Influência do tipo de parto na curva de crescimento, desempenho e características de carcaça em ovinos Santa Inês

• Ano de defesa: 2013
• Autor(a) principal: Correia Neto, José
• Orientador(a): Guimarães, Simone Eliza Facioni
• Banca de defesa: Silva, Fabyano Fonseca e , Pereira, Odilon Gomes , Veloso, Cristina Mattos , Sá, Cristiane Otto de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Nutrição de ruminantes; Produção de ovinos
• Palavras-chave em Inglês: Ruminant nutrition; Sheep production
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA ANIMAL
• Link de acesso: http://locus.ufv.br/handle/123456789/1848

The present study was comprised of two experiments. The first one assessed the effect of gender and birth type on the growth curve of Santa Inês sheep, and compared nonlinear models of growth curve. The study used lambs ranging in age between zero and 330 days, born in 2005, 2006, 2007, 2008 and 2010, raised on pasture with plenty of mineral salt available. To check for the effect of gender and birth type on the weight of the animals, a randomized block split-plot design was used. After the significance of the effects of interaction among time, gender and birth type was observed, such interactions were unfolded. The method of overlapping confidence intervals was used to compare the estimates of parameters A and K. In 2005, males and females had similar growth from 30 to 90 days of age. There were differences for single birth and twin birth lambs from 30 to 330 days. In 2006, there was an interaction among gender, birth and time. For single birth and twin birth lambs, birth weight was different. In 2007, the same behavior seen in 2005 and 2006 was observed for growth between males and females. In 2008, there was an interaction among gender, birth and time. Males and females had similar weight at birth and at 30 days of age. In 2010, there was no interaction among gender, birth and time. Growth of females was similar to that of males in weight at birth and at 30 days of age. Single birth lambs had higher growth at all ages. The Bertallanffy model was shown to be the best one to evaluate growth curve. The greatest difference in growth curves was observed in 2006. It was concluded that year of birth did not affect weight gain comparing males and females. From 30 days of age, single birth lambs gained more weight than twin birth lambs. Males usually reach greater mature weight than that of females and have the same growth rate. The second experiment assessed the influence of creep feeding on weight gain at pre-weaning and also on feed intake, weight gain and carcass traits at postweaning, for single and twin birth lambs. The experiment used 28 sheep and ix 42 lambs confined with their mothers during breast-feeding, with or without creep feeding available. After weaning, 28 single birth and twin birth lambs were confined for 56 days in individual cages, and were fed a diet consisting of corn silage and concentrate. After confinement, the lambs were weighed and slaughtered and their carcasses were chilled for 24 hours at 4 oC. The following were assessed: weight gain during breastfeeding, weight gain, feed intake and feed conversion during confinement; slaughter weight, hot carcass weight and yield, cold carcass weight and yield; biological and commercial yield; cooling loss rate; carcass internal length and carcass depth; carcass compactness index; cuts of neck, shoulder, ribs and leg, and the fractions of bone, muscle and fat in the leg. The experiment used a completely randomized 2 x 2 factorial design. Creep feeding did not affect dry matter intake or feed conversion. Birth type significantly influenced dry matter intake. There were no differences between treatments for cooling loss rate. The weight of the rib and shoulder cuts and carcass length were influenced by birth type. At pre-weaning, lambs that had not received creep feeding did not show lower performance, and creep feeding did not affect the carcass traits of the lambs. At post-weaning, single birth lambs consumed more dry matter while twin birth lambs showed the same performance as single birth lambs.