Ask the Expert Beef > Why Is Third Trimester Nutrition Important?

Why Is Third Trimester Nutrition Important?

Nov 03, 2021

Tara Jo Ellerman
Countryside Feed Nutrition Specialist

The 3rd trimester is a crucial period of gestation; final development of organs, skeleton, lungs, and immune systems along with over 75% of fetal growth all occur in this last part of gestation. A lack of nutrition in the last three months of pregnancy impacts a calf's ability to reach its genetic potential. This is why nutritionists emphasize the importance of proper nutrition in the third trimester!


Protein is an important nutrient for many bodily functions. They are essential to tissue growth and maintenance, enzyme and hormone production, pH and fluid balance, immune system function, strength and structure of bones, muscles and tendons, along with many other important processes. Needless to say, protein is an essential nutrient to both the cow and developing calf!


Carbohydrates are a cows main source of energy. During the third trimester a cow will use about 30% of the energy she consumes to support rapid fetal growth. In most spring calving herds, that extra energy demand comes at a time of year when both temperatures and energy provided by forages is at their lowest. Supplementing energy will help cows support the growing calf, stay warm, and maintain her own body condition.

Vitamins and Minerals

Vitamins A and E are both extremely important nutrients for immune function and battling cold stress that calves need to take in through colostrum. Green grass is a great source of Vitamins A and E, but winter grass does not offer adequate levels of these vitamins to cows, making mineral supplementation important. Milk is typically low in trace minerals such as zinc, copper, manganese, and selenium, which are also important for immune function. Supplementing the pregnant cow will allow adequate levels of these minerals to build up in the liver for the calf to pull from until it starts consuming feed.

Making sure your cows have access to a quality mineral 90-days before calving will help you have healthier calves hit the ground, improve colostrum quality, and help cows breed back faster!


NRC recommendations for mature cows in their third trimester are 7.9% crude protein, and 54% TDN. In the winter months, forages rarely meet these nutrient requirements, making supplementation essentail to a successful calving season.

Several options are available from our Purina and Beef Builder lines to fill the nutritional gap winter forages leave for pregnant cows. Contact your local Countryside Feed representative to discuss a winter cow supplementation program that fits your operation!


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