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When dairy cows leave too soon

Posted: January 21, 2008

Extension Weekly News ArticleFor week of: Jan. 11th, 2007Contact: Robert C. Goodling, Jr.Extension Educator, Dairy/Livestock717-270-4391 rcg133@psu.edu

Dairy cows leave a herd for numerous reasons. Some are sold as heifers for replacements to other dairies, others leave as dairy replacements for other dairies, some leave as a result of health concerns, and some pass away. Initial review of culling in Pennsylvania between 2003 and 2005 showed herd’s averaged a 20% cull rate within a given year, and ranged anywhere from 3% culls to over 50% culls. That would be 20 cows leaving the herd for a 100 cow dairy. The top two reasons why cows left were
injury/other and reproduction. The third highest reason was mortality, which may seem surprising at first. Recent studies suggest that mortality rates have been steadily increasing in dairy cows over the past few years. These mortality losses could affect three segments of a dairy operation: voluntary culling decisions, replacement inventory, and potential production levels.

One of the immediate impacts cow lost to death has on the farm is the culling decisions. The result of an involuntary culling by losing a cow means there is one less chance to cull another cow voluntarily. Ideally, the cow that died could have been one that was going to be culled in the near future, but rarely this is the case. Most mortality cases are unexpected, leaving little time to plan a course of action. By losing a cow, the producer also loses a culling choice and is faced with the decision: which cow should I keep around, if any? This usually means a cow that needs more specialized attention remains in the herd just to maintain herd size.

The death of a cow also impacts the replacement inventory. Once a cow leaves the herd, voluntarily or involuntarily, she will need to be replaced to maintain herd size. Here the producer has two options. First, replace her with a first calf heifer that is about to freshen. Hopefully the herd has an adequate supply of heifers, both pregnant and those nearing breeding age. On average, a 100 cow herd with a cull rate of 30% should have 70 heifers to select from on any given year. Half of these will be under one year, and the other half should be bred and hopefully pregnant. If heifer inventories for the herd are low, or there are no heifers freshening in the immediate future, the producer may be forced to purchase a springing heifer or a cow already in lactation. This can be risky, as stress of moving the animal between locations may affect the health and thus the milk production of the animal.

The final area affected by a mortality case is the impact on milk production. If a cow that dies is at or near peak production, let us say 110 pounds, and she’s replaced by a first lactation cow that starts at say 30 pounds, it will be awhile until that cow will peak, resulting in lower herd production for a few weeks. A riskier scenario would be if the cow that has died is in her first lactation. This cow may not have been in production long enough to cover the $1200-$1500 investment the dairy producer has in her as a replacement. Let’s assume the producer makes a profit of $0.06 per pound of milk for this cow. She would need to produce 20,000 pounds of milk (which is roughly the amount of milk for 1 lactation of the average cow in Pennsylvania) to cover her investment. When this cow dies before she finishes her lactation, she is taking part of the producer’s investment along with her.

No producer likes to see a cow leave the herd as a mortality case. It reduces their chance to cull a different cow, reduces their replacement inventory, and can decrease production. Depending on the age of the lost cow, it may also impact the farmer’s ability to break even on their investment into that cow. Penn State Cooperative Extension will be presenting a one day workshop entitled “More Money with the Same Number of Cows – Reducing Cow Damage and Death Losses”. This workshop will address ways to minimize the impact damaged cows and cows lost to mortality have on the profitability of a dairy operation. The workshop will be held at the following locations: February 19th-
Ickesburg Fire Hall, Ickesburg, PA; February 20th – Family Traditions Lighthouse Restaurant, Chambersburg, PA; February 21st – Shady Maple Smorgasbord, East Earl PA; February 22nd – Cabela’s, Hamburg, PA. Controlling which cows leave the herd may not always be an option, but the best way to manage mortality in a herd is keeping accurate records of mortality and cull cases, as well as adequate levels of replacement animals.

Rob Goodling is the Penn State Cooperative Extension Educator for Dairy/Livestock, Farm & Data Management serving the Capital Region. Penn State is committed to affirmative action, equal opportunity, and the diversity of its workforce. Penn State Extension in Lebanon County is located at 2120 Cornwall Road, Suite 1, Lebanon PA 17042, phone 717-270-4391, e-mail LebanonExt@psu.edu.

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