Replacement Heifers: Tough Decisions and Great Opportunity

Published on Fri, 08/10/2018 - 3:26pm

 Replacement Heifers: Tough Decisions and Great Opportunity

 By Jaclyn Krymowski for American Dairymen Magazine

  Some dairymen make the case that heifers are the most important animals on the farm. There’s some truth to this. It’s important to remember a heifer’s value isn’t based solely on her personal genetics and youth. Rather, emphasis should also be on her as a replacement in the dairy life cycle. Hopefully she is an improvement to her foremothers.

When replacements are at an adequate level, the herd average can be kept on the younger side. A younger herd compared an older one is beneficial for production and quality. The more available replacements can allow for more intense culling pressures on older animals.
Herds in the habit of culling cows with fewer lactations chip away opportunities to generate more replacements. Statistically, if you’re culling at a 40% rate based on a retention of only 2.5 average lactations, your cows are spending as much time in the herd as it took to raise them to get there in the first place.

What turns heifers into optimal cows
The goals of heifer raising are very simple. They are to make sure replacement animals enter the herd when they’re at the optimal weight, stature and age which will contribute to their best production and fertility.

Consider that puberty is based on an animals’ size more so than age. In most heifers, puberty begins when a female is at 50-55% of her mature weight. This means they will usually be about 85% of their mature weight at the time of first calving. Research has shown that heifers of better size, growth, and condition outperform their herdmates. One Australian study found that heavier heifers at 12 months old were more likely to be cycling than their lighter weight counterparts. For example, only 30% of heifers were cycling at 440lbs. comparted to 65% of heifers cycling when they reached 570lbs. Likewise, heavier heifers also had higher conception rates.

Heifers who with an advantage in weight also have a longer-term gain. Research in Tasmania showed that a heifer weighing around 100lbs. more than her contemporaries produced and additional 2,000lbs. of milk, 84lbs. of fat, and 93lbs. of protein over her first three lactations. These heifers are also more likely to be long lasting as milkers.

Adequate nutrition is an important contributor to heifer growth. One benefit of feeding heifers is these animals are much less prone to over conditioning because they put their energy into growth. Excessive fatness in heifers is unlikely unless they won’t calve until they’re over two years old.

Is it worth every heifer?
As much as can be said on the benefits of proper replacement management and turnover, in some circumstances even the best heifer management program isn’t profitable for every heifer that will be born on your farm. Remember, the cost of raising youngstock is often one of the largest expenses on a dairy operation.

The economic, financial and opportunity costs of either raising on farm or through a contract raiser will fluctuate from year to year. The market for heifers, calves and springers are also very influential factors for many. Several state extension services provide helpful worksheets which aid with the bookwork and number crunching.

With all the benefits of replacement animals, it is very typical for most farms to naturally retain every heifer that’s born. However, some discussion is suggesting this may not always be the best strategy. In terms of practical cost savings, selling the bottom 10-15% of heifers born equates to saving the thousands of dollars it would take to otherwise raise them. This is also a track to accelerate your genetic improvement.

Optimal percentage of what heifers to keep is the percentage of calves that minimizes the average net cost of rearing. One study used a retention of 73% of a herd’s heifers for a year. The total net cost ended up being 6.5% lower than when all animals were kept. Of course, the decision of how many replacements are necessary shouldn’t be made solely on the cost. For example, it may be economically feasible to raise a certain number of replacements, but they may put a strain on other resources such as feed, facilities or labor. Other considerations can include the herd size in relation to its stability, reduction or expansion, the cull rate, and the anticipated death loss.

Note that what qualifies the top or bottom percentages of your replacements will vary based on your breeding strategy. For some operations this may be based on genomic testing and for others it could be on type, pedigree or production. It’s important to recall your breeding goals and set distinct benchmark values in your heifer program so the bottom can be culled without hesitation.