% of the total cattle-raising area of Colombia. The temperature throughout the year ranges from 530 to 68° F. In sorne locations it is relatively constant, even though -40° F, an exception, has been recorded. There are two periods of rainfail, April-May and October-November which alternate with periods of no rainfail. The transítion from one period to the next is almost unnoticeable. The precipitation ranges from 850 to 1,050 mm. throughout the year, with an average of 950 mm. The relative humidity ranges from 54 to 85%, with an average of 71%. The dew-point ranges from 45.1 to 49.4° F. throughout the year, with an average of 47.3° F. The hydrologic system is formed by the Bogota River and over 20 srnall tributarles. The Bogota River is the source of water for cattle and at sorne places for people. The river also supplies water for crops and pasture irrigation during the period of non-rainfail and receives the excess of water run-off during the rainy seasons. Lateral and collateral irrigation canais are used for the movernent of water in both directions. About 70% of the savanna is used for grazing cattle. Of this area, 60% is covered with kikuyo grass (Pennisetumc1andstinum Hoscht) and 40% is improved rye and dover. Intermingled in the grazing areas are plots of wheat, barley and potatoes and soon after the crops are.

(17) 6 harvested there is a regrowth of kikuyo grass and the adult cattle are moved into these areas for grazing. Young cattle are kept in permanent grazing areas and not rotated. No definite pattern is followed and the characteristica of each farm surveyed will be described later. The dairy industry has been concentrated around the larger cities; that near Bogota is most extensive because of climatic conditions. The dairy herds la the Bogota area have 50 or more dairy cows; there are very few smaller herds in the area. As a general rule, no males are raised la the dairy herds. The dairy cattle are purebred or "high grade" Hoistein, Brown Swiss, Red Poil, Normandy and Guernseys. Red Poil and Normandy are dual purpose breeds kept for milk and beef production. Sorne herds are machlne-milked ja permanent or portable milking parlors, but the majorlty of herds are hand-milked out la the field. Breeding is done naturaily but artificial inseminatjon is becoming more common, especially in the last decade. Feeding practices are not adequate. Graja of poor quality and concentrates of unknown composition are fed ja very limited quantities. Disease control programs consist of foot aad mouth disease yaccination. There are no systernatic parasite control programs. The veterinarian is called when the manager's treatrnents are jneffectjve. Fertjllty control programs are progressing in the same herds, at about the same rate as the use of artificial breedlng. The vast majority of the dairy farms are owned by "abseatee.

(18) 7 owners." Sorne owners are reluctant to change the conditíons on the farms. Sorne of them spend money on drugs rather thanon feed. Sorne owners will not allow researches to be conducted with their cattle, at no expense to themselves. On the other hand, most owners are most generous in their cooperation and are devoted to the developinent of the dairy industry. These men actively supported these researches and made their interest known to the researchers. A total of 8 farms were surveyed in this area. Bogota Farm 1 This farrn is located 30 miles northwest of Bogota and consists of 2,100 acres, about 80% in kikuyo grass pasture and improved pasture, (rye and dover). The rernainder is under water or not used because of the hilly topographical conditions, The Bogota River runs through this farm, and through the use of canals with laterais supplies water for the cattle and for irrigation. In the rainy seasons, a flooded condítion exists in the pastures, the river overflows, excess rain water stays in the pasture. Water tidrain off" from the mountains contributes to this condition. When the rains cease the canais and laterais are utilized for drainage and the excess water is pumped into the Bogota River. The land on this farm is wet throughout the year and furnishes an ideal environment for parasites to survive. This farm is one of the largest, specialized, coniinercial dairys in Colombia. The cattle are purebred or hígh grade Holsteins and number approximately 1,700, 600 mllking cows, 400 adult dry cows, 300 heifers, 400 calves and4 bulls..

(19) 8 The calves, up to 4 months, are reared in individual stalis but are allowed to graze and exercise in a permanent kikuyo grasa pasture paddock around the barns for a few hours each day. This permanent pasture 18 irrigated with water from the milking parlor area and indudes feces and urine of the cows being milked. These calves are fed milk and clipped kikuyo grass from parasiteinfected areas; the calves receive a small amount of commercial supplement daily, but the purebred calves receive much more than the rest of the animais. Clinical coccidiosis, infectious enteritis and pneumonia are present consistently during the first 4 months after the calves are born. At 4 months of age, the calves are taken to the river bank or edge of a canal, and neck-chained in the open so that they may graze. They are fed milk once a day. They are moved along the bank as they graze the grass close to the ground. These calves are given water from the river, once a day. At 8 months of age the calves are moved to permanent pasture areas. Then, they receive no milk, other feed or care except an occasional "dipping" for external parasites until they reach breeding size at about 22 months of age. In 1964, 38% of the calves under 1 year of age died; 75% of this death loss occurred in the 8 to 10 month age group or about 2 months after the calves were turned into grazing lots. The milking cows are grazed and rotated toward the more succulent pastures, They remain in each pasture for 20 to 30 days, and then are.

(20) 9 moved to a new pasture. The heifers (10 to 12 rnonths of age) follow this same rotation pattern and follow itnmediately after the cows have been moved from the pasture. Sometirnes this pattern is broken due to flooding, or sorne unexpected event. The nutritional status of the calves and young heifers is very poor but the adults on pasture are in better condition. The cows are fed a small amount of grain in the rnilkíng parlor. Calves are frequently purchased to be raised as replacernents, but they are not quarantined nor examinedfor diseases or parasites. The herdsrnan expects to take better care of his cattle after they freshen by feeding a small amount of grain in the milk parlor but does not seern to realize that the animal's body. 15 in. such a condition from. lack of balanced rations and parasitísms that it is unable to make a physiological response in such a short period of time. Vaccination prograrns for Bang's and foot and rnouth disease are used but no parasite control prograrns are followed.. Bogota Farrn 2 This farrn is located 15 miles northwest of the City of Bogota, and consists of 1,400 acres, 700 acres of which are in improved (rye and dover) and kikuyo grass pasture. The 700 improved acres has been divided into 30-acre pasture lots. The lots were graded to a 1% slope from their center to their perimeters. The perirneters are canais, laterais or collaterais on one or all sides. These waterways are used for irrigation when needed, drain-off and to retain excessive rain water in wet seasons and also, as the water.

(21) lo supply for the cattle and the people on the farin. The cattle wade and defecate ja these canais. The water is control-drained from a nearby lake into the canal systein. The cattle population is approximately 433 head, 150 of which niilk, 120 are dry adults, 90 are heifers over 1 year of age, 70 are heifers under 1 year of age, and there are 3 bulis. The calves are placed in individual stalis until 6 months oid, are fed milk twice a day and clipped kikuyo grass from a supposed parasite-free area. The stall area is dirty, dark and humid. Once a week, while cleaning the stalis the calves are allowed to graze la a permaaent grass pasture paddock close to the barns, for a period of about 3 hours,. -. At 6 inonths of age the heifers are allotted into groups of 8 to 10 each and the groups are moved.to peas in a bara. Each group is fed milk once a day plus clipped kikuyo grass and is ailowed access to an irrigation lateral once a day for watering, and then is returned to the peas. At 12 months of age the heifers are moved to pasture lots with older heifers and dry adult cows. When the heífers are large enough to be bred, they are serviced artificially and allowed to remain ja this group and calve la the pasture along wjth the dry adult cows. They are traasferred iato the milking herd after they freshen. The milking herd is divided lato two groups (A and B) and machinemilked in two milking parlors. The milking cows are pastured la the most succuleat pasture lots and are moved to new lots as new growth of grass permits. The dry cows and heifers are grazed ja the same.

(22) 11 rotation pattern immediately following the milking herd and when the lots become "grazed off," the stems of the grass are mowed with a rotary mower, and then the lots are fertílized with inanure from the milk parlor area and calf pens. When the lot is covered with manure it is irrigated by a sprinkler system positioned around the crown of the lot. The excessive water from irrigation or from raí drains into the canais or laterais. Then time is allowed for re-growth of the grass and the grazing process is repeated. A fertility program is foilowed and a graduate veterínarian is on the farm once each month. Vaccination programs for Bang's and for foot and mouth disease are followed. Deaths are reported to occur among the yearlings, but the causes have been ignorad. No parasite control program was followed. Thé income of this farm is from sale of milk and sale of calves to be raised as replacements in other herds, Bogota Farm 3 This farm is located 20 miles north of Bogota and consists of 2,600 acres. The pastura area is reasonably fiat and has a system of canais; laterais are used for irrigation when needed and as drainage canais in rainy seasons. Water is pumped into the canal system and when necessary is pumped out of the canal system into a tributary of the Bogota Ríver. This farm is a specialized, conunercial dairy. The cows are milked.

(23) 12 by machine in a permanent parlor. Milk is tansferred to a nearby building where it is pasteurized, bottled and soid in Bogota as Grade A pasteurized milk. Water from deep drilled wells is used throughout milking parlor, calf barns and pens, processing plant and as drinking water for people. There are 214 dairy cattle of Hoistein and Guernsey breeds; 120 milking cows, 20 dry cows, 70 calves and 4 bulis. Heifers over 1 year and dry cows are kept at another farm. Calves are raised several to a pen until 1 year of age; they have well water to drink, are fed inilk twice a day, plus a commercial calf ration, plus a fresh clipped mixture of rye and dover. At one year of age the heifers in groups are moved to pasture areas and immediately follow the milking herd on rotated pasture areas. The heifers are pasture-bred artificially and calve in the pasture. Then, they are transferred to the milking herd. The milking herd is rotated towards the most succulent pastures and is fed green pasture chop and a commercial grain concentrate mix while milking. This is perhaps the only farm in the Bogota Savanna that employs a fuli-time, graduate veterinarian, who has instituted control programs for diseases, nutrition, fertility and parasites. The parasite treatment program begins in calves at 8 months of age and continues until heifers are 18 months of age. All animals that show evidence of parasitisms are treated. The drug treatments are alt ernated. In 1964 a few animals 12 to 16 months of age died from unknown causes and no autopsies were made,.

(24) 13 Bogota Farm 4 This farm is located 15 miles north of Bogota and has 1,900 acres, 75% of which is cultivated rye and dover mix pastures of about 60 to 80 acres each; the remainder is in kikuyo grass. These lots have been graded to a 1% slope from crown to the perimeters where the collecting canais are. These plots are cultivated with a one-way disc, seeded with a rye and dover mixture, and f requently irrigated to keep the pasture mixture green and growing. The collecting canais surrounding the plots are used to retain the water run-off from raí or irrigation. Thís sanie water is pumped back on the lot when needed for irrigation and is used as drinking water for the mulking cows, heifers and calves staked-out along the banks. The milk cows and heifers drink, wade and defecate in these collecting canals, and the sanie water from these canais is carried to the stakedout calves. The water comes to this area from a tributary of the Bogota River vía irrigation canals and is used for cattle, irrigation and people. There are about 540 Hoistein dairy cattle; 300 milk and there are 90 heifers and 150 calves. The dry cows and heifers over 18 months of age are moved to another farm. The cows are milked in portable milking parlors in the pasture lots The milk cows are pastured on the lush rye-clover pastures for approximately 8 to 10 days, then moved to new pastures. The heifers 12 to 18 months of age immediately follow the niilking cows from pasture.

(25) 14 to pasture and remain an additional 20 days. The pasture then is recultivated, "one-wayed", reseeded and irrigated and is pastured again by the milking cows as soon as the growth of the rye-clover mixture permits. The miik cows again stay 8 to 10 days and are removed. Then the pasture is used to stake out newborn calves in long rows. These calves remain "staked out" in this pasture area until they are 12 months oid. A calf is moved as soon as it grazes the area it can reach. The calves are fed miik twice a day until about 8 months oid and then are given water from a coliecting canal until they are about 12 months oid. The yearlings are grouped and pastured in a rotation system itnrnediateiy foliowing the miiking herd, from pasture to pasture, until they are 18 months oid, at which time they are moved to another farm and are comingled with the dry cows. They do not enter the milking herd until afterthey have freshened. Artificial insemination and fertility control programs are used as well as vaccination programs for Bang's and foot and mouth disease, but no parasite control program has been used. Frequent outbreaks of various diseases occur in this herd and newly purchased animais are neither quarantined nor examined for diseases. In 1964 about 10% of calves under one year of age died, but no autopsies were made.. Bogota Farm 5 This farm is iocated 14 miles northwest of Bogota and consists of 150 acres. The land is reasonabiy level; the grazing and cuitivated arcas are divided by a network of canals bringing water into the farm from a near-by lake. The canais and laterais are fenced so cattle do not have direct access to them. Water for drinking purposes, for cattle and for.

(26) 15 people, is pumped from a main canal into an elevated tank and flows by gravity to drinking cups in calf pens, parlor and permanent drinking troughs in the various pastures. There are 250 Hoistein dairy cattle on the farm, 80 milking, and 50 dry, along with 40 heifers and 80 calves. The calves are reared in individual pens out in the open ánd in barns to four months of age and fed milk twice daily, plus a comniercial calf Leed and clipped rye-clover mix or kikuyo grass. At four months of age the calves are placed 10 to 15 to a group and moved to permanent kikuyo grass pasture lots and here they are kept until 12 months of age and are Led a commercial calf feed. They have reasonably good kikuyo pasture. At 12 months of age the heifers are regrouped and moved to larger permanent pasture (kikuyo grass) and remain in this pasture until they are bred, freshen and are transferred to the mulking herd. The pasture areas are strip-grazed by the adult cows, which are controlled in turn through the use of electric fences. The pastures are of kikuyo grass, or rye-clover mix. Corn is alternated with the rye-clover mix pasture and the corn is fed as silage to the adult cattle. All the farm area can be irrigated from the canais or laterais, if necessary. The land is level and heavy rains result in ponds which stand for long periods. The nutritional status of the animais is good except for calves 6 to 12 months of age, and these calves also are most affected by parasites. In 1965, 7% of these calves died from parasitisms..

(27) 16 This farm has vaccination programs for Bang's and foot and mouth diseases, plus a fertility control program, but has no parasite control program. Bogota Farm 6. This farm is located 30 miles southeast of Bogota and consists of 700 acres of land. The land has been divided into 60 to 70 acre lots for the purpose of irrigation, rotation of pastures and rotation of cash crops. Sixty percent of the land is in kikuyo grass and the remainder is in wheat or barley. The wheat and barley lots are rotated with the kikuyo grass lots but the percentage of each remains about the sanie. Water is pumped from a tributary of the Bogota River into canais and laterals which form the perimeters of the lots. Water for people and for calves is pumped from a canal, filtered, and then used, but water for the cows is not filtered and they have access to the canals and laterals. There are 240 dairy cattle on this farm, 120 are in milk; 80 are calves under 4 months of age and 40 are dry cows. The heifers and dry cows are moved to farm 7 which will be described next. The new-born calves are placed in individual pens fed milk twice daily and kikuyo grass clipped from along the canals, and a homemade calf supplement. The water f cd these calves is filtered. The calves are kept in these pens until 4 months of age when they are moved to farm 7 and placed on pasture with the dry cows and older heifers..

(28) 17 Kikuyo grass pasture is irrigated for the milking cows and they graze approxirnately one month on a lot and then are moved to more succulent grass lots. Sorne dry cows are retained on this farm, to imrnediately follow the rotation of the rnilking cows to eat the grass close to the ground. Sorne of these lots will be cultivated and seeded with wheat and barley. The cows are milked by hand in portable milking pariors in the pastura. The cows are pasture-bred, artificíally. Vaccination for prevention of Bang's and foot and mouth disease is performed regularly, but no parasite control program is followed.. Bogota Farni 7 This farm is located 35 miles northwest of Bogota and consists of 920 acres, This land is divided into 60 to 70 acre lots by fences. Kikuyo grass is used for pasture and the pasture lots are rotated with the planting of wheat and barley but grass pasture comprisas approximaeely 70% of the land usage. Water for this farm is obtained from drilled, deep wells and is used for drinking by the people and the cattle. There is always a shortage of water for anirnals. There are 220 dairy cattle on this farni, 60 milking cows, 90 dry cows and 70 short yearlings and heifers. The grass pasture lots are not irrigated and when the grass is ready to be pastured, the mulking cows are grazed first until the bulk of the succulent grass has been removed. Then, the milking cows are moved to another lot and the dry cows andheifers follow.

(29) 18 onto the first lot. The 4 month oid calves from farm 6 are broughtto this farm, comingled with the older heifers and dry cows and pastured along with the older cattle. They receive no additional feed. The nutritional condition of the cattle on this farm was poor and in 1963, 9% of the 6 to 12 month oid calves died. Vaccination programs for Bang t s and foot and mouth disease are used, but no parasite control programs were in force. Bogota Farm 8 This farm is located 25 miles northwest of Bogota and consists of 1,150 acres. The land is divided into lots of about 70 acres each for irrigation and pasturing cattle. The 70 acre lots have canais or laterals on at least one side and thewater in the canais comes from a nearby lake. Seventy percent of the lots are in rye-clover mix used as pasture. The remainder is covered with kikuyo grass which is also used for pasture. The are 185 head of dairy cattle on the farm, 90 milking cows, 30 dry cows, 20 heifers, 45 calves. The calves are placed in individual pens and fed milk twice a day and a feeding of clipped rye-clover pasture mixture from a parasite-free" area until they are 4 months of age. These calves are allowed to exercise around the barns and milking parlors for a few hours each day. At 4 months of age the calves are placed in permanent pasture in.

(30) 19 groups of 15 to 20; here they remain until they are 1 year of age. Water is pumped to them from an irrigation collateral. At one year of age these heifers along with the dry cows are moved to another farm. The miiking cows are fed a small amount of grain supplement while being miiked in the pariors and are rotated to the best rye-clover pastures for grazing. A group of dry cows. and heifers is retained on the farm to ixnmediately follow the milking cows from lot to lot to utilize the remaining pasture not eaten by the milking cows. The pastures are irrigated when necessary to keep them green and growing and the cattie have access to the irrigation canais and laterais for water. The farm uses vaccination programs for prevention of Bang's and foot and mouth disease but has no program for control of parasites. Death losses occur at the rate of 3 to 4 calves monthly, mostly when the calves are 6 to 12 months oid. Table 1 has a record of the fartns on the Bogota Savanna and detaus the type of cattle, their breeds, nutritionai status, sanitation, parasite control program, and quaiity of management. B. The Cauca Valley The Cauca Valley is located in the southwest part of Colombia, 3,350 feet aboye sea level. It contains approximately 500 square kilometers of reasonably level land.. El.

(31) TABLE 1 BOGOTA SAVANNA FARMS. Farm Number. Type of Cattle. Breed. Nutritiorial Status. Sanitation. Parasite Control. Calves. Management. Cows. BF*1. Dairy. Ho 1 st em. Poor. Poor. No. Individual pens Neck-chained. Pasture. BF*2. Dairy. Hoistein. Good. Poor. No. Individual and Multiple pens. Pasture. BF*3. Dairy. Holstein Guernsey. Good. Good. Yes. Multiple pens Individual pens. Pasture. BF*4. Dairy. Hois tein. Good. Poor. No. Neck-chained. Pasture. BF*5. Dairy. Hoistein. Good. Good. No. Individual pens. Pasture. BF*6. Dairy. Hois t em. Poor. Poor. No. Individual pens. Pasture. BF*7. Dairy. Hois tein. Poor. Poor. No. Pasture. Pasture. BF*8. Dairy. Hoistein. Good. Poor. No. Individual pens. Pasture. *Bogota Farrn. t'). o.

(32) 21 The temperature throughout the year ranges from 750 to 85° F. with an average of 77° F. The precipítation ranges from 1,004 mm. to 1,300 mm. with an average of 1,152 mm. There are two periods of considerable rainfail, March, Apríl and May, and October, November and December. The months of June, July, August, and January and February are reasonably dry periods and result in an alternate wet-dry-wet-dry year. The relative humidity ranges from 52 to 93%, wíth an average of 77%. The dew point ranges from 60.4 to 65.5° F. with an average of 62.8° F. The entire Cauca Valley extends along the Cauca River approximately 250 kilometers and vares from 10 to 30 kilometers wide. This region is believed to be the best agricultural area in Colombia. The climate and high quality of the soil are ideal for many crops, including corn, cotton, dry beans, sugar cane, rice, tobacco and other truck crops. There are 3 pasture forages prevalent in this area, 'Panicum maximum Jacq, Pennisetum purpureum Schumach and Hypharrhenia rufa (Nees) Stapf. The pasture areas are used for grazing the established and growing cattle industry of the area. The cattle industry is somewhat divided into three categories, dairy cattle, dual-purpose .dairy and beef and the beef cattle. The majority of the dairy herds are located near Cali (the Capital of the Department) and average over .40 milking cows per herd..

(33) 22 The predominant breeds are Hoistein, Brown Swiss and Ayshire; these herds are large and have been raised and selected on basis of milk production. The native cattle have been cross bred and very few purebred native cattie remain. The dairy cattle are on pasture constantiy and near the miiking pariors where they are hand-miiked twice daily. Oniy a few herds are machine-iniiked. The milking cows are fed a mixture of clipped pasture grass and a commercial supplement during milking; in addition, most farms feed molasses free-choice. In the better-managed herds the calves are placed in pens shortiy after birth and reared on miik, ciipped grass and a suppiement until one year oid. On other farms the calves remain with their dams on pasture during the day and are kept in pens overnight. The cattie on these farms usually are a native cross and are a dual-purpose type, beef and milk. The beef cattle are Brahma or Brahma-native cattle cross, raised in the valiey or shipped in at about 2 years of age. The arrivais. pasture 1 to 1-1/2 years before they are ready for the market. Most of the sugar refineries are also in the cattie business, principaiiy in dry lot feeding. Cattle in the Cauca Vailey are seriously affected by hemoparasites, gastrointestinal parasites, lung parasites, and bacterial and virus diseases as weii as nutritional diseases. Generaily, cattie are vaccinated for foot and mouth dísease but no other disease control programs are foliowed. Ten typical farms were surveyed in this area, 5 dairy farms, 3.

(34) 23 beef-dairy farms and 2 beef farxns. Table 2 details the farms, type of cattle, breed, nutritional status, sanitation, parasite control and quality of management. C. The Sinu Basin. The Sinu Basin is located in the northern part of Colombia, 60 feet aboy e sea level, and extends along the Sinu River approximately 200 kilometers. The temperature ranges from 68° F to 103° F, with an average of 85° F. The relative humidity ranges from 67% to 93% with an average of 80%. The rainfail ranges from 700 mm. to 1,200 mm., with an average of 950 mm, and a period of heavy rainfali, May to September, usually is followed by a hot dry period from November to April. Because of the unequaldistribution of rainfali during the year there are problems of drainage, flooding and irrigation. The dew point ranges from 74.1° F to 77,1° F with an average of 75.6° F. The area which is reasonably level has a high quality soil and is used for agricultural crops such as corn, cotton, rice, etc. All farms including those considered to be cattle units grow at least one cash crop. There are 3 prevalent pasture forages in this area, Panicum purpuracens Raddi, Hypharrhenia rufa Mees and Panicum maximum Jacq which are used extensively for the cattle industry of this region. There are two predominant native breeds of cattle in the area,. rá.

(35) TABLE 2 CAUCA VALLEY FARNS Farm Nuniber. Type of Cattle. Breed. Nutritional Status. Sanitation. Parasite Control. Management Calves Cows. CVF*l. Dairy. Hoistein. Good. Good. Yes. Individual pens Pasture Cement patios. CVF*2. Dairy. Hoistein. Poor. Poor. No. Multiple pens. Pasture. CVF*3. Dairy. Hoistein. Good. Poor. No. Multiple pens. Pasture. CVF*4. Dairy. Guernsey. Poor. Poor. No. Pasture. Pasture. CVF*5. Dairy. Hoistein. Good. Good. No. Individual pens Pasture on pasture. CVF*6. Beef-Dairy Brahma Native. Good. Poor. No. Pasture. Pasture. CVF*7. Beef-Dairy Brahma Native. Good. Poor. No. Pasture. Pasture. CVF*8. Beef-Dairy Brahma Native. Poor. Poor. No. Pasture. Pasture. CVF*9. Beef. Brahma Native. Poor. Poor. Yes. Pasture. Pasture. CVF*lO. Beef. Brahma. Good. Poor. No. Pasture. Pasture. *Cauca Valley Farm. .is.

(36) 25 Roinosinuano and Costeno con Cuernos (CCC), plus Brahma purebred and crossbred. Except for a few dairy farms near Monteria which ha ya Holsteins and Brown Swiss it is difficult to distinguish between dairy, dual-purpose and beef cattle units. In 1960 the National Government of Colombia imposed a property tax on beef cattle and exempted dairy cattle. Consequently, many beeftype cattle are milked and recorded in the agricultural census as dairy cattle. In this area beef cattle production is the principal farm enterprise. Calves and their dams are pastured together by day. The calves are penned in sheds by night and are again turned to pasture with their dams after milking in the morning. The milking portion of these herds range from 50 to 500 head and they are milked at least part of the year. During the wet period, May to September, the roads become unsuitable for truck travel; milk is then converted to cheese on the farms and is delivered to market when travel becomes easier. Sorne of the herds are vaccinated for foot and rnouth disease but no other organized disease control prograrns are followed. Five farms were surveyed in the Sinu Basin area, 3 were typical beef cattle units and 2 were of the urnilking type0 Table 3 records the farms, type of cattle, breed, nutritior.al status, sanitation, parasite control program, and quality of management..

(37) TABLE 3 SINU BASIN FARNS. Nutritional Status. Parasite Control. Management Calves. Farm Number. Type of Cattle. S F*l. Dairy. CCC* Ibis tein Brown Swiss. Poor. Poor. No. Individual pens on pasture. Pasture. SF* 2. Bee. Romosinuano. Good. Good. No. Pasture. Pasture. S F*3. Dairy. Brown Swiss. Cood. Good. Yes. Individual pens. Pasture. S F4. Bee f. Brahma. Fair. Poor. No. Pasture. Pastur e. S F* 5. B ee f. Brahma. Fair. Fair. No. Pasture. Pasture. f. Breed. Sanitation. Cows. *Sjnu Farm Cos teno con Cuernos. o.'.

(38) 27 III. MATERIALS AND METHODS. 1. General Methodology The three areas of study represent the three more important cattle raising areas of Colombia. Each is in a different climatic region. In August, 1964, 238 letters including a simple questionnaire were mailed to various owners requesting permission to study their farm enterprise from a veterinary parasitological viewpoint, and to collect fecal samples, gain information pertaining to disease conditions in their herds, if any, and observe the general managerial practices. A portion of this letter asked for general information from the owner, concerning the condition and disease problems, if any, of his cattle. An attempt was made, on the writer's part, to determine the owner's awareness of the conditions on his farm, compared to on-the-farm observations as part of this study. A few owners gaye permission to study their farm enterprise, but the great majority of the questionnaires were not returned. Many farms were visited and those selected for this study represent the vtypica1 types" of cattle units, farming methods, managerial conditions in each of the 3 dlfferent climatic and principal -catt1e raising areas. The study plan was to ascertain information concerning the internal parasite population of Colombian cattle and was to be based on fecal egg counts of larvae from cultures, recovery of parasites from sacrificed animais together with other observations pertinent to the.

(39) 28 collection of this information. The numbers of anirnais included in this study were to be proportional representations of the numbers and age groups of cattle at each farrn. Representative numbers were unobtainable and for this reason sorne farrns were studied on the basis of fecal egg counts plus a few sacrificed animais, sorne only by rneans of fecal egg counts, and a few only by sacrificed animais. The Bogota Savanna is represented by 8 farms from which 1,192 cattle were exarnined; 14 calves were sacrificed and examined but these calves were from only 2 farras. The Cauca Valley is represented by 7 farras and a total of 506 cattle fecal samples were exarnined; 5 calves were sacrificed, one frorn each of two of aboye farras and 3 from different farrns not completely included in this study. The Sinu Basin is represented by 5 farras from which 540 cattle were examined; 8 calves were sacrificed and these calves were frora 2 of the 5 farms. The study is based upon a total of 2,238 fecal examinations, internal parasite recoveries from 27 sacrificed animais and a record of observations that were felt to be pertinent to this study. Rectal fecal samples were taken in the forenoon, placed in 4 ounce ointrnent tina, identified, placed in a portable ice-cooled chest and transported to a laboratory. The time lapse between collection and preparation of slides in the laboratory was frequently less, but no more than 3 hours. In the laboratory, a weighed 5-grain fecal sarnple was placed in a.

(40) 29 50 ml beaker, 22 ml of water was added and the beaker allowed to stand 3 to 4 minutes to soften the fecal mass. The fecal mass was then thoroughly mixed with the water and the resultant suspension poured into an ordinary fine-mesh coffee strainer. The effluent was allowed to drain into a 100 ml beaker and the residue in the strainer maneuvered to one side and pressed with a spatula to remove the excess fluid. Eight ml of water was used to rinse the 50 ml beaker; the rinse was poured over the residue in the coffee strainer, and the residue again pressed, and then discarded. The water-fecal material suspension was transferred into two 15 ini centrifuge tubes and was centrifuged at 2,500 rpm for 15 minutes; the tubes were removed from the centrifuge and the supernatant fluid discarded. The material in the bottom of the tube was resuspended in 6 ml of a 1.5 density sucrose solution, with the use of an applicator stick. Sucrosesolution was added to the suspension until the surface of the solution appeared convex at the ruin of the tube. A 22 x 22 mm coverglass was placed atop each tube in contact with the fluid. The brim filled coverglass "capped" tubes were centrifuged at 2,000 rpm for 10 minutes, and then the coverglasses were carefully removed from the tubes and placed wet side down, upon glass slides. The material between the coverglass and the slide was examined with a microscope at 150 diameters, The eggs were identified, counted and recorded by genera, Two coverglasses were examined for each 5 gram fecal sample. The results were converted and recorded as eggs per gran, (epg) per sampled animal..

(41) II.] Identification of eggs was on the basis of síze, stage of development, color, shape, thickness, curvature of egg shell and.degree of internal segmentat ion. The samples taken from the aniinals in the Cauca Valley and Sinu Basin were taken to a local laboratory, weighed and centrifuged as described previously. Most of the supernatant fluid was decanted and the sample was placed in a portable ice cooled chest which was transported to the Bogota laboratory where the material in the bottom of the tubes was re-suspended in a 1.5 density sucrose solution, centrifuged, "capped" with coverglasses, which were examined, and the eggs recorded by genera (epg) per animal. Approximately 20% of the fecal samples taken were examined as previously described; the remaining 80% also were further examined by a Baerman technic to recover nematode larvae from feces. The Baerman technic was performed by placíng 5 grams of feces wrapped in one layer of cheesecloth into the funnel portion of the apparatus. Water at 100° F was used to f 111 the apparatus and after a 10 minute lapse of time an ice cube was placed atop the wrapped fecal material. At 3 hours, 15 ml of fluid was drawn from the bottom of the Baerman apparatus and centrifuged for 5 minutes at 2,500 rpm. The supernatant fluid was discarded and the sediment restored to 2 ml volume. One ml was examined and if larvae were present they were identified, counted, and the results were converted, and recorded as number of larvae per gram of feces per animal examined. The Baerman technique was also used in the studies of lungworms. and in the recovery of larvae from grass,.

(42) 31 The examinations of the sacrificed animais were perforined in the postmortem examining rootns of the respective area laboratories. Immediately after death of the animal a fecal sample was removed from the rectum, set aside and later examined for eggs and larvae of nema t'odes. The trachea and lungs were removed intact and set aside for a moment. The abdominal wall was incised and laid open to expose the víscera. The gastro-intestinal contents of the abomasum, small intestíne, cecum,large intestine and rectum were isolated by tying them with string at the anterior and posterior ends of the section. Thus the contents of the sections of the intestinal tract were not lost and the worms could not move from one to another. The tied sections were removed beginning with the abomasum and continuing posteriorly along the intestinal tract. Each section was placed in a suitable container as soon as it was removed from the abdomen. The liver was also removed íntact and placed in a container. The parasites were removed from the lungs by flushing those organs wíth 2 to 15 liters of normal salme at 98° F. The normal salme was poured jato the trachea through a large funnel while the lobes of the lungs were massaged to allow aír to escape and salme to f 111 the bronchia and bronchioles. The lungs were repeatedly rinsed in this manner until no parasites were seen ja the rinses being poured from the trachea into large glass beakers. These large beakers were allowed to stand until the parasites settled to the bottom, when most of the supernatant fluid was decanted..

(43) 32 The remainder of the fluid with parasites was poured into smaller beakers, and the beakers were identified and filled with fixing solution. The beakers were set aside until the parasites could be examined, counted, sexed, and identified with use of a steroscopic Inícroscope and recorded as number of parasites per animal. The wall of the tied abomasum was incised, anterior to posterior, the ingesta poured into suitable containers and the inucosal lining rinsed several times with approxiinately 3 liters of water. This entire mixture was poured into a 1/80 screened bottom sieve; the residue was washed with a small hose and, water under pressure until the effluent was colorless. The residue in the sieve was weighed, 50% placed in a marked beaker, a fixing solution was added and the beaker was set aside to await parasite recovery, identification and counting. The small intestine was cut into 3 foot sections, stripped with forefinger and thumb to remove ingesta, flushed with the small hose and water under pressure until no material was seen in the effluent. The entire mixture of washings from the sections of the small intestine was poured into a 1/80 screen sieve, as was done with the abomasum, and 50% of the residue was retained in fixing solution, in an identified small beaker, until parasite recovery and identification. The ingesta was removed from the large intestine and the residue handled with the same procedure as for the small intestine. The cecum was emptied and internally rinsed several times. The ingesta and rinses were retained for a short while in a suitable container, as the cecum was everted and examined for any remaining parasites..

(44) 33 The retained mixture was poured through an 1180 sieve, the residue washed and handied as was the residue of the small intestine. Each of the 50% residue samples from the various sections of the intestinal tract were carefully examined. The parasites found were identified as to genera, sexed, numbers converted, and recorded as number of parasites per animal. The liver was carefully exainined for the presence of flukes using the foliowing system. The gali bladder and cystic duct were incised longitudinally and the contents were collected in a beaker. Later these contents were exarnined for flukes, and for fluke eggs. The serous coat (Glisson's capsule) on the parietal surface was incised longitudínally and traversely to expose the parenchyma. The parenchyma was macerated by hand, the ducts opened longitudinally, and when the liver was completely macerated the entire mass was poured through #80 screen bottomed sieve. The residue was washed until the effluent was clear. The residue was fixed in solution, the flukes recovered, identified as to genera, enumerated and recorded as number of genera per animal. 2. Records of Egg Counts in Feces. A. The Bogota Savanna. Bogota Farm 1 A total of 249 animais were sampled, 14,6% of the animal population..

(45) 34 The animais were divided into 5 age-management groups, o to 3, 4 to 8, 9 to 12, 13 to 18, and 24 or more months of age. Table 6 details the groups made, the nuinber of cattle examined in each group and the total animais examined. Bogota Farm 2 A total of 102 animals were sampled from this farm, which represents 23.6% of the animal population. The animais were divided into 5 groups considering the type of management, the youngest (1 month of age) to the oldest (over 36 months of age). The groups sampled were from O to 5, 6 to 12, 13 to 20 months, and there were two groups of milking cows, one of which (A) was being milked in an oid dairy barn, the other (B) la a new, modern, clean barn. Table 8 shows the groups made, the number of cattle examined in each age-group and the total animais examined. Bogota Farm 3 A total of 168 animals were sampled, 78.5% of the cattle population on this farm. There were two different breeds of cattle on this farm. They were under the same management and conditions. Records of each were kept in an attempt to ascertain if there was a difference la the parasite population between the two breeds. The age groups sampled were O to 8, 9 to 12, 13 to 18, 24 to 35 months and over 36 months Holsteins,.

(46) 35 The Guernseys sampled were 13 to. 18. and 36 months and. older. Table 10 details the groups inade, the number of animais examined in each age-group, the number of animais examined from each breed and the total animais exainined. Bogota Farm 4 A total of 40.2%. 218. animals were sampled which represents. of the cattle population.. The cattle were managed loosely in 3 groups; calves up to 1 year, heifers and inilk cows. The calves were divided into 3 age-groups in an attempt to evaluate the parasite population throughout their first year of age and two more groups were designated according to age. They were O to 5, 6 to 9, 10 to 24. or more months of age. Table. 12. 12,. 13 to 18 and. records the groups made,. the number of cattle examíned in each group and the total animals examined. Bogota Farm 5 A total of 190 animais were sampled which represents 75.6% of the cattle population. The cattle were divided into 5 age-management groups and an attempt was made to compare the different management systems within this farm. The groups were O to. 4,. more months of age. Table. 5 to. 14. 12, 13. to. 18,. and 36 or. details the age-groups made,. the number of animals examined in each management group and the total animais examined..

(47) 36 Bogota Farm 6 A total of 50 animais were sampled, which representa 29.16% of the cattle. Two age-groups sampled were O to 4 and 24 or more months of age. Table 16 records the groups made and the number of animais examined in each group. Bogota Farm 7 A total of 80 animais were sainpled, which representa 36.36% of the cattle population. Calves arrive on this farm, from farm 6, at 4 months of age. The age groups sampled were, 5 to 12, 12 to 18, and 24 or more months of age. Table 18 records the groups made, the number of animais examined in each group and the total animais examined. Bogota Farm 8 A total of 90 animais were sampled, which represents 49.7% of the cattle population. The cattle were grouped into 4 age-management categories; they were O to 4, 5 to 12, 13 to 20 and 24 or more months of age. Table 20 records the age-groups, the number of animals in each group and the total animais examined.. B. The Cauca Valley. Cauca Valley Farm 1 A total of 97 animals were sampled and divided into 4.

(48) age groups; they were O to 8, 10 to 14, 16 to 24 and 24 or more months of age. Table 22 details the age-groups, number of animais examined in each group and the total animais examíned. Cauca Valley Farm 2 A total of 139 animals were sampled. They were divided into 4 age groups with respect to the existing management conditions. These age groups were O to 2, 3 to 8, 10 to 18 and 36 or more months of age. Table 24 records age-groups, number of animais examined in each group and total animais examined. Cauca Valley Farin 3 A total of 48 animais were sampled. The milk cows were managed and milked in two groups so a representative sampling from each group was taken. The groups sainpled were o to 2, 4 to 12, and two groups of cows 24 or more months of age. Table 26 details the age-groups, number of animais per group and total animais examíned. Cauca Valley Farm 4 A total of 59 animais were sampled and the cattle dívided into 3 groups as foliows: O to 6, 7 to 18 and 24 or more months of age. Table 28 records the age-groups, number of animais per group and total animals examined. Cauca Valley Farm 5 A total of 77 animais were sampled. The animais were grouped into4 categories; they were 0 to 8, 9 to 12, 13 to.

(49) 38 18 and 24 or more months of age. Table 30 details agegroups, number of animais examined in each group and total animais examined. Cauca Valley Farm 6 A total of 73 animals were sampled and divided into 4 age groups. They were O to 1, 3 to 7, 10 to 18, and 36 or more months of age. Table 32 records age-groups, number of animais examined in each group and total animais examined. Cauca Valley Farm 7 A total of 15 animais were sampled and divided into two age groups, which were 6 to 10 and 24 or more months of age0 Table 34 records the groups and number of animais examined. Cauca Valley Farms 8, 9, and 10 No fecal sampling was done on these three farms because of the difficulties in handling the animais. This part of this study is reported on the basis of sacrificing an animal from each farm for the purpose of worm recoveríes. A 6 to 12 month calf was sacrificed and worm recoveries were made as previously explaíned.. C. The Sinu Basin Sinu Basin Farm 1 A total of 192 cattle were sampled. The animais were grouped jato 9 age-management groups. which included. consideration of the management, breed of.

(50) 39 cattle, and age. There were three different breeds of cattle on this farm and an attempt was made to compare the paras ite populations between the breeds as well as various age groups within the breeds. The age range was from O to 36 months of age. Table 36 records the age-groups, number of animais examined in each group, number of animais examined in each breed and total animals examined. Sinu Basin Farm 2 A total of 110 animais were sampled and grouped into 5 age categories, which were, O to 3, 4 Co 6, 7 to 12, 13 Co 18, and 24 or more months of age. Table 38 details the. age-groups, number of animais examined in each group, and total animais examined. Sinu Basin Farm 3 A total of 71 cattle were sampled. The age-management groups were as foliows: 1 to 4, 5 to 9, 11 to 29, 29 to 36, 36 months and over. Table 40 records the age-groups, animals examined in each group and total animais examined. Sinu Basin Farm 4 A total of 79 animais were sampled. Age groups were made into the foliowing categoríes: 2 to 4, 5 to 7, 36 months and over. Table 42 includes age-groups, animals examined in each group. and total animais examinad..

(51) 40 Sinu Basin Farm 5 A total of 89 animais were sampled. The cattle were grouped into 5 age categories as foliows: O to 1, 2 to 4, 5 to 9, 10 tó 30, and over 36 months of age. Table 44 records age-groups, animais examined in each group and total aniinals examined. 3. Animais Sacrificed A. Bogota Savanna There were 14 animais from the Bogota Savanna, 8 from Bogota Farm 1 and 6 from Bogota Farin 5. All calves were 6 to 12 months of age and all were examined post mortem as previously, described. The calves were purchased from the owners. They were reared as previously described under heading of Farra 1 and Farm 5. The calves were characterized by marked loss of condition, B. The Cauca Valley The Cauca Vahley is represented by 5 sacrifíced aninials. They were from Farms 4, 5, 8, 9, and 10. All of these calves were 6 to 12 months of age when purchased and sacrificed. The calf frora Farm 4 was a Guernsey and was from a poorly managed herd. The calf from Farm 5 was a grade Holstein and was from a reasonably well-managed farra..

(52) 41 The calf from Farm 8 was a native-Brahma cross and from a beef-dairy type farm. The calf from Farm 9 was a light weight "native" and had a previous history of being 9 'dewormed" but no recorda were available as to the date or drug used. The calf from Farm 10 was a light, grade Brahma and appeared to represent a "normal calf" when sacrificed. C. The Sinu Basin This area was represented by post mortem examinations of 8 sacrificed calves. The age range was from 6 to 12 months. The first 6 calves were obtained from Sinu Basin Farm 1 and were native Costeno con Cuernos (CCC), a Colombian dairy breed. All these calves appeared to be in poor condition, the farm and the calves had a recent previous history of parasitisms. The remaining 2 calves were purchased at Farm 2, and were Romosinuano, a native Colombian beef breed. The calves appeared in good condition at the time they were sacrificed. 4. Parasite Control Programs at Demonstration Farms The obvious need for parasite control programs for cattle in Colombia has been established. The purpose of this part of the work was to evaluate the.

(53) 42 effectiveness of control program systems under different conditíons in Colombia. The management conditions on the farms and the parasitic probiems involved were evaluated and with the approval and cooperatíon of the owners a control program was instituted. The programs varied according to the prevalence of various parasites and conditions on the farms and were intentionally designed so as not to drastícally change the general management procedures or interf ere with the farm's daily routine. The objects of the prograrns were to demonstrate results, determine sorne of the economic aspects as costs of programming, costs of losses with the overali idea in mmd to use the successfully programmed farms as dernonstration farms. Four trialswere conducted in the Bogota Savanna area as a basis to establish parasite control programs in demonstration farms, 3 trials were conducted in Farm 1 and one trial was conducted in Farm 7.. /. A. Chemicais Used. Several chemicais were incorporated into the programs and a brief description of them foliows. Diethylcarbamaz me Diethyl carbamazine acid citrate (1-diethy1 carbamayl; 4-methylpiperazine dihydrogen citrate) was developed foliowing World War II as an anti-filarial chemical. This is the most active and nontoxic member of the piperazine compounds and is used for the treatment of the microfilariae of the.

(54) 43 canine heart worm, Dirófilariaimmitis. Diethylcarbaivazine can be administered orally as well as intramuscularly. According to Hawking et al 15 80% of the microfilariae disappear from the peripheral blood within 2 minutes after treatment and localize in the liver capillaries where they are phagocytized within one hour by the reticuloendothelial celis. This work was done with the "cotton rat • The structural formula is:. CH3 —N -. N _CON(C2H5)2. Parker (1957) was the first to use Diethylcarbamazine in the treatment of lungworm infection of calves due tú Dictyocalusviviparus.31 He used experimentally infected calves and found 55 mg/kilo grani body weight effective if given on 5 consecutive days ( the l4th to l8th postinfect ion days) Parker also found the chemical to be an effective treatment in parasitic bronchitis (Dictyocaulus) in the field; the dosage was 22 mg/kg body weight for 3 consecutive days or a single dose of 44 mg/kilogram body weight.. 31. Cornwell 1963, working with Diethylcarbamazine citrate and lungworm infected calves found no adverse effects upon development of immunity in the treated calves! This was conf irmed by Kendall in 1965.. 23.

(55) 44 The chemical was found to be most effective against the sexually irnmature adults when given 14 to 18 days after infection and when given over this period of time, almost completely suspended the patent stage; it was much less effective when given during the patent stage of the disease. The treatment regimen (14 to 18 days after infection) was markedly effective in reducing the expected respiratory increase, fecal larval output and interference with weight gains due to lungworin paras itisms. Cyanacethydrazide This compound known as Hydrazid or Nydrazid was found to be active against experimental tuberculosis in mice by Bernstein and associates in l952. The structural formula is:. N —. C:D. o CNHNH2. According to Elmendorf etal. 1952. Nydrazid was well tolerated in man in daily oral doses of 3.0 mg/kg. 11 The drug was rapidly absorbed and a high percentage was excretad in the urine during the 24 hour period foliowing ingestion. Rubín et al. 1952, reported that the administration of Nydrazid (310 mg/kg/day) for a period of 4 to 16 weeks was not associated with manifestations of drug toxicity.37 The recoinmended dosage for calves is 17 mg/kg when adminístered subcutaneously as one dose per day..

(56) 44a The drug may be given orally as well as subcutaneously and treatment should be given on two consecutive days. Three weeks later the treatment should be repeated. The mode of action upon the lungworms is not well known, and in calves the parasites are expelled 24 hours after the administration of Nydrazid. 38 Thjabendazole Is a stable white crystalline compound whose etnpirical formula is C10H 7N 3 S; it has a molecular weight of 201.3. The structural formula is:. 2, (4-thiazoaly1)-benzimidazole is a broad spectrum anthelmintic with a high degree of efficacy, a good margin of safety and versatility of administration. The compound has been used since 1961 and there are numerous reports of its effectiveness in cattle, sheep, horses and swine.8 According to Brown, et.al . 1961, in addition to removing the adult parasites, Thiabendazole inhibits production of eggs and interferes with development of larval forms of nematodes.4 Neguvon This organophosphorus compound, known as Bayer L 1359 or Dipterex.

(57) 45 (Dylox) is dimethyll-hydrozy-2-trichloroethyl phosphonate. It is soluble in water to 15 per cent and in aromatie hydrocarbons, alcohol and acetone. It has an oral LD 50 to the rat of 450 miligrams per kilogram. It's structural formula:. (CH30)2'— P. —CHCC13 1. O OH The compound has been tested against gastrointestinal parasites of cattle by several workers.. 24,35,36. Neguvon has been used at 110 mg/kg. and it was found effective against the adult and immature stages of Bunostomum phlebotomum, Cooperia !P• and Trichostrongylus axei and the immature stages of Haemonchus place¡ and Oesophagostomum radiatum.36 Banks and Mitten in 1960 found Neguvon was toxic for cattle; signs of toxicity were common soon after dosing. 2 Toxic effects were not related to the dose rate, age, premedication or body conditon of the animais. Riek and Keith 1958 found no correlation between dose rates and severity of toxic signs. 35 The signs of toxicity consisted of increased respiration, salivation, restlessness and looseness of the bowel, B. Trials Conducted Trial 1, Bogota Farm 1 This trial was designed to conf irm a system of preventive medicine and control for the most prevalent parasític problems on this farm..

(58) 46 The design was to introduce a managerial change that would allow the calves to be reared to 4 months of age in a relatively low parasitic environment then be exposed to the natural high parasite population of the farm; to indicate effects of periodical chemotherapy upon the parasitic infectíons; and to reduce the parasitic morbidity and mortality of the calves. The effects of managerial changes and chemotherapy upon the parasite populations were to be measured in terms of calf mortalíty rate, fecal egg counts for gastrointestinal nematodes and fecal larval counts for pulmonary nematodes. Two other parasites Fasciola hepatica and Moniezia sp were found to be present on this farm but no specific chemotherapy was considered. One of the managerial practices on this farm was to keep the calves in individual stalls in the barn from birth untíl 4 months of age; this procedure was continued. For economíc reasons the amount of milk fed was not increased, but the amount of feed supplement was increased about 50%. The calves were allowed to exercise in an enclosed, paved patio a few hours a day but were not allowed to graze as in the past. At 4 inonths of age the calves were taken to permanent kikuyo grass pasture and retained on this same pasture until they were 12 months of age. The practice of grazing calves on limited areas by chaining them, in the previous management systeni, was discontinued. The pasture was contaminated with parasites., The source of water for the calves was changed so that water from the river was no longer used. A,eL,OTECA AG. ØPECU4RM. r491A.

(59) 47 Feed supplement was given to the calves until they were 12 months of age. Fecal egg and larval examinations were conducted monthly beginning at 4 months of age and continuing until 12 months of age at which time this trial was terminated. The trial included 40 calves which were divided into two groups; 25 calves comprised the "treated" group and 15 calves were "not treated" and considered as controis. The "treated" group (25 calves) was given 75 mg/kg Thiabendazole once a month for 4 months; the first treatment was given at 6 rnonths of age (two months after entering the pasture). The "treated" group was also given 40 mg/kg body weight Diethylcarbamazine intramuscularly at 6 months of age. The calves in the "treated" group that were found to be passing larvae of Dictyocaulus sp at the time of the next montly fecal exarninations were retreated with Diethylcarbamazine at 7 months and 8 months of age. Sorne calves received three doses of Diethylcarbamazine. Trial 2 Bogota Farrn 1 This trial was designed to evaluate two calf rearing systems with respect to parasite populations and to make possible better understanding of the timing of chemotherapy. The effects upon the parasites were to be measured by monthly fecal egg counts (epg), monthly fecal larval counts (lpg) and weight gains of the calves (kg/month). Forty calves were equally divided into two groups. The first group was reared in individual stalls in a barn f ron.

Figure

TABLE 1 BOGOTA SAVANNA FARMS Breed Ho 1 st em Hoistein Holstein Guernsey Hois tein Hoistein Hois t em Hois tein Hoistein	Farm	Type ofNumber	CattleBF*1	DairyBF*2	DairyBF*3	DairyBF*4	DairyBF*5	DairyBF*6	DairyBF*7	DairyBF*8	Dairy NutritiorialStatusPoorGoodGoo
TABLE 2 CAUCA VALLEY FARNS
TABLE 8 BOGOTA SAVANNA FARN 2 AGE GROUP IN MONTHS, NUMBER SNPLES EXAMINED
TABLE 10 BOGOTA SAVAA FARN 3 AGE GROUP IN MONTHS, NUMBER SANPLES EXANINED
+7

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