## Bulletin #1078, Calculating the Average Daily Gain of a Dairy Calf or Heifer

By Glenda Pereira, Ph.D., Assistant Professor, and Extension Dairy Specialist, University of Maine Cooperative Extension and Brad Heins, Ph.D., Associate Professor, and Dairy Specialist, University of Minnesota.

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### Introduction

Do you know how your calves are performing? This factsheet is designed to help you calculate the average daily weight gain of dairy calves and heifers. The saying “You can’t manage it if you can’t measure it” is certainly true when we talk about average daily gain (ADG). Keeping a record of birth and weaning weights can be helpful to determine opportunities in calf management and health. In addition, you can use this measure when calculating how much dewormer or medication to give to your animals. Dairy farmers that regularly record calf weights at birth, weaning, and four and five months of age have a better understanding of how to properly manage their female calves, which later become part of the milking string. In fact, ADG can determine lifetime performance as research indicates that Holstein heifers growing at 1.7 pounds per day may produce on average up to 2,276 pounds of milk and up to 90 pounds of fat plus protein during the first 250 days of lactation, compared with a heifer that grows at 1.1 pounds per day (Chuck et al., 2018).

There are many factors that can influence ADG such as environment, nutrition, milk pasteurization, disease events, dam lactation number and single versus twin births. Therefore, the ADG value will depend on your dairy operation. If you do not know what your current ADG is, you can measure weights during the pre-weaning period and establish a goal for your dairy operation.

### How To Measure Average Daily Gain (ADG)

While weighing every single calf is encouraged, this may not be realistic. Select 5 to 10 calves that are representative of your operation. These calves will be the ones you weigh each time hereafter to establish your ADG. Make sure to weigh the calves at the same time point of the day relative to feeding as a gut fill can impact the animal’s weight. You can download an Excel Spreadsheet from Penn State University to track your heifer growth, or you can create a table on a notepad and fill in the weights as you go along; see the example below.

Some farms use calf scales, some of which are equipped to download the weight data automatically into your management software and can be purchased for around \$3,000. Another, less expensive option may be a weight tape which can be purchased for around \$6.00. The weight tape predicts birth weight from heart girth measurements based on an equation developed and provides a more accurate estimate than visual observation. A video with instructions on using a weigh tape can be viewed online.

The most popular weight tape is one made for Holstein calves based on research on Holstein calf growth conducted at Penn State University. The study was based on six University research herds. This weight tape can be used on newborn calves up to about 12 weeks old, or up to 282 pounds. While some may question the validity of the weight tape, a recent study measured the hearth girth of 429 Holstein heifers and found a very strong association (correlation of 0.98) between actual bodyweight and heart girth predicted bodyweight (Heinrich et al., 2016).

### Compare your ADG to the Dairy Calf and Heifer Association Recommendations

The Dairy Calf and Heifer Association recommends that calves should double their birth weight by the time they are weaned if the calf gains 1.2 to 1.8 pounds per day. Keep a record of the calves that are underweight at weaning. Post-weaning, if adequate energy and protein for maintenance and growth are provided, the heifers should be growing at 1.7 to 2.0 pounds per day. Based on the ADG and the recommendation for heifers to reach 55% of mature weight before they are bred, Holstein heifers should weigh 825 pounds at breeding age based on the mature birth weight of 1,500 pounds.

While less data exists for Jersey animals, most Jersey calves weigh 60 lbs at birth and if the calf gains 1.1 to 1.3 lbs per day at the weaning time of eight weeks the weaning weight should be between 122 to 133 lbs. Jerseys should weigh around 550 lbs at breeding age based on the mature birth weight of 1,000 lbs. With the previous calculations, post-weaning, Jerseys should be growing at 1.5 to 1.7 lbs per day.

### Conclusion

Implementing a scale, weigh tape or another method to measure weight can help improve your calf and heifer programs, which impact lifetime performance. Additionally, monitoring calf growth is an excellent way to evaluate calf management and health and can lead to improvements in your current protocols. Be sure to work with your veterinarian and nutritionist to establish your benchmarks and goals.

### Sources

• Heinrichs A.J., B.S. Heinrichs, C.M. Jones, P.S. Erickson, K.F. Kalscheur, T.D. Nennich, B.J. Heins and F.C. Cardoso. 2017. Short communication: Verifying Holstein heifer heart girth to body weight prediction equations. J. Dairy Sci., 100 pp. 8451-8454. https://doi.org/10.3168/jds.2016-12496
• Heinrichs A.J., and C.M. Jones. Growth Charts for Dairy Heifers. 2017. Accessed May 16, 2022. https://extension.psu.edu/growth-charts-for-dairy-heifers
• Chuck G.M., P.D. Mansell, M.A. Stevenson, and M.M. Izzo. 2018. Early-life events associated with first-lactation performance in pasture-based dairy herds J. Dairy Sci., 101, pp. 3488-3500. https://doi.org/10.3168/jds.2017-12626

Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.