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Breed Improvement

Weaning the Whole Herd By Sean McGrath Breed Improvement Co-ordinator For The Canadian Simmmental Association


all is a busy time of year, and for many of us it is the culmination of the work of our cowherds. We get to see how the calf crop has done, assess the status of our breeding programs and move forward into the next production cycle. While one may always be impressed by weaning weights and production levels, it is important to remember that fertility still trumps growth in terms of its importance to profitability. Simmental genetics have added productivity to the commercial industry, and breeders have done a tremendous job adding performance to their cattle over the last 50 years that Simmental has been in Canada. The Simmental breed is widely recognized for their maternal strengths and have perhaps brought more to the industry in terms of overall cowherd productivity than any other aspect of the breed. It could be argued that the Simmental-cross cow has changed the Canadian beef industry. While fertility traits are often viewed as lowly heritable (less influenced by genetics) than traits such as growth, they are still influenced by genetics. One of the historic reasons for this “low” heritability is a lack of good cowherd based data. It is difficult to figure out the influence of genetics on a trait when you don’t have good data on that specific trait. This is one of the primary reasons for the Total Herd Enrollment program where active cows are enrolled every year. Tracking the cows that are bred, and subsequently wean a calf is a key tool to identify maternal genetics. Weaning rate is defined as the number of calves weaned per cow exposed, which is a key indicator of maternal efficiency. The industry average weaning rate is roughly 85% when we look at data from sources such as the Agri-Profit$ program in Alberta, or the Western Beef Development Centre in Saskatchewan. For every cow that is exposed to breeding, her ability to calve and wean a calf is key to industry profitability. An 85% value means that out of every 100 cows exposed to a bull, only 85 calves are weaned. There is a large opportunity for improvement in this number. This is why, it is so important to report every result. By this I mean, that we need to report a result (success or failure) of a cow to wean a calf every year. Let’s look at the following simple example. If we take a cowherd with 5 cows and we fail to report calves for things like unmarketable birthweights, we indirectly raise the birthweights of other calves in relation to the average. This is shown in the Selective BWT Reporting portion of the table. By failing to report the calf with the 110 pound BWT, the remaining calves have their deviation from group average raised, thus increasing their BW EPD (Select BW). Further, we now have a reported weaning rate of only 80% (4 out of 5 cows with a calf) even though every cow successfully calved. Failure to report all calves results in a 20% loss of the most important data to profitability in this case.

If we take this one step further and the poorest weaning weight calf is not reported, we reduce the deviation for weaning weight from the average, thus reducing the WW EPD (Select WW). This may be compounded if we already failed to report the heavy BWT calf (Select WW2). More importantly, the weaning rate is now only 60% (3 out of 5 cows reported a successfully weaned calf). Even though the cowherd actually weaned 5 calves, the data shows that it is well below industry average. This is not a fair representation of what is actually occurring on the important trait of weaning rate.

If we are concerned about making genetic improvement in fertility and cowherd success, it is important to report on every calf and every cow. Weights are important; however, it is more important to ensure that calving and weaning success or failure are reported on all calves, even those that may not be weighed. For example, if you don’t own a scale capable of weighing calves at weaning or if a calf escapes and cannot be weighed at weaning with the rest of the calves it is still important to report the success or failure of the cow to raise and wean a calf. This can be done simply through the submission of disposal codes. If a calf is still active and weaned or died pre-weaning, that information should be reported. Similarly; if a cow does not have a calf or she is sold prior to calving or weaning, this information is also important to note. It is as simple as providing a weaning date or a disposal code and date on the animals. This fall the CSA is working on providing reporting on cows that have been enrolled but have not had a calf or disposal event reported. These will hopefully provide a useful reminder for members to ensure that each cows reproductive success is reported each year. The data can then be used to further enhance the already present benefits of Simmental as a maternal breed of choice.

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11/15/2017 1:55:24 PM

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