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.

La rentabilidad de los establos lecheros está fuertemente asociada con el desempeño reproductivo. Por lo tanto, la identificación de factores de riesgo que comprometen este desempeño es primordial para implementar estrategias que mejoren la productividad. En este estudio, se probaron los efectos del uso de inseminación artificial (IA), hatos grandes y seroprevalencia alta de enfermedades infecciosas reproductivas sobre el desempeño reproductivo. Se incluyeron al estudio 52 establos (10-100 vacas; 959 lactaciones) registrando eventos reproductivos durante 18 meses (partos 2011-2012). Las seroprevalencias de neosporosis, rinotraqueitis infecciosa bovina (IBR) y diarrea viral bovina (BVD) se registraron en cada establo. Se utilizaron análisis de regresión logística múltiples para determinar el grado de asociación (razón de momios, OR) entre factores potenciales de riesgo y variables reproductivas. Establos ≥33 vacas y seroprevalencia alta de neosporosis fueron factores de riesgo para Asistencia al Parto (OR 1.5 y 2.3, respectivamente). Seroprevalencias altas de IBR y BVD fueron factores de riesgo para Días a Primer Servicio>70 Días en Leche (DPS>70, OR 1.3 y 1.9, respectivamente). La IA fue un factor de riesgo común para DPS>70 y Días Abiertos>110 Días en Leche (OR 2.4 y 1.3, respectivamente). Establos ≥33 vacas fue un factor de riesgo para Vacas No Gestantes al Primer Servicio (OR 1.7). En conclusión, la IA, establos ≥33 vacas y seroprevalencias altas de neosporosis, IBR y BVD son factores asociados al desempeño reproductivo en establos de producción de leche a pequeña escala en varias regiones geográficas de México.

Management and production characteristics impact conception rate to first service (CR1S) in small-scale dairy farms, but the impact of body condition score (BCS) and milk production levels on cows’ fertility is unknown. Our objective is to determine the effect of BCS and milk production on CR1S in small-scale dairy farms of western Mexico. Logistic regression models are used to determine the effect of BCS (at calving and first service), 60-d and 305-d milk production, protein and fat production, lactation number, and days at first service on CR1S. BCS at calving does not affect CR1S in cows with three or more lactations (39.5%; p > 0.1). However, first-lactation cows with BCS < 3.0 at calving and second lactation cows with BCS ≤ 2.5 at calving have higher CR1S (63.2 and 67.9%, respectively; p < 0.1). This result is perhaps due to reduced milk production, which leads to lower metabolic stress. BCS ≤ 2.5 at calving is associated (p < 0.05) with a reduced milk yield, explaining partially the observed higher CR1S in these groups. Cows with BCS ≤ 2.5 at first service in the higher quartile of 60-d milk production (≥ 28kg/day) show lower CR1S (23.9 and 51.1%, respectively; p < 0.01). In conclusion, BCS at calving and at first service, 60-d milk production, and lactation number are factors associated with CR1S.

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.

The study aimed to evaluate the effect of subclinical endometritis (SCE) on reproductive performance and identify risk factors for this pathology in small-scale dairies. In four small-scale dairies, 608 lactations were monitored for health issues, nutritional status, and reproductive events, and SCE was diagnosed based on endometrial polymorphonuclear counting (PMN%) at 30±5 (SCE30) and 60±5 (SCE60) days postpartum. The threshold for diagnosis was established according to the quartile distribution of PMN%; 4 % and 2 % for SCE30 and SCE60. Conception rate at first service (CRFS), number of services per conception (SC), and days open (DO) were analyzed for SCE effect through Chi-square or ANOVA. Events of interest were considered in each lactation to perform a risk factor analysis using univariate logistic regression and multiple logistic regression model building. The population attributable fraction was calculated to identify the most important risk factors. Considering both sampling periods, 40.5 % of the cows were positive for SCE. SCE30-positive cows had lower CRFS (38.9 vs 53.7 %), required 0.4 more SC, and had 20.2 more DO than SCE30-negative cows (P ≤ 0.001). SCE60-positive cows had 16 more DO than SCE60-negative cows (P ≤ 0.01). The most important risk factors for SCE30 were retained fetal membranes (RFM) and uterine diseases, while calving season, RFM, and SCE30 status were the risk factors for SCE60. SCE could represent a major problem in small-scale dairies due to its prevalence and negative effect on reproductive performance. Furthermore, there are identifiable risk factors for SCE under these production conditions, which should be considered when designing prevention strategies.