The second in a series of articles, Canterbury-based veterinarian Ben Allott, which looks at topics farmers should consider as part of their sheep and beef animal health plan.
FOOTROT IN SUMMER CAN BE DECEPTIVE
In the middle of a long, hot, dry summer there isn’t a lame sheep to be seen and then almost overnight it can feel like the opposite is true. If you find yourself in the middle of an epidemic of lameness this autumn, first find a little comfort that you are not alone, and second take the time to formulate a robust foot-rot management plan for the year.
While next summer is your opportunity to really get on-top of footrot again, there are good steps and effective interventions that you should discuss with an experienced advisor. Conveyors are an excellent tool for examining feet and footbaths remain essential in at-risk flocks. Footvax footrot vaccine can be a very useful tool to minimize the size of an outbreak when used appropriately, and Tilmicosin antibiotic is proving to be a useful treatment option. Chris Mulvaney has written an excellent guide to the management of footrot in sheep which should serve as the basis for any footrot programme. This can be downloaded from the Beef and Lamb NZ Knowledge Hub.
Merino NZ have been the driving force behind the development of a new footrot EBV to predict an animal’s genetic resistance to developing footrot. This year was the first year that I have seen footrot EBV published in a stud sale catalogue. Look into this in more detail if footrot is an issue for your farm.
LICE CONTROL BREAKDOWNS
It’s really easy to blame the neighbour’s fence-pushing sheep, but most lice control breakdowns are caused by factors a little closer to home than the boundary fence. The truth is that most lice control breakdowns have at their foundation too much wool cover when the chemical is applied and/or not enough active chemical applied correctly.
Pour-on products are most effective when applied directly off-shears. Is this how you use them? Liquid products received their registration claims using high volume, saturation dipping methods (shower/plunge dips/hand wanding). When you get 850 ewes dipped per pod through your jetting race I’m afraid your sheep are not soaked, not even close. Give the money you spend on lice control a decent chance of working: apply the chemical at the right time relative to shearing and get enough on. An excellent resource, ‘Managing Flystrike and Lice: A practical guide for farmers’ was released on the Beef and Lamb Knowledge Hub in August 2019 and this reviews application methods, wool length, chemical families and more.
MID-PREGNANCY FEEDING
The developing embryo fixes itself to the wall of the uterus at day 16 of pregnancy and after this point is relatively robust. The pregnancy after this stage is more able to cope with stressors like shearing and feed shortages.
Underfeeding a ewe so that she loses condition can result in a smaller placenta, lower lamb birthweight, and reduced lamb survival outcomes. However, a mid-pregnant ewe is able to be safely put to work on a maintenance feed allocation, she doesn’t need to keep gaining weight. Now is the time to tidy up lower quality feed to ensure that high quality feed comes away in the spring for lactation. I have become more and more convinced that a well-conditioned ewe that continues to gain weight through the autumn is an animal health liability prone to conditions like bearings, and milk fever later in pregnancy.
WINTER FEED BUDGET
I’m writing this after driving around what has been a very dry summer in North Canterbury. Feed is tight, hoggets are light, and compromises have had to be made. I would encourage a prompt autumn/winter feed budget now while there is still some time to influence feed supply. Autumn and winter growth rates are usually the most predictable which allows you to put a little more faith in the prediction.
Italian ryegrasses can still be sown, autumn nitrogen applications could still go on and winter grazing could be searched for. Carry fewer hoggets, cull harder into the B-flock at scanning and don’t carry that mob of steers. Don’t get bogged down with detailed paddock-by-paddock feed cover estimates. Stick to the big numbers of total supply versus demand. If you are having difficulty estimating animal feed demand go to www.feedsmart.co.nz for an excellent, easy-to-use feed demand an allocation calculator.
SCANNING
Could your approach to scanning save winter feed or help preserve spring covers? Yes and yes. Knowing your twins from singles is obvious – singles need less feed, why feed them like a twin? Knowing your earlies from lates adds additional information if you have the ability and desire to manage more mobs. Later lambing ewes can be held in autumn maintenance rotations, cleaning up lower quality feed for longer. They can also be held on crop, or in winter rotations, then set-stocked several weeks after the early lambing ewes – why allow a late lambing ewe to consume all that feed while set-stocked for several weeks longer than she has to? Start having some discussions around whether your scanning policy could help you improve feed management through a tight winter. To age-scan effectively your scanner will require an earlier scanning date.
TRACE ELEMENT MONITORING
Scanning and the sending of cull ewes and cows to the works offers an opportunity to liver sample cull animals as they go through the works for trace element status. Are your ewes or cows lacking in selenium, copper or vitamin B12? Talk to your advisor about the potential to sample animals using this method.
INTERNAL PARASITES
In last edition’s article I warned about keeping a vigilant eye out for parasite burdens in young-stock following autumn rains. With some rain now hitting dry parts of the country keep in mind the risk of a surge of parasites and talk to your advisor and other farmers about what they are seeing.
SCANNING RESULTS
These will be coming in thick and fast. Hopefully you find yourself bragging at the pub but if your result is disappointing now is the time to reflect and investigate so that next year the feeling is different.
OTHER FACTORS TO CONSIDER
Body condition is key for mixed-age cows. What was their BCS leading into mating. Did they do it too hard through last winter and spring? What can you do differently with this winter coming up?
Live-weight is critical for heifers – they should be at least 60% of mature live-weight as they go to the bull.
BVD – still a very common infection in heifers and cows. Vaccination is an effective tool, the blood testing tools we have are incredibly valuable. If you suspect BVD is behind high dry rates in mated cattle a blood sample from 15 head can be pooled into a single test to look for the level of BVD exposure. A cheap and valuable piece of the puzzle answered. In herds that are vaccinating heifers and cows I frequently find that vaccination of the bull team is forgotten. I believe every bull used for mating in NZ should be tested as BVD free once in its life and then vaccinated every year, without exception.
Bull power – my number for most situations is a ratio of a least 1 bull to 40 cows and even more bulls with heifers. Single sire mating is fraught with risk and the risk of poor results comes with the territory.
Bull testing – most bulls are bought as two-year olds having been service tested at stud, but did you know that many conditions affecting the fertility of bulls develop with age? A prime example is corkscrew penis. A pre-mating check that assesses the serving ability of a bull and semen analysis can be performed easily by experienced operators. Well worth the effort and cost.
Animal health planning tip:
Your vet is human, your vet is busy, and if your vet is anything like me the appearance of being well-organised is more likely due to the clinic receptionist, rather than themselves.
I struggle to remember what is happening on every one of the farms I work with so every time I come up with a good suggestion for a future monitoring event and my client is keen to explore that step I try to note it on my billing docket and get my receptionist to book a future follow-up reminder in my diary.
The next time your vet comes up with a good idea on monitoring faecal egg counts next February, or taking bloods at scanning, or testing the bulls next September, get them to write it on their billing docket so their receptionist organizes their diary for them. This will save both of you forgetting all of the good ideas you just came up with.
