Extension Notes
Susan Fox
Lyon County Extension Agent
for Agriculture/Natural Resources
November 21, 2007
According to Roy Burris, University of Kentucky Beef Extension Specialist, the current feed shortage has stimulated a lot of "panic buying" of low quality feeds and producers are baling anything that will roll up. Dr. Burris says producers have to ask the question "what is your goal for this winter?" Some people would say "just keep ‘em alive until spring". In that case, you might be okay. But, if the goal is to maintain a productive herd, some feedstuffs which are very low in their nutrient content will be a problem. If we don’t address this problem, Kentucky beef producers will see the effects of the ’07 drought on their 2008 and 2009 calf crops.
There are at least three areas of concern for this coming winter/spring. They are: (1) very low protein levels prior to calving can cause weak calves, (2) low energy levels and poor body condition can cause cows to produce low quality colostrum milk that is much lower in maternal antibodies causing lower calf survival rates, and (3) poor body condition of the cows in the spring will dramatically decrease pregnancy rates.
These problems can be anticipated with extended feeding of corn stalks, CRP residue and soybean stubble. These "feeds" are generally lower than 5% crude protein and 50% TDN. Intake by cows will also be much lower than for good quality hay. In a demonstration at Princeton, cows which were offered 28 lb of baled corn stalks daily actually consumed about 18 lb and refused (wasted) 10 lb of the stalks.
According to NRC requirements, an 1100 lb cow at mid to late gestation would require approximately 1.5 pounds of crude protein (CP) and 11 pounds of energy (TDN) per day.
After calving, however, there is a dramatic increase in nutritional needs of the postpartum cow during the first 60 days of lactation. About 18 lb of stalks, for example, will provide only 0.9 lb CP and 9 lb of TDN compared to the required 2.9 and 15.9 lb of CP and TDN, respectively.
That leaves a lot of protein (2 pounds) and energy (6 pounds) which must come from other sources. This difference can’t be met by simply providing a pound or so of a protein supplement. Cows will lose weight/condition rapidly without a great deal of supplementation after calving. We simply must meet their energy and protein needs at this time.
In Dr. Burris’ opinion, the best approach is to limit feed good quality hay and provide the needed supplementation. Low quality feedstuffs can also be limit-fed successfully but are worth considerably less than good hay and require a lot of supplementation. On a "per nutrient basis" commercial feeds are also a better buy than low quality roughage at current prices.
If we don’t feed the cows adequately this winter, we can expect increased calving losses in 2008 and decreased pregnancy rates in the spring which will impact the 2009 calf crop. A body condition score (BCS) cow of 3 will have a pregnancy rate of 51%. At a BCS of 5 the pregnancy rate goes up to 92%.
When cows are permitted to lose weight or if thin cows don’t regain weight before calving, low pregnancy rates will result. Body condition scores of 3 may not be uncommon on many Kentucky farms. Thus, pregnancy rates of about 50% can be expected unless we (1) purchase more nutritionally dense feeds than the nontraditional feedstuffs like corn stalks, (2) have good quality hay available, or (3) feed limited amounts of roughage with adequate energy and protein supplementation. It’s really a matter of "pay now or pay (more) later".
General Management for November
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