Tools for Making Economic Culling Decisions

Successful culling strategies utilize economic and production data. This article discusses metrics that incorporate the current test day and current lactation.
Tools for Making Economic Culling Decisions - Articles
Tools for Making Economic Culling Decisions

A recent USDA Cattle Inventory Report identified that Pennsylvania was down 5,000 head of milk cows at the start of 2014 compared to 2013 (NASS, 2013). Dairy replacement heifers 500+ pounds for Pennsylvania were up 5,000 head, suggesting there are ample replacements for Pennsylvania dairies in 2014. Considering cull prices should remain steady due to lower beef inventories currently in the U.S., greater culling decisions could be made on dairy operations this year. To assist with those tough decisions, there are a few test-day metrics that can help sort out the top and bottom of the average cull list.

Economic vs. Biological Culls

In order to make the most of culls, cows need to leave the herd based on low production or dairy purposes. Fetrow et al. suggested in a 2006 culling nomenclature review that these low production or dairy purpose culls be considered "economic" culls, instead of the more popular "voluntary" culls. Other culls, those typically labeled "involuntary," should be considered "biological" culls. For herds to have success with culling strategies, accurate data is crucial to determining why animals have left the herd. If all culls fall into the biological cull category, the producer's decision to cull is nearly made for them. Cows in the economic cull category allow for greater producer control over which animals stay or leave.

Potential Production Metrics

Making economic culls on current test day production alone may not be enough under current market changes. Variables like lactation to date (LTD) milk and projected 305-d mature equivalent (ME) milk can aid in ranking cows based on overall lactation performance. Potential metrics like Dairy Comp 305 current relative value (RELV) or PCDart Money Corrected Milk™ (MCM) can also enhance the ranking of cows on overall performance. RELV is based on ME305 and is an average of the herd ME. So cows less than 100 are lower than herd average, and those above 100 are higher than herd average. MCM™ is a relatively new metric to PCDart. The variable is a measure of cow productivity based on market values (either component or fluid market) and other milk check values for a specific herd. This allows the calculated value to be based on market value of milk, not just the energy of milk.

A Ten Cow Example

To best demonstrate how different metrics can be used to sort out potential culls based on production, ten cows from a sample farm were selected. Cows were selected based on their reproductive diagnosis of open or do not breed, or based on DIM > 250 and days until due > 100. Cows with current production greater than the herd average (in this case, 80 lbs on the most recent test) were excluded. The resulting ten cows are listed in Tables 1 and 2. Table 1 depicts the current test day production values for the 10 cows, while Table 2 presents some of their current lactation and ME 305D measurements. Just looking at individual values may not clearly show which cow should be culled.

Table 1: Current test day values for ten potential cull cows.
NameLact#Current Test Day
DIM
Current Test Day
Milk
Current Test Day
Fat%
Current Test Day
Pro%
Current Test Day
ECM
Current Test Day
Current MCM™
Cow A4255783.63.18084
Cow B13258473.62.94749
Cow C3391773.13.17380
Cow D22443703.737275
Cow E2331793.84.189101
Cow F2337564.246673
Cow G2251753.43.67887
Cow H11335684.53.58084
Cow I32258863.33.18491
Cow J21200553.32.85351

1Confirmed Pregnant
2Confirmed Do Not Breed
3Confirmed Open

Table 2: Current lactation measures for ten potential cull cows.
NameLact#DIMCurrent Lactation
DC 305 RELV
Current Lactation
LTD Milk
Current Lactation
LTD Fat
Current Lactation
LTD Pro
Current Lactation
Proj 305 ME ECM
Current Lactation
LTD MCM™
Current Lactation
Proj 305 ME MCM™
Cow A42558919,02161452925,84617,88525,647
Cow B32588518,76474955024,73519,32224,176
Cow C339110733,0821,09896430,98732,10030,905
Cow D244314039,6321,7381,32340,78044,83839,841
Cow E233112629,9571,13299536,52132,28037,030
Cow F233710622,17399473430,73725,16330,032
Cow G225110015,64564355728,99017,92329,610
Cow H13359621,82484266029,20922,57028,680
Cow I22589917,06756550928,72416,74428,985
Cow J1200534,93016214015,5044,70815,805

These cows were then ranked by three current test day production metrics and by five current lactation metrics, as seen in Chart 1. Within the three current test day metrics, cows at the top of the list and bottom of the list were consistently ranked. There was a little bit of change for cows in the middle ranking area. In lactation ranks, cows again remained at similar ranks in the top and bottom, regardless of the metric used. The changes occurred again within the middle ranking area. It is important to note there were some large rank changes when comparing current test day to current lactation. This demonstrates the importance of considering both current performance and overall lactation performance when trying to determine which cows may be culled for economic reasons.


Chart 1. Cow Rankings on Individual Production Metrics

Summary

Greater heifer inventories and strong beef prices can put greater pressure on the decisions to cull an animal. For herds to be successful with their culling strategies, greater control over decisions via economic culls is a must. Making those economic culls based on accurate production data (that considers components and current markets) is another critical component. Finally, examining performance for both current test day and overall lactation will enhance the information available to make the final decision.

References

  • Fetrow et al., 2006. Invited Review: Culling: nomenclature, definitions, and recommendations. Journal of Dairy Science, 89:1896-1905.
  • USDA, Cattle (January 2014). National Agricultural Statistics Service. January 31, 2014. Accessed 2/2/2014.

Authors

Data and Records Management Dairy Profitability and Management Dairy Genetics and Reproduction

More by Robert C. Goodling, Jr.