Influência dos sistemas de alimentação sobre a morfometria ruminal, biometria in vivo e as características da carcaça de cordeiros

Abstract

This dissertation have the objetive to evaluate the influence of different types of feeding systems on the morphometric characteristics of the rumen, the qualitative and quantitative characteristics of the carcass and the in vivo biometry of sucking lambs and weaned lambs. The research was carried out at the Universidade Federal de Santa Maria, Santa Maria, RS, Brazil. Thirty-two male lambs were used, not castrated, distributed in four feeding systems, as follows: SP - lambs suckling on ryegrass pasture; SC - suckling lambs in confinement; WB - weaned lambs with exclusive diet of bulky and WC - weaned lambs with exclusive diet of concentrate. Upon reaching the slaughter weight of 30 kg, in vivo measurements were performed on the lambs. After slaughter, aspects related to carcass, proportion of commercial cuts and tissue composition of the palette were taken. Two samples of rumen tissues of approximately 4 cm 2 were collected, one in the dorsal caudal blind (SD) and one caudal 5 cm caudal to the sphincter (RC) region. Microscopic morphometry of papilla height and width, rumen muscular tunica thickness, basal stratum, prickly, granular and stratum thickness were measured after the histological processing. corneal epithelium of the rumen papillae. The surface area of the papillae and the total surface area of the rumen were also determined. This dissertation is composed of three articles. Article 1 refers to lamb carcass traits, comparing the four feeding systems (LP, LC, DV and DC). In this article, the experimental design was completely randomized and the data were submitted to analysis of variance, test F, and the means compared by the Tukey test at 5% of significance. It was concluded that the different feeding systems influenced some characteristics of the in vivo biometry, the quantitative and qualitative characteristics of the carcass and the tissue composition of the lambs' palette, with significant differences between the treatments. Articles 2 and 3 refer to ruminal morphometry. For these articles, the experimental design was completely randomized, with four treatments and a varied number of repetitions, in a 2 x 2 factorial scheme. Data were submitted to analysis of variance and the means were compared by the Tukey test at 5% significance. In article 2, we compared the systems of suckling lambs (LP and LC), it was observed that most of the morphometric characteristics of the rumen of the suckling lambs were influenced by the type of feeding system and that the supply of concentrate to suckling lambs allowed increased ruminal papillae growth. In article 3, weaned lambs (DV and DC) were compared, it was verified that there was no difference in the thickness of the muscular tunica of the rumen of the lambs between the diets, the RC region of the rumen presented a lower papillary development and a greater keratinization of the papillae than the SD region, and the diet with concentrate adversely affected the growth and thickness of the stratum corneum of the papillae.