Principal components for the in vivo and carcass conformations of Anglo-Nubian crossbred goats / Componentes principais para conformações in vivo e das carcaças em caprinos mestiços da raça Anglo-Nubiana

ABSTRACT: This study aimed to identify the principal components (PC) that explain the highest percentages of total variance and best characterize the in vivo and carcass morphologies of Anglo-Nubian crossbred goats. Nineteen carcass morphometric traits and six in vivo morphometric traits were measured in 28 kids at eight months of age. Principal component analysis indicated that five PC were able to explain 83.57% of the total variance in the 19 original carcass traits. Those components were termed PC1-Carcass Size, PC2 - Body Condition, PC3-Carcass Width, PC4-Chest Depth, and PC5 - Hindquarter. For in vivo morphometric traits, the first two principal components explained 78.86% of the total variance. These components were called PC1-In vivo Size and PC2-In vivo Conformation.

RESUMO: Este estudo buscou identificar componentes principais (CP) que explicam os maiores percentuais de variância total e que melhor caracterizam cabritos mestiços da raça Anglo Nubiana, quanto à medidas morfológicas obtidas in vivo, e na carcaça de 28 animais com 8 meses de idade. Foram conduzidas duas análises de componentes principais, sendo uma para 19 características de carcaça e outra para seis características morfométricas in vivo. Os cinco primeiros CP explicaram 82,54% da variância total das 19 características incluídas nessa análise. Estes componentes foram chamados de: CP1 - Tamanho da Carcaça, CP2 - Condição Corporal, CP3 - Largura da Carcaça, CP4 - Profundidade do Tórax e, CP5 - Comprimento do Pernil. Os dois primeiros componentes principais das morfometrias obtidas in vivo explicaram 78,86% da variância total e foram chamados de CP1 - Tamanho in vivo e CP2 - Conformação in vivo.

Heat stress induces expression of HSP genes in genetically divergent chickens.

BACKGROUND: Chickens are animals that are sensitive to thermal stress, which may decrease their production level in terms that it affects feed intake and thus, decreasing body weight gain. The Heat Shock Factors (HSF) and Heat Shock Proteins (HSP) genes are involved in the key cellular defense mechanisms during exposure in hot environments. Aimed with this study to analyze the expression of HSF1, HSF3, HSP70 and HSP90 genes in two local breeds (Peloco and Caneluda) and a commercial broiler line (Cobb 500®) to verify differences in resistance of these chicken to Heat stress treatment. Chicken were submitted to heat stress under an average temperature of 39°C ± 1. RESULTS: Under stress environment, the HSP70 and HSP90 genes were more expressed in backyard chickens than in broiler. There was a difference in HSP70 and HSP90 expression between Caneluda and Cobb and between Peloco and Cobb under stress and comfort environment respectively. HSP70 expression is higher in local breeds during heat stress than in a commercial broiler line. No significant differences were observed in the expression of HSF1 and HSF3 genes between breeds or environments. CONCLUSIONS: HSP70 and HSP90 genes are highly expressed, HSF1 and HSF3 genes did not have high expression in all genetic groups. HSP70 and HSP90 are highly expressed in Peloco and Caneluda within heat stress, these breeds proved to be very resistant to high temperature.

Association of the bovine major histocompatibility complex (BoLA) BoLA-DRB3 gene with fat and protein production and somatic cell score in Brazilian Gyr dairy cattle (Bos indicus)

The effect of the bovine major histocompatibility complex (BoLA) locus on animal health may be due to a direct action of its alleles on immune functions, whereas its indirect effect on production traits might be explained by the better general health conditions of more productive animals. In the present study, the BoLA-DRB3 gene was investigated in 1058 cows belonging to seven Brazilian Gyr Dairy herds (Bos indicus, Zebu cattle). A total of 37 alleles were identified, 15 of them described for the first time in a Zebu breed. A highly significant association (p < 0.02) was observed between allele *54 and a decrease (-26.1 kg) in milk protein yield and there was a significant association (p < 0.05) between this allele and lower (-26.07 kg) milk fat yield. There was also a significant association (p < 0.05) between allele *6 and decreased (-12.47 kg) milk protein and allele *7 and increased (12.72 kg) milk protein. There were also indications of association (p < 0.10) between somatic cell score (SCS) and alleles *3 (SCS increased by 0.54 units) and *31 (SCS increased by 0.46 units). The highly significant association of allele *54 with lower protein yield suggests the possible use of this allele in marker-assisted selection programs.

Relationship between the Porcine Stress Syndrome gene and carcass and performance traits in F2 pigs resulting from divergent crosses

The PSS genotypes of 596 F2 pigs produced by initial mating of Brazilian native boars commercial sows and were characterized by PCR-RFLP and their carcass and performance traits were evaluated. Among the 596 animals analyzed, 493 (82.72 percent) were characterized as NN and 103 (17.28 percent) as Nn. With respect to carcass traits, Nn animals presented higher (p < 0.05) right half carcass weight, left half carcass weight, loin depth and loin eye area, and lower shoulder backfat thickness, backfat thickness between last and next to last but one lumbar vertebrae and backfat thickness after last rib at 6.5 cm from the midline compared to NN animals. Nn animals also showed (p < 0.05) higher values for most of the cut yields, indicating higher cutting yields for animals carrying the n allele and lower values for bacon depth, confirming lower fat deposition in carcass. In addition, Nn animals presented (p < 0.05) lower values for the performance trait weight at 105 days of age. These results indicate that animals carrying the PSS gene generate leaner carcasses, higher cut yields, and that the effects of the gene can be observed even in divergent crosses.