Influence of low-stress handling on reactivity score and pregnancy rate during fixed-time artificial insemination in Nellore cows

Abstract

The objective of this work was to evaluate the influence of low-stress handling (LSH) on reactivity score and pregnancy rate during fixed-time artificial insemination (FTAI) for extensively raised Nellore cows. Multiparous cows (n = 126) were randomly allocated into two groups: G1 (n = 66) and G2, the control group (n = 60). Group G1 was subjected to LSH, in which the animals were handled in a calm and quiet manner, without loud noises or physical aggression, using the point of balance, respecting the flight zone and using flags to supplement handling. Group G2 was handled following the typical procedure, with yelling, kicking and the use of electric prods and sticks. On D0, D8 and D10, FTAI was performed in both groups. Reactivity was scored on D0, D8 and D10 at the squeeze chute, based on the tension score, breathing score, and bellowing score. Using the three criteria above, the reactivity scores were defined as follows: R1 (calm); R2 (slightly reactive); R3 (moderately reactive); R4 (reactive); and R5 (highly reactive). Thirty-five days after artificial insemination, pregnancy was determined using ultrasonography. There was no significant correlation between reactivity score and pregnancy rate in each group or between the pregnancy rates in both groups. However, there was a statistically significant difference between the G1 and G2 groups with regard to reactivity score (1.62±0.05 vs. 2.12±0.07). Low-stress handling influenced reactivity but did not affect pregnancy rate in extensively raised Nellore cows subjected to FTAI.