Rams need to be in good condition prior to mating (BCS 4.0). The reason for this is that they eat very little during mating and tend to lose a lot of weight. Sperm production in the ram takes six to seven weeks. This means that a ram mating a ewe on October 1 will have started producing that sperm in the middle of August. Anything that interferes with sperm production in the run up to mating can have disastrous effects on the ram’s ability to impregnate ewes. Increases in body temperature (even for short periods) will almost certainly render a ram infertile. Be aware of this fact if you have had to treat rams for pneumonia, etc., in the run up to mating. It is absolutely essential to raddle the rams so that you can keep an eye on how mating is proceeding. Start with lighter colours (yellow → orange →green → red → blue → black) and change the colour every 14 days. If a lot of ewes start repeating, suspect that there is a problem with the rams.
Aim to have all routine health treatments carried out before ram turn. Try to have the feet in good condition prior to mating to keep lameness at bay.
There appears to be a lot of interest in breeding ewe lambs this year. Ewe lambs have the potential to increase the output of the flock but they need to be managed carefully to ensure that their subsequent performance is not compromised. The following are important to keep in mind when mating ewe lambs:
- Only mate ewe lambs that have achieved at least 60% of their mature weight. For most breeds this means lambs between 45 and 50kg.
- Do not overfeed the ewe lambs after ram turnout as this has a negative effect on embryo survival. Average quality grazing to maintain or just slightly increase body weight is desirable.
- Ewe lambs should be run as a separate flock from the time the ram is turned out until they are mated again the following year.
- If ewe lambs that rear lambs do not achieve 80% of their mature weight at mating the following year, their performance will be compromised; therefore, they need to get the best grass available from lambing right through until they are ready to be mated again.
- Ewe lambs should be mated close to the time that the main ewe flock is mated to facilitate cross fostering to the main ewe flock and to allow the ewe lambs to be dried off early, so that they have adequate time to recuperate before the next mating period.
- Use ‘easy’ lambing rams: farmer experience would suggest that Vendeen, Charollais, Belclare and Lleyn are some of the breeds that are scoring well here. If you are selecting a ram with Euro Star ratings, opt for one that has five stars for lambing.
- Limit the mating period to three or four weeks and scan the ewe lambs and feed according to litter size.
- The use of a teaser ram 14 days prior to the start of mating can help to compact the lambing period.