Sheep advice: Flock management tips up to and during mating
Sheep farmers are being reminded that the management of the flock over the coming weeks and months will determine next season’s lamb crop.
Sheep specialist at Teagasc, Damian Costello has shared practical management tips for a successful breeding season.
Having ewes in the correct body condition score (BCS) at mating will not only improve flock performance but will also make flock management for the year ahead easier.
Costello said: “For lowland flocks, the aim is to have ewes at least BCS 3 and ideally BCS 3.5 at mating.
“This is usually achieved on good grass with thinner ewes (BCS 2.5 or less) taking eight to 10 weeks to achieve this target.
“On farms where grass supply was hit by drought this year, building body condition on ewes has been more challenging than usual.”
While supplementary silage/hay and concentrate feeding was needed in extreme cases, the Teagasc specialist noted that grass supply is now turning a corner on most farms.
However, according to Costello, it may be necessary to continue supplementation until enough grass is built up to carry the flock through the breeding season.
He said: “In this situation, concentrate supplementation for the thin ewe group could be justified at a rate of 0.5kg/head/day to build condition in the short time left pre-breeding.”
Rams also need to be in good condition at turnout (BCS 3.5 to 4.0) for two reasons:
- They eat very little during the mating season and can lose up to 20% of their bodyweight;
- Thin rams tend to have lower libido and are less inclined to seek out ewes to mate.
Ram health
Costello recommends carrying out any routine treatments before ram turnout to ensure minimal flock disturbance during mating, such as fluke treatment, footbathing, etc.
He added: “Try to have lameness under control prior to mating and continue to monitor during mating so that individual cases can be treated.
“After fertilisation, you are looking to give the embryo every chance of survival and successfully attaching to uterus.
“After ram turnout, avoid things like excessive handling, dipping or sudden changes in diet.”
The Teagasc expert said that it is important to monitor the health of rams in the run up to mating and have sourced any replacement rams in good time.
Sperm production in the ram takes five to seven weeks.
Costello said: “This means that a ram mating ewes in mid-October will have started producing that sperm at the end of August or start of September.
“Anything that interferes with sperm production in the run up to mating can have disastrous effects on the ram’s ability to impregnate ewes.
“Any infection that increases the ram’s body temperature by as little as 0.5°C for 24 hours can render a ram temporarily infertile.”
He added that a spare ram is no harm as a replacement for any ram that may get lame or is unable to function for any other reason.
Planning for adequate homebred ewe replacements
When breeding your own homebred ewe replacements, Costello said that a common mistake is not mating sufficient ewes with your maternal rams.
He said: “The current weaning rate of your flock will determine what proportion of the ewe flock that needs to be mated to a maternal ram to produce enough replacements.”
The table below is based on a 23% replacement rate, assuming that about 50% of lambs reared will be female.
| Number of lambs reared per ewe joined | Percentage of ewes required to produce replacements |
|---|---|
| 1.1 | 47 |
| 1.3 | 39 |
| 1.5 | 34 |
| 1.7 | 30 |
| 1.9 | 27 |
The figures in the table are minimum figures which allows for very little further selection.
The recommended number of ewes per ram is as follows:
- One mature ram to 45 ewes (up to 70 ewes for more active ram breeds);
- One ram lamb to 25 ewes (up to 40 for more active ram breeds).
Ram group mating vs single sire mating
Turning out a number of rams to each group of ewes can help ensure against the ram in the team that may be infertile or sub fertile.
Costello said: “Ideally use three or more rams together per group of ewes.
“This eliminates the effect of the blocker ram – where two rams are run together and the dominant one of them spends a lot of time and energy stopping his comrade from mating.”
When it comes to groups of rams, Costello said not to mix mature rams and ram lambs if possible.
Costello said: “With single sire mating or one ram per group, it’s all the more important to raddle your rams.
“With one ram per group, it’s a good idea, where possible, to rotate rams between groups after 14 days.”
Raddling
Raddling, or marking the ram, is very important, according to Costello.
He said: “Start with lighter colours which can be overmarked by a darker colour (e.g., yellow to orange to green to red to blue to black) and change the colour at least every 14 days, which will show repeats in the new colour.
“If a lot of ewes start repeating, suspect that there is a problem with a ram."
The Teagasc specialist stressed that at this stage, there is "still time to do something about it", which he said is "much better than finding a lot of empty ewes at scanning".
Costello outlined that many people mix raddle powder with oil to make a paste and apply liberally to the area of wool just above the brisket of the ram.
He added: “It’s important to work the raddle paste well into wool and reapply every few days, especially during the first few weeks when rams are busy."
He explained that some prefer to rub raddle crayon onto this area, which again needs to be applied regularly.
The other option is fitting a harness to the ram to which the colour crayon can be attached – the crayon block can be replaced when changing colours.
