The aim of this study was to identify the foremost model that depict the lactation curve of dual-purpose crossbred cows under a humid tropical environment. Six models were compared to describe the lactation curves of three breed groups using 1231 milk records of 160 cows. The breed groups were 0-25%, F1 (50%) and 62.5-75% Holstein x Gyr crosses. Parameters of the models and curves were estimated using non-linear procedures. The best model was determined by the Akaike information criterion. Wood, Sikka and Wilmink models provided a good fit to the lactation curves for the breed groups; however, the Wood model was applied to depict the lactation curves, the day at which lactation peak was reached and milk yield at the peak. The aspect of the curves differed according to the breed group. The low graded Holstein cows had typical standard curves, and the F1 and high graded cows had no lactati...

The aim of this study was to evaluate the effect of Ley-Leygo and Triladyl® extenders and two equilibrium times on individual motility (IM), plasma membrane integrity (PMI), mitochondrial activity (MA) and intact acrosome (IA) in frozen-thawed boar semen. A rich fraction of a total of 20 ejaculates from five boars of a commercial line was used. All ejaculates had a minimum of 80% motility and 85% normal spermatozoa. Each ejaculate was divided into four aliquots: Ley-Leygo and Triladyl® extenders and two equilibrium times (0 and 1 h). The semen samples were thawed at 37 °C for 20 s. The results of the IM and the PMI did not have significant effects for the factors evaluated (p>0.05). There was a significant difference for MA (p<0.05) between the Ley-Leygo (43.57%) and Triladyl® (51.7%) diluents. The IA was 46% for Ley-Leygo and 25% for Triladyl® (p<0.05). The percentage of ...