Effect of milking frequency and melatonin implants during the dry-off period on milk yield and composition in pregnant dairy goats

Abstract

This study aims to evaluate the effects of different dry-off strategies based on melatonin implants or milking frequency on milk yield and chemical composition in pregnant dairy goats. On day -75 relative to expected parturition, 24 Majorera dairy goats were subcutaneously treated with 1 mL of saline or with a melatonin implant. From day -75 to day -60 relative to expected parturition, animals were either milked once daily or once every other day. From day -60 to day 0 relative to parturition, animals were not milked. From day -75 to day -60 relative to parturition, milk yield was recorded, and milk samples were collected to determine gross chemical composition (i.e., lactose, fat, protein and total solids) and somatic cell counts (SCC). Data were analysed using the PROC MIXED procedure of SAS, and the significance was set as P < 0.05. The results showed a faster milk yield reduction in those animals treated with melatonin implants compared to those receiving saline (P < 0.001). In addition, milk yield decreased faster in those animals milked once every other day than those milked once daily. Neither gross chemical composition nor SCC were affected by either the melatonin administration or the milking frequency (P > 0.05). In conclusion, it seems that reducing milking frequency as well as the use of melatonin implants during a 15-day dry-off period are effective strategies to promote a faster transition from late lactation to the dry period in dairy goats. This study was funded by the project PID 2020-113056RA-I00/AEI/10.13039/501100011033.