Culling strategies for beef cattle operations

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1 Agriculture & Natural Resources TIMELY INFORMATION ANIMAL SCIENCE SERIES May 2017 Culling strategies for beef cattle operations Currently, much of Alabama is either abnormally dry, in a moderate drought, or in a severe drought. As we have had to deal with drought conditions way too often in recent years, longer-term forecasts predict dry to droughty conditions will persist for much of Alabama throughout Hopefully that will not be the case, but if it is, making plans now to deal with potentially limited feed, forage, and water conditions could pay dividends down the road. In an effort to provide adequate supplies of feed, forage, and/or water, some options to consider include: 1) Culling unproductive animals now, thus preserving limited feed and water resources for productive cattle. 2) Begin rationing feed and hay now, in anticipation of greater than normal use over a potentially dry summer. 3) Transporting adequate feed to the farm. 4) If ponds and wells that are normally used for watering cattle are at risk of running dry, consider alternative sources of water. 5) Transporting cattle to a farm with adequate feed and water. All of these options can be costly in terms of financial inputs and potential loss of genetics accrued after years of hard work. Being proactive may at least minimize some of the cost. Many Alabama beef cattle operations have already had to cull heavily in recent years due to dry and droughty conditions, and for some that may no longer be a viable option. If culling is an option, always consider the following: If the animal has been treated with any animal health product, have all applicable drug withdrawal times lapsed? A withdrawal time is the time that must lapse from the last administration of an animal drug until food from that animal is safe for human consumption. FDA-approved withdrawal times can be found on the product label. If the animal is sick or lame, is it healthy and/or sound enough to withstand the challenges associated with transportation and marketing. Livestock auction markets can be a great place to responsibly market cattle, even unproductive cattle, but they are not a place to take cattle that cannot safely withstand the rigors of sale and transportation. Some criteria that will assist with culling decisions includes pregnancy status, body condition score, animal disposition, and the health and/or conformation of eyes, mouth, udders, feet and legs. Production records can provide valuable precise information as well. Each of these is explained in more detail below. Check for pregnancy A beef cow needs to produce a calf every year to be an economically viable member of the herd. An important management tool that will improve the reproductive efficiency of a beef herd and reduce annual cow costs is an annual pregnancy examination for every cow. By determining the pregnancy status of beef cows, producers can remove the reproductively inefficient cows from the herd which results in a combination of increased pounds of calf production per cow and lower costs per pound of calf produced. In a herd with a defined breeding season, the identification and removal of open (non-pregnant) cows and replacement heifers allows more prudent utilization of valuable feed and pasture resources for productive animals. In addition, the culling of open, ALABAMA A&M AND AUBURN UNIVERSITIES, AND TUSKEGEE UNIVERSITY, COUNTY GOVERNING BODIES AND USDA COOPERATING The Alabama Cooperative Extension System offers educational programs, materials, and equal opportunity employment to all people without regard to race, color, national origin, religion, sex, age, veteran status, or disability.

2 subfertile cows and replacement heifers improves overall herd fertility in subsequent years, as well as improving pounds weaned per exposed cow and thus income per cow. Identifying open cows early provides more time for investigation and elimination of fertility problems associated with infectious disease, inadequate nutrition, poor bull fertility, and many other problems before the next breeding season. Pregnancy diagnosis and fetal aging also allows for grouping of cows according to estimated calving dates to more effectively meet the management and nutritional demands of gestation, calving, lactation, and rebreeding. For more information about checking the pregnancy status of beef cattle, please refer to ACES publication ANR-1417, Beef Cattle Pregnancy Examination ( Check eyes Check eyes closely for signs of bovine ocular neoplasia, also known as cancer eye. Cancer eye can start as a small spot on the eye or eyelid, but then grow rapidly into the tissues of the head and neck if left untreated. If detected early, veterinary treatment could be attempted, but often the only cure is complete removal of the entire eye and surrounding tissues in the eye socket. Some one-eyed cows will do just fine, but others will be more difficult to handle due to their limited field of vision. If not treated, cancer eye can rapidly grow and spread, and is one of the major causes of cow carcass condemnation. For these reasons, consider culling cattle with early signs of cancer eye sooner rather than later. Signs of cancer eye will vary from animal to animal (Figure 1). The first growth seen may be a small, white, elevated plaque on the eyeball or third eyelid. For other cattle, the first indication may be a skin growth on the lower eyelid called a keratoma. Some affected cattle will have growths on their eyeball that look like warts. Figure 1. Early signs of cancer eye indicated with black arrows. 2

3 Cattle with advanced cancer eye should be humanely euthanized on the farm and not shipped to the local auction market. They will not bring a good sale price, as their carcass will likely be condemned, and they are potentially a poor example of animal husbandry that could place the entire beef industry in a bad light. Check mouth In order to produce a calf that grows well from birth to weaning, a cow must be able to convert forage and feed into milk. That is, she must be able to graze, and to do that efficiently she needs a good set of teeth. As a cow ages, her teeth wear down and may break. Cows in poor body condition may simply be cows with bad teeth that are having difficulty grazing, and cows in poor body condition tend to not breed back. The only way to maintain body condition on a broken-mouthed or smooth-mouthed cow is to supplement her with feed she does not have to graze, which can be expensive. There are some things to keep in mind when evaluating cattle teeth. Cattle have 8 incisors (front teeth) on their lower jaw only. Young cattle have temporary incisors until about 18 months of age, when the two permanent central incisors replace the temporary pair. The remaining permanent incisors then replace the temporary ones at a rate of one pair about every 12 months until all permanent incisors are erupted and in wear by 5 years of age (Figure 2). As cattle age, their incisors wear down and the gums begin to recede from the roots. With further age and wear, the incisors may be broken off or worn to the point that only stumps remain (Figure 3), making it difficult for cattle to graze enough forage to maintain body condition and produce enough milk to wean a good calf if they can even get pregnant. Figure 2. A good, complete set of permanent incisors. Cattle use their lower incisors to shear off forage. 3

4 Figure 3. A broken- and smooth-mouthed cow that has lost one incisor and worn the remaining teeth down to stumps. A cow with a mouth like this will have a very difficult time grazing enough to maintain body condition. Check feet and legs Lame cattle have a difficult time grazing and walking to feed troughs and water. They tend to lose body condition, wean poor calves, and not rebreed. Poor foot and leg conformation leads to lameness, so check cows every time you see them for early signs of lameness. Routine foot trimming in beef herds is not recommended. Beef cattle that cannot maintain sound feet in normal pasture conditions should be considered for culling. The majority of cattle lameness originates in the foot. The American Angus Association has great foot scoring guidelines for yearling cattle based on foot angle and claw set, and these guidelines are very useful when evaluating mature cattle as well (see foot scoring guidelines at the end of this bulletin). Look closely for signs of heritable defects such as corkscrew claw (Figures 4 & 5). Screw claw is particularly common in the outside claws on the hind legs. Cattle with screw claw are more likely to become lame, and therefore they and their offspring should be high on the cull-list. One challenge with screw claw is that it often does not show up until a cow or bull is about two-years old, and by this time they have already produced multiple offspring, some of which may now be part of the brood-cow herd, thus propagating this heritable defect. Evaluating cattle feet using the Angus Association foot scoring guidelines can help identify cattle with a propensity for developing screw claw sooner rather than later. There is no cure for screw claw. 4

5 Figure 4. Foot defect called corkscrew claw. Screw claw is a heritable defect that can cause lameness. Figure 5. A more severe example of corkscrew claw. This animal should be high on the culling list. 5

6 No attempt should be made to sell severely lame cattle at local auction markets. Auction markets will likely not accept severely lame cattle. Even if the auction market accepted the animal, they are at great risk of becoming a downer animal that is unable to move on its own. Downer animals are bad for the animal and bad for the entire beef industry. Depending on the condition, severely lame animals should either be humanely euthanized on the farm or treated and then sold or returned to the herd. Check udder It takes a good udder to raise a good calf. A cow converts grass and feed into milk which her calf converts into pounds of weight. If a cow s udder has poor conformation, poor suspension, or enlarged, pendulous teats, calves will have difficulty nursing. Cows with udder problems will not produce good calves and should be culled. It is particularly important for a calf to be able to nurse shortly after birth so it can ingest colostrum to serve as a source of antibodies to fight off infections. A well-suspended udder with evenly spaced teats will make this easier for the calf (Figure 6). Mastitis, or infection and inflammation of the udder, decreases milk quantity and quality. Cows with mastitis have swollen, often painful udders that frequently result in blind quarters that produce no milk at all even after the infection resolves. Figure 6. An example of an udder with good suspension and evenly placed teats that are normal in size, both of which facilitate ease of nursing for a calf. 6

7 Check body condition score Body condition scoring is an assessment of the relative fat cover of an animal, and is the single best indicator of cattle well-being. Beef cattle are body condition scored on a scale of 1-9, with 1 being emaciated and 9 being obese. An ideal body condition score (BCS) is 5-6. Keep in mind that BCS will fluctuate based on stage of production. For example, lactating beef cows will often lose some body condition due to the high nutritional demands of milk production. Body condition has a direct correlation with reproductive success. Cattle that are too thin (less than a BCS 5) are not as likely to get pregnant as cattle with a BCS of 5 or higher. Some cattle are easy-keepers. In other words, it is easier to keep some cattle in good body condition than it is others. This could be because they are very efficient in feed conversion (which is a good thing), or it could be that they don t put much energy into raising a big calf (which is a bad thing). Or maybe they only have a calf every 400+ days, instead of every 12 months like more productive cows. So, being an easy-keeper can be a good thing, or it can indicate a lack of performance. Ideally, keep cattle that are easy-keepers AND productive. Check disposition Aggressive, ill-mannered cows often produce calves with the same traits. These animals make it difficult to work the rest of the herd, and discourage workers from doing what needs to be done on the management calendar. They are also potentially dangerous for other cattle and human workers, and can destroy working facilities. Consider culling cattle with bad dispositions to make it easier and safer to work the herd. Research has also shown that cattle with nervous or bad dispositions do not eat as much and thus may have lower BCS. Check Production Records After completing the 7 quality checks for pregnancy, eyes, mouth, feet, legs, udder, disposition and body condition scores, utilizing beef production records to make final culling decisions is an excellent tool. Production records detailing the performance level of individual cows provides precise information to make more informed decisions as to what cows should be culled. Culling lower performing cows during times of drought preserves the best genetics of the herd to move forward. In analyzing production records to assess which cows are performing at a high level and which are not, consider both the average calving interval of each cow and the average weaning weight of calves produced for each cow. A calving interval is the period of time, measured in days, from one calving date to the next. Use the recorded date of each calving to calculate an average calving interval for each cow in the herd. An average calving interval of 370 days or less is ideal, as a cow should be expected to calve each year. By performing an annual pregnancy examination, cows and heifers are determined to be pregnant, but cows who consistently calve late in the determined calving season are not cost effective. If cows consistently calve late under normal rainfall conditions, these cows may not perform well under drought conditions. Cows with high average calving intervals should be culled as they are not performing efficiently. After culling cows due to calving intervals, analyze the average weaning weight of all calves produced for each cow. Using your production records, you can calculate or review your herd s average weaning weight. Identify which of your cows are producing an average calf weaning weight that is below this herd average. Cull cows that are not performing to the level of the herd s average weaning weight, as these cows are producing less calf weight and therefore less income. 7

8 Cows not performing productively and efficiently are utilizing pasture, water and land resources that should be directed to more efficient cows with higher performance levels. This should always be a management goal; however, it is even more critical with limited resources during drought conditions. Reference: Alabama Beef Cattle Producers Guide, ANR-1100, Alabama Cooperative Extension System Prepared by: Lisa Kriese-Anderson 1, Ph.D., Extension Specialist; Butch Blaylock 1, Extension Animal Scientist, Retired; Jim Floyd 1, DVM, Extension Veterinarian, Retired; Michelle Elmore 2, M.S., Extension Animal Scientist/Beef Cattle Improvement; Landon Marks 2, M.S., Animal Science & Forages, Regional Extension Agent; Kim Mullenix 1, Ph.D., Extension Beef Cattle Systems Specialist; and Soren Rodning 1, DVM, Extension Veterinarian. 1 Auburn University Department of Animal Sciences 2 Alabama Cooperative Extension System 8

9 American Angus Association FOOT SCORE GUIDELINES Foot angle (5 is ideal) Claw Set (5 is ideal) Guidelines 1 Animals must be scored prior to hoof trimming. 2 When there is variation among an animal s feet, score the worst foot. 3 Score yearling bulls and heifers bulls must be between 320 and 440 days heifers must be between 320 and 460 days females can be scored following guidelines used when collecting mature weights. 4 Older (Note: Foot structure changes as animals age. Scores will be adjusted for age as part of the analysis. Scores should describe the animal as they are at the time of scoring, without consideration of age). 5 Large groups of 18-month or 2-year-old bulls can also be submitted, if available.

10 FOOT SCORE GUIDELINES Foot angle (5 is ideal) 1 Extremely straight pasterns. Very short toe. Unsound Moderately shallow heel and long toe. Somewhat weak pasterns. 8 9 Slightly shallow heel and long toe. Shallow heel and long toe. Marginally unsound. Extremely shallow heel and long toe. Extremely weak pasterns. Unsound. 1 Open, divergent claw set. Marginally unsound. Moderately open/divergent claw set. 2 3 Slightly open/divergent claw set. Slightly straight front and rear pasterns. Ideal. Approximately 45-degree angle at pastern joint. Appropriate length of toe and depth of heel. 6 Extremely weak, open, divergent claw set. Unsound. Straight front and rear pasterns. Marginally unsound. Moderately straight front and rear pasterns. 3 5 Claw Set (5 is ideal) Ideal. Symmetrical claws, with appropriate space between claws. 4 5 Slight tendency for claws to curl. One claw may be slightly larger than the other. Tendency for claws to curl, with one claw larger than the other. 6 7 Moderate scissor claw and/or screw claw. Curling of one or both claws. Near crossing of claws. Marginally unsound. Extreme scissor claw and/or screw claw. Pronounced curling of one or both claws. Crossing of claws. Unsound Access AAA Login at angus.org to submit scores. 9 8