Feeding calves with self-feeders or computerized auto-feeders has increased in popularity in recent years. These systems can have positive effects for on-farm management, especially around labor, but how are these systems impacting calf performance?
To answer that question, the Provimi North America calf and heifer team conducted several controlled studies. Our goal was to see how calves were performing in these systems. What we found was that gains in labor or management efficiency may be coming at the expense of calf growth and performance.
In the various published studies, including three at our Nurture Research Center, our team found that calves fed using automated systems did not consistently consume milk and milk replacer nor as much as they were offered. Interestingly, we saw intake plateau at approximately 3 weeks old.
The result was that calf growth was less than expected, especially as compared to the nutrients the calves were consuming.
Let’s dig into the data
What was probably most surprising was the variation we found in each individual calf from day to day. Figure 1 shows a summary of intake variation from three trials where nearly 50 calves were fed as much milk replacer as they desired.
As the figure shows, we found a variation among different calves, but intake consistently plateaued at approximately 3 weeks old.
Figure 2 looks more closely at individual calf intakes on each of the first 35 days during one of the trials. The minimum and maximum intakes of individual calves were very far from what we would typically see with bottle- or bucket-fed calves.
In research with computerized auto-feeders, calves allowed to drink up to 24 liters daily only consumed about 60 percent of their daily allotment, and calves allotted up to 12 liters per day daily only consumed about 80 percent of what was available.
Again, intakes plateaued at approximately 3 weeks old. There is no clear explanation in any published literature for why this happens.
The challenge of a self-feeder is: The manager cannot see the variation because there are multiple calves drinking from a single feeder. However, these data are available from most computer feeders and can be reviewed by the calf manager.
Did the calves grow?
An important question for any calf manager is: How are the calves growing? Our study found lower-than-expected growth (Table 1) in calves offered and consuming the largest daily allotment of milk. Table 1 shows data from a trial with limited or unlimited milk replacer availability.
While intake of milk replacer differed from 1.4 to 2.1 pounds over 42 days, hip width and bodyweight gain over 112 days was not different. When calves have been forced to consume a diet that varied by approximately 20 percent from day to day, growth rates were reduced approximately 10 percent compared to calves fed the same average amount of milk replacer consistently.
Additionally, when calves were fed more than approximately 1.5 pounds of solids daily from milk or milk replacer, they experienced poor digestibility of dry feed from approximately three weeks pre-weaning up to two months post-weaning.
Calves fed more than 1.5 pounds of solids from liquids consume less dry feed pre-weaning than calves fed less liquid.
The rapid increase in starter intake post-weaning, combined with poor digestion of starter, leaves more undigested feed in the gut, inflating bodyweight gain estimates. Structural growth, measured as hip width, hip height or withers height, was not influenced by gut-fill with undigested feed residue.
A very digestible diet, such as feeding large amounts of milk replacer or saleable milk, can be very expensive for producers. What we’ve learned from several studies is that feeding more milk replacer or milk may not translate into more growth by the time a calf reaches approximately 4 months old.
As this technology evolves, we will need a better way to manage milk and starter feed intake so that proper rumen development is encouraged. One option to develop the rumen is to reduce the milk fed to approximately 1.5 pounds of solids for the last three weeks prior to complete weaning. This allows for more starter intake, which develops the rumen over the three-week period prior to weaning.
Xavier Suarez-Mena, Ph.D., and Tana Dennis, Ph.D., have calf and heifer technical service responsibilities and are a part of the research team at Provimi.
- Calf and Heifer Technical Services
- Provimi North America
- Email Mark Hill
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