Caracterização biométrica e funcional do ovino pantaneiro

Abstract

The objectives with this thesis were: I) to abord the importance of studying the morphological characterization of locally adapted sheep breeds and the use of multivariate analyzes for exploratory data studies (Chapter I); contribute to the biometric characterization of the Pantaneira breed, using linear measurements, weight and body condition, presenting evaluation elements with a focus on multifactorial responses (Chapter II); classify the fiber types of the different biotypes of Pantaneiro lambs, generated according to their carcass yield (Chapter III). Chapter II: 211 Pantaneiras sheep from the conservation herd at the Federal University of Grande Dourados were evaluated. The measurements taken were weight and body condition, 23 quantitative morphological measurements and 9 qualitative morphological variables. Initially, a descriptive statistical analysis was carried out for all quantitative characteristics and subsequently these data were subjected to factor analysis, the formation of a correlation matrix and together with the qualitative data used to induce decision trees. The 4 factors formed were given the names body, shin, height and head, and these contributed to 18, 17, 15% and 13%, respectively, of the data variation. The correlation matrix formed showed the formation of these groups of variables with greater correlations between them. The group of variables associated with the shin (carpal, metacarpal, tarsus and metatarsus) was used to induce decision trees, seeking to understand the relationship between quantitative and qualitative morphological variables. Measurements related to animal cinnamon are capable of generating decision trees with satisfactory accuracy. Chapter III: 33 Pantaneiro lambs with an initial age of 82 days, males, weaned, not castrated, with a body weight of 12.8±3.5 kg were used. Allocated in individual pens equipped with feeders and drinkers. The experimental diet was the same for all animals, formulated to provide an average gain of 250g/day. Weighings and assessment of body condition were carried out weekly. 23 quantitative morphological measurements were collected at the beginning of the experimental period and before slaughter, in addition to the qualitative morphological characterization of the animals. Upon reaching the minimum body condition of 2.75 and weight of 28 kg, the animals were slaughtered. The carcasses were weighed immediately after slaughter and kept in a cold room 24 hours later. At the time of slaughter, samples of the Longissimus thoracis et lumborum, Semimembranosus and Triceps brachii muscles were collected for subsequent evaluation and identification of fiber types. The data measured on the carcass were subjected to factor analysis and subsequent cluster analysis to obtain the biotypes. An average test was carried out to compare the different biotypes formed in terms of efficiency and performance in confinement and fiber types. Quantitative and qualitative morphological measurements were used to characterize the biotypes obtained. The factor analysis generated 4 factors, the first being called muscle, which contributed most to the variability of the data (24%). This factor was composed of hot carcass weight and yield and cold carcass weight and yield, which is why these measurements were used as the basis for cluster analysis, generating 3 biotypes (A, B and C). Biotype A is composed of 11 animals with higher consumption (0.93kg/day) and average daily gain (0.22kg/day) compared to the others, in addition to presenting a better muscle:bone ratio (2.9) and a lower percentage of total bone in the carcass (18.9%). This biotype presented an even higher concentration of red fibers in the three muscles studied Longissimus thoracis et lomborum, Semimembranosus and Triceps brachii, being 45, 38 and 32%, respectively. These animals were also characterized by having smaller body measurements compared to biotype C, making them classifiable as more compact animals. Although more studies are needed to confirm the data, it is possible to verify through this exploratory work that there is, within the Pantaneira breed, a lineage of more efficient animals, with better carcass composition and tissue formation similar to breeds specialized for meat production.