The introduction of controlled grazing (camps and rotational grazing) and breeding (mating season) has resulted in a significant improvement in commercial livestock production.
To livestock producers, a high calving or lambing percentage over a restricted period is still the most important parameter of production performance.
And the most important factor bringing down the cost of production is a controlled calving or lambing season (<3 months) during the optimal nutritional period on the farm.
2 IMPORTANT CYCLES
The livestock farmer works with two biological cycles:
- The environmental cycle (caused by rainfall and temperature changes) which determines how much grazing is available at different times of the year.
- The production cycle for the type of livestock farmed. This will determine the various levels of nutritional needs at different times of the year.
MAJOR DIFFERENCE IN NUTRITIONAL NEEDS
- The most basic example is to consider the protein needs of beef cattle during 2 different production stages.
- This example shows clearly that the protein needs of a cow that’s calved, and now needs to conceive again, is 100% higher than for a dry cow.
This high need for protein from grazing can only be met during a limited period of the year. If cows calve at a time when there isn’t good grazing, and the farmer wants the cow to conceive again within 4 months after calving, the shortfall in daily protein intake has to be supplemented by a lick.
The protein intake of a cow can be calculated as follows:
- A cow eats 10 kg of poor-quality grass with a crude protein content of 5%.
- 5% of 10 kg is 0.5 kg or 500 g of protein per day.
- A dry cow needs an extra supplement of 100 g of protein per day.
- A cow that has calved during a period when only poor-quality grass is available will need an extra 700 g of protein a day to maintain milk production for the calf and to be able to conceive again when mated with the bull.
The cost of supplementing protein to a single cow that has calved outside the best calving period can be high. It is obvious that this practice is not economical for any beef cattle producer.
MAIN GOAL OF MANAGEMENT
The main management goal of profitable beef cattle farmers is to control the breeding of cattle in order to let them calve just before the best grazing will be available.
This leads to the situation where the best grazing is available for 2 to 3 months after calving, when the protein needs of the cow are at their highest. It’s also when the cow has to conceive again to be able to produce 1 calf per year.
DIFFERENCE BETWEEN SMALL STOCK AND CATTLE
- The difference between small stock (sheep and goats) and cattle is the length of the pregnancy.
- In small stock with an average pregnancy of 5 months, the lambs will be weaned at 3 to 4 months, so in a 12-month production cycle they will be mated again to rams only after the lambs have been weaned.
- Supplementary feeding in small stock is therefore more effective because the ewes do not have lambs and will improve their condition rapidly for optimal conception, even under poor grazing conditions (see table 3).
- Cows are pregnant for 9 months, so mating must take place 3 months after calving in order to produce 1 calf per year.
- This fact makes it more difficult to provide supplementary feeding before mating takes place, because the cow would use much of the supplement to produce more milk.
PREPARATION FOR MATING
The only factor over which the livestock farmer has any control is when the mating period starts.
This will, in turn, determine when livestock will lamb or calve (see table 4).
The main goal of preparation before mating is to get livestock into optimal condition for conceiving again.
- In small stock, strategic supplementary feeding started 30 days before mating can be very effective in improving conception rates.
- In cattle it is critical that mating be controlled to ensure that cows only calve just before the availability of the best grazing.
- It is not cost-effective to try to supplement cows in bad condition in order to get them pregnant again.
- Supplementation must already have been provided before calving to get the cows to calve while in good condition.
- Effective parasite control before the start of mating is also very important.
- Livestock needing the most care and preparation before mating are young ewes and cows that have given birth for the first time.
- These young animals are under severe stress because they must conceive again while still growing themselves.
- Give them the best available grazing, supplementary feeding and parasite control you can.
- The aim of producing one lamb or calf from each female animal in the herd can be achieved by farmers who follow a controlled breeding programme.
- This article was written by Dr. Danie Odendaal and first appeared in Farming SA.