THE PROLIFIC MERINO BREED AND ITS UTILIZATION POSSIBILITIES

Veres, László
Magyar, Károly

Horváthné, Irén

Komlósi, István
Jávor, András
Debrecen University of Agricultural Sciences
Debrecen, Hungary

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ABSTARCT

As the authors see, the Prolific Merino bred in Eastern-Europe and in Middle-Asia can be the same possible crossing partner as the Border Leicester in Britain and in other Commonwealth countries. The 75-80 percent of the 200 Prolific Merino nucleus flock at Debrecen is FecB homozygous carrier. First lambing was at 704 days of age on average, the average prolificacy rate was 198 percent and the lambing intervals were 298 days. Seven thousand doses of deep frozen semen from 16 New Zealand imported Booroola Merino and their homebred offspring were conserved in plastic straws, 1500 doses were used for progeny testing of young rams, 500 doses were exported. The average conception rate of 21 rams by 497 intrauterine inseminations had occasionally big individual ram differences (10-100 percent). Eighty-seven percent of our stock rams and 50 percent of ewes were born by target mating through intrauterine insemination from deep frozen semen, so that great genetic variability and progress can be maintained. Besides the keeping of the homozygous the major task is the increasing of bodyweight and improving the inclination of the continuous lambing. Prolific Merino ewes were crossed with Texel rams. F1 lambs would grow + 15 percent (up to 30 kg), had better culling out percentage, + 4 percent, than the Prolific Merino lambs.

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INTRODUCTION

In countries with developed sheep breeding (primarily in Great Britain) and in large sheep product exporter countries (Australia, South Africa, New Zealand) three-breed crossing became general (Croston and Pollott, 1994). In this way they utilized the advantages first of all of classical and secondly of complementary heterosis. In these crossings mainly Border Leicester breeds were used as B partners.
In Eastern-European and Middle-Asian countries with mainly Merino or Merino related breeds, we think of a similar role for the Prolific Merino, the breeding of which was announced in 1982 and which was approved as a new breed by the Hungarian Agricultural and Breed Qualification Institution in 1992. The direct breeding programme of the breed was carried out in the Debrecen 200 ewe nucleus flock. We have reported its results earlier (Veress et al. 1995, Magyar et al. 1997). The ewe stocks of other controlled and producing enterprises are tupped by rams bred at the nucleus flock. As a result, the genetic development of the ewes in these enterprises besides individual selection is based on primarily Debrecen rams that carry the FecB gene homozygously.

MATERIAL AND METHODS

The breeding of this breed had started from the Hungarian Merino: the crossings were made with Booroola Merino rams bought from New-Zealand which carry the prolific gene. The weight of mature rams is 80-90 kg, which produce 7 kg of greasy wool with 55-60 percent rendement, with a length of 11 cm and 20-26 microns fineness. The weight of mature ewes is 50-55 kg, which produce 4.5 kg greasy wool of 9 cm length and 20-22 microns fineness, annually. The average age at first lambing was 704 days. Ewes carrying the prolific gene are very prone to multiple lambing, lambing rate is 1.2-1.3 annually, and they are capable of 200 percent progeny by lambing. Although they are 10-15 percent smaller than the Hungarian Merino, and have slower development, they are more capable of frequent lambing, produce more milk, and are good mothers.

RESULTS

In the Debrecen nucleus flock of the breed:
· After tupping the ovulation rate (OR) is examined. We consider a ewe to be homozygous for the prolific gene if it has an OR of four or higher in frequent lambing; 75-80 percent of ewes are homozygous.
· Ewes carrying the gene homozygously are further selected according to their frequent lambing capabilities, body size, and fine wool production. Between 1986 and 1993 the average progeny rate was 198 percent and the average relambing interval was 295 days (Veress et al., 1995) (Table 1).
· We carry out 30-35 target-matings per year, intrauterine inseminations with deep frozen semen of rams that are not alive but proved to be excellent in the above-mentioned characteristics. This way genetic development can significantly be speeded up and genetic variability can be maintained. So far we have inseminated 497 ewes with deep frozen semen from 21 rams, the average rate of conception was 53 percent with very large individual differences (10-100 percent). Eighty-seven percent of stock rams and 50 percent of ewes are the results of target mating, done with frozen semen through intrauterine insemination.
· So far, sperm from 34 rams of 16 ram-lines we collected and preserved 7 000 doses of deep frozen semen while we preserve sperm of other promising rams. Sixty percent of the reserve is from 10 homozygous carrier ram-lines, and the other 6 ram lines are preserved for developing further homozygous ram-lines. So far we have used 1 500 doses of sperm for progeny and a further 500 doses were exported.

We consider our main objectives are to be improving live-weight gain in lambs, increasing the mature weight, improving ewes' propensity for frequent lambing and good milking, and retaining good wool production. Between 1986 and 1993 only 4.4 percent of the ewes gave birth to 4-6 lambs, 39.5 percent to two lambs and 17 percent to three lambs. The relatively lower progeny rates, compared to the Booroola Merino breed is due to the application of the frequent lambing technology and better lamb survival.
At the experiment site we have carried out model crossings with Texel rams to produce slaughter lambs and F1 ewes. The Texel F1 lambs are capable of 15 percent higher daily live-weight gain during the suckling and fattening period. At 25-30 kg live-weight they had 4 percent higher killing out, they achieved a significantly better muscle structure than the Prolific Merino lambs. The F1 crossbred ewes retained for breeding had a weight increase of 20-30 percent, their wool production has improved, and they produce 26-30 micron crossbred quality. The maternal performance of the cross will be published later.

Table 1. The average lambing interval according to litter size for Prolific Merino ewes

**P0.05

CONCLUSIONS

It is possible to maintain homozygosity for the FecB gene and on the other hand to moderate the litter size by frequent lambing. Those breeds that have large prolificacy (>200%) can be used in a frequent lambing system, to produce all-year-round lambs. It appears that in a breeding integration in Eastern-Europe and Middle-Asia the Prolific Merino could well be used in three-breed cross breedings as the partner for the first crossing partner (Veress et al., 1995).

REFERENCES

Croston, D. & Pollott, G.E. 1994. Planned Sheep Production. Blackwell. Oxford.
Magyar, K. - Veress, L. - Tassi, Zs. - Pécsi, T. -Horvathné, I. & Babik, S. 1997. Sheep breeding programme and results to date II. In: Állattenyésztés és Takarmányozás. Vol. 46. No. 1:41-50.
Veress, L. - Magyar, K. - Komlósi, I. - Horváthné, I. & Kovács, Z. 1995. Sheep breeding program and results to date I.. In: Állattenyésztés és Takarmányozás. Vol. 44. No. 4: 301-315.