Replacement heifer management, is, on the majority of suckler farms a key area where there is scope to reduce costs, increase sales and streamline management. Here Drystock Adviser, Colm Kelly, addresses some of the messages and issues coming back at farm level
Nationally 23% of suckler herds calve replacements at 22-26 months of age. A percentage of herds purchase replacements and therefore have less control or incentive to improve this figure. A significant cohort also choose not to calve homebred replacements until they are much older. What are the messages coming back at farm level?
Heifers not strong enough:
The target is to have heifers at 60% of mature weight at mating. A benefit of the BEEP S scheme was to quantify for the first time in many cases the ‘working’ weight of their suckler cows. Many with mixed herds report significant differences between heaviest and lighter cows. This information is useful in estimating the weight target of heifers particularly when comparing a heifer to her mature dam. A key part of meeting that weight target now is to get heifers to grass first. They are lighter stock which do not cause much damage in wet conditions and are suited to fields away from the yard where suckler cows would not be turned out until later in the spring. They are also a relatively small number so if they are strip grazed and moved regularly they are manageable in challenging conditions.
The early turnout gets the heifers off what in many cases is poor/average silage and gets them adapting to a grass diet which will drive compensatory growth. There is a good opportunity to weigh heifers going out to grass to see how the winter diet has performed and to quantify where heifers are in relation to their target. Once mating is completed it is also important to keep heifers on a good level of nutrition as their next target is 80% of mature weight at calving down. Target heifers that were born early in your calving season as these have the best opportunity to make the weight target.
It is key that heifers meet their weight targets. Generally where farmers have run into problems stems from two factors - missing weights and bull selection. Bull selection is really key here and I would say go easy as possible particularly starting off. Heifers are easy to AI as they tend to show heat for a much longer period than cows and have better conception rates. You can also synchronise heifers which may make it easier to manage.
The benefit of using AI is that you can pick a bull with significantly more records than a stock bull. A heifer calving figure of less than 7.5% (go as low as practical) and better than 90% calving reliability with decent carcase traits is the peace of mind option. Don’t get too greedy on calf quality, with heifers keep the road safety slogan ‘arrive alive’ in mind. Once a heifer has a live calf with little or no assistance you are already winning.
Stunted growth/poor fertility:
Some fear heifers being stunted. Once a heifer receives adequate nutrition there is no evidence to support this. Calving does not stop a heifer’s growth and she will continue to add weight annually until she hits her mature weight.
After calving takr care that heifers are not bullied at the feed face and that they get to grass as soon as possible. This will improve their condition prior to mating the same which can be said for all cows. Where cows are indoors for an extended period meal supplementation will be required for lactating animals. This raises the question of coordinating calving date with turnout as prolonged periods indoors on poor diets is a likely cause for poor fertility in all ages of cows in many suckler herds.
Bigger heifer bigger calf:
The economics of this argument don’t hold water if you are incurring 6-12 months additional feed costs for a marginally better calf who is now 6-12 months behind a calf born to a 2 year old heifer.
Heavier heifer will leave a higher cull value:
If you are aiming to have a cow with a long productive life-span of up to 12 years of age the additional cull value spread across this time becomes a less significant figure. Using the analogy of a used car although you might get on well when you sell it the amount you have spent in diesel, tax and insurance over the time you had it dwarfs the final sale figure.
Table: Weight targets at different projected mature weights:
|Mature Cow Weight||Weaning Weight||Bulling Weight||Calving Weight|
|Target % of Mature Weight||60%||80%|
|600kg||260 - 280kg||360kg||480kg|
|700kg||300 - 320kg||420kg||560kg|