New AI programme a big hit with the replacement suckler heifers at Greenmount

Dr Norman Weatherup, Beef Technologist, CAFRE, Greenmount

90 percent of suckler heifer replacements are in calf after two Ai’s, resulting in 28 fifteen month old heifers, in calf to a bull in the top one percent for calving ease due to calve down over a three week period at Greenmount Hill Farm.

This success was achieved by combining the best practices in our local suckler industry with those used in large scale heifer operations in the USA. Getting the heifers in calf involved heat detection and AI for five consecutive days. Any heifer not AI’d was given a single prostaglandin injection which induced heat over the next four days. Thus 31 heifers were AI’d once over a nine day period, significantly reducing the amount of heat detection required. Any heifer that repeated three weeks later was AI’d again. However, success is not just about the AI programme it is about making the right management decisions based on the right information.

So what are the right decisions?

Selecting replacement heifers for the suckler herd

Replacement heifers for the CAFRE suckler herd are first identified before they are born!
Heifers are only selected from cows with hybrid vigour and that have acceptable teat and udder traits as “problem” udders are highly heritable.
Only heifers born early in the calving period are selected as these are born to the most fertile cows.
Any heifers that do not have acceptable liveweight gain while suckling are rejected as their mothers did not have adequate milk.
Finally, any unusually large heifers are also rejected in an effort to reduce the mature weight of the cow herd.

Post weaning management

After weaning, heifers are managed to attain 60-65 percent of their mature weight at bulling to ensure the maximum number of heifers having had at least one, and preferably two, cycles before mating commences.
At CAFRE, widely used AI sires with proven calving ease are selected to mate with 15 month old heifers. This year, the AI sire is in the top 1 percent of the breed for small birth weight, short gestation length, calving ease and calving value.
No more than two opportunities to conceive are given to select fertile heifers that calve down in a short period.

Where can I get the right information?

Important information including calving interval and calving spread for your herd can be accessed through your local CAFRE Beef & Sheep Development Adviser by taking part in a Suckler Herd Fertility Challenge training programme.

Summary

Select and manage heifers carefully to meet long term performance targets.
Synchronised mating for heifers is essential to ensure they calve down with the main herd as second calvers because the bulling period for the main CAFRE cow herd is only of 63 days duration.
Calving heifers over a short period allows for adequate supervision and time to resume cyclicity before the subsequent mating period.
Use proven calving ease sires.
Contact your local CAFRE Beef & Sheep Development Adviser about the Suckler Herd Fertility Challenge training programme.

Synchronised heifers showing heat activity