| IMPORTANCE OF CULLING OF DAIRY ANIMALS
DR. SHALINI MISHRA, BENGALURU Culling is defined as the departure of cows from the herd because of sale, slaughter, salvage, or death. Culling is an important cost for dairy farms. At the same time, culling is a way to increase herd productivity and profitability, as keeping diseased and unproductive cows might result in lower herd milk production and deteriorated reproduction. In order to maximize profitability, the proportion of voluntary culling (selling for dairy purposes or culling due to low production) should be highest among the total culling rate. The word comes from Latin language word “colligere” which means “to collect”. In animal husbandry this means to collect the good ones so as to separate them from the bad ones. Over the time culling has been considered mainly as the removal of the undesirable animals from the desirable ones. This removal can be in any form like separating the animals, killing the incurably diseased animals or selling away the animals. Sometimes, in dairy herd some animals are unproductive. These animals usually underperform and total farm production comes down. In such situation it is desirable to cull the unproductive animals so that herd should contain only the good high productive animals. In dairy husbandry culling and selection are very important. We can consider these two events as two faces of one coin. When some animals are selected for their better characteristics it automatically means that those animals who are poor performers will be culled. Profitability in the dairy industry is not only extremely variable, but also is influenced by many factors making it very difficult to quantify exactly what led to an operation being profitable or unprofitable in any given time period. Thus, it is common to establish benchmarks or “rules of thumb” as profitability proxies. For example, producers and their lenders might focus on debt/cow as a measure to watch as an indicator of how well the dairy is performing financially. Production measures, such as milk/cow/day, pregnancy rate, and cull rate are also often used as indicators of both production performance and ultimately economic performance. However, a critical question to ask is: ‘Are these proxy measures that people often rely upon useful?’ That is, how well do measures such as these relate to profitability? Many of these measures have been used for a long time indicating they have stood the test of time and thus they must have some merit. However, as the dairy industry continues to consolidate and face tighter margins, producers and those people working with them should constantly evaluate the effectiveness of using these measures for making decisions. In other words, it will become increasingly important to recognize the relationship that exists between benchmark measures and profitability. Culling is elimination or weeding out of undesirable animals from the herd, for reasons of uneconomic,, poor production, or very poor reproductive ability, with sterility problems and breeding, irregularities, very poor conditions, stunted growth, suffering from incurable illness, or disease animals found to be positive for serious infections diseases like Tuberculosis, Johnes disease, Brucellosis, lost one or more quarters and teats of the under due to chronic mastitis resulting in marked reduction in milk production. Undesirable breed characters present in young animal. When the herd is a pure bred herd leading to disqualifications family lines, exhibiting heritable characters like supernumerary teats, loose horns in cows of certain breeds. Disable animals due to injury or loss of organ, extreme lameness leading to unmentionable conditions, un healed fractured animals etc. come under the animal proposed or culling. The culled animals carry lower values and a separate list is made for such called animals and it is known as culling list. |
When the culling cows for poor production, the entire lactation at yield is considered and preferably first two lactations are observed and if the lactation yield is less than what is expected from the breed or herd, The animal is included in the culling list. Very old animals are culled, as their maintenance will be uneconomical.
Male animals or other animals surplus in the farm or not useful in the farm and they are culled. Calves born with congenital defects like congenital fibrosis of the eye, total blindness or some other defects are included in the culling. Calves born much below the normal birth weight are included in the culling. Yearlings animals male or females, stunted much below their normal body weight, potbellied conditions bad confirmation are culled. Dairy Animal Management Valuation and culling is done on the farms every year at least once in year. In some farms culling is done twice a year however doing it once a year is must.
Tips for Culling in dairy animals
- Do not move non-ambulatory animals to market under any circumstances.
- Make the decision to treat, to cull, or to euthanize animals promptly. Sick and injured animals should be segregated from the herd
- Delay transport of an animal that appears to be exhausted or dehydrated until the animal is rested, fed, and dehydrated.
- Milk all cows that are still lactating just prior to transporting to a packing or processing facility.
- Use a transportation company that is knowledgeable about your animal care expectations and provides for the safety and comfort of the animals during transport.
- Do not transport animals to a packing or processing facility until all proper treatment withdrawal times have been followed.
- Do not transport animals with a poor body condition, generally a Body Condition Score of less than 2 (1-5 scale).
- Do not transport animals that require mechanical assistance to rise and are reluctant or unable to walk, except for veterinary treatment. When using any handling device, abuse must not be tolerated.
- Do not transport animals with bone fractures of the limbs or injuries to the spine. Animals with a recent fracture unrelated to mobility should be culled and transported directly to a packing or processing facility.
- Do not transport animals with conditions that will not pass pre-slaughter inspection at a packing or processing facility. If unsure, consult with your veterinarian before transporting an animal to a packing or processing facility.
The Classification of Culling Reasons
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Voluntary Culling
Age
Low milk yield
Conformation (including poor udder shape)
Behaviour
Involuntary Culling
Reproduction problems
Fertility (including barren, abortion, displaced uterus)
Calving difficulties
Diseases
Infectious diseases
Mastitis (including 3 Quartered)
Lung problems (including TB reactor, TB inconclusive and pneumonia)
Others (including “infectious disease”)
Non- infectious diseases
BSE
Lameness (including all feet and leg problems)
Metabolic diseases (including milk fever)
Digestive disorders
Alimentary problems (including displaced abomasum and liver damage)
Others (including “non-infectious disease”, arthritis, “ill”, peritonitis,
meningitis, heart and kidney problems)
Injury (including wire)
Downer cow (not milk fever)
Other udder problems (including slow milker)
Management policy
Unknown reason (including no given reason).
Culling Decisions
Appropriate times to cull cows from the herd depend on the reasons behind the culling. In cases where cows have developed severe health problems, removal from the herd may need to be immediate. In situations where cows are being culled for low performance or other less urgent factors, it often makes sense to wait until after nursing calves are weaned. If market conditions are such that even cows weaning low-performing calves are generating a profit, it may be cost-effective to hold onto these cows in the near term and then market them before they become unprofitable. Production conditions can also influence the best time to remove cows from the herd. During drought or other conditions where forage and feed resources are limited, culling deeper into the herd is often appropriate.
Cull cow receipts generally account for 15 to 20 percent of gross income in beef cow-calf operations. Cull cow price levels and seasonal trends should be taken into consideration when deciding when to sell cull cows. When cull cows prices are trending upward, it is often advantageous to wait to market cows if the increasing values can cover added production expenses from holding over cull cows. It may also be advantageous to retain cull cows until weight and body condition can be added. Unlike feeder cattle prices, cull cow prices generally increase on a per pound basis with increasing cattle weights. If cull cow prices are trending downward, however, it may be advisable to market cull cows in a timely manner before more money is invested in cow maintenance, particularly if this investment will not likely be recovered.
Pregnancy Status
One of the greatest determinants of profitability in a cow-calf operation is reproductive rate. Open (non-pregnant) cows are a drain on resources. They consume feed, forage, and other resources without producing a marketable calf to contribute to expense payments. Cows that are open at the end of the breeding season should be at the top of the cull list. Cows that calve outside of a controlled calving season are also potential culls, particularly when feed and forage supplies are running short. Late calving cows should be scrutinized as well, because they have less opportunity to breed back to stay within a controlled breeding season.
Poor Performance
Poor calf performance is usually the result of inferior genetics, poor dam milk production, calf illness, or a combination of these factors. Cow passing on inferior genetics to their calves for economically important performance traits and cows with unacceptably low milk production are potential culls. If poor calf performance is due in large part to calf sickness and not associated with the dam, then the dam may still have a productive future in the herd.
While herd genetic improvement is largely dependent on sire selection, the dam contributes half of the genetics to the calf. Culling cows with EPD values that do not compare favorably with breed or herd averages for economically important traits contributes to herd genetic improvement. Many breed associations publish breed averages and percentile ranking tables for EPDs for active dams.
Age
The productive lifetime of a beef cow is variable. As long as teeth, udders, feet, and legs are sound, many older cows are often still able to perform well. Breed composition and production environment can play a role in longevity. Florida research on Brahman-influenced cows indicated that there was consistent rebreeding performance through about 8 years of age and a decline in reproductive performance after 10 years of age.
An even steeper drop in reproductive performance occurred in cows beyond 12 years of age. That is not to say that individual cows will not be productive through an advanced age though. Ideally, cows should be culled for advancing age prior to a sharp decline in reproductive or maternal performance. In addition, with an emphasis on herd genetic improvement, younger beef females are often genetically superior to older cows.
Mouth
Teeth wear with normal use over time. Gritty feeds and forages accelerate tooth wear. Soil type can affect how long teeth remain sound, with sandy soils typically being harder on teeth. Cows can eventually wear their teeth down to a stage where grazing effectiveness is severely impacted. This results in poor body condition despite adequate available nutrients. “Smooth-mouthed” cows have teeth worn down to the gums. Cows may also lose teeth at any age from being knocked out by blunt force or from gum disease or infection resulting in a “broken-mouthed” condition. These cattle may dribble feed and have a hard time consuming adequate quantities of feed or forage. Lumpy jaw is another condition of the mouth that can negatively impact grazing ability. Annual inspection of the teeth and mouth during routine cattle working is recommended.
Udder
Udder soundness affects milk production, milk consumption, and ultimately calf weaning weights. Proper udder attachment in a beef female is important for a long, efficient, productive life. A sound udder should be firmly attached with a strong, level floor and four properly formed teats proportional to body size. Weak udder suspension results in pendulous udders that are difficult for a sucking calf to nurse. Balloon or funnel-shaped teats are also difficult to nurse and may hurt calf milk consumption and weaning weight. Balloon teats are also sometimes an indication of past mastitis (a bacterial infection of the mammary tissue). The udder should be healthy and free of mastitis in all four quarters for good milk production.
Stuctural Soundness
Structural soundness is important from the standpoint of functionality. Structural problems subject the joints to excessive wear and stress that can eventually hamper mobility. Cows that have difficulty moving around the pasture may be less active grazers. Cows need to be sound enough for effective grazing and successful pasture breeding. Condition and performance of structurally unsound or crippled cattle often goes downhill. Obvious structural defects can decrease the market appeal of an animal as well.
Lameness is a major reason for culling cattle. Lameness leads to decreased performance, decreased reproductive efficiency, weight loss, and increased treatment costs. A study of five large western feedlots showed that lameness accounted for approximately $121 loss per lame animal. Many conditions can be the cause of lameness in cattle including foot rot, laminitis, joint injury, and fescue toxicosis.
Health Problems
Cancer eye can impair a cow’s ability to raise her next calf. Culling is often the best option once an affected cow has weaned her calf. Another health issue that may determine if a cow should be culled from the herd is Johne’s disease. Johne’s disease is a chronic, incurable, contagious infection of the intestinal tract.
Calves usually become infected when they nurse udders that are contaminated with infected fecal material or when they are housed in contaminated pens or pastures. Johne’s disease causes severe, explosive diarrhea and weight loss in adult cattle leading to enormous production losses in infected herds. Since there is not an effective treatment or cure for Johne’s disease, the best way to keep infected cows from spreading it to others in the herd is to cull them. Blood or fecal culture tests may be performed to identify infected cattle.
Prolapse is another potential health concern that may necessitate culling. A vaginal prolapse occurs when vaginal tissue protrudes through the vulva where it is exposed to the outside environment, potential injury, and disease-causing agents. Uterine prolapse is a condition in which the uterus is pulled through the birth canal with the calf or afterbirth. Vaginal prolapse typically occurs during late gestation as calving approaches, while uterine prolapse usually occurs at or shortly after calving. Because vaginal prolapses (unlike uterine prolapses) are likely to reoccur and are known to have a genetic component, cows suffering from this condition should be marked for the cull list.
Disposition
“High-headed” cattle are dangerous and should be prime candidates for culling. Culling for unacceptable disposition reduces the risk of injury to both cattle and people. Mississippi State University animal scientist, Dr. Rhonda Vann, has conducted several studies indicating that excitable calves often sacrifice growth performance and Quality Grade compared to calmer calves. Colorado State University studies have also shown that excitable cattle are more likely to produce dark cutter carcasses, which are subject to severe discounts. Because calves inherit a genetic component of temperament and also pick up habits from their dams during the suckling phase, bad attitudes can be propagated within the herd without selection pressure for acceptable disposition.
REFERENCE-ON REQUEST
https://www.frontiersin.org/articles/10.3389/fvets.2018.00343/full
