A balanced feeding program is designed to meet the nutritional requirement of the animal. Size of animal, stage of production, environmental conditions, health status and body condition; all impact the requirements. The first two nutrients of concern when balancing rations are protein and energy. The following table has recommendations for energy (TDN) and protein for mature cows on a dry basis.*
Animal | % TDN | % Protein |
Cows Mid Pregnancy | 55 | 7 |
Cows Late Pregnancy | 60 | 9 |
Cows Lactating | 65 | 11 |
* Alberta Agriculture Fact Sheet AgDex 420/52-4
With tight feed supplies, adding straw, slough hay, or forage seed aftermath to pregnant cow rations extends the higher quality forage supply and reduces cost. The cow’s nutrient requirements need to be met to prevent various problems.
Straw is included as a filler when feeding a high quality forage to pregnant cows. Using feed test results to develop a balanced ration, the inclusion rates the two feeds is calculated. After the protein and energy requirements are met, attention must be paid to macro and trace minerals along with vitamins A, D, and E.
As forages mature, fibre content increases. There are two types of fibre that are used when balancing a ration. Acid Detergent Fibre (ADF) is used to determine the energy content in forages, and Neutral Detergent Fibre (NDF) is an indirect measure of how much feed an animal is able to consume daily. NDF content in higher quality forages is approximately 45 to 50%, and is between 65 to 75% for cereal straws and can be higher for other types of straw.
NDF is the most difficult component for the rumen microflora to digest. When total NDF content in a ration exceeds 60% or NDF intake exceeds 1.2% of animal body weight on a dry matter basis; feed intake is reduced. Animals will appear to be very full when the ration is at or exceeds NDF limits. Daily feed intake can be reduced by 3 to 5 pounds or more. This reduces the amount of nutrients consumed on a daily basis.
Inclusion rates of each feed must meet energy and protein requirements, but also not exceed the upper limits for NDF intake.
For more information about feeding low quality forages to cows, contact Barry at 403-741-6032 or bjyaremcio@gmail.com