Paul Beck, Oklahoma State University State Extension Beef Cattle Nutrition Specialist
In every drought cycle some producers have an earlier end to the drought than others and some are more severely affected by drought than others. As producers liquidate productive cows due to drought, there is opportunity to ship in cows with high quality genetics that otherwise would be in the prime of their productive life. But often these cows have been held on to for too long by a producer waiting for the “ranch saving rain” that never materialized, with too little grass and little to no hay or feed in reserve. It is hard to turn loose of genetics we have been building and working toward for years, so you can understand the thought process, nevertheless these cows have become much too thin and weak to survive a severe weather event, let alone be productive. However, with the right management, these cows can be a massive benefit in building a cowherd for your future, or a windfall for short term gain if sold when the market correction occurs (it always does).
There are reasons why these cattle are cheap:
Thin cows have less cold tolerance. Cows in good condition can withstand temperatures below 32°F reasonably well, thin cows with thin haircoat may have a lower critical temperature of around 40°F. For every degree below the lower critical temperature energy requirements increase by 1%. A winter storm hitting thin cows with little protection can be a disaster. Dana Zook and I covered feeding cows through cold weather events in the Cow Calf Corner Newsletter from December 19, 2022 refer to https://extension.okstate.edu/programs/beef-extension/cow-calf-corner-the-newsletter-archives/2022/december-19-2022.html for more details.
Thin cows have more problems calving. This is especially true for heifers. It takes a lot of energy to expel a fetus and often new heifers run out of power before the process is even getting going. If we take too dramatic steps to improve the condition of the cow, we can influence the size of the calf. My rule of thumb is over nutrition on a 3rd trimester cow can increase the calf weight by 10%. This is not usually a problem for a mature cow or a well-developed heifer in good condition. A 10-pound heavier calf can be disaster for a 750-pound weak thin heifer.
Thin cows have weaker calves. Calves born from assisted births are usually weaker and take longer to get up and start nursing. Both the cow and the calf are exhausted. This will delay the uptake of colostrum, which has huge effects on health and resilience of the calf. Undernutrition during fetal development limits production of fat in the calf, especially the essential brown adipose tissue needed for quick energy early in life. If calving happens during a cold winter storm the calf may wind up laying in the cold wind and freezing to death.
Thin cows produce less (and weaker) colostrum. As mentioned above colostrum is essential for early passive immunity transfer from the cow to the calf. Maternal antibodies in our research often are still found in the calf for up to 4 months. Calves that get limited or no colostrum shortly after birth are less resilient to disease more likely to succumb to scours or respiratory disease before weaning and have more health issues throughout production.
Glenn Selk explains why colostrum is important for newborn calves. SunUp TV from January 4, 2021. https://www.youtube.com/watch?v=ieiW3htJtEk and the long-term effects of inadequate colostrum from January 9, 2021. https://www.youtube.com/watch?v=Sfni3cB6G0M&t=39s
Mark Johnson, OSU Extension beef cattle breeding specialist, provides management tips for calving during the winter and ways to successfully give colostrum to newborn calves from SunUpTV on January 8, 2022. https://www.youtube.com/watch?v=gvCtLOgrGE4
Thin cows have problems rebreeding. Research at OSU from the 80’s and 90’s has shown us the importance of body condition at calving on post-partum interval and rebreeding success. Cows in BCS 3 have been shown to have 20-day longer post-partum interval and 20% lower pregnancy percentage than cow in BCS 5 (90-days to first breeding vs 60 and 60% pregnancy vs 80%). Cows that needed assistance during calving also have lower rebreeding percentages.
Cows calving in thin body condition have also been shown to have improved pregnancy rates when they are increasing in body condition before breeding. Increasing body condition during lactation is not easy and is expensive because of large increases in protein and energy requirements, but it can be done in the right situations.
Mark Johnson, OSU Extension beef cattle breeding specialist, explains how manage body condition scores in beef calves on SunUpTV’s Cow-Calf Corner from October 3, 2022. https://www.youtube.com/watch?v=9Dcjk-keMzk&t=130s
Savvy operators can manage through these challenges and have successful outcomes with these challenging sets of cows. Having a clean calving pasture with plenty of cover from the weather that is handy to the working facilities is a must. Adding flesh to thin cows post-calving is not easily done using hay and supplement. We have had much greater success putting young pairs on high quality wheat pasture or limit feeding a high concentrate TMR(see Dr. David Lalman’s discussion on a recent Rancher’s Thursday Webinar for more information https://extension.okstate.edu/programs/beef-extension/ranchers-thursday-lunchtime-series/wintering-cows-with-limited-forage.html) to cows than trying to supplement along with even good quality hay.