Culling Decisions: Dairy Cows

Culling animals from the herd is a necessary part of any livestock operation. Understanding herd turnover and making optimal culling decisions using sound criteria is important to improving herd performance, efficiency and overall profitability. Culling cows from the herd today will make way for upcoming replacements which are the next generation of genetic improvement in the herd. These decisions need to be balanced with optimizing cow longevity. Culling decisions have important welfare and economic considerations. Some key culling questions to ask are:

  • How many cows exited the herd last year or suitable timeframe? What were the reasons for removal?
  • How many adult cows died or were euthanized on the farm?
  • What body condition were culled cows in when they exited the herd? Where were they sold? What price was received? Was it the highest price?
  • What is the herd's average longevity and overall herd turnover rate? How does it compare to the industry average?

Herd turnover rate will determine the number of heifers to raise to replace cows leaving the herd. The herd's turnover rate is based on the number of cows leaving the herd either by involuntary (died or euthanized) or voluntary (decision based on performance) reasons.

Cull cow welfare

Cull cow welfare is of upmost importance. In the Canadian National Dairy Study, most producers indicated that they had little knowledge of the final destination of cull cows shipped from their herd.1 When assessing cattle for transport ask yourself, "Is this cow fit to ship?" recognizing cull cows could be in the marketing system for 7-14 days. Increased time in the marketing system can exacerbate pre-existing conditions like lameness. Dairy producers should consult their veterinarian to discuss cull dairy cow welfare and options for cull dairy cows that are not fit to ship.

Every cow should be assessed before shipping for fitness for transport and sale. Assess cows for signs of disease, lameness score, body condition score (BCS), injury, if the cow needs to be dried off and that all drug withdrawal times have been met. Discuss with a veterinarian options for cows that are unfit to ship as they may require treatment, or conditioning, before sale or may require on-farm euthanasia.

For welfare recommendations related to shipping cull dairy cows refer to following resources:

Trends in culling and markets

In Canada, the culling rate of dairy cows from farm is between 26-33%3. In 2018, reasons for exit from the herd from included:

  • reproductive issues (31%)
  • low milk production (16%)
  • high somatic cell count/mastitis (15%)
  • sickness (11%)
  • feet/leg problems (9%)3

The record keeping "disposal codes" in DairyComp only allow a producer to choose a single-reason for exit from the herd, however cows may have more than one condition. Reproductive issues are the top reason for culling of dairy cows but are associated with underlying issues like lameness and metabolic disease.4

There is a tendency for more cattle to be culled in the late fall and early winter months. The number of culled dairy cows are impacted by number of incentive days and market changes. These trends translate into additional cattle at the sale barns and abattoirs and may result in cattle experiencing longer times in the marketing system.

A recent study at Ontario sale barns assessed cull cow condition in the sales ring. The researchers assessed lameness, body condition, hock lesions and tail presence. Cows that had an obvious limp (uneven or irregular step, favouring one or more limbs) sold for a lower price ($0.05 less/kg) than cows with an acceptable gait (no limp present)4. Unacceptable body condition (<2.0 BCS ) had more of an impact on price ($0.20 less/kg) than cows with acceptable body condition score. Ensuring cows are in good condition can result in larger returns and higher income per cull cow.4

Risk for Involuntary and Voluntary Culling

Knowing the risk periods for when cows are most likely to be culled is one way to assess risk factors on the farm that could be increasing the number of involuntary culled animals. An assessment of herd turnover may identify areas to improve with the goal to minimize the number of cows that are culled involuntary, which can increase cow longevity and improve herd profits. Cows are more likely to exit the herd in:

  • early lactation (days in milk <150)
  • late lactation (days in milk <250)

The peripartum period has many challenges that can contribute to an increased risk for involuntary and voluntary culling including reproductive disease, metabolic disease, poor production, and mastitis with the risk of a cow being culled for these reasons declining after 150 days in milk.5

A cow's risk of being culled from the herd increases with age. Generally, primiparous cows have different reasons for being culled compared to multiparous cows. Primiparous cows are more likely to be culled due to poor milk production, milking temperament, and feet/leg problems. Whereas multiparous cows are more likely to be culled due to mastitis/high somatic cell counts (SCC), metabolic diseases and feet/leg problems.5

The risk is the same for both multiparous cows and primiparous cows to be culled later in lactation for infertility, which increases rapidly after 200 days in milk as they near the end of lactation and are not in calf for the next lactation. 5

Early Culling Decisions: Building a Culling Criteria

Knowing what herd size is needed for adequate milk production will help determine criteria for early culling decisions while controlling costs and optimizing the price received for cull cows. There are many factors that can go into developing culling criteria and consultation with the herd's veterinarian and farm advisors can help determine what is best for the herd.

Herd turnover rates may vary based on the current market conditions, replacements' availability, mortality on the farm, disease control, herd size and overall business plan. To determine a herd's turnover rate, add your adult mortality and voluntary culling percentage together (see equations below). This will help determine the number of replacements needed.6

  • Adult Mortality percentage is equal to the Number of cows that died per year divided by the Average inventory of dairy cows per year multiplied by 100
  • Culling Rate percentage is equal to the Number of culled cows per year divided by the Average inventory of dairy cows per year multiplied by 100
  • Herd Turnover Rate percentage is equal to the Adult Mortality rate percentage plur Culling rate percentage.

If adult cow mortality on farm is more than 5%, consult a veterinarian to determine the cause(s) of death and implement prevention strategies to reduce the risk of cows leaving the herd prematurely. High mortality rate and culling for health reasons can impact the operation's economic viability as you will need to raise more replacements and is an animal welfare issue.

Factors used to identify cows to cull will vary from farm to farm as farms have different disease challenges, production goals, and herd performance. Early culling decisions require a producer to determine which cows to cull or keep, breed back or not, keep milking or dry off. Considerations should be made to target improved productive lifespan of cows by optimizing cow comfort and preventative health measures.7 Some areas to analyze include:

  • reproductive performance: longer days open, not pregnant, increased AI services
  • udder health: high somatic cell, chronic udder health issues
  • disease status: test positive for Johne's disease or bovine leukosis
  • milk performance: bottom 10% for milk production and components
  • feed efficiency: body condition, economic return (milk over feed)
  • genetic merit: parent averages for index like Pro$, genomic test results

Genetic merit and progress towards genetic goals are important in making culling decisions. Consulting individual cow records and determining lifetime performance will be important in making these decisions. One strategy to consider when making culling decisions is to determine the economic value of cows in the herd and make decisions based on their ranking. There are a variety of tools available to help determine cows that are in the bottom 10% for performance in your herd including:

  • Lactanet and Holstein Canada's Compass is a web-based tool that is available to help evaluate and manage your herd's genetics
  • DairyComp, robotic milking system software or other herd management software can also analyze overall herd performance

Conclusion

Earlier culling decisions will allow producers to prepare cull cows for market and will improve the price received at market and overall welfare of the cow. It will also allow producers to better assess the economic returns on each cow while balancing longevity and improving overall herd performance. Speaking with a veterinarian and farm genetic advisors can help with developing a plan with both economics and welfare in mind.

Sources

  1. Roche, S.M. et al. 2020. Canadian National Dairy Study: Describing Canadian dairy producer practices and perceptions surroundingcull cow management. J Dairy Sci. 103(4): 3414-3421.
  2. Farm Food Care. (2016) Should this animal be loaded? Cattle, Goat and Sheep.
  3. Canadian Dairy Information Centre. Culling and replacement rates in dairy herds in Canada
  4. Moorman et al. 2018. Associations between the general condition of culled dairy cows and selling price at Ontario auction markets. J Dairy Sci. 101:(110)10580-10588.
  5. Heise et al., 2015. The genetic structure of longevity in dairy cows. J Dairy Sci. 99:1253-1265
  6. Fetrow, J., K. Nordlund, and D. Norman. Culling: Nomenclature, definitions and some observations. 2006. J Dairy Sci. 89(6):1896-1905
  7. De Vries, A. (2020) Symposium review: Why revisit dairy cattle productive lifespan? J Dairy Sci. 103 (4): 3838-3845.

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