Calving season is in full swing for many producers. Now that cows/heifers have their calves at side, you might notice some of the cows are on the thin side. A pregnant cow with a full winter hair coat can be difficult to estimate her true body condition. Is it too late to supplement those cows now?

Research has shown that cows in moderate body condition score have the best probability of cycling and conceiving early in the breeding season. The target body condition score is 5 for cows. A body condition score 5 cow would be described as the last two ribs being visible with minimal evidence of fat in the brisket, over the ribs, and around the tail head. The individual spinous processes would not be visible. So, if the cow’s body condition is five or higher, there is no reason to provide additional feed for weight gain. However, you want to provide the required nutrients to maintain them in the desired body condition.

It is normally recommended that young cows (2-year olds) be in a body condition score of 6 at the start of breeding season. You would not see any ribs on a body condition score 6 cow, but would see some fat depositions present over the tail head and in the brisket. 

Thin cows are known to be slow to return to estrus and may not rebreed on time to stay on a 365 d calving interval. Also, it is hard to put weight on cows during lactation, since the additional energy provided in the diet will be first directed to milk production rather than weight gain. One key to improving the cow’s body condition score is making sure that the present ration is providing all of the nutrients required for this stage of production to prevent further declines in body condition scores. Research conducted by Houghton and others at Purdue showed that thin cows that were increasing in body condition had higher pregnancy rate than thin cows that were decreasing in body condition (Table 1).

Is it too late to supplement post calving?

Supplementing cows post calving can be a difficult balancing act between getting weight on the cow versus too much milk for the calf. First, sort off the thin cows so they are not competing with cows in moderate or better conditions for feed. This management will ensure they are getting the planned nutrients. Second, test the feedstuffs to know the actual nutrient content for developing the balanced ration for the desired weight gain. Third, monitor the cows and calves to ensure that you are seeing the desired results. You may not be able to get all of the weight gain onto the cows during this period, but focusing on getting the animal in a positive plane of nutrition will improve the probability of the cow cycling during the breeding season. 

Another consideration before starting to supplement post calving is the amount of time between now and the start of the breeding season. If the cows will be moved to quality grass with enough time for weight gain before breeding, then providing supplemental feed may not be warranted. However, you still want to ensure that the cow’s nutrient requirements are being met until green grass is available so that she will not continue to lose weight.

Source: Julie Walker