Effects of cow-calf contact on feed intake, milk production and energy balance in dairy cows in early lactation

Abstract: The objective of this study was to compare the production level, feed intake and energy balance in early lactation of non-suckled cows against cows in a cow-driven cow-calf contact (CCC) system. CCC systems have become interesting to evaluate as they are thought to provide a more natural behaviour for both the cow and calf, several studies have reported higher growth and better health in calves kept in these systems. Reports on how the cows’ production and health are affected are fewer with varying results and often dependent on the type of contact system, type of feed and feeding management. There is also a need to evaluate potential difference in milking techniques, as the majority of reports are based on conventional machine milking and not from automatic milking systems (AMS). The production level on a farm is highly dependent on the animal’s welfare and a high feed intake supporting high production and energy status, therefor, the relationship between these factors are interesting to evaluate in a whole day contact system. Twenty-two treatment and nineteen control cows in different parities (12 vs. 6 first parity, 4 vs. 3 second parity, 6 vs. 7 older cows in treatment and control groups respectively), were included in the study between 4 and 50 days in milk (DIM). Daily observations of feed intake, feeding behaviour, milk yield from an automatic milking system (AMS) and body condition score (BCS) was collected, milk samples were taken every fortnight for analysing milk composition and blood samples were taken twice a week during the first two weeks postpartum for evaluation of non-esterified fatty acids. All cows were feed ad libitum of roughage from automatic feeders which enabled continuous recordings of the time spent eating and amount of eaten feed for each individual. Number of meals per day, visit duration, meal size, feeding rate and dry matter intake (DMI) was compared in order to study the feeding patterns between the two treatments. The results suggest that feed intake was similar in both treatments, while the treatment group had a more efficient feeding pattern. Treatment cows had fewer visits per day, longer meal durations, bigger meals, higher feeding rates and longer intervals between feedings. Harvested milk yield was significantly lower in the treatment group due to calf’s milk intake, however, when estimating the energy corrected milk (ECM) (based on the energy mobilization) both treatments had a similar milk production. The BCS was more stable in the treatment group compared to the control cows, also non-esterified fatty acids (NEFA) values were lower in this group, indicating the that the control group was less able to adapt their feed intake to the lactation during this period. The study period included in this thesis was short and occurred during early lactation, therefor it will be important for future studies to investigate the entire lactation to confirm these findings and get a better picture of the cow’s performance in these whole day CCC systems.