Choosing the right genetics is key
Finding the perfect blend of genetics that promotes easing calving yet plenty of growth potential can be a challenging task. Producers must weigh the pros and cons of choosing to utilize a low birthweight bull for calving ease yet potentially lose ground on calves’ growth and weight.
Birthweight Relation to Growth: Though smaller calves aid in an easier birth, they will have some catching up to do when it comes to growth.
“It’s difficult to make the blanket statement that lighter calves are always at a disadvantage to their heavier-born counterparts, nevertheless, those that are born lighter do have a bigger hurdle to jump in their early lives,” Andy McCorkill, University of Missouri Extension Regional Livestock Specialist, said. “Calves that are born lighter than the herd average will have to gain more weight to meet target goals at weaning.”
Livestock specialists encourage producers wanting to strike a balance between calving ease and growth to pay close attention to herd sire’s EPDs. A good practice includes selecting herd bulls with acceptable Calving Ease Direct (CED) and Weaning Weight (WW) numbers. “CED is a measure of how calves born of a sire should be born. As the CED number increases, the likelihood of calving difficulty decreases,” McCorkill explained.
Another EPD producers may want to evaluate is Calving Ease Maternal (CEM), this is a measurement of how daughters of a particular sire should perform when calving. When analyzing EPDs, remember higher CED and CEM numbers indicate reduced incidence of calving difficulty. Though finding a balance between calving ease, birthweight, and weaning weight can be a challenge, livestock specialists say the effort can payoff.
Calving Ease Heifers: Calving ease EPDs are at the top of the list when it comes to traits producers will want to evaluate when looking for herd bulls to use on heifers because heifers have not reached their mature size yet. “Following the MU Show-Me-Select protocols has been proven to significantly reduce the incidence of dystocia related problems and has become a standard recommended practice for many area veterinarians,” McCorkill said.
The program utilizes protocols that consist of several management steps. Heifers undergo a pre-breeding exam conducted 30 to 45 days prior to the start of breeding season. The pre-breeding exam should include pelvic area measurements and evaluation of the reproductive tract. “Heifers that have a pelvic area of under 150cm2 are generally considered as a risk, as they may not be big enough to birth a calf unassisted,” McCorkill explained.
During the pre-breeding exam heifers are evaluated and given a reproductive tract score. Reproductive tract scores range from 1 to 5. A reproductive tract score of 1 indicates the heifer is completely immature, and a score of 5 indicates she is already cycling. “Many of the producers I work with have reached the point that all tract scores of 1 and 2, and those with small pelvis measurements are culled at this point before they incur any additional expense or get big enough to take a big price hit at the market,” McCorkill stated.
Additionally, utilizing herd bulls that rank at the top of their breed for CED and from a breed that is complimentary to the operation’s herd genetics plays an important role in heifers calving successfully. To find acceptable CED numbers by breed, the University of Missouri Extension has charts online or in the local extension offices.
Calving Ease Mature Dams: Livestock specialists advise when it comes to a mature cow herd the focus on calving ease isn’t as big of a concern as it is with heifers. In the case of a mature cow herd, the emphasis can be more about pairing the right traits with a bull battery to meet the operation’s end goal.
“Striking the balance of calving ease, growth and carcass traits to meet your end game is a difficult challenge, but that’s what makes the breeding business fun, and it is worthwhile. With the use of EPDs, data from past and present reproductive evaluation and a close eye on functional characteristics of individuals, that balance can be found,” McCorkill stated.
