When it comes to sire selection, it is important to keep in mind that the capacity of the sire is made up of both what you can and what you cannot see.
The phenotypical traits that distinguish the physical attributes of the bull are what you can see – feet and legs, frame size, testicular development, shoulder set, length, hip and head. To make this visual assessment complete, it is important to look at his dam and see her age, structure and udder development.
What you cannot see when selecting a sire is the potential for that sire to make genetic improvement through his progeny. This is expressed through EPDs or expected progeny difference(s). This set of numbers is specific to each breed and indicates a probable variance below or above the breed average for a trait. For example, Red Angus and Black Angus are considered different breeds and their EPDs are not interchangeable.
Read Also
Horns aren’t unlocking anytime soon on livestock transport standards
Standards good enough meet the definition of “humane” animal transportation still vary widely between what what industry wants, what animal rights advocates want and, between the two, what federal regulators decide is good enough.
An EPD value incorporates the animal as an individual with the averaged ancestral performance. The information is presented as pounds above or below breed average for heritable traits within the breed. Those traits most frequently reported include calving ease, birth weight, weaning weight, yearling weight, maternal calving ease, and maternal weaning weight. Some may also include important carcass traits such as rib-eye area or backfat thickness. Longevity, stay-ability, maintenance energy as well as heifer pregnancy may also be available.
Some breeds, such as Texas Longhorn, do not have EPDs and potential buyers have to research the history of the dam and sire of the progeny to make a decision. In most breeds, calving and weaning weights are available but they may not be incorporated into an EPD. Why an EPD over a weight? EPDs are five to nine times more accurate than individual performance data for predicting genetic outcome.
Calving ease
Calving ease (CE) is the ease with which a bull’s calves are born. When reading the EPD of a potential sire you want this number to be high. A CE of 8.0 is more desirable when breeding heifers than a CE of 1.3. An 8.0 calving ease will ensure easy calving and the birth weight (BW) EPD will correspond to the negative. For easy-calving sires look for a birth weight that is expressed as below zero. For example, the BW may read -1.6 which indicates a lighter calf compared to a bull with a 1.6.
When breeding first-calf heifers, look for easy-calving (CE) bulls that sire lighter calves. Older cows may be more tolerant of bigger calves and you can select accordingly, focusing on a live calf with more growth. When selecting replacement heifers, the focus needs to be on maternal traits, such as milk.
Buying a herd sire is no easy task. Single trait selection can be counterproductive. The more information there is, the easier it will be to select a sire that balances ease of birth, milk, growth and carcass traits. Next to BW on the EPD list is weaning weight (WW) and WW predicts the difference in average 205-day weight of the bulls calves compared to calves of other bulls within the breed. A positive value such as 39.5 would be more desirable than a lower value of 22.0 when it comes to weaning weight. It also hints at the milking ability of the dam.
At 365 days the yearling weight (YW) predicts the weight of that bull’s progeny against other sires within the breed. Looking for growth in a terminal program? If so, select sires that have high values in weaning and yearling weights and carcass characteristics.
Maternal attributes are the backbone of any cow-calf operation. The goal is fertile, feminine and functional females that calve without assistance and milk well. Maternal calving ease (MCE) is an indicator of the ease in which a sire’s daughter will calve as a first-calf heifer. Again, a higher number indicates unassisted births from that sire’s daughters. There is no need to worry about completely sacrificing growth. The maternal weaning weight (MWWT) is the expected weaning weight of a bull’s daughters expressed in pounds. Again, a higher value is preferred.
The mother of all maternal traits is expressed as maternal milk (MILK) and that is the milking ability of the bull’s daughters. The EPD predicts the average 200-day weight of a bull’s daughters’ calves. This too is recorded in pounds of calf at weaning weight above or below the average. A positive value reflects an above-average milking ability and is a strong consideration for replacement heifers.
In addition to the EPDs attached to each breed, buyers should insist on a breeding soundness evaluation. The most current research indicates that 20 per cent of bulls across breeds in Alberta are sub-fertile. If a semen test and scrotal measurement was not conducted, it increases the risk of sub-fertile males in any group of herd sires. Some breeds have scrotal size EPDs.
Herd sire selection is the most important activity in a cow-calf operation as it contributes to nearly 90 per cent of genetic improvement over three generations. The numbers are there, as expressed in EPDs, to help you select the right sires for your goals.
BrendaSchoeppisamarketanalystandtheownerandauthorofBeeflink,anationalbeefcattlemarketnewsletter.Aprofessionalspeakerandindustrymarketandresearchconsultant,sheranchesnearRimbey,Alberta. [email protected]
———
Themostcurrent researchindicates that20percentof bullsacrossbreedsin Albertaaresub-fertile.
