Abstract The characteristics of milk are controlled by several genes, with emphasis on the four genes from casein, CSN1S1; CSN1S2; CSN2 and CSN3, which are responsible encoding of fractions the milk protein. The study of genetic variants in these genes, seek to investigate alleles, insertions or deletions, that can directly reflect on productive characteristics, indicating differences in milk quality, composition and yield. The CSN1S1 and CSN3 genes were analyzed in lactating Murrah buffaloes using nucleotide sequencing. An SNP was found in the amplified fragment of the CSN1S1 gene, located in nucleotide number 2,123 of the promoter region in position nt-258 (A/G). As for the CSN3 gene, two SNPs of exon number 4 were identified in codons 33 (ACC/ATC) and 34 (ACC/ACT) of the analyzed fragment. This study contributes to important associations between genetic variants and the desired characteristics of milk and its derivatives in future studies, because the variants found may be associated with the quality of milk, enabling genetic selection to be assisted by molecular markers, indicating a major advance that makes it possible to select animals early.

Abstract Given the growing use of alternative sources of protein, studies on the commercial viability of amazonians wild species, based on the yield of their carcass, are still scarce in the literature. To evaluate yields of carcass and commercial cuts of caiman meat (Caiman crocodilus yacare), according to sex and weight categories, besides analyzing their revenue. Thirty animals in termination phase were selected, separated by sex and weighed. The cuts analyzed was of 59.7% in relation to total live weight, and of 70.7% in relation to the carcass. Regarding the yields of the cuts, the average weight difference in detriment to the sex of the animals was minimal, however, in the weight categories, animals classified as intermediate and heavy (5.9–9.1 kg) resulted in higher cut weights (p < 0.01) and consequently in revenue for most of the meat cuts (66.7%), especially for tail, back, and sirloin fillets. It can be concluded that the carcass yield of caiman is high, and that heavy animals resulted in higher yields of prime cuts, emphasizing the need to carry out studies that prioritize the cost/benefit ratio taking into account the age and weight of the animals.