Neila Lidiany Ribeiro

Physiological and biochemical blood variables of goats subjected to heat stress – a review

ABSTRACT 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.

Effects of the dry and the rainy season on endocrine and physiologic profiles of goats in the Brazilian semi-arid region

Abstract 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.

Threatened Goat Breeds from the Tropics: The Impact of Crossbreeding with Foreign Goats

Local goat breeds are able to adapt to specific environments due to the long process of geographic isolation, natural and—notably morphological—artificial selection they were submitted to, which resulted in characteristics that have allowed them to survive in harsh and poor environments. Continuous crossbreeding has promoted a quick replacement and decrease of local breeds, which has been relevant in Brazil. Although they are less productive than specialized foreign breeds, they are fully adapted to the tropics and, therefore, are able to produce with those particular conditions. They play important social and economic roles within the different continents, as they are essential in adverse areas where farming is difficult, and, in most situations, they are the only source of animal protein available for humans. In Brazil, for example, despite the numerous threats posed to local goat breeds, they still have a fair number of alleles by locus and good levels of heterozygosis. This is a concerning scenario that, alone, is enough to stimulate the establishment of conservation programs of local goat breeds in the country. The use of foreign breeds in tropical countries must be looked into carefully, especially in the case of extensive systems of production where local breeds prevail. Under these conditions, a challenge is faced: to increase meat production while maintaining genetic diversity within the breeds. Sustainable production systems may be accomplished if the great advantage of local breeds’ multiple functionalities is considered.

Effects of season on the quality of Garfagnina goat milk

Abstract The Garfagnina goat is an endangered native goat population from Italy. This study aims to give a contribution to the milk quality assessment of the native goat during the two productive seasons, spring and summer, and to verify the relationships between some meteorological data and physiological and milk quality parameters. Individual milk samples were taken in the two seasons. Physiological parameters and meteorological data were also registered. All the milk samples were measured for volume and analysed for: dry matter, total nitrogen, casein, ash, lactose, fat, milk fatty acid (FA) composition, number and diameter of the fat globules, and rheological parameters. There were not differences in the average diameter of the milk fat globules (2.27 ± 0.28 μm) and in milk gross composition between the two seasons, except for lactose which was significantly lower in summer. During summer a significant increase in some long-chain FAs such as CLA c9,t11, C18:1 t11, C18:0, C18:3 n3, C20:0, C22:0, C22:2 was observed, whereas short-chain FAs (C6:0, C8:0, C10:0), which are responsible for the development of unpleasant aromas, as well as monounsaturated C16:1, C17:1 c9, C20:1, C22:1 and polyunsaturated FAs C20:2, C20:3 n3 decreased. The average PUFA n6/PUFA n3 ratio was 1.7 and the lowest values were recorded in summer. In summer a worsening of the clot, which was less firm, was found. Environmental parameters were found to be linked to the milk FAs, while heart rate and skin temperature were negatively linked to milk yield and lactose, respectively.