Raising Replacement Heifers
Raising replacement heifers is one of the most significant costs in managing a dairy farm, but it’s also one of the most important investments in the future of your herd. Taking the time and resources to raise new heifers to be healthy from a young age will pay off in happier cows, higher fertility, better milk production, and lower costs in illness and injury. The following guidelines will help you to choose and raise new cows.
Tips for Selecting Replacement Heifers
Each farm has its own ideal for breed characteristics and phenotypes. This individual type will influence which calves will be the best fit for your particular farm. But the following tips will help you choose the best replacement heifers for productivity and longevity.
- Avoid calves from cows with aggression or other behavioural issues
- Choose from heifers that became pregnant early in the breeding season
- Choose calves that were born early; they’ll have a better chance of getting pregnant early
- Look for the highest growth rate from birth to weaning
Start with High-Quality Colostrum
Maintaining optimal nutrition and health between birth and breeding age is essential to making sure your replacement heifers are productive and disease-free in the long term. And calf health starts with colostrum. Ensure that within four hours of birth, each calf is consuming about four quarts of colostrum, either from the mother or through a replacement. This will provide the calf with the antibodies it needs to protect it from disease. You can read more about colostrum in our article on calf management. After about a month, you can begin integrating grain into the feeding schedule.
Monitor Weight Growth
The target weight for replacement heifers will vary based on breed. For heifers at 13 months old, target weights are between about 250 and 330 kg. Look up target weights for your particular breed or cross-breed; weight is a key factor in determining fertility. Monitoring weight regularly will allow you to adjust early using supplements and avoid long-term issues. The first winter is a key transition moment to monitor body weight. If calves are not on track to reach their target weight at the start of winter, you should add supplementation.
The spring after the first winter is when heifers will go through a growth spurt. For heifers turned out in a grass pasture, you can expect to see gains of at least 1 kg a day. If sufficient pasture is not available, you’ll need to add additional concentrates. For heifers on a silage-only diet, you should expect a slower spring gain of about 0.3 kg a day. This means calves will need to be heavier in the winter in order to hit their 13 month target.
Maintain a Healthy Environment
Next to nutrition, a calf’s environment is the largest factor influencing its health. Calves’ immune systems are delicate, and they’re also highly susceptible to stress. You need to make sure they are living in clean, healthy spaces to prevent serious health issues. Each dairy farm has its own calf housing system depending on your resources, layout, and environment. But there are some guidelines that all farms should follow for calf housing:
- House calves indoors for the first three weeks
- Ensure calves have good shelter from the rain
- Make sure there is constant ventilation, whether calves are indoors or outdoors
- Minimize contamination by keeping newborn calves separate and sanitizing hutches between different calves
- Provide straw or other good insulating bedding
Develop a Vaccination Program
A consistent vaccination program is a key to protecting the health of replacement heifers, both as calves and during breeding. Early respiratory diseases can seriously damage future productivity. You want to vaccinate against BRD before weaning. As heifers approach breeding age, your focus can switch to preventing reproductive diseases. You’ll want to work closely with your veterinarian to schedule these vaccines. Evidence suggests that some modified-live vaccines, such as those for IBR and BVD, may temporarily decrease productivity by affecting the ovaries. Therefore, it’s important to schedule these vaccines one to two months before you plan to start breeding. As you likely know, veterinarians can get extremely busy approaching breeding season, so it’s best to plan ahead to ensure you can vaccinate your replacement heifers with plenty of time.