A few weeks ago I wrote a quick overview outlining the dietary needs of a first-calf heifer during her third trimester and post-partum. This is such an important topic that my colleagues and I felt it was worth revisiting more in-depth. How a first-calf heifer’s nutritional needs are addressed can determine whether she will become a productive member of the herd or end up being culled early on.
Investing in the future
First-calf heifers need to be viewed as a long-term investment. You will put a greater amount of resources towards her care during her first pregnancy with the knowledge that the first calf will be lighter than those of her mature counterparts. The money spent on her upkeep as opposed to that of a mature brood cow will be higher. Despite the initial outlay, if she is supported properly through her first pregnancy and during lactation, her future profitability will increase exponentially. On the other hand, not providing her with the necessary support can affect breed back or even her long-term potential and ability to produce good calves.
Maturation timeline
The typical heifer will reach puberty at around 12 months of age. This means that the majority of first-calf heifers are bred at 12 – 14 months. Many production heifers are less than two years old when they give birth to their first calf. At this point, they are still directing a tremendous amount of their energy into the development of bones and soft tissues. Cows reach maturation at about two years of age but will continue to grow until they are seven years old.
Most cows cannot reliably calve beyond ten years of age, making quick, successful breed back all the more important.
Feeding for two
Because heifers themselves are immature, their dietary requirements are greater to ensure that they continue to grow properly while maintaining the needs of their calves both before birth and during lactation.
A general rule of thumb is to give first-calf heifers 30% more energy than she was receiving prior to calving. When a heifer starts to lactate, she can lose body condition rapidly if energy needs are not being met by her feed and forage intake. Her ability to consume as much as a mature cow is also less, meaning that although her nutritional requirements are only slightly higher, she must be receiving premium-quality feed and forage to bridge that consumption gap.
According to the University of Nebraska – Lincoln, an ideal diet for lactating first-calf heifers consists of a minimum of 62% TDN (total digestible nutrients) and providing 10% – 11% crude protein. This can be achieved by feeding a high-quality forage (it’s a good idea to have your forage tested to establish nutrient content) and, if the nutritional values are not high enough, supplementing with a concentrated feed such as silage, distillers grains, corn, or cubes. Alternatively, cereal grain pasture grazing supplemented with a mineral and protein source is a viable option. Protein tubs are also an excellent option, as they allow the cow to establish her own intake needs and are readily available.
Separating out first-calf heifers and either placing them in their own pen or with older cows/low BCS animals will ensure that they are receiving the extra nutritional support they require.
The role of rumen pH in nutrient absorption
You can feed the highest-quality forage and feed to your cattle, but if they are experiencing an acidic rumen, you may as well be throwing half of that feed away. The rumen’s complex functions depend on a neutral rumen environment to work properly.
All cattle are susceptible to developing SARA (sub-acute ruminal acidosis). First-calf heifers and brood cows, however, may be more susceptible due to fluctuating hormone levels, increasing demands on their vital systems, and the need for additional nutrient intake. Concentrated feeds can contribute to the overall problem, as they are more difficult to digest and, as such, stimulate acid production.
SARA triggers the body to release cortisol, the primary stress hormone. Unfortunately, too much cortisol in circulation can trigger the brain to shut down appetite and suppress the immune system. This can, in turn, increase rumen acid that kills off beneficial microbial populations and damages the villi.
If a pregnant animal is experiencing SARA, she is not able to optimize her feed utilization, due to the compromise of her digestive integrity. This often results in smaller calves at birth. In addition, colostrum quality will be diminished and milk output will also be affected. As she is further depleted, she will lose body condition and may have difficulty breeding back.
Keeping the rumen pH in check is perhaps the most important part of maintaining a healthy first-calf heifer.
Body condition score
You probably don’t have to be told that one of the absolute best tools in your arsenal against poor performance in your stock is body condition score. Free and easy, monitoring the BCS of your first-calf heifers will give you the ability to recognize minor issues before they become big problems.
There are two BCS scales used in North America – one that runs from 1 – 5 and another 1 – 9. For the foremost, a heifer that is sitting at around 3 – 4 is in ideal body condition. On the 1 – 9 scale, they should rate between 5 and 6.
If it’s noted that a cow’s BCS is declining, you have a very small window of opportunity to correct the deficiency before it becomes a major issue. The rate of breed back decreases significantly with just one Noble.org has an outstanding and free printable BCS sheet. A drop of just one point in BCS may lead to as much as a 25% decrease in the chance of successful breed back.
Choosing the right bull for the first-calf heifer
In mature cows, the goal is to birth heavy calves with rapid growth potential. In these cases, choosing a bull that consistently produces larger calves is a sound practice. In the first-calf heifer, however, it can be dangerous to both her and the calf. The likelihood of complications during the birth itself increases. Assuming the calf is born successfully, she may not be able to keep up with the lactation needs placed on her.
Larger calves will not only require more nutritionally in utero – they will also place greater demands on the heifer during lactation. She may not be able to consume adequate amounts in order to produce enough milk. In addition, a calf that feeds on larger meals and grows more rapidly can quickly deplete an immature cow, affecting breed back and overall health.
Using a bull that is known to sire smaller birthweight calves is a wise choice for first-calf heifers. An easier birth and subsequent lactation period will help ensure that she has enough energy to put into her continued growth and maturation.
First-calf heifers are a challenge, but one that you can easily manage and navigate if you use the right tools and approach. Providing her with what she needs now will help to secure her as a productive member of your breeding herd for years to come.
