Extension Education: Consider Cow Requirements in Planning for Winter
As many ranches are purchasing and storing hay for this winter, an important consideration is how much feed to buy.
Total winter forage needed depends on the quality of the hay, as well as several other factors discussed below. In all situations, providing adequate nutrition is critical. From pre-calving through breeding, the cow’s nutrient requirements – especially energy and protein – are at their highest, while cold weather and wind only add to their energy demand. Maintaining cattle in good nutrition through calving is critical for good breeding success in the spring.
The following factors describe the elements that have a definite impact on the cows’ overall requirements.
Cow size or weight
As hay and grain prices remain high, range-based operations will continue to look for ways of reducing ranch feed expenses. One of the first items that many operations consider is actual cow size.
As Table One describes, cow requirements, in total digestible nutrients (TDN), obviously increase as cow weight increases. While the cow’s total feed requirement can be reduced by decreasing frame size and mature weight, there are also potential sacrifices in feedlot average daily gain and final carcass weight for those who retain ownership.
Stage of production
As Table One illustrates, cow requirements change dramatically depending on what stage of production the cow is in. Energy requirements, increase by approximately 30 percent as cows transition into late gestation and then by an additional 30 to 35 percent during early lactation.
Although there are many factors to consider, many range-based operations have either studied or adopted a later calving season to better match their cow’s requirements with the quality and availability of forage that naturally occur in late spring. Regardless of operation or calving season, recognizing and adjusting the nutrition program to match requirements during calving is critical.
Age and weather
An often overlooked factor that can dramatically affect feed requirements is age.
Younger cows, especially first calf heifers, are continuing to grow and mature while competing for feed with mature cows and producing their first calf.
Producer surveys and case studies suggest that this group of younger cows have poorer, or lower, body condition and are more difficult to get re-bred. Adjusting management by managing the younger cows separately, or with older, thinner cows, will help to keep these genetics in the herd.
Weather also has effects on cow requirements.
This winter especially has reminded all of us what a tremendous impact weather can have on the cow’s ability to maintain her weight. As wind chill – a combination of wind speed and temperature – drops below 20 degrees Fahrenheit, the cow must expend additional energy to maintain her own body temperature.
For each degree drop below 20 degrees wind chill, the cow’s energy requirement increases by one percent. Therefore, a negative 10 degree wind chill means an unprotected cow will require 130 percent of her normal requirement to maintain weight.
Body condition and
Maintaining adequate fat cover going into the fall is an important management consideration for the herd. Thin cows, because of reduced fat cover and lack of insulation, require an additional one pound of hay just to maintain weight.
Similar to size, as milk production increases, the cow’s energy requirements also increase.
Table Two suggests that as milk production increases from 10 to 20 pounds, energy requirements during early lactation increase by 30 percent.
It is important to keep in mind that selecting for lower milk production ultimately reduces the mother cow’s energy and feed requirement, but it also will negatively affect fall weaning weights of the calves and therefore potential income.
Other factors that can impact energy requirements include: internal parasite load, which affects the ability of the cow to absorb and utilize nutrients in feed and forage; conditions of the feeding area, as deep muddy lots can impact the cow’s performance; and method of feeding, which determines the amount of hay waste.
Recognizing changes and factors affecting nutrient requirements, while also analyzing and balancing rations to match feed requirements, can have a dramatic impact on efficiently utilizing feed resources and reducing feed costs while maintaining adequate cow nutrition.