Many producers and auction markets are realizing the many benefits of palpating heifers prebreeding. I will try and highlight some of these and explain how this may economically benefit your operation.
With the advent of very early-maturing breeds it is not unusual for unwanted pregnancies to occur if breeding bulls are left out late.
Some heifers can breed as early as four to five months old. By palpating early, these pregnant heifers can be identified and removed from the breeding group.
If they are not heavily pregnant (less than four months) abortion is a possibility as long as there is ample time for rebreeding. My advice for heavily pregnant animals is to calve them out. A fair percentage will calve normally. Palpating will at least identify them and give you an opportunity to segregate and watch them.
In palpating open heifers, we are looking for several things. An intact uterus is necessary to conceive and evidence of cycling is detected by palpating both ovaries. With many large herds the records of twin calves can often be lost with the grafting of twins to other cows.
Freemartins (heifer calf born twin to a bull) can be detected by a skilled veterinarian and eliminated, as often only a very rudimentary uterus is present. Conversely in about five per cent of freemartin cases an intact uterus with two ovaries are present and they can be retained.
Ranchers who purchase heifers often get caught with several of these, since freemartins grow very well and present as top-end heifers at auction.
Various strategies for grading the development of the reproductive tract have been tried. These are based on size of the reproductive tract and degree of functioning to the ovaries.
Veterinarians basically want an adequately developed uterus with ovaries that are showing some sign that cycling is occurring. This is more critical the closer to breeding season that the palpating is done.
If we select this way we are selecting for early maturing. Keep in mind certain breeds develop earlier than others. If you have lots of grass, freemartins will exhibit growth approaching that of bulls. They commonly still cycle from rudimentary ovarian tissue, so will keep the bull busy all summer.
Pelvimetry can also be performed at the same time. A Rice or Krautman pelvimeter are both accurate in experienced operators’ hands. Both measure minimum height and maximum width. I am most familiar with the Krautman tool, which then calculates pelvic size in cm2 and can predict the birth weight in lbs. of calf a cow could have with no to minimal assistance.
A cruder approach is when palpating using your outstretched hand to at least identify the very small pelvises. This will help avoid potential C-sections or hard pulls next spring. Generally speaking the larger the body weight the larger the pelvic size. A researcher from Alberta did prove it was possible to select for larger pelvic size, while keeping body weight the same.
Miscellaneous problems are also detected at palpation time. I have picked up problems such as peritonitis, kidney problems, uterine infections etc. All these conditions make it undesirable to keep the heifer as a replacement and conception is usually poor anyways.
In rare instances, rectums are even scarred down as a result of previous bouts of coccidiosis. If they are unable to be palpated they should not be kept.
Processing heifers at this stage allows a very good opportunity to give your booster of blackleg and protect them from the major reproductive diseases IBR and BVD.
Weighing is also an extremely useful tool. The top five per cent of heifers are usually culled for several reasons. They are large and will command a good market price, plus fertility is generally poorer since they have more masculine tendencies.
Producers are realizing the more moderate cow is the most efficient. Large heifers end up being very large cows and if bred have extremely large calves. This is a principal definitely worth considering. I have lost track how many times over the years a producer’s largest, and in his or her eyes, best heifer comes open at preg-checking time.
Palpating heifers is a relatively quick procedure with many intrinsic benefits. It is a very common practice to perform now with open heifers being sold for breeding. Purchasers can buy with confidence knowing reproductive soundness has been checked. Unwanted pregnancies are eliminated and the percentage open rate in the fall can definitely be cut down substantially.
If synchronization programs with MGA, prostaglandins or the new CIDRs are utilized, it’s possible to get the majority of your heifers calving early. Think of having your replacement heifers palpated this spring, especially if grass is in short supply.
Roy Lewis is a large animal veterinarian practising at the Westlock Veterinary Centre. His main interests are bovine reproduction and herd health