Weaning strategies: groups, friends and vaccines

By Roy Williams, DCHA Leadership Class member

Groups
The concern about large group pens causing more stress may be not only unfounded, but opposite of reality: Faevevik, Andersen, Jensen, and Boe observed that calves in larger groups were less aggressive toward each other; displaced other calves from the feed trough less often; and engaged in more positive behavior than did calves placed in smaller groups.(1)

We should also keep in mind that in a "natural" setting (beef herds on pasture), in large herds, groups of calves may be seen lying essentially on top of each other, suggesting that calves have a natural instinct to seek out larger groups of other calves.

Friends
The work of Faevevik, Andersen, Jensen and Boe also points out another important component of reducing stress: the calf must have one or more other calves with which it is already familiar prior to being moved. Therefore, a simple way to decrease the duration of the stress event associated with moving a calf to a new pen is to insure that the calf moves with one or more other calves with which it is already familiar (its friends). Thus, calves in individual pens should be allowed to interact with one or more other calves while in the individual pens.

Vaccines
A controlled study done in Ireland almost 20 years ago demonstrated, by means of biochemical analysis, that calves vaccinated within one day of weaning show a much higher response to the vaccine than do calves vaccinated two weeks before or two weeks after weaning.(2) This same study shows that the antibody level produced by the vaccine given at 43 days (6 weeks) of age generally peaked about 2 weeks after vaccination, and then dropped significantly by 85 days (12 weeks) of age. In this study, a second vaccination at 12 weeks of age resulted in a far higher antibody level by 14 weeks of age. In a second trial, calves vaccinated at 3 weeks of age showed a similar 2-week interval between time of vaccination and an initial peak antibody level. This was followed by a decline in antibody level until about 8 weeks, after which the antibody level rose 50% to 80% above the peak at 5 weeks. In all cases, the antibody level was from 25% to 100% higher in calves weaned at 42 days as compared to calves weaned at 84 days.

Based on these results, you should vaccinate your calves two weeks before you wean them so that their antibody levels are high when they are weaned. However, to obtain maximum protection 2 to 3 months later, those same calves should be revaccinated at weaning. Choose vaccines whose label directions are consistent with this strategy. As always, be sure you and your veterinarian agree on your vaccination program!

References
1. Faevevik, Andersen, Jensen, et al. Increased group size reduces conflicts and strengthens the preference for familiar group mates after regrouping of weaned dairy calves. Applied Animal Behaviour Science. 2007; 103: 215-228
2. Pollock, Rowan, Dixon, et al. Effects of weaning on antibody responses in young calves, Veterinary Immunology and Immunopathology. 1992; 33: 25-36