By Maurice L. Eastridge, Professor and Extension Dairy Specialist, Department of Animal Sciences, The Ohio State University
We know that personality of children in the same family can vary immensely, caused by genetics, birth order, changing parenting styles, and other factors. Have you ever related these differences to dairy calves? Previous research has revealed that food animals that are generally calmer or less reactive, versus more excitable, have improved growth rates, meat quality, and milk production; improved immune function, and decreased physiological responses to stressful events. Dairy cows that are more excitable in the milking parlor produce less milk, milk out slower, and have reduced lifetime production efficiency.
Given this prior knowledge, researchers at the Animal Welfare Program at the University of British Columbia conducted a study with 56 dairy calves to identify personality traits that may be associated with feeding behavior and performance. Calves were housed in seven groups with eight calves in each group with access to automatic milk feeders and free choice water, hay, and calf starter. Calves were assigned to 1 of 4 milk-feeding allowances (1.6, 2.1, 2.6, or 3.2 gallons per day of milk) within each group of eight calves, with each group containing two calves on each allowance. Milk was reduced to 50% of the allowance at 42 days of age and reduced by 20% per day from day 50 until calves were completely weaned at day 55. At 27 and 36 days of age, each calf was subjected to three novelty tests (novel environment, human approach, and novel object). Seven different behaviors were scored, but interactive, exploratory-active, and vocal-inactive were the most important in explaining calf behavior. Calves with more exploratory-active began to consume starter at an earlier age and had greater starter intake and overall average daily gain. Calves that were more interactive and vocal-inactive (less vocal) had more unrewarded visits to the milk feeder during the weaning phase. Calf starter also was fed through the automated feeder system, and overall, it took 19 days for the calves to eat 0.10 pounds per day, 36 days to first eat 0.50 pounds per day, and 42.5 days to eat 1.5 pounds per day of calf starter.
Some general conclusions from this research are:
- Personality traits explain individual variability in the development of feeding behavior, solid feed intake and weight gains, and behavioral responses of dairy calves.
- It is important to identify calves that are struggling to make the transition from milk onto solid feed so that performance and welfare are not compromised. Calves that are struggling with the transition can have an extended transition or other exceptions to assist them with the changes during this critical period.
- Characterization of calf personalities at around three weeks of age can identify animals that are most likely to make this transition smoothly and to identify calves that would benefit from additional assistance.
- Calf behavior and performance have been used to access when individual calves are ready to move to an automated milk feeder. Additional evidence is still needed, but information collected during the time calves are using the automated milk feeder may help to identify potential personality differences among calves that warrant variation in the transition of calves to a weaned state.
Even though the dairy industry in moving toward more group housing of pre-weaned calves, using the data collected in the automatic milk feeding system and careful daily monitoring of the calves by employees can help to identify health, performance, and personality differences for individual management of the calves to best meet their needs.