Efecto de la sombra de un rodal de Eucapyptus en verano sobre el comportamiento y el peso de terneros al destete en un sistema de cría bovina en el norte de Buenos Aires.

Abstract

Shade helps to reduce the negative effects of heat stress, modifies animal behavior, and contributes to increase production rates in beef and dairy cattle. More information is needed on these effects in the north of the province of Buenos Aires, which has a temperate climate. Animal behavior, and weaning weight were evaluated in a herd of 50 pregnant Aberdeen angus cows divided in two groups. Each group was placed in a 35 ha plot. One of them was shaded (S) with 4.5 ha of Eucalyptus sp. and the other one with no access to shade (NS). The states of ingestive and thermoregulatory behavior of cows and calves were recorded using 20-min instantaneous scan sampling on each group, at three times of the day, on 10 days with THI>80 in the summer (2021 & 2022). Calves from each group were weighed at the time of weaning. A greater ingestive behavior with shade was demonstrated (S=826; NS=733; p=0.0005), in cows (S=442; NS=375; p=0.0270) and calves (S=384; NS =358; p=0.0046). The thermoregulation was higher in the NS treatment (S=624; NS=717; p=0.0065), verified by resting in the drinking area at noon and afternoon. A higher herd weight (kg b.w.) of S calves was recorded (S=11,544; NS=11,157; p>0.05). The S females had a higher average of kg b.w. (S=226.25; NS=214.64; p<0.05), but not the males (S=235.15; NS=242.93; p>0.05)