Mr. Dusty Sonnenberg, OSU Extension Educator, Henry County; Dr. Stephen Boyles, Extension Beef Specialist, The Ohio State University; and Dr. Michael Looper, USDA-ARS
The national average cull rate for dairy cows is 35% in the United States. With this in mind, the question is not if a cow should be culled, but rather when. As discussed in a previous article, a variety of factors go into determining when a producer culls a cow. In most years, the average dairy producer will cull 1 out of 3 cows. Often, these are the milk cows with poor feet and legs, udder and teat problems, high somatic cell counts, and chronic mastitis.
This presents an interesting component to discuss when considering an impact on the beef (meat) industry in terms of quality assurance. Withdrawal times and holding milk out of the tank are watched very closely for treated cows in milk. Nonetheless, approximately 3,000 tanker loads of milk are condemned annually in the United States due to drug residues being detected in the milk. That is an average of 8 to 9 tanker loads of milk condemned per day.
When cows with high somatic cell counts and chronic mastitis are culled, often they were being treated. Most likely that drug has both a withholding time for the milk, but also a withdrawal time for the slaughter of that animal. Just like the contaminated milk tankers, while unintentional, if the proper withdrawal time is neglected and the drug residue is detected during an ante mortem or postmortem inspection, that carcass will be condemned. This situation is compounded by the fact that oftentimes the medications are being administered as a dosage based on the weight of the animal. A well-intentioned producer can easily overestimate the weight of an animal being treated and administer too high a dose. In addition, if the cow is sick, the metabolism may be functioning slower than normal, thus the drug may not be processed by the body as quickly as under normal conditions. Yet, another factor to consider is extra label drug use as prescribed by a veterinarian. In an extra label use prescription, the withdrawal period will be extended from what is listed on the medication and must be re-calculated. The end result is that the withdrawal listed often is not sufficient for the cow's system to purge itself, and a drug residue situation will occur.
In a recent study of antibiotic residue rates in dairy cull cows compared to beef cull cows, three times the antibiotic residue rate was found in cull dairy cows. From a beef (meat) industry quality assurance standpoint, feeding cull dairy cows for a given period of time after they are taken out of the milking herd not only can improve body condition score and potentially yield grade, as discussed in the January 2005 issue of Buckeye Dairy News, but also can do a great deal in alleviating potential drug residue concerns in cattle being processed for beef.
In terms of the economics of feeding cull dairy cows, many variables must be calculated in the decision making process. The rate of gain is greatest when feeding cull cows from 28 to 56 days. One reason is during this period they have lower maintenance requirements. Feeding cull cows grain-based diets much longer than 2 months shows a decline in the rate of gain and will thus increase feed cost per pound of gain. The idea is to feed to facilitate cheap gain. There have been some questions asked regarding feeding left-over or waste feed from the previous feeding from the milk herd back to the cull cows. Producers should be cautious if considering practice, as it is not typically recommended due to biosecurity issues.
The most profitable feeding management scheme is affected by the cost of feed inputs. Based on information from feeding cull beef cows, slower gains over the winter may be profitable if the cost of hay is relatively cheap. Expect dry matter intake (DM) of cows fed grain-based diets to be approximately 2.5 to 3% of bodyweight. Normally, there should be 60 to 80% concentrate in a grain-based diet. One can expect 3 lb/day or better of gain if the diet contains 80% grain and compensatory gain is expected.
The protein requirement of cull cows does not appear to be particularly high. Crude protein levels of 9.5 to 11% of dietary DM are probably adequate. Keep in mind that the mineral supplementation program for grain-based diets and roughage-based diets are not the same. Calcium supplementation will be higher than phosphorus supplementation if feeding a high grain ration.
Other livestock costs such as veterinary and medical expenses, farm utilities, power and fuel, and marketing expenses can be around $0.10/lb of gain. Excluding labor, management, and facilities, costs per pound of gain can range from $0.45 to 0.50.
One final point to consider is the overall health of the cull cow being considered. Health and ability to gain weight are extremely variable in cull cows. Not all cull cows are suitable for additional feeding. Dairy producers should evaluate each cull cow on an individual basis.
With an average of 33% of the U.S. beef production consisting of meat from market cull dairy cows, there is an obvious opportunity to increase the overall net farm profits by proper management of this often overlooked segment of the enterprise. With that opportunity, however, comes the responsibility to ensure a safe and quality meat product being supplied to the marketplace.