Optimal Strategies with Automated Calf Feeding
Using right approach with automated feeders helps calves reach goal weight and still grow after weaning
To reach a key objective of doubling a newborn dairy calf's weight by the time it reaches two months of age, you have to feed substantial amounts of milk or milk replacer. Since you have to increase the number of meals the calf consumes as you strive for that objective, an automated feeding system can come in handy.
Traditionally, individually housed dairy calves, fed two meals a day in a bucket, have received eight to 10 percent of their birth weight per day. A calf weighing 45 kilograms at birth would have received 4.5 litres of milk or replacer per day.
In recent years, calf-rearing has changed substantially on many farms. With the advent of automated feeding systems, free-choice feeding, group housing and so on, most calves now consume much more milk or replacer-some up to 12 litres per day. During the milk feeding period, Holstein calves are expected to reach 90 kg at two months of age.
Researchers have responded by developing strategies to optimise weight gain, and preserve the benefit of increased milk or replacer consumption at weaning.
In one recent study, researchers used an automated milk feeder to evaluate two milk replacer feeding regimens: a limited milk allowance regimen of up to four litres of milk per day, and a free-choice regimen of up to 24 litres per day.
Calves allowed free access to feeding drank about eight litres on average in 12 visits to the feeder per day during the first three weeks. Calves on the restricted diet drank half the amount of milk in twice as many visits, and spent a lot more time at the feeder.
System efficiency affected
More time spent at the feeder significantly affected the system's efficiency since it could host fewer calves. Results also showed concentrate consumption during the first three weeks was not much different between the two groups, suggesting hunger among calves on the restricted diet.
From week three to week six, the free-choice calves increased consumption to about 10 litres per day, drinking one litre per visit. Calves on the restricted regimen got four litres but had to visit the feeder twice as often as the other group.
During that period, calves receiving low volumes of milk replacer consumed significantly more concentrate. This suggests these animals increased concentrate intake to compensate.
Increasing the liquid portion of the diet reduces concentrate intake during the milk feeding period. This may lead to reduced weight gain and even weight loss at weaning time-offsetting the benefit from the greater amount of milk fed earlier on.
You may need to implement a specific weaning strategy since the days following weaning are a stressful period for the calf. Minimizing stress will improve overall performance and prevent an offset of the gains from the greater amount of milk fed.
Weaning at six weeks
A recent British Columbia study suggests the optimal weaning age should be around six weeks. In that study, researchers compared abrupt weaning with gradual weaning among groups of calves fed large mounts of milk. They evaluated four different weaning treatments: 22 days, 10 days, four days and abrupt weaning.
Before weaning, every calf was allowed to drink up to 12 litres of milk per day. When calves consume substantial amounts of milk, this study shows, gradual weaning is the better option. As the amount of milk offered decreases, concentrate consumption increases. Weaning calves over 10 days appears to be the best way to optimise weight gains.
A 22-day weaning period reduces weight gain, while four days allow too little time to stimulate increased starter intake. Abrupt weaning gets the least desirable result for starter intake and weight gain.
With automated systems, you can now program the feeder's computer to allocate milk or replacer for a specific calf over a preset time period. That helps you achieve the objective of doubling its weight in its first two months of life.
T.F. Borderas, A.M. de Passillé, J. Rushen. 2009. Feeding behaviour of calves fed small or large amounts of milk. J. Dairy Sci. 92:28432852.
B.C. Sweeney, J. Rushen, D.M. Weary, A.M. de Passillé, 2010. Duration of weaning, starter intake, and weight gain of dairy calves fed large amounts of milk. J. Dairy Sci. 93:148-152.
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