In the first of a series covering late summer and autumn, Canterbury-based vet Ben Allott discusses topics you should consider as part of your sheep and beef animal health plan.
These are not intended to be comprehensive reviews but rather to serve as quick reminders for discussions you should have with your advisers and other farmers over the coming weeks.
Ewe udder disease: Recent work published out of Massey University has shown ewes tupped with a normal udder lost 12% of their lambs during the next lambing season while ewes tupped with an udder defect lost 30-40% of their lambs after lambing. In addition, lambs born from ewes with an udder defect will have lower pre-weaning growth rates – up to 35g/day.
Uddering ewes a month after you have weaned lambs should become part of your summer animal management plan because carrying ewes with udder defects has now been shown to be very costly.
Bought-in ewes/mixing age groups?
Over the years I have encountered many situations of high dry rates at scanning, or high rates of abortion, where mobs of pregnant sheep from different sources have been mixed after tupping. There is often a suspicion that one of the groups of ewes was carrying a bug that the other group had never seen before.
In many cases, sheep exposed to an abortion-causing virus or bug before they are tupped will develop immunity and will go on to have a normal pregnancy. However, if they are exposed to the bug for the first time while pregnant, high rates of pregnancy loss may occur.
My standard advice if asked about when to mix bought-in stock, or when to mix different age groups that have been managed separately – “Either mix them up well before tupping, or keep them separate until they have lambed.”
The flushing effect
With many areas of the country now very dry, making the most efficient productivity gains with feed on-hand will be at the front of most farmer’s minds. A ‘rising plane of nutrition’ (a ewe gaining weight) for the 10 days before and 10 after the start of tupping will result in a lift in ovulation rate.
This increase in ovulation rate will be largest in ewes that are of low body condition score (BCS) while in ewes that are already well-conditioned the lift can be very small indeed. Many dryland farmers I have learnt from have had great success using brassica crops as autumn flushing feed.
Trace elements and ovulation rate
Both selenium and iodine are commonly discussed in relation to tupping performance. Supplemental iodine has been shown in multiple New Zealand trials to have increased the scanning percentage and to have reduced lamb wastage in flocks of low iodine status.
Selenium deficiency has likewise been shown to play and important role in the fertility of sheep and the survival of lambs. There is no ‘one rule’ to suit all farms but if you have not investigated the trace element status of breeding sheep on your farm then now is the time to start looking into it.
If you haven’t used teaser (vasectomised) rams before then have a conversation with farmers in your circle about their experiences. Teasers can be used to trigger ewes into cycling, and to synchronise their ovulations. You need to get good advice about preparing ewes for a strong teaser effect and on the timing of teaser introduction relative to mating dates – don’t just wing it. Situations where I see opportunity around using teaser rams:
Hoggets/two-tooth mating – young sheep have narrow cycling seasons and generally peak fertility is not reached until the third cycle of the season. Teaser rams can be used to trigger maidens into cycling earlier in the season and to ‘get rid’ of lower fertility ovulations before the true breeding season.
Early mated terminal ewes – I have observed that cross-bred ewes mated in February often have higher dry rates and poorer take to the first cycle. Teasers can be very effective in improving the scanning performance of early mated ewe mobs.
Synchrony – Teasers can be used to synchronise ewes and condense mating periods. This can be really useful (e.g: advance average lambing date without changing the start of lambing) but can also come with a few pitfalls (e.g: need for more ram power, very tight lambing pattern and susceptibility to spring storms).
Fly protection through mating
While conditions are dry, fly pressure is often very low and the risk easily forgotten. Fly strike, even extremely small spot-strikes, can have massive effects on dry rates in affected mobs. Prior to mating have a walk through each mob of ewes, consider their wool length, dag accumulation, and the areas of the farm you are going to send them for tupping.
When rain arrives on your property is the risk going to be high or low for each mob?
The three common reproductive diseases of sheep that we vaccinate for are campylobacter (campy), toxoplasmosis (toxo) and salmonella. Have you put these vaccination dates in your diary AND have you ordered your product? Ring your vet ASAP if the answer is no.
If you are a farmer who does not monitor faecal egg counts (FEC) and routinely drenches whole mobs of ewes prior to tupping, you need to discuss the risk of this approach with an experienced adviser. If you are a farmer who does not monitor ewe faecal egg counts and never drenches any ewe on the farm, you need to discuss the potential for lost productivity with an experienced adviser.
If you don’t know the efficacy of the drench product you use on your farm against the six major internal parasites of sheep you need to find this out. I strongly recommend routine monitoring of FEC to guide informed decision making.
Should you be drenching terminal ewes, maternal ewes, two-tooths, hoggets? How many in each mob, which ones, with what product? Look hard for a source of good advice, go to a Wormwise workshop and listen to switched on farmers in your district.
Watch out for drought breaking and parasite surges in young sheep.
Rain after a prolonged dry spell brings huge relief, the reassuring sight of a rapidly growing green pick, and some respite from months of dust. It often also brings with it a huge wave of internal parasite larvae.
Trade lambs and ewe hoggets on short pasture can quickly develop large parasite burdens, often well before their FEC increases. Start watching young sheep closely 7-10 days following rain and be prepared to act quickly. Two-tooths, and older ewes are not immune from these effects either. Keep talking about how you might modify your current plan with your expert advisors if conditions throw you a curve ball
Want more detail? My number one recommended resource for preparing sheep for tupping is “Making Every Mating Count – Beef and Lamb NZ”. A full PDF can be downloaded online or request a copy from your local Beef and Lamb extension manager
- Ben Allot is a North Canterbury Vet.
Shared Google calendars for farm management plans.
If you currently utilise a specialist farm management software platform then you already have this covered but for those of you that don’t, a low-cost option of sharing your farm management diary with staff, advisers, and business partners is to utilise Google calendars.
Set-up a gmail account, e.g: firstname.lastname@example.org
Input your farm management dates into the Google calendar that comes with this account.
Google calendar allows you to link (share) these dates with the email account of anyone you want to. Simply google “How to share my google calendar” for a full list of instructions.
Staff can then receive daily reminders, and can add appointments themselves, to one central electronic calendar that everyone is working from.