Selection and Selection and management of bulls, management of bulls, cows and calves intended cows and calves intended for breedersfor breeders

Setting goals for beef cattle Setting goals for beef cattle breedingbreeding

Some traits that commercial breeders consider for selection goals, include:◦ Low birth weight for ease of calving. ◦ Weaning weight or pre-weaning rate of gain. ◦ Post-weaning rate of gain. ◦ Efficiency of feed conversion. ◦ Mature mass. ◦ Mothering ability. ◦ Carcass traits. ◦ Conformation.

The Selection and The Selection and Management of Breeding Management of Breeding BullsBullsThe right geneticsAge of bullsManagement on the day of

turnoutThe start of the fourth week of

the mating period Rotating bulls

The right geneticsThe right geneticsSelect top quality bulls to maximise the

outputAssessing the genetic package a bull will

pass onto his offspring is often more difficult than assessing structural aspects.

Some of the physical traits are of limited value as indicators of genetic merit.

Much more useful information is provided by recording differences in performance among animals run under the same conditions.

If differences are observed in situations where animals are given the same opportunity to perform then it is more likely that the differences are due to variation in genetic merit.

Age of bullsAge of bullsExperienced mature bulls can

easily cope with around 40 cowsIn comparison young bulls in

their first mating season can only cope with around 15 cows and even then only for a short 3 – 4 week period.

Management on the Day of Management on the Day of Turnout.Turnout.

When the bull is turned out there is a good chance that at least one of the cows will be in season.

It is therefore sensible to wait for half an hour and watch if the bull serves successfully ie successfully enters the cow and jumps.

This is particularly important for young bulls being used for the first time.

The Start of the Fourth The Start of the Fourth Week of the Mating Period Week of the Mating Period The most critical time to check how well the

bull is performing. A fit fertile bull should stop around 60% of

the group in the first 3 weeks. For a bull running with around 35 cows this

would mean around 17 – 21 cows becoming pregnant in the first 3 weeks.

The remaining 15 cows would come back into season over the second 3 week cycle.

On average this would be less than one cow served per day

Rotating BullsRotating Bulls

Traditionally move bulls between groups of cows every 3 weeks to minimise the impact of an infertile bull.

Unfortunately rotating bulls tends to have the reverse effect, making it difficult to identify problem bulls unless precise records are both kept and fully analysed each year.

The more effective and much safer way of more rapidly identifying an infertile bull is to closely observe cows at the start of the fourth week of the mating period as described above.

Selection of Selection of cows/heifercows/heiferSelect heifers at weaning based on these

economically important factors:

◦ Early birth in the calving season — early born heifers will have a head start on development, reach puberty sooner and have higher conception rates earlier in the breeding season

◦ Heavier weaning weights ◦ Utilize adjusted weaning weights to account for age

differences ◦ Fertility of the dam ◦ Calving ease ◦ Milking ability ◦ Structural soundness and frame size ◦ Disposition

Calf selectionCalf selectionweaning weight, yearling weight, birth weight feed efficiency