Reasons that cows in Dairy Herd Improvement programs exit the milking herd (2014)

H. D. Norman, L. M. Walton, and João Dürr

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TABLE 1. Percentages of cows (ALL BREEDS and CROSSBREDS) completing lactations.
TABLE 2. Percentages of cows (ALL BREEDS and CROSSBREDS) leaving the herd except for dairy purposes.
TABLE 3. Percentages of HOLSTEIN cows completing lactations.
TABLE 4. Percentages of JERSEY cows completing lactations.
TABLE 5. Percentages of AYRSHIRE, BROWN SWISS, GUERNSEY, MILKING SHORTHORN, and RED & WHITE cows completing lactations.
TABLE 6. Percentages of CROSSBRED cows completing lactations.
TABLE 7. Percentages of HOLSTEIN cows leaving the herd except for dairy purposes.
TABLE 8. Percentages of JERSEY cows leaving the herd except for dairy purposes.
TABLE 9. Percentages of AYRSHIRE, BROWN SWISS, GUERNSEY, MILKING SHORTHORN, and RED & WHITE cows leaving the herd except for dairy purposes.
TABLE 10. Percentages of CROSSBRED cows leaving the herd except for dairy purposes.

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For decades, dairy producers have designated reasons why cows leave the milking herds through Dairy Herd Improvement Association (DHIA) recordings. Information given when cows complete lactations or are removed from the herds place the animals into 4 destination codes (DC): remained in herd, sold for dairy, sold for slaughter/salvage, or died. Those removed from the herd are given more descriptive codes, i.e., termination codes (TC). The TC system has added codes across time and in addition choices offered to producers vary slightly between Dairy Records Processing Centers (DRPC). All DRPCs include TCs on each lactation record before forwarding to the national dairy database. The frequencies of the codes are provided annually to summarize reasons for voluntary and involuntary culling as they have considerable economic impact on producers. Rate and reason for culling also provide beneficial information for economic studies on dairy management.

Currently there are 2 TC choices for cows that remain in the herd when their lactation ends, and 10 choices (TC codes) for cows that leave the herd. For cows that stayed in the herd, the TC indicates whether their lactations ended as planned (TC=0) or ended unexpectedly as a result of an abortion (TC=8). For those cows “sold for slaughter or salvage”, 8 more TC choices provide more detailed information about why they left the herd.

Historical studies of survival of U.S. dairy cattle have been reported by Nieuwhof et al. (1989) and Hare et al. (2006). Those studies grouped cows by calving year and tracked them until they left the herd. That method provided comprehensive information, but unfortunately the results are quite dated due to having to wait until all animals in the original group leave the herd. Our alternative approach (used here) provided more current information by summarizing reasons cows left the herds last year. This report is based on lactations with completion dates between January 1 and December 31, 2014. Results using this method are impacted considerably by annual fluctuations in milk and feed prices.

Selected summaries are provided by parity and breed (including crossbreds). Crossbreds were categorized into 2 groups depending on the extent of heterosis: those with heterosis of >90% (CB90) and those with heterosis of 50 to 90% (CB50). The CB90 group was primarily first-generation crosses between 2 breeds (F1s) or offspring of a third-breed sire and an F1-crossbred dam of 2 other breeds; the CB50 group was predominately backcross offspring from an F1 dam and a sire from 1 of the F1 parent breeds.

Table 1 shows the frequency of codes by breed disregarding parity. The percentage of cows that completed their lactations and stayed in the herd averaged 64.3% across all groups. Purebreds ranged from 62.2 to 66.8%; Jerseys were highest, Holsteins were at 63.8%. Crossbreds were higher than the purebreds with 69.4% of CB50s and 69.1% of CB90s remaining in the herds for an additional lactation. All purebred and crossbred groups had 0.3 or 0.5% of lactations ended by an abortion.

TABLE 1. Percentages of cows (ALL BREEDS and CROSSBREDS) completing lactations by reason for termination and breed (2014). ¹Breed is determined from individual cow records, and cow's breed is used to determine the breed for herd counts. For example, a Holstein herd with a few Jersey cows would be included in the herd count for both Holsteins and Jerseys. The total number of herds across all breeds is much higher than the actual number of herds in Dairy Herd Improvement programs.

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Because of breed differences in the percentage of cows remaining in the herd, percentage sold for other reasons was often reversed. Across all groups, the cows coded as sold for dairy was 3.4%; percentage of Holsteins and Ayrshires were the extremes for purebreds at 3.1% and 7.9%, respectively. Percentages of crossbreds sold for dairy (2.3 and 3.1%) was low. For all groups, unspecified reasons, low production, reproduction problems, and mastitis/high somatic cell score (SCS) accounted for 9.8, 6.3, 4.8, and 4.1%. Crossbreds were intermediate to Holsteins and Jerseys in percentage reported culled for reproduction, mastitis/high SCS, or locomotion. Percentages of crossbreds sold for low production was similar to the average percentage of all purebreds. The percentage of Holsteins and Jerseys that died was similar (5.6% and 5.5%). The lowest percentage of animals coded died was for Milking Shorthorn (4.0%).

Table 2 shows the percentages derived from only animals that left the herd excluding those sold for dairy purposes. This gives a clearer picture of the relative importance of the various reasons for exiting. Unfortunately, for 30.6% of all cows leaving the herd, the reason was unspecified (26.7 to 37.1%), the highest in every group. Low production or reproductive problems (depending on breed) were generally the next most frequent codes assigned for cows exiting the herd (7.7 to 23.9%). Low production was the second most frequent reason in Holsteins, Milking Shorthorns, and crossbreds, while reproduction problems was second for Ayrshires, Brown Swiss, and Red & Whites. Death was the second most frequent reason for Guernseys (23.9%) and Jerseys (21.2%). Death and mastitis/high SCS were also important causes for departures (14.5 to 23.9% and 8.4 to 13.9%, respectively).

TABLE 2. Percentages of cows (ALL BREEDS and CROSSBREDS) leaving the herd except for dairy purposes by reason for termination and breed (2014). ¹Breed is determined from individual cow records, and cow's breed is used to determine the breed for herd counts. For example, a Holstein herd with a few Jersey cows would be included in the herd count for both Holsteins and Jerseys. The total number of herds across all breeds is much higher than the actual number of herds in Dairy Herd Improvement programs.

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More detailed information by parity is in Table 3 for Holsteins, Table 4 for Jerseys, Table 5 for other purebreds, and Table 6 for crossbreds. Purebreds other than Holsteins and Jerseys and crossbreds groups were combined because of small numbers, especially in later parities. Clear differences across parity are evident for all groupings as each were less likely to complete the lactations as they aged. Although 73.5% of Holsteins remained in the herd when lactation 1 ended, those percentages dropped to 66.6, 58.1, 50.4, 44.5, and 38.8 as lactations 2 through ≥6 ended. Likewise, Jerseys remaining was 71.7, 71.7, 66.0, 58.6, 53.1, and 46.5%. Other purebreds and crossbreds declined as well across lactations, from 71.9 to 48.2% and from 77.4 to 45.3%, respectively.

The probability that lactations were terminated by abortion was low (0.2 to 0.5%) for all lactation and breed groups. The frequency of recorded abortions has declined from 0.7% in 2007 and 2008 (Norman et al., 2009) to 0.3 and 0.4% in 2014. Percentage sold for dairy purposes generally decreased as lactation number increased as younger cows are preferred due to their longer expected life.

Because of the declining percentage staying in the herd and sold for dairy across parities, one would expect those leaving the herd for other reasons to increase. The trends across parity are clear and consistent for Holsteins. Holstein cows sold for mastitis/high SCS increased from 2.0 to 8.6%, for locomotion issues from 0.8 to 3.7%, for low production from 5.3 to 9.0%, and for reproductive problems from 4.1 to 6.4%. The largest increase was for those sold with reason unspecified, from 6.7 to 19.3%. The percentage of Holstein that died increased from 3.2% during lactation 1 to 11.5% during lactations ≥6. The percentage of cows of the other breeds that left for these five reasons increased across parities as well.

TABLE 3. Percentages of HOLSTEIN cows completing lactations by reason for termination and parity (2014).

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TABLE 4. Percentages of JERSEY cows completing lactations by reason for termination and parity (2014).

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TABLE 5. Percentages of other purebred cows (AYRSHIRE, BROWN SWISS, GUERNSEY, MILKING SHORTHORN, and RED & WHITE) completing lactations by destination category, reason for termination, and parity (2014).

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TABLE 6. Percentages of CROSSBRED cows completing lactations by destination category, reason for termination, and parity (2014).

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Tables 7-10 show the percentages of Holstein, Jersey, other purebred, and crossbred cows, respectively, assigned to the various termination codes by lactation number for all animals that left the herd except for those sold for dairy purposes. Within all 3 purebred groups and parities, “sold for unspecified reasons" accounted for the highest percentage of exiting (28.4 to 37.8%). This could represent all reasons not designated, or simply indicate no reason was given; most likely more of the latter. Died (14.7 to 23.8%) and sold for low production (12.7 to 26.8%) were the next most common code assigned in all breeds, usually followed by sold for reproduction (9.0 to 19.6%). Mastitis/high SCS (8.9 to 15.2%) was the next most frequent reasons for leaving. Two codes added to the TC list recently were assigned infrequently, sold for locomotion (1.1 to 6.5%) and for udder problems (0.0 or 0.1%). Perhaps there were no comparable codes within some of the DRPCs that translated into these.

TABLE 7. Percentages of HOLSTEIN cows leaving the herd except for dairy purposes by reason for termination and parity (2014).

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TABLE 8. Percentages of JERSEY cows leaving the herd except for dairy purposes by reason for termination and parity (2014).

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TABLE 9. Percentages of other purebred cows (AYRSHIRE, BROWN SWISS, GUERNSEY, MILKING SHORTHORN, and RED & WHITE) leaving the herd except for dairy purposes by reason for termination and parity (2014).

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TABLE 10. Percentages of CROSSBRED cows leaving the herd except for dairy purposes by reason for termination and parity (2014).

References

Hare, E, H.D. Norman, and J.R. Wright. 2006. Survival rates and productive life of dairy cattle in the United States. Journal of Dairy Science 89:3713–3720.

Nieuwhof, G.J., H.D. Norman, and F.N. Dickinson. 1989. Phenotypic trends in herdlife of dairy cows in the United States. Journal of Dairy Science 72:726–736.

Norman, H.D., J.R. Wright, and J.E. Lombard. 2009. Reasons that cows in Dairy Herd Improvement Programs exit the herd. AIPL Research Report CULL1 (9-09).