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In The Paddock
Seasonal sheep flock management tips April 2002

Potential benefits from hogget mating — but high management requirements

Key Points

  • Hogget mating has high management requirements. It should be attempted only if these requirements can be met.
  • Ewes that lambed as hoggets have improved lambing performance as 2-tooths and for the rest of their lives.
  • Breed and/or strain of sheep has a significant impact.
  • Hoggets should be mated at around 40 kg at a condition score of 3 or better, using 2 rams per 100 hoggets.
  • Good growth rates after weaning are essential in order to achieve these targets.
  • Vaccinate hoggets for toxoplasmosis and campylobacter before joining teasers or entire rams.
  • Aim for growth rates of 80–100 g/day from mating until mid-pregnancy and for a target weight of about 52 kg at lambing.

Successful hogget lambing requires high standards of management. It should only be attempted if the farm and management system can meet these requirements.

The opportunity cost of the additional feed consumed must also be outweighed by the benefits of mating and lambing hoggets.

Trials have shown that ewes that lambed as hoggets may be lighter and clip less wool as 2-tooths. However, these differences do not persist past the 2-tooth season.

Two-tooths that lamb as hoggets have lower barrenness and higher lambing and weaning rates. This appears to be due to improved mothering ability.

Ewes that lambed as hoggets produced 20 per cent more lambs in their lifetime than those that didn't lamb as hoggets.

Romney, Coopworth and Perendales have hogget lambing rates of 20–70 per cent, with the higher rates being achieved only by very highly fertile/fecund strains of these breeds. Some new breeds such as the Finn and East Friesian have more oestrous cycles and begin cycling earlier, resulting in higher hogget lambing rates.

With better feeding, hoggets' lambs can wean at similar weights to the ewe mob's lambs. This means they can be kept as replacements, thereby shortening the generation interval and improving the rate of genetic gain.

To further speed up the rate of genetic gain, ram hoggets can also be used with care.

Target liveweights and feeding

Hoggets that show oestrous are more productive over their lifetimes — even if they are not lambed as hoggets.

Breed aside, mating weight is the key to achieving oestrous and consistently high lambing rates from hoggets.

Many farmers and consultants now use a liveweight of 40 kg and a condition score of 3 or better on 1 May as the minimum target for hogget lambing.

To achieve this, good ewe lamb growth rates are essential. After weaning, ewe lambs should be offered 1500–2000 kg/ha of high quality pasture. This means not grazing below 4–5 cm.

If these pasture conditions cannot be met, a high quality specialist forage crop or pasture should be used.

There is some debate on the merits of shearing hoggets before mating. While hogget shearing can stimulate ovulation, it appears that the key to getting this response is to have plenty of high quality feed on offer after shearing.

Because shearing stimulates appetite and increases maintenance requirements, animals will lose weight if feed is short. This is exactly the opposite to what is intended.

To maximise conception rates, ewe hoggets should be on a rising plane of nutrition at mating.

Aim to reach the 40 kg target about a month before mating, then reduce the rate of gain to about 50 g/day until the rams are withdrawn. This will ease the pressure on feed supplies at a time when the main ewe mob also needs to be gaining weight and condition.

Mating management

Hoggets should be given Toxovax at least one month before mating or the introduction of teaser rams, preferably by 1 March. Campylovexin should be administered twice before mating, with a four week interval between vaccinations. The last vaccination can be given as the ram goes out.

Hoggets start cycling about a month later than ewes. To bring them into oestrous earlier, some farmers run them with teaser rams for the month before mating. Others graze their hoggets next to the main ewe mating mob, where the presence of rams and mating activity has the same effect.

Many farmers join entire rams with ewe hoggets on 1 May and mate for two cycles. With well-grown hoggets the choice of sire breed is not as critical as frame size at lambing. Use a ram:ewe ratio of 1:50.

Because hoggets aren't on heat for as long as mature ewes, it's best to mate in small, easy contour paddocks. When mating with ram hoggets, give the ram hoggets sexual experience by running them with a small group of older ewes, before putting them with the ewe hoggets.

Feeding in early- and mid-pregnancy should aim to achieve growth rates of 80 g/day, or about a 12 kg gain in liveweight over winter. The industry average is considerably less than this, so liveweight gains over winter will need to be higher than at present if mating hoggets is to succeed.

More information

  • Schick, G. 2001. Hogget mating. Will you follow the trend?, Wool Grower Summer 2001:Pp 25-26.
  • Willoughby, L.; Gavigan, R. 2001. Hogget mating and lambing — A discussion paper. WoolPro internal paper: 11pp.
Northern North Island: Sally Hobson tel 07-823 3321 or 025-924 751
Hawkes Bay/East Coast: Lew Willougby tel 06-835 1888 or 025-434 417
Southern North Island: Richard Gavigan tel 06-376 0006 or 025-499 851
Nelson/Marlborough/Canterbury: Alan Marshall tel 03-343 7913 025 329 399
South Canterbury: Julia Mackenzie, tel 03-680 6782 or 025-782 353
Otago: Robert Pattison, tel 03-489 9021 or 025-323 094
Southland: Aaron Meikle, tel 03-203 9071 or 025-846 377
 

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