Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: David K. Lunt x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Objective—To evaluate effects of vaccination of feedlot steers against bovine neosporosis on weight gain, feed intake and efficiency (feed intake per gain), and carcass characteristics.

Design—Longitudinal observational study.

Animals—60 weaned Brangus steers seronegative for Neospora caninum.

Procedure—Steers were assigned to age-matched control and treatment groups. Steers in the treatment group received N caninum vaccine on days 79 and 106, while control steers received 2 placebo injections. For each steer, serologic status for N caninum was determined on days 0 (weaning), 51, 79, 106, 135, 163, 191, 219, and 247 by use of an ELISA; body weight was determined on the same days and at slaughter (day 259). Daily feed intake per steer was measured from days 79 to 259.

Results—Seroconversion occurred in 23 of 30 (76.7%) steers in the vaccinated group. Immediately after vaccination, average daily gain, average daily feed intake, and feed efficiency were significantly greater in the treatment group than in the control group, but these differences did not persist. No differences between groups were found in regard to live weight at slaughter, hot carcass weight, dressing percentage, or quality grade; however, steers in the vaccinated group had significantly lower yield grades than did control steers.

Conclusions and Clinical Relevance—In feedlot steers, use of this vaccine against N caninum was safe and did not affect overall feedlot performance or meat quality; effects on yield grade require further evaluation. (J Am Vet Med Assoc 2003;222:624–627)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the effects of serologic status for Neospora caninumon short-term weight gain, feed intake, and feed efficiency (feed intake/gain).

Design—Longitudinal observational study.

Animals—34 weaned mixed-breed beef steers.

Procedure—Serologic status for N caninum was determined for each steer on days 0 (weaning), 88, 116, 144, 172, and 200, using an agglutination test. Individual steer body weight was measured on days 0, 88, 116, 144, 172, 200, and 242 (slaughter). Daily feed intake was monitored from days 116 through 242. Serologic status was matched to animal performance for the period immediately following serum sample collection. A mixed mode, using repeatedmeasures with an unstructured covariance matrix, was used in the analysis. Breed, age, and pen effects were controlled for in the analysis.

Results—A reduction in average daily gain for the period following a positive serologic result was detected for the entire trial (6 measurements/steer). This may have been attributed to a significant impairment in feed efficiency rather than to an impairment in feed intake. Changes in serologic status in individual steers over time were common; additionally, the effects of serologic status on steer performance were also transitory.

Conclusions and Clinical Relevance—Significant reductions in short-term weight gain and feed efficiency were associated with the presence of antibodies against N caninumin postweaning beef steers. (J Am Vet Med Assoc 2001;219:1259–1262)

Full access
in Journal of the American Veterinary Medical Association