A pregnant cow’s feeding needs will vary depending on the size of the fetus. A large fetus may make it impossible for the cow to consume low-quality forages and readily digestible supplemental feeds. Therefore, it is imperative to create a feeding plan based on her nutritional needs.
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Energy requirements
The net energy requirement for pregnant cows is the total energy retained by the gravid uterus and mammary gland during pregnancy. It is calculated by calculating the weight of a Holstein x Gyr calf and dividing that figure by the uterine dry weight. The fetus accounts for about 80% of the uterine dry weight. In addition, the NRC model uses a linear regression equation to estimate the calf body weight.
Net energy requirements are calculated using the NRC’s (2001) equation. During pregnancy, cows retain energy that was previously in the udder and gravid uterus. The ratio between net energy requirements and calf body weight (kg) is also calculated. The net energy requirement for pregnant cows is approximately 75% higher than that of the nonpregnant animal.
Protein requirements
Protein requirements in cows are particularly high during lactation and pregnancy. The female body is especially susceptible to the effects of dry season, and it is crucial to supply adequate amounts of protein to support healthy follicle development on the ovaries. This is especially true for early and late pregnancy, when the energy requirements are high.
While the protein requirements in cows depend on age, breed, and region, the amount of protein required by pregnant cows rises significantly later in gestation. During the last two months of pregnancy, the fetus grows rapidly, placing a large demand on the maternal protein supply. This enables the production of high-quality colostrum, which is vital for lactating and nursing cows.
Energy balance
The energy balance of pregnant cows is different than that of other animals, so it is important to understand how to feed them appropriately. During this time, the cows need more energy than they are consuming. This is referred to as the transition period. The first part of this period is very important for cows since this is when the milk production peaks. It is also during this time when the cows tend to lose weight.
Energy balance is critical for pregnant cows, as it determines the reproductive performance of the animal. In addition to the energy requirements, the reproductive performance of the cow is affected by her current and past energy status. In many cases, cows with lower BCS at first breeding tend to have less success at conceiving. Furthermore, diet changes during the early lactation period are not enough to compensate for the loss of BCS. It is therefore vital to control BCS at calving to ensure a healthy calf.
Mineral requirements
Mineral requirements for pregnant cows vary from individual to individual and depend on a number of factors including age, weight and expected performance. Mineral deficiencies can result in decreased performance, decreased disease resistance and even reproductive failure. This can lead to significant economic losses. Mineral deficiencies may be caused by inadequate mineral content in feeds or poor biological availability of minerals. Other substances in feeds can also interfere with mineral absorption.
Maternal nutrient status is particularly important during pregnancy and lactation because the fetus depends on the dam for all essential nutrients. Minerals, particularly trace minerals, are essential for developmental processes in the fetus. Improving maternal nutrient status during these critical periods can significantly impact the development and health of the offspring. Therefore, nutritional strategies for pregnant cows should be tailored to the critical stages of development.
Vitamin requirements
A pregnant cow’s body needs the appropriate balance of vitamins to support its growing baby. She can store about four months’ worth of Vitamin A in her liver, but lack of green forage can deplete this supply. Vitamin A can be supplemented through injections. A single injection two weeks before calving can help a cow overcome a drop in her body reserves around calving. However, this method of supplementation is not recommended for non-deficient cows. Additionally, late-gestation cows may experience adverse reactions to vitamin injections, especially if they are also receiving vaccines.
The vitamin A content of mineral supplements can be calculated by considering 200,000 IU per pound. Assuming a pregnant cow weighs 1,300 pounds, she would get about 25,000 IU of vitamin A per day. But this amount is insufficient for her to meet her nutritional requirements. The recommended dose is 2 ounces of this mineral per head per day.