With the upcoming uncertainty of sheep and lamb prices with Brexit, minimising losses and maximising outputs has become essential; but how are we going to increase the amount we sell relative to ewe numbers?
- Lambing percentage
- i.e. the total number reared
- Growth rates
- Lambing pattern
- early lambs have more growth time before sale
- tightly concentrated age ranges benefits lamb health and reduces labour and other input costs.
There are clearly significant ewe factors involved, as well as young-stock management, but the rams have a heavy involvement in the lambing percentage and pattern. Each ram has to be capable of a decent conception rate, to catch as many ewes as possible, as early in the breeding period as possible. The poorer his conception rate, then the more ewes will repeat cycle, and the more that will end up as barren.
A ram’s productivity is on a sliding scale too. It’s not simply a matter of having a fertile ram. Sub-optimal fertility is far more common than total infertility, although it is possible a physical defect or malformation might prevent him from serving ewes.
A low fertility ram is very difficult to identify especially when working in a large team of rams, as they will get some ewes pregnant. Often the ram will mark a ewe with the raddle but might not be the one getting her pregnant. Approximately 15-20% of rams aren’t up to scratch. If it is poor sperm quality that is affecting performance, this can be due to temporary factors; any cause of stress, pain or general illness will affect sperm quality.
Further to this, subfertile rams can actually prevent the more fertile rams from tupping if they are more dominant. Often, I hear people say they like to keep an older ram so he can just do 2 or 3 but this can sometimes lead to poorer overall conception rates.
So how can you ensure your rams are raring to go?
Make sure there are no health problems leading up to tupping. Rams must be healthy for at least 6-8 weeks prior to the mating season, as sperm production takes this long from start to finish.
- Freedom from lameness is key, not only will this affect sperm production, but it also interferes with the ram’s ability and desire to get about and serve ewes.
- Control of ectoparasites, eg. lice or scab.
- Control of worms and fluke. This may be better done by checking faecal egg counts rather than by blind dosing, and that’s a separate conversation to have with your vet.
- Body condition. The rams should have a score of 3.5-4 out of 5 and, like the ewes, should be on a rising plane of nutrition in the run up to breeding. Poor body condition is one of the most common reasons for reduced fertility and rams will tend to lose some condition while working.
The AHDB ram MOT is a great starting point to check rams over with the 5 Ts: toes, teeth, testicles, tone and treat. You will definitely weed out the most dodgy rams this way; for more info you can check with your vet or check out the AHDB ram MOT info.
With all this sorted you are half-way there. Whilst there are never any guarantees, a full veterinary breeding soundness examination offers peace of mind that rams are capable of doing the job. This includes:
- General health check and physical examination.
- Detailed assessment of reproductive organs, including scrotal circumference.
- Collection of semen sample and assessment of volume, density, motility and individual sperm characteristics.
Numbers of rams:
The number of rams is very important to achieve the best pregnancy rates. The ratio of rams to ewes should be well considered and is only correct if all tups are fully fit and fertile. Below shows a guide on how many tups to ewes you should have for each situation. It is worth noting that if you are thinking of synchronising your ewes for early lambing the first thing you need to look at is ram numbers.
- 1:40 is fine if all rams are firing on all cylinders.
- 1:30 if teasers are being used for a tighter lambing period, teasers can be at a rate of 1:100
- 1:10 – Sponging for synchronisation
- 1:5 – Sponging + PMSG for early lambing
- 1:25 – Rams serving ewes that have had Regulin implant
- 1:50 – If rams and ewes have had Regulin implant
Teasers can really help group lambing tightly together at the start of the season, but this will only work if all the guidelines are followed. Teasers must meet all the same standards as the rams apart from being able to release any sperm and ewes must have total separation (sight, sound and smell) from any males for several weeks prior to tupping for the effects to fully work.
Because temporary factors can be just as important as permanent ones you cannot rely on rams purely on the basis of previous seasons’ success. We recommend testing all rams on an annual basis. Can you afford to take the risk? Discuss this with your vet before time ticks away.
Written by Harry Eastwood BVetMed MRCVS