Canterbury-based veterinarian Ben Allott says sheep farmers need to thinking about a number of factors going into mating including the use of teaser rams, the health of their ram flock, ram ratios, the pre-mating management of their ewes and whether or not hogget mating will be an option this year.
Ewes should be going into mating on at least a flat – and preferably rising – plane of nutrition and in a year where feed resources are tight, farmers might consider using a brassica crop or grain for flushing.
Ben says farmers will get the best flushing response from ewes with a lighter Body Condition Score, so economically, flushing feed might best be partitioned into ewes that will give the greatest response.
Ideally grain should be fed in the 10 days before and 10 days after mating and allocation should be based on the quantity and quality of the pasture or forage the ewes are eating. The FeedSmart app www.feedsmart.co.nz is an excellent tool to help work out appropriate feed allocations in a pasture- based system.
Mineral or trace element deficiencies should be addressed in the lead up to mating and Faecal Egg Counts carried out, particularly in younger sheep or older ewes that are under feed pressure.
“Monitoring will allow farmers to have an evidence-based discussion with their animal health advisor about their drenching programme.”
For farmers using teaser rams timing is critical. Ben says there should be exactly 17 days between when the teaser ram goes out and when the entire ram is introduced.
Before rams are set to work, they should be checked for soundness, Brucella ovis and other sexually-transmitted diseases and consideration given to wool length and the risk of flystrike. If ewes are to be shorn prior to mating, Ben recommends this occurs at least, but preferably more than 3 weeks prior to ram introduction.
While the widespread dry conditions mean flystrike risk is currently low in many areas, rain during mating could put rams (and ewes) at risk of flystrike if they are not clean. Bringing ewes in for fly treatment during mating may not be feasible so consider the risk with different mobs and plan to mitigate this before the ram goes out.
Similarly, rain could see Facial Eczema spore counts soar in susceptible areas, so farmers in those regions need to keep a close eye on local spore counts and manage accordingly.
Hogget mating should be a seasonal decision and Ben says farmers need to carefully consider whether they mate all, a proportion or none of their hoggets given the season and possibility of tight feed resources.
“It’s not just about getting them in lamb, it’s about ensuring they are well-grown out when they lamb in the spring and when they go to the ram as two-tooths.”
Hoggets to be mated should be selected on a minimum weight (eg only those 42kg and over), not a mob average (eg average 44kg, as a significant proportion will be below 40kg)
All of these topics are covered in detail in the Make Every Mating Count resource book: https://beeflambnz.com/knowledge-hub/PDF/making-every-mating-count