DHI Notes...

October 07 | Visual heat detection still works | Bennet Cassell

State DHI averages for important management areas in September 2007

Management area	Sept 2007	Change from last year
Rolling herd average milk	21698	-29 lbs.
Peak yield in heifers	75	-1 lbs.
Days to first breeding	95	0 days
Days open	165	-1 days
Net Merit of proven service sires	296	$10
Herd turnover less dairy sales (%)	28%	-1%
Monthly average SCS	3.2	-0.2
Feed cost per cwt. (milking cows)	$5.90	$0.25
Milk blend price	$21.47	$8.16

The coming of cooler weather brings with it a need and an opportunity. The need is to get cows pregnant, particularly those that calved several months ago and were not successfully bred during summer’s heat or were not bred at all due to press of harvest season, quiet estrus displays, or something else. The opportunity is to take advantage of cooler weather through a more aggressive breeding program. Options for aggressive programs are more varied than they were several years ago, and include a variety of synchronization programs. I want to encourage producers to continue to include heat detection in the “aggressive” category. Cows will still come in heat without drug intervention. Many of them really don’t have to have five or more shots before first breeding. Producers have to LOOK for those heats, however. Mature, high producing cows don’t mount very often, and may be in heat for only a few hours. They will be most active when encouraged to interact with other cows, as when on dirt exercise lots or during trips to and from the milk parlor. One of the best aids to heat detection is an accurate heat expectancy chart, which can be generated easily by DHI after test day or on demand with PCDART or other herd management software. Carry the list in the barn, and look for standing estrus or other signs of heat on each cow on the list. Tail chalking is an excellent practice when properly used. It can help identify which cows have been ridden, but may help even more because cows expected to come into heat have been identified to apply or refresh chalk and are easy to spot in a group. With larger herds, easy to read ID tags are more important than ever, as is a note pad and a pen that works to write down which cows are in heat. The old AM-PM rule still holds for time of insemination – in heat in the morning, breed in afternoon, in heat in the evening, breed the next morning. Conception rates are best for cows bred by the AM-PM rule on standing heats. Perhaps it is no longer realistic to expect to breed all cows on standing heat in larger herds, but it is not necessary to give up on it entirely, either. The money for those synchronization drugs can be spent in other ways – like on semen from high ranking bulls to use on cows in standing estrus!

Bennet Cassell
Genetics and Management