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Accelerated heifer feeding, lactation on grazing dairy farms

Scott E. Poock and Stacey Hamilton Published on 24 November 2015
calves feeding

The interest in accelerated heifer-feeding programs, specifically pre-weaning, has garnered much attention during the past 10 to 15 years.

There have been a number of research projects analyzing these intensified feeding programs utilizing high-protein milk replacers or milk (pasteurized) versus the traditional milk replacers (20 percent protein/20 percent fat).

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The traditional milk replacers have been fed at 8 to 10 ounces of dry matter (DM) twice a day mixed in 2 quarts of water. This level of milk replacer does not meet the calf’s needs for growth (and at cold temperatures does not meet maintenance); therefore, the calf has to begin to eat calf starter sooner.

On the other hand, the accelerated programs increase milk replacer (protein 26 to 28 percent, fat 15 to 20 percent) DM and decrease calf starter intake, which has yielded more lean growth during the pre-weaning period.

Studies of increased levels of protein and DM with intensified programs have reported an increase in several parameters in Holstein cattle on conventional dairy farms. Many studies in the last 15 years have clearly shown the advantage of increased growth among heifers on an intensified milk/milk replacer program.

This has been accomplished by supplying the necessary energy and protein above maintenance requirements. Actual protein needs for maintenance are low but rapidly increase for growth. At 26 to 28 percent protein, the accelerated products are comparable to that found in whole milk.

In addition, several studies have seen decreased days to conception among the heifers on the accelerated programs. Subsequently, there is a decreased age at first calving. The range in the decrease is 14 to 27.5 days younger at calving. There is an economical benefit of $31 to $62 per heifer by getting them into lactation sooner.

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Another area that has been addressed is the health of the calf. Some papers have shown slight increases in the immune cells’ responses to infection or stimuli, while others have seen decreased sickness and death.

One particular study from Minnesota saw an 18 percentage point decrease in deaths for intensified milk-feeding heifers (pasteurized milk) versus traditional (2.8 percent versus 21 percent, respectively).

Another study from Cornell University inoculated calves with cryptosporidia. The Holstein steers that were fed an accelerated milk replacer had fewer days of diarrhea, less dehydration, greater growth and better feed efficiency than traditionally fed calves.

Finally, the peer-reviewed literature has shown an increase in production for those heifers fed an intensified feeding program. More than half of the studies have shown a statistical or trend in the difference in production. This difference is the primary economic benefit to the accelerated feeding programs.

Given the data from Holstein heifers from conventional dairy farms, we decided to see if similar or proportional differences would be seen with pasture-based heifers.

Two groups of heifers at the University of Missouri’s Southwest Center Dairy Farm were fed either an accelerated milk replacer (28.5/15) or a traditional milk replacer (20/20). The calves were born February or early March of 2012 and 2013.

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Heifers were high-percentage Holsteins or Jerseys, along with crossbreds (Holstein x Jersey). The calves were raised in groups of eight heifers on 10 nipple mob feeders. Heifers receiving the traditional milk replacer were fed 7.5 ounces in 1.5 quarts the first week (per feeding) and then 10 ounces in 2 quarts through 8 weeks old, when they were weaned.

The accelerated group was fed 7.5 ounces in 1.5 quarts the first week (per feeding), 12.5 ounces in 2.5 quarts the second week, 15 ounces in three quarts for weeks three through five, and then 10 ounces in 2 quarts for week six.

At weaning, the heifers in both groups had to be consuming more than 2 pounds of grain per head per day. This was not a problem for either group, as all were consuming grain as they should. The heifers on the accelerated program were weaned at 6 weeks old, and the traditional program were weaned at 8 weeks old.

Before describing the results, it should be noted that there were a total of 32 heifers on the traditional milk replacer and 43 on the accelerated. The difference was due to the fact the heifers were raised in groups and required a full pen before starting the next group.

Heifers were monitored for bodyweight gain weekly during the pre-weaning phase and then monthly until yearlings. Likewise, health, reproductive efficiency, and first lactation milk response were tracked.

First, the heifers on the accelerated feeding program gained more weight during the pre-weaning period. This was true for both years of the study. In the first year, the heifers maintained the advantage through breeding.

This did not follow through with the heifers in the second year, as the traditional heifers “caught up” or experienced compensatory growth in relation to the accelerated group. Also, there was no difference between groups at freshening in regard to bodyweight.

Second, we saw no difference in disease incidence or deaths. None of the calves in either group had to be treated, nor did any die. The system on the dairy, as well as many pasture-based seasonal farms, is an all-in-all-out system, which is used for roughly three months and then empty until the next calving season.

Historically, at the Southwest Center’s dairy, there had been little disease or death among calves when the dairy personnel cared for them.

Third, we did see an increased conception rate to first service among the accelerated group. The accelerated group had a 74 percent pregnancy rate to first service for both years, while the traditional were 66 percent.

Subsequently, fewer of the accelerated heifers were culled for not getting pregnant in the proper breeding period. Likewise, for heifers in the first year, more of them were pregnant at first service during the first lactation as well.

Finally, when we looked at milk production of the first lactation, the accelerated group produced approximately 500 pounds more milk (P=0.12). This difference was made more apparent once we adjusted for parental averages.

The adjustment for parental averages was utilized to account for the different breeds and crossbreds in the herd. Results of the first-year lactation for heifers born in 2013 are pending.

Like the Holstein heifers in confinement dairy farms, we saw an increase in growth during the pre-weaning phase. This growth advantage was maintained until breeding for the first group of heifers – but not the second year’s group. There was a trend for better reproduction at breeding as yearlings.

Likewise, more of the heifers from the accelerated group subsequently conceived to the first service during their first lactation. Finally, with adjustments for parents, an increase in milk production was seen. However, these parameters should be studied with larger numbers of heifers to enhance statistical analysis.  PD

Stacey Hamilton, Ph.D., is with the University of Missouri – Columbia.

PHOTO: Studies of increased levels of protein and DM with intensified programs have reported an increase in several parameters in Holstein cattle on conventional dairy farms. Photo provided by Scott E. Poock.

Scott E. Poock
  • Scott E. Poock

  • Associate Extension Professor
  • University of Missouri Veterinary Extension
  • Email Scott E. Poock

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