The most important factor that is influencing beef production is reproduction. But why is reproduction so important?
First, with a higher reproduction rate, there are more calves that could be sold, raising income and profit. Second, with more weaner calves, selection will be more intense, which will lead to a higher genetic improvement rate. Third, more calves reduce the overhead cost of the enterprise.
Precision farming practices with a beef herd are possible and can be done anywhere. More attention to the management of our national beef herd is needed as the actual performance is too low.
Subsistence farmers have additional problems to overcome in order to increase their reproduction rate. They make use of communal grazing, making it very difficult to manage which cows are mated to your bull. However, there is a solution for every problem.
To improve the genetic value of the beef herd, it is necessary to know the outstanding as well as the weak points of the female herd. This is extremely important as it will influence the choice of breeding bulls when buying. To buy the correct bulls for the females in the herd is one of the most important actions that can improve the quality of the breeding stock.
The reproduction cycle (see Figure 1), consists of the following:
Calving season
Heat/oestrus
Mating/breeding season
Pregnancy
These factors will be described in detail in this article.
Calving season
The calving percentage is critically important, as the number of calves weaned is the major factor in the productivity of the beef herd. Calving percentage is even more important than weaning weight.
For example: There was a study group in the Eastern Cape that decided to select and improve their calving percentage. They increased the calving percentage from 60% to 85%. The result was an astonishing increase of 40% more meat produced per hectare.
Thus, more calves weaned must be a priority!
More calves weaned mean more calves to select replacement heifers from (see Figure 2). It can be seen that with a calving percentage of 70%, there are not enough replacement heifers on average to maintain the number of breeding cows in the herd. The calving percentage must be 80% or above!
A few tips when the cows have calved:
Keep the first-calf cows separate from the adult cows as the adult cows will dominate the young cows at the water and lick troughs. The young cows can be successfully kept with the other heifers on the farm, and as soon as they calved for the second time, they could be moved to the adult cow herd.
Give the heifers the best camps to graze as they will need more nutrients than the cows, maybe from planted pastures. These heifers are still growing, they started to lactate and most probably started cutting teeth and now have to become pregnant again.
Heat/Oestrus
In the first month after giving birth, the cow will not show any signs of heat as she is still recovering. Her uterus must shrink a lot to its original size before she can ovulate again.
Approximately 40 to 60 days after calving, the cows should be coming into heat. The cows that are more adapted to their environment, as well as more fertile, will come into heat.
Those not showing heat must be investigated thoroughly to make sure they are still welcome in the herd.
The cows need to become pregnant again within 90 days after calving in order to have a inter-calving period (ICP) of around 365 days. The average ICP of a well-managed herd should be less than 380 days. This figure is an important measure of the fertility of the breeding cows in the herd.
A heifer that calved down will need more time to recover as her uterus takes much longer to shrink back to normal size. Thus, the heifers will be bred about four to six weeks before the adult cows. This extra time once she calved down will be enough for the heifer to be in breeding condition once the breeding season starts.
Breeding season
The upcoming breeding season is the start of the successful calving season of the next year. Cows that are calving early in the calving season are the most fertile, are the best adapted to the environment and will wean the heaviest calves.
Thus, these cows must be in good condition as they have to conceive during the first few weeks of the breeding season. Cows that are calving late every calving season tend to keep on doing so, until they will not become pregnant and will still be open after the breeding season has ended.
An open cow before the winter months is something that must be avoided at all cost as its only result will be a reduction of profit.
It is really important then for the cows to become pregnant early in the breeding season. Care must be taken to ensure the condition of the breeding cows will be good. If the cow is in an increased weight phase, she will become pregnant much easier.
She has to receive better pasture in the four to six weeks before the breeding season starts. A production lick (approximately 1kg to 1,2kg/cow/day) can also put her in this increased weight phase.
With the start of the breeding season, the cows must be in a condition score of between 3 and 3.5. It is an objective to get approximately 60% of the cow herd pregnant within the first four to six weeks of the breeding season. The importance of the condition and condition score is shown in Figure 3.
Bulls are also very important as they contribute 50% of 25 to 35 calves’ genetics annually versus the cow that contributes only 50% of her own calf’s value every year. Thus, the best bulls that can be afforded must be bought. A breeding bull has to possess these characteristics:
He needs to have a good libido (the will to service a cow);
He must have the ability to service a cow;
He has to produce and ejaculate good-quality, normal semen;
He must be able to walk far distances, and see and smell in order to service the cows in heat.
Here are a few tips regarding breeding bulls and their management:
It is better to have one bull too many than one bull less than required;
Make use of bulls that are performance tested as this makes the selection for the correct bulls much more accurate;
Performance-tested bulls will also lead to a faster genetic growth of the breeding herd;
Do not use bulls with extreme faults to correct other faults; use well-balanced bulls;
Bulls have to be tested annually for fertility as well as venereal diseases.
Weaning
The calves born early in the calving season are mostly the healthier, stronger and heavier calves and will wean the easiest. Factors that influence weaning weight:
Breed: Milk production differs and it leads to different weaning weights;
Cow size: Size is positively correlated to milk production, but also with a longer ICP; it is therefore better to use cow efficiency as a selection method;
Age of the cow: Weaning weight increases with the cow’s age until around five to eight years as milk production increases; thereafter milk production decreases again and weaning weight drops;
Production status of the cow: If the cow did not calf last season, she will wean a heavier calf now due to more body reserves that she has; make sure a female daughter is not kept as replacing heifer;
Sex of the calf: Bull calves are on average 7% heavier than female calves;
Season: Climate differences will play a role in weaning weight;
Twins: A twin will have a smaller weaning weight than a single calf;
Try to decrease the stress levels of the calves as it will lead to stronger and healthier calves with fewer mortalities.
As it is very important to increase the production level of our national cow herd, reproduction is critically important.
Farmers need to take responsibility by buying the correct breeding bulls, managing the herd at an optimum level and making use of tools to improve the reproduction rate. Contact an animal scientist to assist you in achieving a better reproduction rate.