Respostas fisiológicas, produtivas e comportamentais de ovelhas Santa Inês submetidas a manejos considerados estressantes e desempenho de seus cordeiros / Physiological, productive and behavioral responses of Santa Inês ewes subjected to stressful managements and performance of their lambs

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

29/05/2012

RESUMO

With the objective to evaluate the susceptibility of ewes to stress and its relation to milk production, 50 Santa Ines females were submitted to four stressful challenges during two successive lactations (1: standard physiological stress through ACTH administration; 2: weaning; 3: first milking; 4: change of milker). In ewes, it were evaluated the physiological, productive and behavioral responses and in lambs behavioral responses and weight gain. In first lactation, lambs were weaned with 60 days of age and in the second according to the treatments: 1st Group with 60 days of age and the 2st Group with 45 days of age. Most of the studied ewes were considered median susceptible to stress, therefore, it was not possible to classify them statistically, as few animals were considered high or low susceptible. After ACTH administration and first milking stress, cortisol level presented the highest concentrations at 60 minutes and after 5 hours, basal concentrations were reestablished. However, after weaning, cortisol level remained high, presenting the greatest values in the weaned group at 45 days (P<0.05). The change of milker caused stress and later promoted higher cortisol release (P<0.05). The behavior observed in milking parlor was positively correlated with time of milking, milk production and reactivity, as some animals presented more restless behavior and reactive during milking with higher frequency of kicks, pawing and urination. Milk production was significantly higher (P<0.05) in the second fortnight of lactation and the duration of lactation was estimated in seventy five days. For both lactations, the contents of total solids, fat, lactose, minerals and protein increased (P<0.05) along the period. In both lactations, the frequencies of maternal-offspring behaviors observed decreased along the days, in function of higher interest for solid feed in detriment of milk. There was no influence of lactation and age at weaning in lambs weight at birth and at weaning (P>0.05) and ewes recovered body weight some weeks after birth.

ASSUNTO(S)

weaning weight behavior comportamento cortisol cortisol estresse milk quality peso ao desmame qualidade do leite stress

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