Managing cow nutrition and body condition score during late pregnancy
Greg Lardy
January 14, 2008
Feed costs make up a significant portion of the overall cost of operating a cow-calf or seedstock operation. In fact, most data collected in this region indicates that feed costs make up 60 to 70 percent of the total costs you incur (this includes the cost of summer grazing and winter feeding). It’s also important to remember that the feeding program during late pregnancy has important impacts on the future productivity and profitability of the resulting calf crop.
Recent research at a number of institutions is beginning to show that cow nutrition during pregnancy has lasting impacts on the offspring. This concept is known as ‘fetal programming’ or the ‘Barker Hypothesis’ after the scientist who first published papers on the topic.
For most of you, your cows are now well into the third trimester of pregnancy. If you haven’t done so already take time now to evaluate cow condition and determine whether or not the cows are in adequate condition for calving. Cow condition is simply a measure of the overall energy status of the cow.
Ideally, in late winter and spring calving herds, body condition score at calving should be 5 for mature cows and 6 for heifers. This will ensure the cow has adequate body reserves to lactate as well as prepare for the next breeding season. Body condition score at calving also has impacts on colostrums production and calf health.
Intervention strategies to improve body condition
Unfortunately, at this time of year, the only remaining intervention strategy to deal with thin cows is to provide additional nutrients (usually in the form of a supplement). In the fall (August or September) you could also take advantage of early weaning as an additional means of improving body condition score by reducing the cow’s nutrient requirements.
At this time of year, supplementation strategies may take the form of providing better quality forages (more energy and more protein) or providing additional supplement to meet the increasing need for nutrients that the third trimester cow has. Because of the cold weather we typically experience this time of year, there will be many times when you will need to do both (e.g. better forage and supplementation) in order to improve body condition score in the winter.
Be sure to have your forages tested in order to more cost effectively develop your supplementation program and to improve the nutritional status of your cow herd. Balancing rations without having a laboratory analysis of the forages you are feeding will likely either cost you more money (in the form of supplements which may not be needed), not meet the nutritional requirements of your cow herd because you overestimated what nutrients were in the forage, or both. In any case, the results will not be satisfactory.
Nutritional impacts
Subsequent Reproduction. Cow nutrition (as measured by body condition score at calving) affects cow reproduction in the subsequent breeding season. Data collected at Colorado State University in the 1970’s indicates only 66 percent of thin cows (BCS 1-4 at calving) were cycling 90 days after calving. This means that one-third of the cows in the thin category will not have a chance to calve in the first 21days of the subsequent calving season.
Colostrum Production. Thin cows produce colostrum with lower quantities of immunoglobulins. Immunoglobulins are important in calf health because the calf is dependent on immunity from colostrums to protect it from immune challenges during its early life. Calves with inadequate colostrum intake are more likely to become ill as well as more likely to be susceptible to immune challenges later in life.
Subsequent productivity of the calf. Recent research from the University of Nebraska (Martin et al., 2007) indicates that providing the proper protein nutrition for the cow during late gestation can have important impacts on subsequent productivity and reproduction in the heifer offspring born to those cows. In their research, heifers born to protein supplemented dams were heavier at weaning and at the start of the breeding season and had increased pregnancy rates compared to heifers born to cows which did not receive a supplement.
Summary
Managing cow body condition score and ensuring adequate nutrition during the third trimester of pregnancy is one of the most important management decisions you make each year. Cost effectively meeting the nutrient needs of your cow herd will provide dividends in future productivity of the cows and the calves.
Literature Cited: J. L. Martin, K. A. Vonnahme, D. C. Adams, G. P. Lardy, and R. N. Funston. 2007. Effects of dam nutrition on growth and reproductive performance of heifer calves. J. Anim. Sci. 85: 841-847.
Greg Lardy can be reached at gregory.lardy@ndsu.edu