Beefmaster is a synthetic breed that is made up of Brahman, Hereford and Shorthorn. Years of selective breeding have ensured that that the best characteristics of each contributing breed is kept. Beefmaster have always been very strict on culling on vital characteristics such as poor weaning mass and poor cow fertility. This has ensured the capable animals are all that are bred with.
The strength in ranking with other breeds for weaning mass as well as cow fertility is what gives the breed its true value. These traits are traditionally not correlated or genetically coupled to each other. So, the major question is how did Beefmaster get it right to be very strong in both these characteristics at the same time ?
Fertility as a genetic trait will always remain hugely important because of its contribution to financial viability of any herd. Many publications have estimated the heritability for fertility as low. There are thus many non-genetic factors such as environment that play a role. To name one, Single-sire natural mating data from a beef cattle herd in tropical Australia were used to estimate heritability of cow fertility ( hc2 ), heritabilities of bull fertility ( hb2 ) and genetic correlations between cow and bull fertility (rg) Estimates of hc2 and hb2 were low, averaging .11 and .08, respectively. The pooled estimate of rg was 0.16, indicating that cow and bull fertility are favourably genetically correlated and therefore that cow fertility could be genetically improved by indirect selection on bull fertility, or some more heritable component of bull fertility.
Adaptability seems to be the foundation to the fertility performance of a herd and thus individual animals. One of the keys to surviving in the cow-calf production system is adaptability, which is determined by how well one’s cows fit the environment they live in. Hair Coat, Tick Ressistance, Condition throughout the year, Early Pregnancy in the breeding Season are major easy to spot indicators. The herd pregnancy rate should be 90 percent or more. A goal should be set that more than 95 percent of the cows exposed to the bull last year should be ready to calve or already have calved this year.
Nonpregnant cows are not adapting to the local conditions and need to leave. Another indicator of adaptability is calving distribution. Two-thirds of the cows should calve within three weeks of the start of the calving season and 90 percent should have calved within six weeks in a highly adapted herd.
Research has shown that body condition is the No.1 indicator on the ability of a cow to calf, rebreed and maintain a 365-day calving interval. Remember, if the cow is thin, she needs to gain weight for her sake and her unborn calf. Upon birth, the best colostrum is needed in that first drink so the calf stays healthy. Fertility is one of the most vital traits linked to the profitability of a Beef Herd, and is closely associated to fertility levels in a herd.
Where does the second trait, that we consider so important come into the picture? The influence of the sire on weaning weight has been estimated as reasonably high in several breeds. Estimates of heritability and the standard error for Hereford, Angus and the combined breeds were 0.33±0.08, 0.32±0.16 and 0.32±0.07, respectively. For the purpose of this article we will accept the heritabilities of weaning weights as listed. These are higher than those of fertility and significant to be included in even the most basic of breeding plans.
Many estimates regarding the correlation between weaning weight and cow fertility show a negative correlation between the two traits. Some breeds are exceptional at one or the other trait but not many breeds are exceptional for both these traits. Fair speculation surrounds the logic of how this was achieved.
The foundation of exceptional fertility is influenced by the adaptability of the individual cows. It is now to consider if weaning mass is similarly influenced.
Environmental limitations are a reality in any beef production herd. The efficient production of saleable beef is a key concept in the financial survivability of any herd. Some of these concepts can be listed as follows:
Feed Conversion Efficiency /Residual Feed Intake
Residual feed intake is calculated using a regression equation involving metabolic body weight and average daily gain, where a more efficient animal will have a negative or low RFI, indicating they consume less than predicted whilst maintaining the same level of production
Cow Maintenance Value
The Cow Maintenance value is expressed as an index where below 80 is very poor and 80 to 120 is within the acceptable range. This is greatly associated with the Mature Cow Weight. The higher the cow mass (measured at time of weaning) the higher the cow maintenance value. Oversized cows are normally not the efficient converters of grazing to weaning mass.
Cow Calf Ratio at Weaning
The mass of the calf at weaning divided by the mass of the cow at weaning gives a ratio. Many breeds have herd averages between 42% and 50 % The better cows in a herd are around 50% and some even higher.
Successful beef producers realize that real success is measured in the profit and loss statement of their beef herd, Many commercial cattlemen sell their calves immediately after weaning. In these marketing programs weaning weight is an economically relevant trait .as it is directly associated with the income and costs of production. Adaptability in tropical beef cattle can be assessed by measurable traits such as growth under the influence of environmental stressors.
Two of the most vitally important traits in profitable cows are excellence in fertility and in heavier weaning weights. These traits are not genetically correlated so why is it that the Beefmaster breed can simultaneously show growth in both traits and feature right at the top of any breed ranking in both these traits. The common key seems to be the attribute of adaptability that serves as a foundation to each and every cow’s ability to wean a heavy calf aswell as falling pregnant every season.
Keep the focus on fertility and weaning mass. The Rest will look after itself.
References
