3. ISRAELI AGRICULTURAL RESEARCH ORGANIZATION TRIAL

The trial was started in 1970 at the Volcani Centre, Agricultural Research Organization at Bet Degan. It aimed to improve fecundity of both mutton Merino (MM) and Awassi (AW) sheep under an intensive management system (zero grazing), and to improve daily gain of the fat-lambs produced.

3.1 Breeding Plan

The breeding plan reported by Goot (1975) involved the crossing of MM and fat-tail AW ewes by imported Finn rams. Six Finn rams were imported from Finland in 1970 followed by 4 rams in 1973, 4 rams in 1977 and finally 3 rams in 1982.

The Fl ewes were either mated to the fat-lamb sire breed, e.g. Suffolk (SF) or Assaf (As), or inter se mated to produce F2 for a selection programme within each breed group.

The MM ewes were hand served and AW ewes were synchronized and artificially inseminated. Without such treatment, it was practically impossible for the Finn rams to copulate with the fat-tail AW ewes (Goot, 1975).

Table 10: Performance of 1/4 Finn ewes under small farmers' conditions in Sharkia Province.

3.2 Preliminary results of the Finn crosses

The results of the 1st phase of the trial were reported by Goot (1975) and Goot et al., (1976). They can be summarized as follows:

-	81 percent of Finn X MM (FM) and Finn X AW (FA) first crossbred hoggets (approx. 14 months old) lambed vs. 64 percent for MM and 33 percent for AW hoggets. Average lambing percentages were 120, 100, 80 and 30 for the four breed groups, respectively.
-	The 2-6 year old FM crossbred ewes produced 0.3-0.8 more lambs/ewe mated than MM. There were too few FA ewe records to be analysed.
-	There were no differences in growth rates of MM and Fl lambs, but birth weight and 150-day weight of F2 lambs were smaller than MM lambs.
-	Mortality up to 120-days was the highest in MM lambs followed by F2 and Fl lambs. Finn crosses were more affected by outbreaks of pneumonia in the summer months.

3.3 Assessment of Finn crosses under an accelerated mating system

Another project was initiated, in collaboration with USAID, to evaluate the potentiality of the Finn crosses under an accelerated mating system, and to test other Finn crosses with AW, and compare them with Romanov (RV) crosses with AW and MM.

The mating was set up in the accelerated mating system in June, September and December/January. The ewe-lambs were mated as close to these months as possible after syncronization and hormonal treatment with PMS. The ewes were hand served, and usually 2 oestrous cycles were allowed as a mating period. Ewes failing to conceive would be rebred within a few months in the following mating season.

Ewe-lambs were mated at the age of 244+48, 265+42 and 219+10d for FM, FA and 3/4 AW, respectively. Forty-eight to 62 of them conceived in the first mating season, 34-52 percent in the second and 4 percent in the third. Number of lambs born/hoggets lambed was 1.75, 1.73 and 1.41 for the three breed groups, respectively (Goot et al., 1984a).

Reproductive performance of FM, FA ewes and their interbred generations under accelerated lambing were reported by Goot et al., (1980) and Goot et al., (1984a). Actual lambing frequency/year was 1.4 for FM and 1.2 for FA. Number of lambs born to FA ewes (2.6) was insignificantly higher than those born to FM ewes (2.34). Within FM ewes, there were no differences between generations but within FA ewes there was a significant (P<0.05) drop in number of lambs born/ewe lambed for the Fl to the F2 and following generations (Table 11).

Table 11: Reproductive performance of FM, FA ewes and their interbred generations under an accelerated lambing programme (Israeli trial).

^* EP: ewes present; EL: ewes lambed; EEL: ewes eligible for breeding; LB: lambs born.

When data were pooled over genotype and generations, ewes mated out of season (Dec.-April) performed significantly less than those mated in season (June-Sept.) by 19 percent of ewes lambed and by 0.16 percent lamb/ewe lambed.

The expected lambing to lambing interval in the applied accelerated mating system ranged from 7 to 9 months, but in FA ewes it ranged from 7 to 12 months. There was a big gap between January and June matings. Percentage of dry ewes based on ewe mated in each period was 10 percent in June, 15 percent in September, 18 percent in Dec./Jan. and 23 percent in April.

Due to unforeseen circumstances, most of 3/4 F 1/4 AW ewes and some of the 1/4 F 3/4 MM and all the 1/2 As 1/4 F 1/4 AW ewes were transferred to a private commercial farm. The rest of 1/4 F 3/4 MM were raised in another private farm. The management system was different in the two farms from that in Bet-Degan and therefore, contemporary comparisons were not possible. However, data from the two private farms were analysed and reported by Goot et al. (1984a). The general conclusion drawn regarding these crosses was: differences between 1/4 Finn and 1/2 Finn and between 1/2 Finn and 3/4 Finn on the other hand were less than that expected, assuming linear increase in prolificacy with the increase in Finn blood (Table 12). Difference in management and age groups involved in each breed group is a possible reason for this discrepancy. The reported figures, however, were based on unweighted mean of year, age and season groups.

Table 12: Reproduction performance of different Finn groups in the Israeli trial.

^* LB: lambs born; EL: ewes lambed

3.4 Seasonal sexual activity of Finn crosses

Seasonal differences in sexual activity of Finn crosses were investigated and reported by Amir et al., (1980) and Amir et al., (1984). Length of sexual season was similar in FM and MM ewes, but FM ewes started their season later (beginning of August) and terminated later (beginning of March) vs. June and January for MM, respectively. The last oestrus in the season in FA ewes was detected by February-March, except for one ewe (out of 14 studied) which showed normal cycling throughout the year. The ewes resumed normal cycling activity in June-September, meanwhile silent ovulation during the anoestrous period (April-May) occurred in almost half the FM and FA ewes as detected by plasma progesterone concentration twice weekly.

Post-partum oestrus for FM and FA ewes lambed in October and early November occurred within 60 days in 9 percent of the cases. Days for post-partum oestrus averaged 41.3 and 36.9 days for FM and FA ewes, respectively. Most of the ewes, however, had an active ovary within 4-6 weeks post-partum. Ewes lambing in January, did not exhibit oestrus until the next sexual season.

Conception rate and litter size of FM and FA ewes bred at different months of the year are shown in Table 13.

Table 13: Lambing rate and litter size of Finn crosses at different mating seasons in the Israeli Trial.

Response of ewes to exogenous hormones for oestrous synchronization was similar in different months during both sexual season and anoestrous period. Conception rate, however, was insignificantly higher with natural rather than induced oestrus (Table 13). Within oestrus induction, the conception rate was significantly lower in April than June or December. No significant differences were found in litter size of ewes bred at different months which ranged from 1.7 to 2.0.

Some trials using artificial photoperiod and the introduction of the ram for improving fecundity in FM and FA ewes were reported (Amir et al., 1984). Artificial lighting did improve the fertility of the ewes. The introduction of the rams was of value, although the number of animals used was small. The results of different trials on sexual activity of the Finn crosses indicated the suitability of FM and FA ewes for a frequent mating schedule to breed more than once/year.

3.5 Lamb and carcass performance

Finn-AW crossbred lambs performed marginally better than the Finn-MM lambs (Goot et al. 1984c). The authors reported that AW and FA dams, having plenty more milk than MM and FM ewes, stimulated the growth performance of their lambs, but the differences were statistically insignificant. Overall, Finn cross twin-born lambs showed similar mortality to that of singles, and was significantly less than that of triplets and quadruplets. Mortality from 0-150 days in Finn-crossbred lambs averaged 22 percent in the experimental flocks and 11.5 percent in the commercial farms.

Goot et al. (1984b) pooled together information available on carcass performance and carcass composition of lambs involved in different fattening trials (Table 14). Awassi lambs needed twice as long as Finn crosses to attain slaughter weight. Genotype differences were insignificant in daily gain, which ranged from 291 g for 3/4 FA to 343 g for AS FA lambs. Apart from the very high coefficient of variation in Awassi due to wide weight range, the most noticeable feature was the clear reduction of the fat tail in the crossbreds, by 93 percent in FA and by 88 percent in AS FA.

Kidney and intermuscular fat contents were similar in all Finn crosses and were significantly higher than in MM and AW. Internal and subcutaneous fat was higher in AW and FA lambs than other genotypes. Total carcass fat was the highest in AW, intermediate in Finn crosses and the lowest in MM. The contribution of the Finn genotype to fat composition appears to be in two opposite directions; reducing the fat-tail and subcutaneous fat in Finn-AW crosses and increasing internal and intermuscular fat in both Finn-AW and Finn-MM crosses.

Using AS and SF as terminal sires for fat-lambs did not show encouraging results as compared to the performance of Finn cross ram-lambs (Goot et al. 1984c).

Table 14: Lamb and carcass performance of different genotypes studied in the Israeli trial.

3.6 Finn vs. Romanov first crosses

In 1975, 5 Romanov (RV) rams were imported from France to compare the performance of Romanov crosses with MM (RVM) and AW (RVA) to the Finn crosses. Difficulty in mounting of RV rams was reported (Goot et al. 1979).

There was no significant difference between the two prolific breeds in lambing and reproductive performance of their 1st cross. Romanov sires, however, greatly increased the incidence of pigmented and kemp fibres in the wool of their progeny. RVM ewes gave slightly higher percentage of twins than the FM ewes. There were also some sets of triplets in RVA which reflected in a higher lambing percentage than FA (Table 15). Neither body weight nor daily gain of Fl lambs was affected by the sire breed. The F2 progeny with Finn blood was heavier at birth and grew faster to weaning than with RV blood 4.1 kg and 233g/day vs. 36kg and 198g/day, respectively.

Further contemporary comparisons for Finn and RV crosses with AW were reported by Goot et al. (1984b). They analysed 3-year data comparing Fl of FA and RVA under an accelerated lambing programme. They had similar figures in different reproductive performance traits, but the results were in slight favour of the RV crosses.

Table 15: Contemporary comparison between Finn-AW(FA) and Romanov-AW (RVA) in accelerated lambing in Israel.

^*EP: ewes present; EEL: ewes eligible for breeding; EL: ewes lambed; LB: lambs born