Monitor heifer weight
Weighing heifers is a relatively simple means to monitor animal performance, and this practice is a must for precision-feeding dairy heifers successfully. With a precision-feeding system, heifers must be weighed to allow one to know what amount of feeding is required, while maintaining the growth rates needed for breeding at a given age or for calving at a given BW. Scales or weight tapes can be used for heifers with equal success.
- Weigh heifers at the same time of day (relative to feeding); otherwise, alterations in gut fill can impact average daily gain (ADG) calculations.
- Weighing heifers once per month is best, but once the system is stable, less frequent weighing can work as long as body condition is observed regularly.
- It is best to weigh all heifers; however, on some farms, it may not be realistic, as heifer numbers may be labor prohibitive. In this case, weighing a representative group (10% to 25%) of the heifers in a pen each time will suffice. It is important to be sure that this group is representative of the entire group.
- Monitor individual heifer and group gains against benchmark weights, and alter management, specifically feed intake strategies, as needed.
In any group-housed heifer facility, minimizing variation in size and age of heifers in each group is important, and it remains important in managing a precision-feeding system. Typically, beyond 4 months of age, heifers should be housed with other heifers as close to the same age as possible and always in groups with less than 200 pounds (90 kg) of BW variation within the group. Often, this means having groups with 2 to 4 months of age variation at the most. Post-breeding, this number can be increased to 300 pounds (136 kg) of BW spread between animals within a group.
In precision-feeding systems, heifers will need adequate bunk space, often 14 to 24 inches of feed bunk space per heifer as they progress from 4 months of age to pre-calving or 22 months of age. Precision-fed heifers will not have access to feed available at all times of day; thus, all heifers in a pen must have access to the feed bunk at the same time. Overly aggressive and timid heifers are very susceptible to over- or under-nutrition when feed bunk space is limited. If precision-fed heifers on a high-forage diet have feed available 12 to 16 hours/day, feed bunk space is often not an issue. If heifers are fed 30% to 40% concentrate diets and feed access is limited to 6 to 8 hours/day, feed bunk space can become an issue. Use common sense to see if all heifers are satisfied and are growing uniformly when using these feeding systems.