There is probably no management tool that impacts more aspects of heifer rearing than monitoring the weight of heifers. Weighing and monitoring heifers frequently is especially critical for precision-feeding systems.
Critical times to weigh heifers would include after weaning, before breeding, at breeding, at pregnancy confirmation, and prior to calving. Average daily gains should be calculated and body condition scores also should be monitored. Based on research, ADG of Holstein heifers should be 1.75 to 2.00 pounds per day.
Weighing heifers is a relatively simple means to monitor animal performance, and this practice is a must for precision feeding dairy heifers successfully. Weighing heifers is increasingly important when precision feeding dairy heifers since an inappropriate level of diet restriction can lead to rapid gains and fat heifers or gains lower than desired. Electronic scales can be placed in alleys or some other easy-to-handle location to make heifer weighing less of a chore. Basically any time a heifer is handled, she should be weighed. With a precision-feeding system heifers must be weighed to allow you 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 body weight.
A few recommendations for effectively weighing heifers:
- Weigh heifers at the same time of day (relative to feeding). Otherwise alterations in gut fill can impact ADG calculations.
- Weighing heifers once per month is best, but once your system is stable, less-frequent weights can work as long as you at least observe body condition.
- 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 of heifers in a pen each time will suffice. It is important to be sure that this group is representative of the entire group and that the same heifers are weighed each time.
- Monitor individual-heifer and group gains against benchmark weights, and alter management – specifically, feed-intake strategies -- as needed.
- If you are in need of a spreadsheet to monitor heifer weights and average daily gains, consider the Penn State growth monitor spreadsheet series.
In any group-housed heifer facility, minimizing variation in size and age of heifers in each group is important, and it remains important in precision-feeding-system management. Typically, beyond 4 months of age, heifers should be housed with other heifers as close to the same age as possible. They always should be in groups with less than 200 pounds of weight 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 of weight spread between animals within a group.
To read more insights from Heinrichs on precision feeding heifers, including nutritional requirements and example rations, follow this link.