Vacas crecimiento

Growth
COLLEGE OF AGRICULTURAL SCIENCES

Monitoring Dairy Heifer

Growth
INTRODUCTION
these breeding and calving age guidelines. also are prone to more problems at calving. adequate level of protein before breeding.

Monitoring Dairy Heifer

Raising dairy heifers to an adequate size and with an age at first calving between 22 and 24 months can optimize profitable milk production.This achievable goal requires proper nutrition and feeding management so heifers are large enough to breed at 13 to 15 months old. Both contract heifer growers and dairy producers who raise their own replacements should follow

On many dairy farms, heifer management is not the most critical part of the day-to-day activities; however, chronic neglect of nutrition, feeding management, andpreventative health care can lead to stunted growth. This results in heifers that calve much later than 24 months of age and that produce considerably less milk during their lifetime than those that are properly fed and well grown. Undersized heifers not only are smaller and less productive, but they

On the other hand, accelerating the growth of heifers until they become fat also reduces their lifetimemilk production and longevity. Overfeeding concentrates or high-quality forages such as corn silage can cause this condition. Published research studies show that excessive energy intake (140 percent of the National Research Council’s recommended amount) before breeding can decrease the rate of development of the secretory tissue in the cow’s mammary gland and thereby reduce the number of alveolarcells available for milk synthesis. Feeding to achieve accelerated growth rates after breeding does not appear to hinder mammary development. Optimal secretory tissue development also can be aided by ensuring that heifers receive an

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MONITORING DAIRY HEIFER GROWTH

MEASURING HEIFERS
The success of a heifer-rearing program can be evaluated by monitoring the height and weight of calves andheifers and comparing the results against breed averages for a specific age group. Although most dairy producers, consultants, feed industry representatives, and veterinarians can recognize underconditioned or overconditioned animals, it is difficult to visually determine whether a heifer’s height or weight is normal for her age. Measuring and weighing heifers allows them to be compared tostandards that can indicate a problem in the heifer program. To estimate a dairy animal’s body weight, use a weight tape, which is accurate to within 5 to 7 percent of the actual body weight. Make certain that the animal is standing with her head upright. Pull the weight tape snug, but not too tight, around the heart girth just behind the front legs and shoulder blades. When measuring the height at thewithers, hold the animal’s head upright on a clean, hard, level surface, and make sure that she is standing comfortably and not pulling against the halter. Measure the animal at the highest point of the withers. Hip height or width can be measured with less concern about the orientation of the animal’s head. Measure body length with the animal straight and with its head held forward and upright.Proper placement of weight tape Heart girth (inches) 65” Withers

Proper placement of measuring stick

Level

25”

Read height here

Close-up of heifer measuring stick

Figure 1. Weight by Month of Age—U.S. Holsteins
Weight 1600 (lb.) 1400

95th Percentile

1200

1000 75th Percentile

800

600 5th Percentile 25th Percentile 400 Median 200

0 0 2 4 6 8 10 12 14 AGE INMONTHS 16 18 20 22 24

MONITORING DAIRY HEIFER GROWTH

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Figure 2. Height by Month of Age—U.S. Holsteins
Height (in.) 60 95th Percentile 55 75th Percentile 50

GROWTH CHARTS
Figures 1 through 7 (beginning on page 2) depict the results of measuring a large number of heifers of various breeds throughout the United States. The Holstein population was part of a nationwide USDA study...