Q.   At what age or size should you start breeding heifers?
A.   The heifer should attain two-thirds her mature size before she is bred. Example: If the animal's expected mature weight is 1000 Ibs., then she could be bred at 650 Ibs. or over. Many breeders like to breed heifers at 14 to 15 months of age in order to have them calve when 24 months old. If she has reached the desired weight and has had several good heat periods she should conceive when bred by artificial insemination (AI). Heifers not exhibiting normal heat periods, or who have not attained adequate size, should not be bred until they do. In general, heifers seem to settle better than cows when bred artificially.

Q.  How many days after freshening should you start breeding cows?
A.   The amount of time you wait after freshening (calving) depends on: (a) The amount of weight loss between freshening and the time you want to breed the cow. The greater the weight loss, the longer it takes for the cow to have a normal heat period, (b) Whether or not the cow had calving problems, (c) Whether she is cycling normally, (d) When you want her to calve the following year.

Q.   How do you detect the heat period?
A.   Detecting the heat period is very difficult if you have only one or two animals. In the early stages the animal will often pick another to butt heads with. Very often a clear vaginal discharge will be present. Later, usually within 24 hours, she will stand when mounted and/or will mount other animals. After the 'standing' period, the cow sometimes will butt heads again. A small amount of bloody discharge often appears on the tail within 48 hours after a standing heat.

Q.  How do you know when to breed the cow during the heat period? Also, how many times should the cow be artificially inseminated?
A.   Ideally, the animal should be bred at the end of standing heat. After reaching maturity, females will have approximately 21-day heat cycles. The length of the heat period varies greatly between animals. It is best to observe and record all heat periods the cow has, to help determine the pattern she exhibits while in heat. If the timing of the breeding is accurate, the cow should have to be inseminated only once each heat period. If the period is longer than anticipated, or the signs of heat are questionable, breeding more than once at 24-hour intervals can be helpful.

Q.  What are the factors that reduce the animal's conception rate?
A.   One factor to consider is that the cow may not be in a normal heat. (a) This is most commonly caused by an energy deficit. The effects can range from not cycling at all to cycling internally, but not exhibiting noticeable outward signs. The most common reason for this is that the cow is using up more energy feeding herself and her calf than she is consuming, causing her to experience a negative energy balance and loss of weight. The first cornpensation for this energy deficit by the cow is to cease reproductive activity. (b) Cystic ovaries may cause a hormonal imbalance that prevents the cow from having a normal heat period.

Other factors to consider are: Timing of the breeding. Quality of the semen. Handling of the semen. Heat stress. If the cow's internal temperature gets over 104 degrees, the conception rate is severely decreased.

The expected conception rate on cows bred artificially with normal heat periods is 50 percent.

Heat detection can be aided by the use of prostaglandin injections or syncromate-B implants. Neither of these products will make the heat exhibition stronger, however, they can markedly improve the timing of the breeding.