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Objective

To evaluate age and scrotal circumference as predictors of semen quality in young beef bulls.

Design

Cohort study.

Animals

1,173 beef bulls < 15 months old.

Procedure

During initial breeding soundness examination, variables for bulls producing > 70% morphologically normal spermatozoa were compared with those for bulls producing < 70% morphologically normal spermatozoa. Mean and 95% confidence interval for age and scrotal circumference were constructed to detect differences between groups of bulls over all observations and within the 5 most common breeds. For these 5 breeds, x2 analysis was used to evaluate differences in the proportion of bulls that had values less than the population mean for scrotal circumference, age, and percentage of morphologically normal spermatozoa. Multivariate regression was used to quantify variation in the proportion of morphologically normal spermatozoa that could be explained by age and scrotal circumference.

Results

Mean (± SD) age and scrotal circumference differed significantly for bulls that produced > 70% morphologically normal spermatozoa (12.7 ± 1.1 months and 35.6 ± 2.7 cm) and bulls that produced < 70% morphologically normal spermatozoa (12.1 ± 1.2 months and 34.8 ± 3.3 cm). The proportion of bulls younger than mean age at first examination and the proportion producing > 70% morphologically normal spermatozoa differed among breeds. Age and scrotal circumference explained only 11 % of the variation in semen quality.

Clinical Implications

Among young beef bulls, those that were older and had larger testes were more likely to produce > 70% morphologically normal spermatozoa. Age and scrotal circumference were not sufficient predictors of semen quality. (J Am Vet Med Assoc 1999;214:1664-1667)

Free access
in Journal of the American Veterinary Medical Association

Summary:

A field trial was conducted to measure differences in performance between selenium-supplemented and nonsupplemented heifers on a 1,200-cow California dairy. One hundred seventeen 19- to 27-month-old Holstein heifers were randomly assigned to treatment (n = 59) and control (n = 58) groups. A federally approved, commercially available, sustained-release intraruminal selenium bolus was administered to each heifer in the treatment group. Blood samples were taken from treated and control animals to assess selenium values before and after bolus administration and again after introduction to the milking ration. Production data were obtained from an on-farm computerized record system for each heifer during her first lactation.

Mean blood selenium concentrations in treated heifers were higher than those in control heifers from posttreatment day 30 until after calving. Data analyzed in midlactation and late lactation indicated no significant differences between treated and control groups in somatic cell count, days not pregnant, total milk produced, or times bred.

Free access
in Journal of the American Veterinary Medical Association

Summary

Seventy-two lactating dairy cows with left displacement of the abomasum were blindly assigned to treatment by use of the roll-and-toggle procedure or right paralumbar fossa pyloro-omentopexy. All cows were from the same large dairy herd, and survival in the herd and daily milk production were measured for 120 days after treatment. The mean cost was $256.50 for roll-and-toggle cases ($50 for the procedure, $95.70 in milk loss and $110.80 in livestock losses). The mean cost was $406.40 for the pyloro-omentopexy cases ($150 for the procedure, $87.80 in milk loss, and $168.60 in livestock losses). A possible interaction with metritis was discovered, in that pyloro-omentopexy cases cost about $100 more than roll-and-toggle cases when metritis was absent (31 cases) or moderate (32 cases), and cost several times more when metritis was severe (9 cases). Results of the study were in agreement with those of other studies that indicated that the closed repositioning and stabilization techniques are generally less expensive and have comparable results with open repositioning and stabilization techniques. Veterinarians may wish to consider use of this nonsurgical technique for the routine correction of left displacement of the abomasum in dairy cattle.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate the efficacy of a commercially available killed bovine viral diarrhea virus (BVDV) vaccine to protect against fetal infection in pregnant cattle continually exposed to cattle persistently infected with the BVDV.

Animals—60 crossbred beef heifers and 4 cows persistently infected with BVDV.

Procedures—Beef heifers were allocated to 2 groups. One group was vaccinated twice (21-day interval between the initial and booster vaccinations) with a commercially available vaccine against BVDV, and the other group served as nonvaccinated control cattle. Estrus was induced, and the heifers were bred. Pregnancy was confirmed by transrectal palpation. Four cows persistently infected with BVDV were housed with 30 pregnant heifers (15 each from the vaccinated and nonvaccinated groups) from day 52 to 150 of gestation. Fetuses were then harvested by cesarean section and tested for evidence of BVDV infection.

Results—1 control heifer aborted after introduction of the persistently infected cows. Bovine viral diarrhea virus was isolated from 14 of 14 fetuses obtained via cesarean section from control heifers but from only 4 of 15 fetuses obtained via cesarean section from vaccinated heifers; these proportions differed significantly.

Conclusions and Clinical Relevance—A commercially available multivalent vaccine containing an inactivated BVDV fraction significantly reduced the risk of fetal infection with BVDV in heifers continually exposed to cattle persistently infected with BVDV. However, not all vaccinated cattle were protected, which emphasizes the need for biosecurity measures and elimination of cattle persistently infected with BVDV in addition to vaccination within a herd.

Full access
in American Journal of Veterinary Research