It's hard to believe that my "little" girls are growing up! Princess is now 17 months old, Liza and Tori are both 12 months old, and the baby, Promise, is six months old. Little Dave, the bull is now 12 months old. What all of that means is that this summer I will begin breeding my second generation. This is pretty exciting to me because I will be one step closer to having the herd I have been working towards for three and a half years now. My desire is to someday have an entire herd of miniature cattle but it has been a slow process considering that I have had many more bull calves than heifer calves during this time. We typically strive to breed the Jerseys when they are around 15 - 18 months of age. I have been holding off a bit on Princess not only because she is so small but also because I would rather have her first calf be born in the spring rather than in the winter.
With all these thoughts of breeding the young heifers in the coming months, I decided it was probably best I started keeping a little better track of their heat cycles. Since Tori was in standing heat today, I can anticipate that she will come back in heat in 21 days. By keeping a record of when she cycles, I will know when to put her in with the bull (or if I were going to artificially inseminate, this information would be even more helpful!)
I found a great article online called Heat Detection Strategies for Dairy Cattle. While the article is really written for large dairies, it has a lot of useful information even for the family cow owner. For instance, this section on what signs to look for is very informative for individuals who may not be familiar with understanding the heat cycle of cattle:
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.
Well, there was certainly a lot of activity out in the field today and there was no doubt that Tori was in standing heat. I will be watching and keeping track of her cycles and probably in July or August be putting her in with the bull.
Isn't this fun? I love it!
(Picture of Pretty Victoria)