This review aimed to present the current status of the studies about the role of physiological, hematological, biochemical and hormonal variables on the blood of goats raised in adverse environments. Scientific work in recent years has allowed for the evaluation of how goats of distinct breeds react to edaphoclimatic effects to maintain homeothermy according to adaptability to the environment. The exposure of goats to heat stress causes changes in the physiological functions with impact on production and productivity of the animals. There is evidence that the central nervous system is sensitive to temperature changes, and some cells are agiler in the cold than in heat. In conclusion, we say that regardless of the breed, the raising environment and its climatic variables can trigger physiological, biochemical, hematological and hormonal alterations that result in a reduction of the heat production for maintenance of homeothermy. All these changes have a substantial impact on production and productivity.

Dados de pesos aos 205 (P205), 365 (P365) e 550 dias de idade (P550) de três rebanhos da raça Nelore criados no Estado da Paraíba em regime de pasto, no período de 1975 a 1990, foram utilizados. Os efeitos genéticos direto e materno foram estimados pelo Método da Máxima Verossimilhança Restrita aplicada a um modelo animal. Foram incluídos os efeitos fixos de ano-mês-sexo, fazenda e idade da vaca, como (co) variável linear e quadrática. As médias dos quadrados mínimos e respectivos erros-padrão dos P205, P365 e P550 para as três propriedades estudadas foram, respectivamente, 149,00 ± 22,28 kg, 198,40 ± 38,84 kg, 256,99 ± 55,65 kg; 145,10 ± 21,31 kg, 182,83 ± 30,38 kg, 247,45 ± 50,57 kg e 162,12 ± 14,23 kg, 246,66 ± 23,11 kg, 332,83 ± 35,02 kg. As estimativas de herdabilidade para o efeito genético direto dos pesos aos 205, 365 e 550 dias de idade foram 0,16 ± 0,05, 0,40 ± 0,11 e 0,76 ± 0,25, respectivamente. Nesta mesma ordem, para o efeito materno dos P205, P365 e P550, os valores de herdabilidade foram 0,36 ± 0,05, 0,44 ± 0,15 e 0,01 ± 1,10. As correlações para os efeitos genético direto e materno para P205, P365 e P550 foram, respectivamente -0,70, -0,74, e -1,00. O efeito materno foi importante apenas na fase pré-desmame.

This study investigated the effect of season on the endocrine and adaptive profiles of a Brazilian Creole goat population in a semi-arid region of Brazil during the dry and the rainy season. We considered physiological, morphological, biochemical, haematological, hormonal and anatomical profiles. The experiment used 80 adult goats (2- to 5-year-old) and lactating (160 ± 14 days of lactation length) goats, with an average daily milk yield of 500.9 ± 13 g. Physiological parameters (rectal temperature, RT; respiratory rate, RR; heart rate, HR; skin temperature, ST) were high (p < .05) in the afternoon in both seasons. There was a significant effect of season (p < .05) on anatomical parameters (hair diameter, HD; hair length, HL; coat thickness, CT). Haematological, biochemical and hormonal parameters were also significantly affected by season (p < .05). We measured the biochemical and hormonal characteristics changes during different seasons; metabolism was reduced during heat stress and accelerated during cold stress. These hormones facilitate the physiological parameters involved in the adaptation process. Our results confirm that the adaptive capacity of the animals cannot be described solely by RT and RR.