Bull Selection: Beef Kay Farmer Madison County High School edited by Billy Moss and Rachel Postin July 2001

Why is Bull Selection Important? The bull contributes 1/2 of the genetic makeup of his offspring He’s the most important individual in herd Use a bull to improve the quality and performance of your herd

It can be estimated that 87% of the genetics in your cow herd are a result of the last 3 bulls in your cow’s pedigree. Name these three breeds

Selection Criteria: Sires Varies depending on the use of the calf and the age of the cow being bred Low BW bulls are an advantage for heifers, but not necessary or desirable for larger, mature cows Look for more growth and size when breeding larger framed, mature cows

Genetic Tools - Selection Use EPD’s and other estimates of genetic potential to make permanent improvement in the genetic level of the herd Effective when heritability is moderate to high –ex: growth- high heritability –ex: reproduction- low heritability

Why Is Heritibility Important Commercial: sell cattle by weight ^ Weight at various ages is heritable WW is estimated to be: ~ 30% heritable YW is estimated to be: ~ 45% heritable

Genetic Tools - Crossbreeding Breeds can be crossed to improve heratability traits that are low Ex: Reproductive Performance - Crossing Angus bulls on Brahman cows (Brahman cattle reach sexual maturity later than other breeds)

What is an EPD Expected Progeny Difference The difference between EPD’s of two bulls is the expected difference in progeny averages when bulls are mated to similar cows in a herd # expressed in pounds & can only be used as a comparison for animals in the same breed

Which Bull Would You Select to use on mature cows when growth is the most important trait to you?

Use of EPD’s Use only to compare two or more bulls EPD’s allow valid comparisons of all bulls of the same breed, but they do not allow you to compare bulls from different breeds

EPD Charts Most breed associations provide EPD’s for : 1. Birth Weight (BW) 2. Weaning Weight (WW) 3. Yearling Weight (YW) 4. Maternal Milk 5. Carcass

Birth Weights High Birth Weight EPD’s 1. Calving Difficulty when bred to first calf heifers 2. Increased Cost and death loss

The American Angus Association suggests that sires with a birth weight EPD in excess of 3.0 pounds should not be used on first calf heifers in most cases

Weaning & Yearling Weights

What is the difference between a sire with a 45 pound EPD for yearling weight versus one that has an EPD of 5 pounds? –A. Progeny with 20 lbs. difference in YW –B. Progeny with 30 lbs. difference in YW –C. Progeny with 40 lbs. difference in YW –D. Progeny with 50 lbs. difference in YW

Scrotal Circumference Yearling bulls with large scrotal circumference sire daughters that show estrus at an earlier age Be sure to select a bull with a SC of at least 30 cm at one year of age

Milk Measured in terms of how it affects weaning weight of a calf Milk EPD on a bull is an estimate of lbs. of a calf at weaning produced by the bull’s daughter due to her milking ability

Breeding Plan Replacement Heifers Mate 1st calf heifers to bull with low BW, calving ease & large scrotal circumference Expect to use as many heifers as possible from these matings as replacements

Breeding Plan Main Cow Herd Mate the remaining cows to bulls which have EPD’s that meet market criteria Look for bulls with higher EPD’s for growth & carcass yield

How Many Bulls Will I Need Age: 1. Yearling (15 mos.) cows per 90 days year old- ~ 40 cows per 90 days Condition: 1. Poor nutrition - influence semen quality 2. Fat bulls lack stamina to breed a large number of cows

Factors Affecting A Bull’s Value # of calves the bull may sire Performance level of the herd on which bull is to be used Type of breeding system you select Bull’s Pedigree

Summary Look for traits that are economically important to you Demand & buy bulls with total performance records that will improve your herd Selecting and buying a herd bull is the quickest way to make genetic improvements in your herd besides using Artificial Insemination