Evaluation of the parasitological and production responses of a cow/calf operation to an anthelmintic program with ivermectin.

The efficacy of a treatment schedule using ivermectin, given subcutaneously at the rate of 200 micrograms kg-1, to control gastrointestinal parasitism and its effect on liveweight gains was assessed. Two herds with a total of 466 Hereford X Brangus cow/calf pairs were used. Each herd was on six pasture plots of comparable size, stocking rate, and quality and quantity of forage. Pasture groups were paired across the two herds. Pasture groups from one herd were randomly assigned to nonmedicated control and the other three to ivermectin treatment. Treatment assignments per pasture group were reversed in the other herd. The control group contained 118 cows and 112 calves and the medicated group 121 cows and 115 calves. Cows were treated in early July and the calves in late July or early August. Cattle from one herd were weighed on Days -28, 0 (day of cow treatment), 30 (day of calf treatment), 58, and 86, while the other herd was weighed on Days -29, 0 (day of cow treatment), 27 (day of calf treatment), 61, and 89. Day 0 was not the same calendar day for the two herds. Fecal samples for parasite egg counts were obtained from the rectum on weight days from five cows and six calves from each pasture; in most cases the same cattle were sampled each time. Calves treated with ivermectin gained (P less than 0.05) more weight than control calves between day of treatment for cows and the end of the trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a single strategically timed dose of fenbendazole on cow and calf performance.

A 168-day study was conducted to evaluate the effect of a strategically timed treatment with fenbendazole on anthelmintic efficacy and performance of beef cows and calves. Eight groups of 10 Angus cow/calf pairs were allotted on 7 May 1987 to eight similarly managed 4.86-ha pastures (bermudagrass/tall fescue) on the basis of cow age, and calf sex and weight. At that time, four groups of cows received a dose of fenbendazole (5 mg kg-1) with their calves receiving fenbendazole at the same dosage 28 days later. Treated calf average daily gain (ADG) was 0.04 kg greater (P less than 0.05) than control calves (0.82 vs. 0.78 kg) during the 168-day study. Treated cow ADG was 0.09 kg greater (P less than 0.05) than control cows (0.40 vs. 0.31 kg). Although there was a reduction (P less than 0.05) in fecal egg counts following treatment of the cows, the numbers of eggs generally were low compared with egg counts of calves. From Day 28 through Day 112 post-treatment, fecal egg counts of treated calves were lower (P less than 0.05) than those of control calves. However, fecal egg counts from treated calves increased post-treatment until there were no differences (P greater than 0.05) between treated and control calves at the end of the study. The pregnancy rate tended to be higher (P = 0.12) for treated cows (98%) than for untreated control cows (75%). The actual calving rate was higher (P = 0.03), for treated cows (90%) than for untreated control cows (68%). Results indicated that a strategic anthelmintic treatment can improve cow and calf performance, but that calves born in late winter or early spring may need more than one therapeutic dose during the nursing period on pasture.

Effect of an anthelmintic program with morantel tartrate on the performance of beef cattle.

A field trial was conducted to determine (1) the effectiveness of an anthelmintic program using morantel tartrate (MT) to control subclinical gastrointestinal parasitism among cattle on pasture and (2) the effects of the program on the performance of cattle. Two Hereford herds, each on a separate pasture with forage of comparable quality and quantity, were used. A stocking rate of .62 ha/cow-calf was maintained in both pastures. One herd consisted of 124 cows and 122 calves and served as a non-mediated control group. The second herd consisted of 126 cows and 124 calves. Cows and calves from the latter group were treated with a bolus formulation of MT at a dosage of 10 mg/kg body weight at the beginning of the trial and again 55 d later. Calves were treated again 42 d after the second treatment. Cattle were weighed individually each month and rectal fecal samples for nematode egg counts were obtained from 36 cows and 36 calves from each group at that time. These donor cattle were selected at random at the time of the first weighing; fecal samples were then obtained from the same animals throughout the study. Eggs of the Cooperia-Ostertagia-Trichostrongylus complex predominated in all fecal samplings. There was no difference in the number of nematode eggs from the two groups of cows. However, the medicated cows gained significantly more weight than the controls and had an average weight gain advantage of 28.8 kg. The medicated calves had significantly lower average egg counts and made higher weight gains than the unmedicated calves. The medicated calves had an average weight gain advantage over the control group of 11.1 kg.

Poultry offal ensiled with lactobacillus acidophilus for growing and finishing swine diets.

Poultry offal (heads, feet, viscera) from a broiler processing plant was ground and mixed with corn, dried molasses and a Lactobacillus acidophilus culture. Fermentation was shown to be effective in batch sizes of 3.8, 75.7 and 208.1 liters, as well as a 1,360-kg silo. It was generally complete at 72 h. In trial 1, rats were fed silage mixtures of 60:30:5:5, 45:45:5:5 and 30:60:5:5, offal, corn, molasses and inoculant, respectively. Rats did not gain as well when fed the silage diets (P less than .05) as when fed the basal diet; however, the ranking of silages was 45:45, 60:30 and 30:60, offal-to-corn ratio for rat daily gains and feed conversions. In trial 2, growing-finishing pigs were fed the 60:30:5:5 silage at rates of 0, 10, 20 and 30% of the diet. Average daily gains and feed-to-gain ratios were not affected by including offal silage at up to 20% of the diet, but 30% offal silage in diets resulted in depressed gains (P less than .05) and increased feed-to-gain ratios. Carcasses were not different among treatments for dressing percentage, length, average backfat and percentage of ham, loin, shoulder, lean cuts and primal cuts. Carcasses from pigs fed 20 and 30% offal silage had significantly darker and firmer loin-eyes than those from control fed pigs. Marbling was higher (P less than .05) in loin-eyes from pigs fed 30% offal silage as compared with those from pigs fed 0% offal silage.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of sow dietary lipids and choline on piglet survival, milk and carcass composition.

Twenty-one crossbred gilts and 75 crossbred sows were randomly assigned to six treatments for examination of the effect of lipid feeding and choline level on baby pig survival. Dietary variables were supplemental fat and choline in a 3 X 2 factorial arrangement. Fat treatments were no supplemental fat, 10% corn oil and 10% animal fat; choline treatments were 0 and 500 ppm supplemental choline from choline chloride. Baby pig survival and litter weight at 21 days were improved (P less than .05) by supplemental fat. Lipid treatments also improved (P less than .05) percentage survival among piglets in the weight ranges of 909 g or less, 1,136 to 1,362 g and 1,363 to 1,589 grams. Lipid feeding increased survival by 18.5% among the piglets weighing less than 909 grams. Piglets fasted for 60 hr had 47.7% less (P less than .05) total lipids and 90.5% less (P less than .05) glycogen than 12-hr-old, nonfasted piglets. The feeding of corn oil significantly affected percentages of carcass fatty acids. Percentages of palmitic, palmitoleic, oleic and linoleic acids decreased during fasting, indicating good utilization, while percentages of stearic and arachidonic acids increased, indicating poorer utilization during fasting. Milk from control sows, which had received a gestation diet containing 4% added poultry fat prior to treatment, was only slightly lower in energy and lipid content (nonsignificant) than milk from sows on the lipid treatment. Corn oil affected (P less than .05) the percentage of fatty acids in milk. Additional choline appeared to have no beneficial effect in any phase of the experiment. Choline did not increase lipid mobilization or piglet survival.

Effect of heat increment and level of dietary energy and environmental temperature on the performance of growing-finishing swine.

Three experiments were conducted to evaluate levels and sources of dietary energy for growing-finishing pigs during cool and warm seasons. The specific objective was to determine the effect of lower energy diets containing more fiber during cooler temperatures. In Exp. 1, lower energy diets supported daily gains equal to those of pigs fed higher energy diets during low temperature trials, but gains were decreased (P less than .05) during high temperature trials. Feed conversion was improved with each increment of dietary energy and pigs were more efficient converters of feed during warm-season trials. Calorie utilization trends were not the same during cool and warm-season trials. Bermudagrass and alfalfa meal were used in lower energy diets in Exp. 2 and bermudagrass was used in lower energy diets in Exp. 3. Daily gains were not different in these trials, but trends in gain and feed conversion were similar to those in Exp. 1. In general, carcass traits did not differ significantly as a result of dietary treatment in these experiments. there was less (P less than .05) backfat on carcasses from low dietary energy groups during summer trials in Exp. 1 and 3. In all experiments, shoulder percentages were higher during warm-season trials. The data were combined with earlier data to illustrate dietary energy sources and levels and environmental temperature interactions and effects on average daily gain, and carcass traits. The response of gain, dressing, ham, belly and lean cut percentages as a function of metabolizable energy differed (P less than .05) between seasons. The effects of diet formulation and environmental temperature on growing pig performance and carcass traits are discussed.

Efficacy of fenbendazole against tapeworms in calves.

Forty-five commercial-grade Angus calves naturally infected with tapeworms (Moniezia sp) were used in 2 controlled experiments to evaluate the cestocidal efficacy of 3 dosage levels of fenbendazole, methyl-5-(phenylthio) -2-benzimidazolecarbamate. In the 1st trial, 15 calves were divided into 3 groups of 5 each. One group served as nonmedicated controls. Other groups were drenched with fenbendazole at dosage rates of 10 and 15 mg/kg of body weight. Thirty calves used in the 2nd experiment were divided into 3 equal groups. One group served as nonmedicated controls and the other 2 groups were drenched at dosage rates of 7.5 and 10 mg/kg. Calves were necropsied 13 days after treatment. Doses of 10 and 15 mg/kg were 100% efficacious in reducing the number of tapeworm scolices, and a dose of 7.5 mg/kg was 91.7% effective. Signs of toxicosis were not observed in medicated cattle from time of treatment to necropsy.

Anthelmintic efficacy of febantel against gastrointestinal helminths in calves.

Three dosage levels of febantel were tested for anthelmintic activities in calves under field conditions. A total of 20 feeder calves affected with naturally occurring gastrointestinal parasites were used in the controlled test. The calves were allotted to 4 groups of 5 each on the basis of degree of parasitism, body weight, age, and sex. Calves in groups II through IV were treated with febantel paste formulation at dosage levels of 5, 7.5, and 10 mg/kg of body weight; calves in group I were used as nonmedicated controls. Calves were euthanatized and necropsied 7 days after treatment. Medications were 97% to 100% effective against the adult forms of Haemonchus placei, Trichostrongylus axei, Cooperia pectinata, C oncophora, Nematodirus spathiger, and Oesophagostomum radiatum; 93% to 98% against Ostertagia ostertagi; and 78% to 95% against Trichuris sp. There were no differences in efficacies of the 3 dosage levels used against adult worms. Efficacy varied from 61% to 96% against larvae of O ostertagi. Activity was not detected against the tapeworm Moniezia benedeni. Medicated cattle did not show signs of intoxication.

Cestocidal activity of albendazole in calves.

Sixty commercial-grade calves naturally infected with tapeworms (Moniezia benedeni and M expansa) were used in a controlled experiment to evaluate the anthelmintic efficacy of 4 dose levels of albendazole. Calves were randomly divided into 5 groups of 12 each. One group served as non-medicated controls. Other groups were drenched with albendazole (methyl [5-(propyltion)-1H-benzimidazol-2-yl] carbamate) at dose rates of 20, 10, 5 and 2.5 mg/kg of body weight. Calves were necropsied 14 days after treatment. Doses of 20 and 10 mg/kg were 100% efficacious in reducing the number of tapeworm scolices, and doses of 5 and 2.5 mg/kg were 97.8%. Medicated cattle did not show signs of intoxication.

Efficacy of morantel sustained-release bolus in control of gastrointestinal nematodes of weaned calves during the autumn-winter grazing season.

A 168-day study was conducted to evaluate the efficacy of morantel tartrate sustained-release bolus (MSRB) in controlling gastrointestinal parasitism in weaned calves during autumn-winter grazing in the temperature climate of southern United States. Sixty-two weanling Angus heifers were used to assess treatment differences. Six sentinel heifers were necropsied to assess pretrial gastrointestinal worm counts. The remaining 56 heifers were assigned to 4 groups of 14 heifers each and were placed on four 4.86-hectare dormant Bermuda grass pastures (1 group/pasture) that had been no-till interseeded with cereal rye in early October. Heifers in 2 groups were given 1 MSRB in early November; the other 2 groups served as nonmedicated controls. Three heifers (principals) from each of the 4 groups were necropsied on posttreatment days 57, 112, and 168 (end of study) for total worm recovery. Eight 5-month-old tracer steers, raised worm-free from birth, grazed the 4 pastures (2/pastures) for the first 21 days of the study and then were kept in drylot for 21 days before being necropsied. Level of larval contamination of pastures grazed by control and MSRB-treated heifers were comparable, because the mean number of nematodes recovered from tracer steers grazing the control and MSRB pastures were 47,449 and 53,835, respectively. At 28 days after treatment, MSRB-treated heifers had lower (P less than 0.05) mean egg counts/g of feces than did control heifers (280 vs 13).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of ivermectin on performance of beef cattle on Georgia pastures.

A total of 469 cows and calves from 2 herds, each on 6 pastures, was used to evaluate the anthelmintic efficacy and animal-performance benefits of ivermectin given subcutaneously at a dosage of 200 micrograms/kg to nursing beef calves and their dams during a grazing season. Pastures were paired across the 2 herds. Three pasture groups from 1 herd were randomly assigned to either a nonmedicated control or to a medicated group. Treatment assignments were reversed in the other herd. The control groups comprised 110 cows and 108 calves, whereas 127 cows and 124 calves were treated with ivermectin (200 micrograms/kg). The cows were treated once, in late spring, and the calves were treated twice, once in late spring and again in midsummer. Cattle from one herd were weighed on days - 12, 21, 49, 77 (day of 2nd treatment for calves), and 105, and the other herd was weighed on days - 6, 23, 57, 86 (day of 2nd treatment for calves), and 113. Rectal fecal samples for nematode egg counts were obtained from approximately 25% of the cattle in each pasture on weighing days; usually, the same cattle were sampled each time. Calves treated with ivermectin gained (P less than 0.05) more weight than control calves up to the 2nd treatment date and up to the termination of the study. There was no significant difference between treated and control cows, with regard to weight gain over either interval. Treated calves had fewer positive fecal egg counts (P less than 0.01) and passed fewer eggs (P less than 0.05) after both treatments than did control calves. There were no differences in either number of eggs or number of negative cows between treatment groups. Adverse reactions attributable to treatment were not seen.

Effect of a once-daily suckling program on gastrointestinal parasitism in Angus cows and calves.

Over a 2-year period involving a total of 168 Angus cows and their calves, 2 studies were conducted to evaluate the effect of once-daily suckling on cow reproduction, calf growth, and gastrointestinal parasitism. Experiment I compared 2 restricted suckling (RS) groups with 1 normal suckling (NS) group. Each group consisted of 24 cows with their calves (24 cows-calves/group = 24 cows and 24 calves/group). In the RS groups, suckling by the calves was restricted to once a day for 45 days, and then the calves were allowed to suckle normally throughout the remainder of the experiment. In the NS group, the calves suckled normally throughout the experiment. Experiment II compared 2 groups of RS cow-calves (24 cow-calves/group) with 2 groups of 24 NS cow-calves/group. In experiment I, there were no differences (P less than 0.05) in pregnancy rate or in the average number of nematode eggs/g of feces (epg) between the cows from the 2 treatment groups. The RS calves consistently had higher epg counts than did the NS calves during the 45 days of RS (169 vs 62 epg, P less than 0.05) and from the time of their return to pasture until weaning (266 vs 186 EPG, P = 0.27). The RS calves also had a higher average coccidia oocyst count during the RS period only. In experiment II, RS cows had a higher pregnancy rate (87.6% vs 66.0%, P less than 0.05) and a shorter postpartum interval (83 vs 101 days, P less than 0.05) than did NS cows.(ABSTRACT TRUNCATED AT 250 WORDS)