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Background: Farm profitability depends on raising healthy calves, which rests on successful feeding and management programs. Objective: To determine the effects of weaning weight on growth performance, feed efficiency, behavioral traits, as well as feeding cost of Holstein-Friesian and Brown Swiss calves. Methods: Sixty-seven newborn dairy calves were allocated into four weaning-weight groups [60 kg (n=18), 65 kg (n=19), 70 kg (n=18) and 75 kg (n=12)]. Body weights (BW) and measurements were recorded at birth, weaning, and four months of age. An instantaneous sampling method was used to collect behavioral data. Results: Daily weight gain of Brown Swiss calves was higher than Holsteins between weaning and four months of age (p<0.05). During pre-weaning, daily weight gain of calves weaned at 60 kg was lower than the other three groups (p<0.05). Feed efficiency of Holstein-Friesian was higher than Brown Swiss calves in the period between birth and four months of age (p<0.05). Chest depth of calves weaned at 60 kg was (p<0.05) lower compared to the other groups. Water drinking behavior during the pre-weaning period was notably higher in calves weaned at 75 kg (p<0.05). Conclusions: Our results suggest that dairy calves can be weaned at 60 kg of BW without detrimental effects on performance, and their feed cost per kg weight gain is significantly lower compared to higher weaning weights. [ABSTRACT FROM AUTHOR]

The objective of this research was to determine the effects of different initial fattening ages on the fattening performance, carcass features, and meat quality traits of Holstein Friesian bulls. A total of 24 Holstein-Friesian intact males were used in the study. The bulls were allocated to the initial fattening age groups named as Young Group (8-10 months old) (YG), Middle Aged Group (12-14 months old) (MAG) and Older Group (15-17 months old) (OG) and then placed in the feedlot based on three age groups at feedlot entry. The data that has normal distribution were analysed by using the LSMM in GLM, while others were analysed by using the nonparametric Kruskal - Wallis H test. The average daily weight gain of the YG, MAG and OG were 1.09 ± 0.27 kg, 1.01 ± 0.48 kg and 0.95 ± 0.60 kg (p < 0.01), respectively. Additionally, YG was the most effective group in terms of feed efficiency ratio (FER) compared to others. However, carcass measurements and carcass weight had lower values in the YG. Effects of age at feedlot entry had also insignificant effect on the carcass traits. Besides, measurements of the carcass muscularity including area of Musculus longissimus dorsi (MLD), SEUROP carcass conformation scores of the bulls in the MAG, and OG were superior to Holstein Friesian bulls in the YG. Different initial fattening ages had no significant effects on the chemical composition of MLD samples except for percentage of protein value. In conclusion, taking animals into feedlot at early ages resulted in accelerated weight gain, higher marbled meat, and improvement of the FER of Holstein Friesian bulls reared in harsh environmental conditions of the Eastern Turkey. However, the young animals had the lowest carcass weights and carcass measurements along with muscularity parameters. [ABSTRACT FROM AUTHOR]