25 Feb 2019
Drought, feed and heat stress will have major impacts on 2019 autumn, winter and spring lambing and NSW Department of Primary Industries (DPI) has advised producers to condition score ewes before joining and pregnancy scan after joining.
DPI livestock researcher, Gordon Refshauge, said these two tools will help ensure producers can manage the nutritional needs of their flocks to get the best outcomes this season.
“Ewes should have a condition score of at least 2.5 prior to joining, ewes in a poorer condition are less likely to conceive,” Dr Refshauge said.
“Two weeks on improved feed prior to joining for ewes scoring less than 2.5 will lift fertility and ovulation rates for those leaner ewes.
“Ewes should be pregnancy scanned to identify dry, single and twin bearing ewes.
“The sooner ewes can be scanned the better, as feed can be matched to suit single and twin bearing ewes, and there may still be time to rejoin dry ewes - shortening day lengths give ewes a natural lift in fertility and ovulation rates.”
The ideal time to scan is 75 to 100 days after joining commenced.
Scanning identifies stock which can be sold and allows producers to target feed to single and twin-bearing ewes, which require different levels of feeding during mid and late pregnancy.
Late spring and early summer rains can deliver pasture growth, which will lead to an increased ovulation rate, higher pregnancy rates and more twins.
Twin-bearing ewes which conceived in low body condition will need improved nutrition from mid-pregnancy or the health of the ewe and lamb production can be impaired.
Dr Refshauge said high temperatures will also impact on the ability of sheep to produce lambs.
“Ewes experiencing nine hours of 41°C temperatures lose 100 per cent of embryos up to three days old,” he said.
“The highest risk conditions are hot days coupled with hot nights as sheep cannot lose heat from the body.”
Low pregnancy rates may be due to rams suffering from ovine brucellosis or in low condition, which will impair sperm count and sperm quality. When rejoining flocks with high percentages of dry ewes, suspect rams should not be used and producers should contact a veterinarian if brucellosis is a concern.
Media contact: Bernadette York (02) 6938 1664 or 0427 773 785