Post by Tammy on Apr 1, 2010 20:29:39 GMT -5
Found an article that although written for large dairies, has a lot of good information for the family cow owner.
Here are a few things I pulled out of it:
More than 90 percent of cows should show heat by 50 days postpartum. Cows should cycle every 21 days by that time.
The most reliable sign a cow is in heat is standing to be mounted by a herd mate. Each stand lasts only 4 to 6 seconds. Cows average about 1½ mounts per hour and are in heat 6-8 hours.
Therefore, cows are only in heat a little more than a third of a day and only spend a total of 3 to 5 minutes actually standing to be mounted. It is easy to under-stand why cows must be observed for heat several times daily.
Also, producers should monitor secondary signs of heat. These include:
* mounting other cows
* clear mucous discharge
* chin resting and rubbing
* swollen red vulva, frequent urination
* muddy flanks and ruffled tailhead
* bawling, restlessness, sniffing behavior
* decreased milk production and off feed
These indicators may signal that a cow is in heat, coming into heat or going out of heat. However, base the decision to inseminate on standing heat, not on secondary signs of heat.
The article goes on to explain when the optimum time for breeding would be within the heat cycle:
Highest conception occurs if animals are bred 4 to 14 hours after onset of heat. With good heat detection, time of breeding should follow the AM-PM rule. An animal in heat in the AM should be inseminated that PM. An animal in heat in the PM should be bred the next AM.
Although the traditional AM-PM rule has proven reliable in most cases, studies in Virginia and Tennessee have shown no difference in conception when breeding cows on a once-a-day schedule in the morning compared to the AM-PM rule. Animals in heat in the AM are bred that morning. Animals in heat in the PM (after 12 noon) are bred the next morning (or AM). Breeding animals once per day would be more efficient for many Georgia producers, especially when artificially breeding heifers. However, producers must continue to monitor heat activity a minimum of twice each day (AM and PM). Producers can consider once-a-day breeding as an option to the AM-PM rule.
Another section of the article I found to be of particular interest was the segment discussing the use of herd mates to help detect heat:
Herdmates play an important role in a heat detection program. Pregnant cows, or those in the early half or luteal phase of their cycle, do not make good heat detectors. Cows in heat, or cows coming into or going out of heat, make excellent detectors. As the number of cows in heat increases, the number of mounts per heat period also increases.
Thought this might be helpful to some and wanted to share!
Tammy
Updated link: 2.20.11
Here are a few things I pulled out of it:
More than 90 percent of cows should show heat by 50 days postpartum. Cows should cycle every 21 days by that time.
The most reliable sign a cow is in heat is standing to be mounted by a herd mate. Each stand lasts only 4 to 6 seconds. Cows average about 1½ mounts per hour and are in heat 6-8 hours.
Therefore, cows are only in heat a little more than a third of a day and only spend a total of 3 to 5 minutes actually standing to be mounted. It is easy to under-stand why cows must be observed for heat several times daily.
Also, producers should monitor secondary signs of heat. These include:
* mounting other cows
* clear mucous discharge
* chin resting and rubbing
* swollen red vulva, frequent urination
* muddy flanks and ruffled tailhead
* bawling, restlessness, sniffing behavior
* decreased milk production and off feed
These indicators may signal that a cow is in heat, coming into heat or going out of heat. However, base the decision to inseminate on standing heat, not on secondary signs of heat.
The article goes on to explain when the optimum time for breeding would be within the heat cycle:
Highest conception occurs if animals are bred 4 to 14 hours after onset of heat. With good heat detection, time of breeding should follow the AM-PM rule. An animal in heat in the AM should be inseminated that PM. An animal in heat in the PM should be bred the next AM.
Although the traditional AM-PM rule has proven reliable in most cases, studies in Virginia and Tennessee have shown no difference in conception when breeding cows on a once-a-day schedule in the morning compared to the AM-PM rule. Animals in heat in the AM are bred that morning. Animals in heat in the PM (after 12 noon) are bred the next morning (or AM). Breeding animals once per day would be more efficient for many Georgia producers, especially when artificially breeding heifers. However, producers must continue to monitor heat activity a minimum of twice each day (AM and PM). Producers can consider once-a-day breeding as an option to the AM-PM rule.
Another section of the article I found to be of particular interest was the segment discussing the use of herd mates to help detect heat:
Herdmates play an important role in a heat detection program. Pregnant cows, or those in the early half or luteal phase of their cycle, do not make good heat detectors. Cows in heat, or cows coming into or going out of heat, make excellent detectors. As the number of cows in heat increases, the number of mounts per heat period also increases.
Thought this might be helpful to some and wanted to share!
Tammy
Updated link: 2.20.11