ABSTRACT This study aimed to evaluate the lactation curve of female Murrah buffaloes, using mixed nonlinear models (NLM), across three lactation periods (180 d, 210 d, and 240 d). A total of 5334 data on daily milk production (kg) were analyzed. The data were collected every seven days in the interval of one to 250 days of lactation, corresponding to 221 lactations and 145 females, with calvings from 2017 to 2019. The data came from a herd located in the Centro municipality, Tabasco, Mexico. Five NLM were evaluated: Wood (WOD), Wiltmink (WIL), Cobby (COB), Brody (BRO), Sikka (SIK). The best fit model was selected based on the mean prediction error, mean absolute percentage error (MAPE), prediction error variance, coefficient of determination (R2), concordance correlation coefficient (CCC), Akaike (AIC) and Bayesian (BIC) information criteria. A regression analysis was performed between the observed and predicted values. All the NLM had a R2 above 0.91. They tend to underestimate the predictions, without residual autocorrelation. The MAPE showed an average value of 23.5%. The best fit model was WOD, followed by SIK and BRO. For WIL and COB, the mixed model did not improve the fitting. The shortest lactation period showed the best fit, followed by the 210 d and 240 d periods. The relationship between observed:predicted values fluctuated from 0.65 to 1.00, with an average value of 0.94. The use of NLM transcended in the AIC and BIC. The evaluated models showed goodness of fit, with good predictability, but low values in accuracy and precision of prediction.

Abstract The objective of the study was to evaluate the effect of feeding finishing pigs with a wet diet (feed:water, 1:1), versus a dry diet based on sorghum and soybean meal (15.0% CP, 3,200 kcal ME/kg DM), on the productive behavior, carcass composition and meat quality. Sixteen (York-Landrace x Duroc) crossbred pigs weighing 68.4 ± 2.4 kg were individually housed and assigned to two treatments (n= 8 replicates per treatment): DF, dry feed; WF, wet feed. Feed was offered daily in two equal portions (0800 and 1500 h) for 5 wk. Individual live weight (LW) and feed consumption were recorded every week in order to calculate the daily weight gain (DWG) and feed efficiency (FE). The carcass composition was measured; the meat quality was assessed in samples of Longissimus dorsi. Wet-fed pigs had higher (P<0.05), final LW (108.4 vs 101.9 kg), and DWG (1.043 vs. 0.990 kg/day) than dry-fed pigs. DF pigs had lower intake (wk 5) and feed efficiency (FE) (by wk 3) than WF pigs (Treatment x Week Interaction, P<0.05). WF pigs had greater leg and hot and cold carcass weights (P<0.05). The weight of the loin, ribs, and shoulder, and the protein content, water holding capacity, and pH of meat were similar (P>0.05) between treatments. The hardness, adhesiveness, chewiness, and toughness values were lower (P<0.05) in meat from WF pigs. In conclusion, the wet-fed pigs had better productive performance, carcass composition and meat characteristics than the dry-fed pigs.

Resumen El objetivo del estudio fue evaluar el efecto de la alimentación húmeda de cerdos en finalización (alimento:agua, 1:1) de una dieta basada en sorgo y harina de soya (15.0% PC, 3,200 kcal EM/kg MS), sobre el comportamiento productivo, composición de la canal y calidad de la carne. Dieciséis cerdos cruzados (York-Landrace x Duroc) de 68.4±2.4 kg de peso fueron alojados individualmente, y asignados a dos tratamientos (n=8 repeticiones por tratamiento): AS, alimentación seca; AH, alimentación húmeda. Alimento fue ofrecido diariamente en dos porciones iguales (0800 y 1500 h) durante cinco semanas. Semanalmente se registraron el peso vivo (PV) y el consumo de alimento individuales, para calcular ganancia diaria de peso (GDP) y eficiencia alimenticia (EA). Se midió la composición de la canal; la calidad de la carne fue medida en muestras de Longissimus dorsi. Cerdos AH tuvieron mayor (P<0.05) PV final (108.4 vs 101.9 kg) y GDP (1.043 vs 0.990 kg/día) que los cerdos AS. Cerdos AS tuvieron menor consumo (semana 5) y EA (semana 3) que los cerdos AH (Interacción Tratamiento x Semana, P<0.05). Cerdos AH tuvieron pesos mayores de pierna, canal caliente y fría (P<0.05). Lomo, costillas, paleta, contenido de proteína, capacidad de retención de agua y pH de la carne fueron similares (P>0.05) entre tratamientos. Valores de dureza, adhesividad, masticabilidad y resistencia fueron menores (P<0.05) en carne de cerdos AH. En conclusión, los cerdos que recibieron alimento húmedo tuvieron mejor comportamiento productivo, composición de la canal y características de la carne que cerdos que recibieron alimento seco.

Abstract: The objective of this study was to evaluate the effect of recombinant bovine somatotropin (rBST) on ovarian activity and quantity and quality of transferable embryos in goats during seasonal anoestrus. We used 30 multiparous goats synchronized with goats synchronized with CIDR short protocol and superovulated with FSHp, assigned to three treatments (n = 10): T1 = control, without rBST, T2 = 100 mg rBST y T3 = 200 mg rBST. Quantitative variables were analyzed using the Kruskal-Wallis test, and the percentage of estrus and embryos recovered by the Chi-square test. A greater number of CL were registered in goats assigned to T3, followed by T2 (p = 0.002). The number of recovered embryos and blastocysts was higher in T3 (p = 0.001). The morula number was higher in T1 (p = 0.001). The application of rBST at the onset of estrus increases ovarian activity and the number of transferable embryos in goats.

Resumen: El objetivo del estudio fue evaluar el efecto de la somatotropina bovina recombinante (rBST) en la actividad ovárica, cantidad y calidad de embriones transferibles en cabras durante el anestro estacional. Se utilizaron 30 cabras multíparas sincronizadas con protocolo corto de CIDR y superovuladas con FSHp, asignadas a tres tratamientos (n = 10): T1 = control, sin rBST, T2 = 100 mg rBST y T3 = 200 mg rBST. Las variables cuantitativas se analizaron mediante prueba de Kruskal-Wallis; el porcentaje de estro y de embriones recuperados, mediante prueba de Chi - cuadrada. Las cabras del T3 tuvieron mayor número de CL, seguidas del T2 (p = 0.002). El número de embriones recuperados y de blastocitos fue mayor en T3 (p = 0.001). El número de mórulas fue mayor en T1 (p = 0.001). La aplicación de rBST al inicio del estro incrementa la actividad ovárica y la cantidad de embriones transferibles en cabras.

ABSTRACT We evaluated the effect of some environmental factors on age at first lambing (AFL) and lambing to conception interval (LCI) of Pelibuey ewes under the humid tropical conditions of Mexico. Ewes grazed on Tanzania (Panicum maximum), Bermuda (Cynodon dactylon), and Brachiaria grass (Brachiaria humidicola) and received hay in the corral in the months of grass scarcity. Reproduction was continuous during the year. Data of 839 lambings from 334 ewes registered from 2009 to 2017 were analyzed using survival analysis procedures. The statistical model for AFL included the effects of year, season, and litter size at lambing, whereas that for LCI included year and season plus parity number of ewe and litter size at weaning. The overall means ± SD for AFL and LCI were 551.6±144.8 and 145.4±113.1 days, and their medians were 510 and 98 days, respectively. Only year of lambing had a significant effect on AFL, whereas LCI was affected by year, parity number, and litter size at lambing (P<0.05). Both AFL and LCI means did not show any trend with advancing years. The largest AFL and LCI means and medians corresponded to the first-parity ewes. In addition, single birth ewes had the longest LCI means and median. Therefore, year of lambing affects AFL, whereas year of lambing, parity number, and litter size at weaning affect LCI of Pelibuey ewes, indicating that these factors should be considered in the development of sound strategies to improve sheep production.