Effect of the climatic environment on ingestive behavior of F1 Holstein x Zebu cows

Abstract

SUMMARY The objective of this study was to evaluate the ingestive behavior of five different genetic groups of F1 Holstein x Zebu (HxZ) cows during lactation during the summer. The evaluated groups were: Holstein x Gir, Holstein x Nelogir, Holstein x Guzonel, Holstein x Nelore and x Indubrasil. The experiment it occurred place during the summer in the Farm of Agricultural Research Company of Minas Gerais, located in Felixlândia- MG. A completely randomized design with factorial arrangement 5 × 4, five crossings and four periods of observation, with ten repetitions was used. The measurements of climate variables were made using dataloggers and calculated the black globe temperature and humidity index. There was the percentage of animals grazing, rumination, urination, defecation, water intake and salt intake during the day and at night every 30 minutes. The F1 animals used did not affect the grazing behavior due to high BGT values. There was a higher frequency of rumination and idle period in the morning, showing a natural behavior of cattle. Defecation was higher during the day, coinciding with the period of greater movement of animals. Water consumption was greater in the post- milking and the salt consumption in the afternoon. There was a positive statistical correlation between BGT and grazing, and negative correlation between BGT and leisure. Thus, the F1 animals grazing behavior has not changed because of the high BGT values, explaining the adaptability and resilience of five genetic groups, being a viable option for warm climate regions.

Análise termográfica aplicada na produção de calor corporal de vacas F1 HxZ manejadas em diferentes microclimas

“…Os valores propostos por Buffington et al (1981) foram recomendados com base em estudos desenvolvidos com vacas Holandês. Diante disso, estudos atuais comprovam que animais mestiços suportam ambientes sob condições de ITGU em situação de perigo e emergência, sem interferir de forma prejudicial nos parâmetros fisiológicos e produtivos desses animais (Diniz et al, 2017;Castro et al, 2018;Pereira et al, 2018).…”

“…No microclima 2, foi registrado o mesmo comportamento, porém com valores superiores no turno da tarde (33,6°C), seguidos do turno da manhã (31,8°C), da noite (20,3°C) e da madrugada (15,0°C). Valores semelhantes do microclima 2 foram encontrados porPereira et al (2018) durante o verão, quando, no turno da manhã, a temperatura média do ar foi de 33,8°C e, à tarde, de 33,5°C. Pode-se verificar que, em ambos os microclimas, a temperatura do ar não ultrapassou a zona de conforto sugerida porSilva (2000), entre 7 e 35°C, para bovinos mestiços.Tabela 2.…”

Ingestive behavior and infrared thermography of Holstein × Zebu crossbreed cows in the final third of gestation in different pastoral environments

“…Furthermore, some regions record extended periods of low rainfall. Air temperatures above 25 °C can cause thermal stress in pure Holstein cows (Bermam et al 1985); however, F1 Holstein × Zebu animals may exhibit greater tolerance to stressful environments without modifying productivity (Castro et al 2018;Pereira et al 2018). This is because they unite the Holstein breed's productivity and the rusticity of the zebu breeds, conferring these animals' adaptability to the diverse environmental conditions existing in regions of tropical climate (Ruas et al 2014).…”

“…In the months before the rainy season, sporadic rainfall may occur, causing pasture regrowth and subsequent vegetative growth. Growth conditions and grass structure associated with temperature, humidity, and solar radiation variations throughout the day may influence the ingestive behavior, welfare, and subsequent productivity of crossbred cows (Castelán-Ortega et al 2016; Pereira et al 2018). There are few studies of these factors in the literature using crossbred F1 Holstein × Zebu cows (Pereira et al 2018).…”

Using infrared thermography to measure the body surface temperature of crossbred cows and calves in the semi-arid region of Minas Gerais, Brazil

“…Dairy cattle are animals that respond well when raised in temperate environments, but Brazil is a predominantly tropical country, with high temperatures during the year in most of its territory, which causes heat stress in a way that the use of adapted animals to different climatic conditions is of greater interest (Castro et al 2018;Pereira et al 2018).…”