How to get the most out of your breeders in Northern continuous mating systems
Year-round mating is common practice for northern Australian beef properties, due to the difficulty in managing the bulls across extensive areas. As a result, many calves are born during the dry season, when the nutritional quality of feed is low, and the nutritional demands of a lactating cow cannot be met. The consequences of this are poor reconception rates, high mortalities, and low rebreeding rates. There are several management strategies that can be implemented into year-round mated systems that can improve rebreeding rates, reduce supplementation and mustering costs, decrease mortality rates, and overall increase your profit margins.
Set your heifers up for success!
The first step in setting your heifers up for success, is matching their calving window, with high pasture quality and quantity. This will increase the chances of them getting back in calf and decrease supplement requirements. First calf heifers commonly miss their second conception due to poor body condition and the nutritional demands associated with rearing a calf. By keeping the first and second calf heifers in separate groups to the main breeder herd, calving windows can be managed from the start, and supplementation can be targeted when required. Table 1 outlines the ideal heifer management steps.
Table 1: Setting up heifer calving patterns for success (Northern Gulf example)
| Process | Month | Management |
|---|---|---|
| Weaning | May | 1. Segregate heifers into their own paddock |
| First mating - 2 years old - 300kg in weight | January | 1. Put bulls out |
| July | 1. Remove bulls 2. Pregnancy test (foetal age) to desired calving window 3. Cull empty heifers |
|
| Second mating | January | 1. Put bulls out |
| July | 1. Remove bulls 2. Wean calves heavier than 120kg, especially if heifers are less than BCS 3 3. Pregnancy test (foetal age) to desired calving window 4. Transfer pregnant heifers to main cow herd 5. Depending on overall herd numbers and main herd calving rates, empties can be either be culled or placed in a separate paddock until being put back with the bull the next January |
Figure 1 compares the timing of joining with the timing of calving and anoestrus, pasture quality, supplement quality and age at weaning.
Download and modify your own annual heifer management plan here.
Segregation of the breeder herd
Segregating the breeder herd into different classes is a great strategy to reduce stock handling, tailor nutritional management, and reduce unnecessary supplementation costs. This can be done through either a) segregating the breeder herd into wet and dry groups only, or b) further segregating the dry group based on calving time by foetal ageing.
a) Segregating the breeder herd into wet and dry groups only:
- Pros: Less paddock infrastructure required and reduced labour costs
- Cons: Less information available to target supplementation
b) Further segregate the dry group based on calving time by foetal ageing:
- Pros: Better targets nutrition management to calving time, reducing mustering costs as all calves will be a similar age, only need to bring the mob in once to brand, wean etc.
- Cons: More paddock infrastructure is required and labour costs for skilled foetal aging professional
Table 2 shows the annual management plan for two breeder segregation systems.
Table 2: Management plan for breeder herd segregation systems (Northern Gulf example)
| Breeder segregation system | Muster round | Management |
|---|---|---|
| Wet and dry only | May | 1. Draft into wet and dry groups and segregate in separate paddocks 2. Wean calves heavier than 120kg 3. Cull cows that have come into two consecutive musters dry or for age, identifying them by bang tailing or tagging - change tag colour each time |
| September | 1. Wean calves heavier than 120kg 2. Cull cows that have come into two consecutive musters dry or for age, identifying them by bang tailing or tagging - change tag colour each time |
|
| Wet, dry and foetal aging | May | 1. Pregnancy test (foetal age) and segregate into several calving groups based on expected month of calving (Table 3 below) 2. Wean calves heavier than 120kg 3. Cull empty and ages dry cows |
| September | 1. Wean calves heavier than 120kg |
Table 3 shows an example of the division of calving groups following foetal aging, the predicted calving and weaning months, and likely supplementation and early weaning requirements for three foetal aged groups. The number of calving groups will be dependent on the number of paddocks available for segregation.
Table 3: Foetal aging calving group management
| Calving Group | |||
|---|---|---|---|
| Characteristics | A | B | C |
| Expected calving date | May/Jun/Jul/Aug/Sep | Oct/Nov/Dec | Jan/Feb/Mar/April (next year) |
| Predicted weaning time (next year) | September round or May following year (early weaned) | May round | September round or radical early weaning in May |
| Supplementation and early weaning requirements | These cows are calving in the dry season. They require supplementation and calves will need to be weaned early to maintain cows body condition. | These cows will be calving in the late dry season/early wet season. They will require supplementation to maintain their body condition score until the wet season improved feed quality and quantity. | These cows are calving during the wet season and, if not weaned in May, will carry a calf through the dry season. They will require supplementation and calves will need to be weaned early to maintain cows body condition. |
Figure 2 illustrates the age at weaning for each of the calving groups across the year, as well as the pasture quality and supplement requirements from calving to weaning.
Download and modify your own annual breeder management plan here.
The above strategies need to be used in conjunction with good grazing land management, early weaning, supplementation, vaccination, and culling for age and fertility. To learn more about these strategies, please visit the FutureBeef website, or speak to your local Beef Extension Officer.
Implementing a large change in breeder management can feel overwhelming but focusing on small changes and building on this overtime can result in a huge improvement to the productivity and profitability of your business. The above strategies are generalised advice and may not apply to your specific situation. Department of Agriculture and Fisheries Beef Extension Officers are here to help you tailor management decisions for optimising your business. Find your local beef extension officer here.