Get full benefit from those new labour-saving calf-feeding systems by taking a hard look at your weaning program.
If you're thinking of introducing a labour-saving calf-feeding system to your operation, or if you've already taken the plunge, consider a weaning program evaluation as part of the package. This can help ensure that you reap the system's full benefits.
Computer-controlled feeders and low-cost free-choice systems using acidified milk or milk replacer are two examples of the newer technologies for feeding dairy calves. They have a lot of potential to save labour.
These systems also offer the advantage of generally providing more milk to your calves than traditional rearing methods have offered. More milk gives calves a better chance to reach their full genetic potential for growth and enhances overall animal health.
European and North American researchers have recently published several studies showing that feeding more milk or milk replacer to calves increases rate of gain and results in fewer signs of hunger. In free-choice feed systems, calves have been reported to consume more than 12 litres of milk per animal per day.
However, when weaning calves consuming high quantities of milk or milk replacer, you do face some challenges. A common pitfall is a decline in average daily gain during the week following weaning-as much as 50 per cent less than the week before weaning. This decrease is typically attributed to an inadequate intake of calf starter after weaning. While the benefits of accelerated milk feeding programs still outweigh this drawback, improved weaning management could help.
A recently published Danish Institute of Agricultural Sciences study examined weaning by giving calves either a high or low milk allowance and using two different weaning strategies. Calves were given eight litres a day or 4.8 litres a day of milk replacer. Individual calf starter intake was also recorded during the study. Weaning was done gradually from day 52 to day 68.
The researchers weaned half the calves from the high- and low-quantity groups by reducing portion size but keeping the number of portions fed per day the same. Remaining calves in each group got the same portion sizes but fewer portions per day. The table opposite shows the two weaning schemes.
Before weaning, the low-quantity calves visited the milk feeder more often [44.3 versus 26.8 visits per day] than the high-quantity group and spent more time at it [51.1 vs. 41.5 minutes per day].
Calves on low-quantity milk feeding had many more trips to the feeder when they received no milk, likely reflecting their hunger for it. Low-quantity calves spent considerable time sucking the milk feeder with no milk coming out. These calves consumed more calf starter [463 grams versus 243 g per day] than the high-fed group. However, the low-fed calves had a lower average daily gain [657 g versus 737 g per day] than the high-fed group. Their higher calf starter intake did not adequately compensate for the reduced quantity of milk received.
There were few differences between the two weaning strategies used in this study. Calves had a tendency to spend less time at the milk feeder immediately after drinking when the number of milk portions was reduced but the total time spent at the feeder for all visits was the same for both weaning methods.
It's important to note that these researchers used only two weaning approaches. There's not enough evidence to say that these are the best or only ways to wean calves off high milk volumes.
The Danish researchers recommend that you offer calves a higher quantity of milk because the calves are less likely to experience feelings of hunger. They will spend less time at the milk feeder than they will with a lower amount.
More studies will probably be published on weaning calves using various milk feeding systems. Some Ontario experiences have suggested that abrupt weaning may be necessary at times.
Unfortunately, reduced rates of gain are still common immediately after weaning but they should not be excessively depressed from pre-weaning rates or last long. Monitor calf starter intake and rate of gain before and after weaning. Adjust your weaning program by altering milk portion number or portion quantity if you're not satisfied with the results you get.
Weaning methods and milk quantities [high or low] and minimum number of daily milk portions [litres / number of portions] for large breed calves used in the Danish study.
Jensen, M. B. 2006. Computer-controlled milk feeding for group-housed calves: the effect of milk allowance and weaning type. J. Dairy Sci. 89: 201-206.
This article first appeared in the Ruminations column of The Milk Producer Magazine, May, 2007.
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