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  • Author or Editor: William B. Epperson x
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Objective—To assess the effect of subclinical, naturally acquired gastrointestinal nematode infestation on weight gain in yearling cattle kept on pasture.

Design—Prospective study.

Animals—799 Bos taurus yearlings kept on pasture with 2,805 herd mates in eastern and central South Dakota.

Procedure—11 trials were initiated at 9 sites from 1999 through 2001. For each trial, approximately 10% of cattle in each site's pasture group were identified, weighed, and administered a bolus of ivermectin (sustained-release formulation) prior to turnout. A similar subgroup of nontreated control cattle was identified and weighed prior to turnout. For each trial, treated and control groups remained with the larger pasture group throughout the entire grazing season. At the end of the grazing season, weight measurements and fecal samples were obtained from all treated and control cattle; average daily grazing gain was calculated and compared between these 2 groups.

Results—Treatment of grazing cattle with ivermectin increased average daily gain by 0.0459 ± 0.01 kg/head/d (mean ± SEM; 0.1 ± 0.02 lb/head/d), compared with that achieved in control cattle. Control cattle had significantly greater fecal egg counts at grazing season end than treated cattle.

Conclusions and Clinical Relevance—Compared with anthelmintic-treated cattle, yearling cattle with naturally occurring gastrointestinal nematode infestations kept on pasture in the US Northern Plains had a decreased average daily gain equivalent to 6.6 kg (14.5 lb) less gain in a 143-day grazing season. Strategies for control of nematode populations in pastures should be considered to ameliorate this production loss. (J Am Vet Med Assoc 2005;226:779–783)

Full access
in Journal of the American Veterinary Medical Association


To evaluate effectiveness of an allicin-based product in neonatal calves inoculated with Cryptosporidium parvum.


Randomized controlled study.


43 neonatal calves.


Calves were inoculated with 1.5 × l06 or 7.5 × 105 C parvum oocysts within 2 days after birth. Calves were given an allicin-based product once after inoculation or daily for 7 days after inoculation or were not treated. Calves that developed diarrhea were treated by administration of the product. Fecal consistency scores and weight gains were statistically evaluated.


Mean daily weight gain and severity of diarrhea in calves 4 to 21 days old were unaffected by prophylactic use of the product. However, intensive prophylactic administration may have delayed onset of C parvum-induced diarrhea in calves inoculated with the lower dose of oocysts.

Clinical Implications

Administration of an allicin-based product did not alter duration of C parvum-induced diarrhea or enhance weight gain in neonatal calves. However, intensive prophylactic administration of an allicin-based product may delay onset of diarrhea in calves exposed to C parvum oocysts. (J Am Vet Med Assoc 1998;212:987–990)

Free access
in Journal of the American Veterinary Medical Association


Objective—To determine the prevalence and temporal onset of lung lesions in lambs and the impact of lung lesions on growth of affected lambs.

Animals—259 crossbred wether lambs from a single flock in the upper Midwestern United States.

Procedure—An observational study was conducted. Lambs born in the spring and fall were slaughtered at finished weight or at a predetermined time point. Lungs of each lamb were examined and classified as normal, moderate lesions (consolidation > 5% but ≤ 50% of any lobe), or severe lesions (consolidation > 50% of any lobe). Data were examined to detect effects of prevalence or severity of lung lesions on growth and carcass traits.

Results—57 of 89 (64%) spring-born lambs had lung lesions characterized by consolidation of lung tissue. A small number of lambs had pulmonary adhesions or active abscesses. In contrast, only 31 of 108 (29%) fall-born lambs had lung lesions. Severe lung lesions were associated with a significant reduction in average daily gain. Severe lung lesions were not detected until the middle of the finishing period and were associated with culture of Mannheimia haemolytica or Pasteurella multocida.

Conclusions and Clinical Relevance—Analysis of results indicates that the prevalence of severe lung lesions can be quite high in lambs. Severe lung lesions can lead to greatly decreased growth performance of lambs.

Full access
in American Journal of Veterinary Research