Should you
If things are dry or you’re in full drought mode, there are some important decisions to make now regarding whether you want to put your sheep through the mating process.
Are animals in good condition?
Animals in light condition or those that are losing weight in the three weeks before mating will have poorer ovulation rates and are less likely to get pregnant than ewes which are gaining weight over the same time period.
Worse, low condition ewes (condition score 2.5 or less, or light store condition) will tend not to have a second cycle because they are not ovulating.
Under favourable conditions, it is usual for ewes to lose up to 10% of their mating weight before lambing, so an animal with a condition score of 2.5 or less should not be mated unless you are going to feed above-maintenance over winter, or she’s likely to lose her lamb, and possibly not survive herself.
The pros and cons of waiting
Under drought conditions, the date the ram goes out has a critical influence on the profitability of next season’s lamb crop. The conflict is between mating before ewe live weights decline or gambling by waiting for expected rain to lift ewe condition.
If you delay mating by 3-4 weeks (eg, put the ram out on April 10 instead of March 15), there are pros and cons:
Advantages
• Ewe live weight may be increasing due to higher feed quality; • Naturally higher ovulation rates (>10%) = more ewes in lamb; • Better opportunity to set up winter rotation; • Easier to identify those ewes that are unlikely to survive the winter and should be sold; • Less chance of ryegrass staggers, zearalone (a mycotoxin in pasture), facial eczema.
Disadvantages
• Ewe liveweight may be much lower, meaning lower ovulation rates and more dry ewes; • Later lambing and weaning; • Longer maintenance feeding required; • Possibly lambing into rougher weather; • Shorter time before the onset of the summer dry, meaning earlier weaning, less desirable feed/weather; • Potentially more dystocia and bearings if pre-lamb feeding is not well managed.