Editor's note: The following answer is provided by Al Kertz, dairy field technical service and research, Milk Specialties Global Animal Nutrition.
Q: What about using feed-restriction programs for growing dairy heifers?
A: Limit-feeding of dairy heifers requires management attention and skill to achieve desired results. And, successful limit-feeding will be dependent on achieving a higher level of feeding and heifer management.
Potential benefits to limit-feeding are to reduce feed costs, reduce nutrient excretion and reduce feedstuffs needed. In various research trials, limit-feeding of heifers has produced targeted average daily gain if dietary protein and energy concentrations have been adjusted to provide the same amount of protein and energy as for free-choice fed heifers. It has also resulted in similar first-lactation milk yields as free-choice fed heifers, decreased manure excretion, increased efficiency of nitrogen utilization, and has been shown to work if adequate bunk space is provided for all heifers to eat at the same time. This is especially critical for heifers lower on the social order.
There are some limitations to implementing a limit-feeding strategy, such as realizing that heifers will vocalize to a minor extent for about one week. Adequate bunk space must be available for all heifers to eat at the same time, or the more timid heifers may be limited in their intake. Lack of adequate bunk space could result in uneven or lower rates of gain with heifers. Consumption of edible bedding can also confound dry mater intake and average daily gain.
Limit-feeding heifers can have advantages in decreasing manure output, reducing feed usage, and increasing feed efficiency.
Mason-Dixon Farms in Gettysburg, Pa., began utilizing limit-feeding of high-energy diets for their heifers in July 2006. Heifers started the limit-feeding program at about four months of age and weighing about 275 to 300 pounds. Primary benefits realized were lower feed costs and less manure.
There were five groupings of heifers, each with their own ration. Their diets had been developed by trial-and-error by the nutritionist and the calf/heifer manager. The nutritionist indicated the need for published credible data showing the absolute amount of metabolizable energy and metabolizable protein for limit-fed heifers, and for a software program to optimize diets.
In addition, the following observations were made about the limit-fed program for heifers:
- Reduction in feed cost due to improved conversion efficiencies.
- Adequate bunk space is required for all stock to eat at one time.
- Bawling is common in the barn when people or feed equipment are nearby.
- Boredom is a concern with an empty bunk for as much as 16 hours a day.
- More tongue-lolling and pen-mate sucking.
- Feed delivery is easy since no one needs to make a bunk call — just feed to the head count.
But this past January, Mason-Dixon Farms discontinued this program for three reasons:
- Cost per head per day ceased to be advantageous because they had plenty of forages on hand.
- Grain prices were higher than in 2006.
- It was cheaper to go back to a traditional ration, which cost less out-of-pocket.
Furthermore, the nutritionist was not comfortable with balancing the ration to meet heifer needs without adequate limit-feeding software to accurately predict performance, especially against metabolizable energy and protein input requirements.
Therefore, this program can be beneficial with a given set of factors, but then not as beneficial at other times or as factors change.