Changes in milk yield, composition, and udder morphology during early lactation according to weaning management...

Seventy-two early-lactation Sicilo-Sarde ewes were used to evaluate the effect of weaning system (WS) on milk yield (milked and residual), milk composition, and mammary morphology. Lambs were weaned at 30-35, 45-50, and 60-70 days for early (EW), semi-early (SEW), and late weaning (LW), respectively. Ewes (4.28 ± 0.77 years old) were divided into three groups based on the WS. Four milk recordings were performed during the first 45 days of milking (at days 7, 15, 30, and 45). The residual milk (RM) fraction was collected following an oxytocin injection. Additionally, external mammary morphology was assessed using six linear measurements and three udder and teat scores.WS significantly affected (p < 0.05) milked yield (MM) and total milk yield (MY); however, RM was not affected (p > 0.05). SEW and LW ewes produced more MM and MY than EW ewes. Furthermore, MM, RM, and MY traits were influenced by the ewes' overall milk production level. Milk composition for both MM and RM did not vary with WS (p > 0.05), except for the lactose percentage, which was higher (p < 0.05) in the RM of the SEW and LW groups. Regarding morphology, WS only influenced udder height, cistern height, and teat diameter at the base (p < 0.05). Sicilo-Sarde ewes generally exhibited deep udders and short, horizontally inclined teats. Udder traits and teat diameter showed significant moderate correlations with all milk traits (p < 0.05; r = 0.27-0.39). In conclusion, SEW increased milk production compared to EW and followed the same trend as LW during the study period, without compromising milk quality. These results suggest that SEW could help farmers increase the volume of marketable milk.