The situation is simple:
- The calves are starting to hit the ground
- Young heifers are still expected to grow out (at first calf, they are generally 85% of their expected mature weight)
- The heifers?۪ maintenance requirement has nearly doubled overnight
- Heifers are expected to return to pregnancy status in the near future
What happens next is determined by the management systems enforced between operations.
Let us look at the further expectations we have on these heifers.
We now expect them to provide milk to their new born calf, maintain condition at a minimum, hopefully continue to grow out and most importantly, return to oestrous within a defined time period.
The culmination of these requirements can mean:
- Lower Body Condition Score (BCS)
- Longer period of anoestrous
- Lower pregnancy rates for 2nd Calf
Adequate Body Condition plays an integral part in giving breeders a better chance at conceiving. The aim of breeding stock is to maximise the productive lifetime of every cow. Allowing breeders to slip in condition below BCS 3 can have profound effects on the fertility of the herd. Research done in America in 1986 ? 1988 highlighting the relationship between BCS and percentages pregnancy tested in calf. The culmination of over 8 research projects, averaging 1000 breeders per project confirmed the following relationships.
Body Condition at Calving*
% Cows pregnant
Intermediate (2 or less)
Good (3 or better)
*Body condition scores converted from USA measures to Australian; range 1 ? 5
This information was compiled by our consulting nutritionist, Vincent Posada.
Cattle partition energy in the following order of priority:
- Growth (heifers)
If heifers are not receiving enough energy, their return to oestrous can be severely slowed as it is not prioritised by the breeders?۪ energy partitioning system. A dip in nutrition can have a huge effect on overall performance of the herd. A program that aids breeders to maintain BCS 3, particularly young heifers (both 1st and 2nd calf heifers), can result in very positive effects on the number of breeders that return to pregnancy status.
For something as simple as checking the condition of these animals, you can have large impacts on return for the whole business. If the breeder herd is not in suitable Body Condition Score, less cows will be able to return to pregnancy.
In order to keep to a 12 month cycle, breeders need to be back in calf 80 ? 85 days after calving. A feeding regime can help ensure breeders are ready for their next joining. Targeting nutrients that are limiting in the diet of the breeders has multifaceted benefits. Situational differences will dictate which option is needed for individual situations. In some circumstances, a dry loose lick supplement may not be enough nutritional aid to ensure young heifers can keep up with maintenance, their own growth, high lactation demands AND reproduction. In these situations, Production supplements may fit into the program to provide adequate assistance to the young, developing breeder.
The real aim of any breeding enterprise should be to maximise the productive lifetime of breeders. Lower pregnancy rates mean that cows that miss one joining, or are joined later, are overall decreasing the productivity of the entire herd. If you think of it in terms of a motor vehicle?۪s fuel efficiency, how much pasture does a breeder ?burn?۪ and how many calves does she return ? The ideal is to have more calves per kilogram of pasture intake over the breeder?۪s life.
Have you taken a good look at your Post-Calving Care Program for your young heifers lately?
Posada, V, ANCS, ?Nutrition & Productivity of Breeding Stock?
Meat & Livestock Australia 2006, ?Managing the breeder herd?, Meat & Livestock Australia Limited