Mating management in Sheep

Ciaran Lynch, Sheep Specialist, discusses mating management. He looks at; ewe:ram ratio, raddling rams, grouping up, fertility issues, and ram lambs.

Rams

Rams have a major impact on a flock and its future performance and require additional management at this time of the season. Most rams have a tendency of leading a relatively trouble free and intervention free existence for most of the year until mating approaches when by some miraculous chance they tend to develop problems! However, these problems probably exist for most of the year but only get noticed as rams start to get more attention. By now some rams will have already been introduced to ewes or on the point of being turned out with ewes, whilst others still have a few more weeks to wait. It is always recommend to closely inspect rams in the lead up to the breeding season and deal with any issues but that doesn’t just stop at turnout.

Ewe:Ram Ratio

There is variation in the level of activity displayed by rams both within and across breeds and management can certainly play a role in this but in general a guide to number of ewes per ram is as follows:

• A mature ram to 45 ewes (up to 70 ewes more active ram breeds)
• A ram lamb should be joined with a smaller number of ewes in a ratio closer to 1 to 25 (up to 40 for more active ram breeds)
• Synchronised ewes or where the ram effect was used effectively will require lower ewe to ram ratios for the high demand period

Raddling rams

Unfortunately the use of raddle on rams during the mating period is one management practice that is often underutilised on farms. Some producers will ideally opt to change colour on a weekly basis, but try at minimum aim to change colour every 14 days to detect fertility issues. Start with lighter colours (yellow → orange →green → red → blue → black) take note of the date colours were changed.

There are two raddle options that are widely available in agricultural and veterinary supply stores:

1. Powder form that is then mixed with oil to form a viscous paste. This is applied liberally to the wool just above the brisket. This needs to be topped up during periods of high activity as the marking colour on freshly served ewes begins to fade.
2. Crayon form, generally these are used in conjunction with harnesses although some may choose to apply the crayon directly as above. When used with a harness it is vital they are fitted correctly and adjusted as needed during mating as they may move with mounting activity and use. Care also needs to be taken as ill fitted harnesses can result in brisket sores. Similar to the paste these crayons will need to be replaced with use.

Raddling rams during the joining period does require some effort but it has a number of important benefits for your flock.

1. Firstly it allows the level of mating activity and ram performance to be monitored, this will also give an indication of the expect demand on resources such as housing times for different groups etc. for the subsequent lambing. This provides potential cost saving on concentrate but perhaps more importantly it can help reduce the levels of dystocia and lamb mortality associated with over feeding particularly during the latter part of lambing period
2. Regular changing of raddle colour allows for early detection of ram fertility issues i.e. if a large number of ewes are being over marked with different colours (i.e. repeat mating’s) it may indicate a ram fertility issue and action needs to be taken to address this.

Grouping up

How the ram performs during the joining period will have a major impact on flock productivity. A number of flocks will use single sire mating (1 ram per group) to achieve the aims of breeding programmes in their flock. While necessary in certain cases it is also inherently risky. To mitigate some of this risk when using single sire after the first 14 to 17 days mating rams should be rotated around mating groups or ideally mobbed up with a group of three rams, thereby reducing the odds of an infertile ram mating a ewe on a repeat cycle. This is good practice for many flocks even where single sire mating is not used. By using at least three rams in a mob eliminates the effect of the blocker ram, where two rams are ran together and the dominant one of them spends a lot of time and energy stopping his comrade from mating. An additional benefit to reducing ewes and ram groups as the joining period progresses is its influence on grassland management by:

1. Reducing the number of fields being grazed - easier to close up fields
2. Increasing the grazing pressure resulting in ewes grazing heavier opening covers quicker and ewe spending less time grazing out lower covers

Fertility issues

For rams any increase in body temperature from as little as 0.5°c for a short period in the 6 weeks leading up to mating and during the mating period can render a ram infertile or compromise their fertility. Any sign of infection, lameness etc. needs to be treated promptly and effectively. There is a perception that antibiotic treatment of rams in the lead up or during mating will render them infertile, this is not the case. However, letting an infection develop that will cause an increase in temperature certainly will render the ram infertile.  Rams can also be sub fertile during the joining period so their performance and the level of ewes repeating needs to be monitored. Once again this is where using raddle is a good early indicator and if in doubt the ram in question needs to be removed and replaced.

Ram activity during the joining period can also be affected by an injury caused either as a result of fighting or mounting activity. Occasionally this may only require a temporary removal but care needs to be taken as anything that may impair the rams activity can result in fewer mating’s occurring. Rams in poor condition will have reduced activity and spend less time seeking out ewes in oestrus so these need to be monitored closely particularly as mating progresses.  

Ram lambs

Rams are a significant investment for any flock, with most coming in as ram lambs it is worth considering how these are managed during the first year. In all cases these lamb are susceptible to worm burdens, more so during periods of high activity. They need to be treated appropriately before and after the joining period. Aside from the issues previously mentioned its worth remembering that these lambs are still growing and developing. Many (not all) of them are coming off a high level of feed and a somewhat easy life back to what is a highly active workout on a somewhat restricted grass only diet. Where it is advisable to recoup as much of this investment by getting them to mate a sufficient number of ewes in the flock you also need to consider how this will impact the rams lambs longevity. Perhaps it’s worth considering taking them away from the ewes slightly earlier than the mature rams (e.g. after 3 weeks of mating) to avoid injury towards the tail end of mating and to give them time to recoup body reserves. This may help extend their time in the flock – just something to consider. Remember post mating all rams need to be treated for any ailments and some supplementation should be provided to replenish reserves, it’s a relatively small investment relative to the ram themselves.

The Teagasc Sheep Specialists issue an article on a topic of interest to sheep farmers on Tuesdays here on Teagasc Daily. Find more on Teagasc Sheep here. For any further information or assistance contact your local Teagasc Office here: Advisory Regions.