Factors contributing to milk yield variation among cows in a cow-calf contact system in early lactation

The conventional dairy production system involves separation of the cow and calf at around 24 hours of birth. Due to public concerns regarding this early separation, a few farmers are taking up the cow-calf contact system. However, some farmers have cited a great variation in milk yield delivered to the parlor between the cows with this being detrimental as it leads to low farm returns. The study’s main objective was to determine the source of variation in milk delivered to the parlor among cows in the cow-calf contact system. The study employed the use of milk yield records for the first 28 days of lactation for 110 fall- and spring-calving cows from a farm running a full-time cow-calf contact system to investigate factors leading to variation in milk delivered to the parlor among the cows. There was a great individual variation of milk delivered to the parlor among the cows with the range between the highest and the lowest average being 22 L/d. The sex of the calf had an effect on the average milk delivered to the parlor with cows with female calves having the higher average milk yield (Wald=5.61, df=1, P=0.020). Additionally, the lactation number of the dam had an effect on the average milk delivered to the parlor with cows in their third lactation and above having the highest milk yield average (Wald=20.90, df=2, P=<0.001). From the results of this study, it can be concluded that the sex of the calf and lactation number of the dam affect milk yield delivered to the milking parlor in a cow-calf contact system.