Of the diversity of proteins and high digestibility, goat milk will be a food of significant value for infant nutrition. The genetic polymorphisms of milk proteins play an essential role in the different degrees of allergic reactions. This work aimed to identify the proteins and peptides in the composition of goat milk and compare them to those in cow’s milk. The work was performed with goats French Alpine, Nubian, and Creole breeds and Holstein Friesian milking cows at the Universidad Autónoma de Querétaro, Amazcala. We investigated the relative abundance of goat and cow milk protein fractions by SDS-PAGE resolution and the densitometric analysis of gels. The protein alfa-casein was (17.67 ± 0.46) for Creole, (19.18 ± 0.88) French Alpine, (17.35 ± 0.49) Nubian, and (35.92 ± 1.96) Holstein cows. The relative abundance obtained from alfa-casein was statistically different between goats and cows, and this protein was vital because it is a protein related to allergies. On the other hand, the amino acid in position 67 of the beta-casein from three goat breeds is a Proline, so it is assumed that the beta-casein variant of goat milk is an A2-type. The latter has excellent relevance for infant nutrition and differs from cow milk.

In order to evaluate the morphostructural variability of the Black Creole goat (BCG), the present study was carried out in a population of 226 animals from eight localities and 14 morphometric variables were taken. Descriptive statistics for the variables were obtained and 10 of these presented variation coefficients of less than 10%. The degree of harmony in the morphology of the population was determined by the number of positive correlations with significant differences (p < 0.05), including a correlation test using Spearman’s method. In order to reduce the matrix of variables, a principal components analysis was performed, and it was evaluated based on Kaiser’s criteria (eigenvalue > 1). Finally, a hierarchical analysis of conglomerates using Ward’s method was performed using the Euclidean distance to evaluate the distances among localities. Morphometric variables were also included to visualize the relationship among the localities and their average per variable. The results showed that the animals evaluated presented a certain degree of homogeneity and maintained a highly harmonic model. The BCG population showed a high aptitude for milk production, which confirmed the zootechnical purpose of the breed. The BCG populations evaluated maintain similar morphostructural profiles specific to them that can distinguish this population from other animal breeds.

The objective of this study was to determine the effect of replacing soybean meal (Glycine max) with sesame meal (Sesamum indicum) on productive traits, carcass characteristics, and gross profit margin (GMP) in fattening lamb’s diets. For this, 42 Katahdin lambs were divided into three treatments in duplicate: basal diet + soybean meal (100S), basal diet + sesame meal/soybean meal (50/50SA), and basal diet + sesame meal (100A). Dry matter intake, daily weight gain (DWG), total kg gained (KgT), feed conversion (FC), and feed efficiency (FE) were evaluated; upon reaching the weight for sale, the animals were slaughtered, and hot carcass weight (HCW) was evaluated. The results were analyzed with a completely randomized design with repeated measures. Regarding time, no differences were found between treatments, for DWG (0.171 ± 0.006 kg/d), FC (6.7 ± 0.55), FE (0.175 ± 0.02), KgT (2.86 ± 0.13 kg), HCW (50.97 ± 0.79 kg), as well as for chest depth (26.96 ± 0.33 cm), leg width (20.63 ± 0.028 cm), leg diameter (60.7 ± 0.44 cm), and ribs width (24.05 ± 0.14 cm). GPM was 16.50%, 18.63%, and 19.97% for 100S, 50/50SA, and 100A, respectively. Overall, in fatting lamb diets, replacing soybean meal with sesame meal by either 50% or 100% substitution could be a feasible feeding strategy as in both cases, gross profit was increased, and no negative effects were found for productive traits and carcass quality.

Desde su llegada a México, las cabras han experimentado un largo proceso de adaptación y selección, dando como resultado animales locales de elevada rusticidad. Sin embargo, la importación de razas mejoradas y el intento de sustituir a los genotipos criollos por éstas, ha llevado a gran parte de este ganado al borde de la extinción. Un ejemplo es la cabra criolla negra (CCN), reconocida por su rusticidad y la calidad de su leche. El objetivo del presente trabajo fue caracterizar genéticamente una población de CCN. Se utilizaron 30 microsatélites, obteniendo; el número de alelos por marcador (NA), el número medio de alelos (MNA), número efectivo de alelos (Ae), la heterocigosidad observada (Ho) y esperada (He), el contenido de información polimórfica (PIC), el índice de fijación calculado con el estadístico F_IS y el equilibrio de Hardy Weinberg (HWE). La población fue comparada con 13 razas caprinas del proyecto BioGoat. Los resultados mostraron que existe una elevada diversidad genética en este ganado. Se obtuvieron 243 alelos con un MNA de 8.1 alelos por locus. Los marcadores resultaron muy informativos con un PIC de 0.6. La He promedio de 0.71 y Ho de 0.62 puede indicar que existe un ligero desequilibrio en la población. La distancia de Reynolds mostró que la CCN se encuentra más distanciada genéticamente de la población Anglonubia y más cercana a la Murciano-Granadina. Los resultados aquí presentados sugieren que la población CCN representa una estructura racial bien diferenciada de las poblaciones incluidas en el estudio.