Question

Just inquiring what exactly to use to boost fertility in both the ram and ewes prior to mating so as to achieve a high percentage of lamb per ewe? Is there anything on the irish market to administer as a dose or feed to improve performance? I’m a fresh face to sheep breeding so your help would be appreciated

Answer

In general ewes have a higher fertility than cows. However, management is still very important to maximise reproductive performance. Certainly nutrition in the prebreeding season and throughout the breeding season is a vital part of good ewe flock management. By far the most important nutritional influences on fertility are energy intake and body condition of the ewes at this time. It is imperative that the ewe reaches the beginning of the breeding season in good body condition, i.e. body condition score (BCS) of 3.0 – “Fit Not Fat”. Both thin ewes and overfat ewes will have problems with infertility. Thin ewes often do not have normal reproductive cycles as their energy is directed to maintaining body function at the expense of reproduction. On the other hand, fat ewes often have problems with hormone production and with the metabolism of reproductive hormones by the liver. One of the most important things you can do as a sheep farmer is to regularly body condition score the ewes in advance of the breeding season in order to ensure that ewes reach the breeding season at the correct BCS.

Fertility will also be boosted when ewes are on a rising plane of nutrition, i.e. they should be on a diet that allows weight gain up to the required BCS prior to breeding. Obviously this should be avoided for the ewes that are already approaching a state of being overfat. Some people also place a lot of weight on the influence of mineral deficiencies in infertility problems. However, this is usually not a major player on most Irish farms. Certainly, if you are farming the flock on marginal land, it is no harm to give them a dose of a routine trace mineral drench prior to the breeding season. The mineral that has been shown to have a direct influence on the development of the lamb’s nervous system when severe deficiencies occur is copper. Copper deficiency, especially from mid-gestation onwards can lead to “Swayback”, a condition where lambs are born with an inability to properly control their limb function leading to a swaying hindlimb gait. If there is a history of copper deficiency in your area or your flock, it is definitely worthwhile giving the ewes copper boluses or trace mineral boluses containing copper – NB sheep are extremely susceptible to copper poisoning so do not oversupplement , especially if there is also added copper in the sheep meal; another common cause of copper poisoning is the use of cattle boluses by mistake – take great care to avoid this as copper poisoning is invariably fatal.

In terms of infectious causes of infertility, toxoplasmosis can certainly be a problem in many flocks, especially where there are large cat populations in the vicinity. It is advisable to vaccinate against toxoplasmosis prior to tupping. We are also coming into the important time of the year for the prevention of liver fluke infestations. It is important that ewes are dosed for both fluke and worms prior to the breeding season to maximise fertility and productivity.
The other main thing to ensure is that there is a correct ram to ewe ratio, i.e. there should be 1 ram to 10 ewes if the ewes are synchronised or else 1 ram to 25-40 ewes if non-synchronised, depending on the age of the ram. All of these considerations together should help to ensure that your fertility is maximised.

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