Wednesday, June 10, 2015

Temperament and Acclimation to Human Handling Impact Productive and Reproductive Efficiency in Bos indicus-Influenced Cattle

Dr. Reinaldo F. Cooke
Oregon State University

AI causes some extra work in the summer, but saved a lot of extra work in the winter during calving season.

Temperament is the behavioral response of cattle when exposed to human contact. Temperament is a heritable trait, up to 50% of the variation is due to genetics.
How do we assess temperament? Currently we use the chute score, a 1 to 5 scale:
1. Calm with no movement
2. Restless movement
3. Frequent movement with vocalization
4. Constant movement, vocalization, shaking of the chute
5. Violent and continuous struggling

Breed type was the greatest source of variation, and sex, age, and production system were also factors affecting temperament.
What is the interaction of temperament and production? Animals with excitable temperament are more paranoid, thus they have their head up looking for threats rather than in a feed bunk eating.
As temperament worsens, cortisol increases. How does this affect reproduction?
Increased cortisol limits LH levels which impairs ovulation. In addition, pubertal heifers had lower cortisol levels compared with pre-pubertal heifers. As temperament score increases, pregnancy rates decrease in bull bred cows (no human intervention). Cows with an excitable temperament had an 8% lower pregnancy rate.
Excitable temperament is detrimental to overall productivity of beef operations.

Decker's Take Home Message:
Selection tools are available to select for appropriate temperament. Avoiding excitable cattle not only improves handler safety, but also improves production and reproduction.
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