A ram classing procedure has been developed in the form of a lattice which embraces all types of selection decisions which a ram breeder is called upon to make in a breed for which wool is a major objective (Dolling et al. 1993). The lattice is developed here in a manner which would service Wiltipoll breeders in the classing of individual rams and ewes, both during the back-crossing phase from Wiltshire Horn to Wiltipoll and once the Wiltipoll breed is established.

The ram-classing lattice embodies a structured procedure whereby rams in a breed reared primarily for wool production may be classed taking into account all four groups of characters which a breeder encounters. The groups are of characters appraised visually (Group V), of characters resulting from identified genes (Group G), of characters employed in a selection index (Group I), and of characters assessed by measurement other than those in a selection index (Group M).For each character accepted as a selection criterion, a flow chart leads the breeder to one or another of the four groups.The heritability of each character in Groups V or M is taken into account in the classing of a ram, together with his degree of expression of the character. For characters in Group G, the relationship of the ram to sheep known to have expressed the character is considered.The lattice accommodates a rise or fall in the importance attributed to any character without any change having to be made to its structure. Similarly, it can readily accommodate the addition of any character to a breeder's selection criteria; or the deletion of any character.

The following procedures for listing loci in ruminants were proposed at the 1991 1st Workshop on Genetic Nomenclature of Farm Ruminants organised by COGNOSAG (Committee on Genetic Nomenclature of Sheep and Goats): identification of locus, genomic location, gene effect classification (24 entries), summary of alleles and, for each allele, after identification, phenotypic effect, inheritance and breeds implied.This * Correspondence and reprints set of procedures is intended for the first edition of the MIS, MIG and MIC catalogues (mendelian inheritance in sheep, goats and cattle, respectively) and is a basis for future data banking.ruminants / loci / listing procedures / nomenclature R.ésumé -Procédures de listage des loci et allèles des ruminants 1991.Au cours du premier Atelier de Nomenclature Génétique des Ruminants de Ferme organisé par le COGOVICA (Comité de Nomenclature Génétique des Ovins et Caprins) en 1991, les procédures suivantes de listage des loci chez les Ruminants ont été proposées: identification du locus, localisation sur le génome, effet du gène (24 entrées), tableau des allèles et, pour chaque allèle, outre l'identification, l'effet phénotypique, l'hérédité et les races concernées.Conçue pour être utilisée dans la première édition des catalogues MIS, MIG et MIC (Mendelian Inheritance in Sheep, Goats and Cattle resp), cette grille peut servir de base pour une future banque de données.ruminants / loci / procédures de listage / nomenclature

Reproductive performance of Poll Dorset x South Australian Merino (PD x M) ewes was superior to that of South Australian Merino (M) genotype with 10% more pregnant ewes, 11% more lambs born per pregnant ewe, and a 7% better lamb survival rate. This resulted in 22 more lambs slaughtered per 100 ewes exposed. Merino ewes produced more greasy wool (6.08 vs. 4.35 kg) of finer fibre diameter (27.5 vs. 32.9-mu-m) than PD x M ewes. Mature liveweight at mating of PD x M ewes was 17% more than that of M ewes (57.8 vs. 50.1 kg). Carcasses of lambs from PD x M ewes were heavier (18.7 vs. 16.8 kg), shorter per unit carcass weight (698 vs. 783 mm carcass length per 16.9 kg carcass weight), and fatter (13.0 vs. 11.6 mm; GR fat depth) when evaluated at similar carcass weight as compared with carcasses of lambs from M ewes. Skin weight and skin wool characteristics of lambs were similar between genetic groups.Under 1987 and 1988 Australian wool and sheep meat market price conditions, the economic worth of M ewes per unit metabolic weight (mature weight0.75) was 45% more profitable than that of PD x M ewes.

des ruminants 1991.Les directives pour la nomen- clature des gènes du mouton (Ovis aries L) et de la chèvre (Capra hircus L) élaborées au

The carcass and non-carcass characteristics of 121 Suffolk-sired lambs from South Australian Merino (M), Poll Dorset X South Australian Merino (PD X M) and Border Leicester X South Australian Merino (BL X M) ewes were compared in two pen experiments (PEI 1 , PE 2 ) at Turretfield Research Centre, South Australia. When lambs were slaughtered at the same liveweight and carcass characteristics adjusted to constant carcass weight (15.6 and 15.7 kg; PE 1 and PE 2 , respectively) there were no significant differences between breeds of dam for fat depth C, or for percentages of chemical fat (ether extract), protein, moisture and ash. At constant liveweight (e.g. 36.4 kg, PE 2 ) dressing percentage was higher for BL X M and PD X M compared with M progeny (44.6 and 44.5% vs. 39.9%, respectively). Differences due to breed of dam were detected for some of the non-carcass characteristics, adjusted for slaughter weight in either PE 1 or PE 2 , but on no occasion were the differences significant in both experiments. Greasy fleece weight, measured in PE 2 only, was heavier for M compared with BL X M progeny which in turn was heavier compared with PD X M progeny (1.60, 1.29 and 1.11 kg, respectively). We concluded that differences between Suffolk-sired lambs from South Australian Merino, PD X M and BL X M ewes were small for most carcass and non-carcass characteristics when compared at the same carcass weight and slaughter weight, respectively. The relative economic merit of the breeds, therefore, is more likely to be determined by factors other than those examined in the present experiments.

The heritability of and phenotypic and genetic correlations among weaning weight (WW). greasy fleece weight (GFW), scouring yield (YLD), clean fleece weight (CFW), fibre diameter (FD), crimps per inch (CR) and staple length (SL) were estimated in a flock consisting of a control and 2 selection lines of South Australian Merino sheep. The effects of type of rearing, age of dam and sex were also examined. Estimates were compared with those currently in use in WOOLPLAN (National Performance Recording Scheme for non-pedigreed sheep) and in other studies. In general, agreement between the present study and other estimates was good, but there were some exceptions, namely: (i) standard deviation of GFW and FD; (ii) 'adjustment factors' for day of birth, type of rearing and age of dam for GFW, CFW and liveweight traits; (iii) heritability of YLD; (iv) phenotypic correlations of GFW and CFW with FD, and between YLD and CFW and (v) genetic correlations of WW with GFW, CFW and FD. It is concluded that special attention should be given to these exceptions in order to decide whether alterations to current 'accepted' parameter values are justified.

Various densities of black sheep (0, 2%, 9.5%, 21.4% and 50%) were run with white sheep for a period of 10 weeks. The groups were yarded on average once weekly. The number and lengths of melanin-pigmented wool and kemp fibres were measured in carded wool samples from the white fleeces. All groups containing black sheep produced white wool with higher levels of pigmented fibres (an increase of 8- to 64-fold) than the control group (P< 0.05). The extent of contamination of white wool by pigmented fibres increased with the density of black sheep. Both pigmented wool and pigmented kemp fibres occurred frequently in the contaminated wool samples and the fibres mainly had lengths less than 10 mm. The results provide evidence of the risks involved in the practice of including pigmented sheep in white sheep flocks.

The effects of breed of dam (South Australian Merino (M), Border Leicester x Merino (BL x M) and Poll Dorset x Merino (PD x M)), type of birth (single and twins) and sex of lamb (wether and ewe) on the efficiency of the ewe (organic matter intake per unit (liveweight)0.75 and clean wool weight per unit intake) and of the ewe-lamb(s)) unit (liveweight and carcass weight per unit intake) were examined in two pen experiments (PE1, PE2) and a grazing experiment (GE). Each single-born lamb in PE1 and PE2 was slaughtered at weights =32 and =35 kg, respectively, and twin-born lambs when their combined weight doubled that of singles. In GE all lambs were slaughtered on the same day at 35.5 kg mean liveweight. Ewes rearing twins ate 19% more (P < 0.05) organic matter per unit (liveweight)0.75 during lactation than those rearing singles, the other effects of breed and sex were not significant during either late pregnancy or lactation. BL x M ewes grew 32% less (P < 0.001) clean wool per unit intake than did M ewes in PE, whereas the breed difference in GE was not significant, PD x M ewes grew 39% less wool than M ewes in GE (P < 0.001). Ewes rearing twins were 23% less efficient in converting food to wool than those rearing singles in PE, (P < 0.01), the corresponding difference in GE was not significant. There were no significant differences between breeds of dam for efficiency of the ewe-lamb unit when lambs were compared at the same age. However, when lambs were grown to the same liveweight the M ewe-lamb unit produced 14% (P < 0.001) and 8% (P < 0.05) more liveweight and carcass weight per unit intake than the BL x M in PE,. These results include adjustment for the effects of type of birth and sex. In all experiments ewes with twin lambs were about 45-55% and 35-45% more efficient than those with singles on a liveweight and carcass weight basis, respectively (P < 0.001), the effects were independent of whether the lambs were at the same age or the same liveweight. We conclude that efficiency of conversion of food to carcass weight on a flock basis will be largely dependent on variation in reproduction rate and to a lesser extent on breed of dam, and on breed of dam only when lambs are slaughtered at the same liveweight. In contrast, the effects of breed of dam on efficiency of food conversion to wool fibre were large.

ABSTRACT The occurrence of melanin pigmented wool fibres in the skirted white fleece wool from 1-year-old Corriedale ewes, having either least (group 1), most (group 3) or an intermediate level (group 2) of black nose skin pigmentation, was investigated. Thirteen of the 87 fleeces analysed had the equivalent of 10 to 389 isolated pigmented fibres per 100 g of scoured wool. The mean diameter of the pigmented fibres was similar to that of the fleece specimens analysed and they occurred singly or in small groups within individual staples. Large numbers of isolated pigmented fibres in fleeces were widely distributed, and constitute a serious problem of identification by visual inspection. Fibre darkness and the number of fleeces found with pigmented wool fibres were two measurements which showed a significant association ( P < 0·001 and P < 0·05, respectively) with nose skin pigment group. With one exception from group 2 the results support the suggestion that the usual selection for dark nose skin in this breed may be antagonistic to selection for a white fleece. The pigmented lengths of fibres were found to be independent of nose skin pigment group.

South Australian strong-wool Merino, Poll Dorset and Border Leicester rams were joined to 766 South Australian strong-wool Merino ewes at Minnipa Research Centre, South Australia. The survival, body growth and carcasses of the wether progeny were assessed at 3-4 1/2 months of age. The survival, body growth and wool growth of the ewe progeny were measured from birth to 16 months of age. There were no significant differences between breeds in lamb survival at birth or from 3 to 16 months of age. Merino lambs had the lowest lamb survival between birth and three months of age, the difference being significant (Pt0.05) with Border Leicester x Merino (BL x M) lambs and close to significance (P-0.07) with Poll Dorset x Merino (PD x M) lambs. At three months of age PD x M and BL x M lambs were 19 and 11% heavier respectively than Merino lambs (all differences P < 0.05). Corresponding differences at 16 months of age were 31 and 28% respectively (PD x M and BL x M did not differ significantly from each other; other differences P < 0.05). A greater percentage of BL x M (92 .5) and PD x M (89 .5) lambs grew to a marketable weight (27 kg or greater) than did Merino (63.8) lambs (P < 0.001). Dressing percentage and carcass weights were higher and mean grade scores lower for both PD x M and BL x M breeds compared with the Merino (P < 0.05). PD x M lambs had higher dressing percentages and lower grade scores than BL x M lambs (P < 0.05). Carcass weight, adjusted for differences in fasted liveweight, and carcass grade score, adjusted for differences in carcass weight, were higher in the PD x M breed than either the Merino or BL x M (P< 0.05). BL x M and strong-wool Merino ewe hoggets grew similar amounts of clean wool, and 26-31% more clean wool than the PD x M. There were differences (P< 005) between all breeds for both staple length and fibre diameter, the BL x M having the longest staples and greatest fibre diameter. We concluded that PD x M lambs were superior to the South Australian strong-wool Merinos for meat production, but BL x M and Merinos grew more wool to hogget age. The relative economic merit of the breeds may vary with the prices of the products measured in this study and with the value of the ewes for sale at hogget age.

The effects of breed of dam (Merino (M), Border Leicester x Merino (BL x M) and Poll Dorset x Merino (PD x M)), breed of lamb (Suffolk sired (S)) and sex of lamb (castrate male, female) on the efficiency of the ewe (organic matter intake per unit metabolic weight and clean wool weight per unit intake) and on the efficiency of the ewe-lamb unit (liveweight and carcass weight per unit intake) were examined. The effects of breed of dam and breed of lamb were differentiated by a system of cross-mothering of all lambs at birth. Each lamb was slaughtered at = 35 kg liveweight. The two crossbred types ate less organic matter per unit metabolic weight than did M dams during late pregnancy, but there were no differences during lactation. Compared with the absolute intake of M dams, PD x M and BL x M ewes ate 11 and 18 % more throughout the experimental period (224 days). The conversion efficiencies of food to wool of PD x M and BL x M dams were 59 and 66 % of that of Merinos. There were no significant differences between breeds of lamb or between lamb sexes for either intake per unit metabolic weight or clean wool growth per unit intake of the ewe. There were no significant differences between breeds of dam or between lamb sexes for either lamb liveweight or carcass weight per unit intake. This applied whether the lambs were at the same age or at the same liveweight. Ewes rearing S x (PD x M) and S x (BL x M) lambs had higher carcass weights per unit intake than did those rearing S x M lambs.

In order to measure the variation of colour related to some external and internal factors, 136 samples of wools were collected in 1979 and 1980 in a flock of black Polwarth sheep kept in the South of Victoria State, in Australia, 38" latitude South in open air all year long.The genetic formula of these animals at Agouti, Brown and Extension loci was probably aa, B+B+, E+E+.The animals were female or wethers, they were rugged for control or non rugged with a coat opaque to visible and U.V. radiations and cut off at 2.5, 3.5 months or one year of wool growth.The colour measurements were made with a colour atlas based on the D.I.N.System.Except for very rare cases, the growing wool (at the base of the staple) was in the grey scale (which goes from pure white to jet black, without a hue component).With age one could see a greying or silvering of the coloured fleece.This is due to an increase in the number of white fibers and seems independant from light exposure.Due to exposure to solar radiation there was a fading of the staple to the range ot browns.This means the addition of a spectral colour component : the hue, orange in this case.The fading first affects the tip on the staple, about 2 cm after one year of exposure, and is less intense on the average with lighter greys.In a second step the middle staple is affected, after at least 3.5 months.The middle staple fading is less intense but affects a longer length : about 4 cm after one year of exposure.The brown shades after fading overlap the shades genetically induced by mutants at the Brown locus B.There were some rare cases of spontaneous browning from the base of the staple not due to the light of sun but in these animals the hairy parts remained jet black or dark grey.Greying and fading were mainly restricted to the fleece and result probably from physical properties of the wool fibers deriving from their greater fineness compared to the coarse hair of hairy parts.In the fleece there was a range of individual variations inside our Polwarth strain for fading and greying which may be explained by genetical differences.Due to the fading with light the yarns of common mixed coloured wool from spinning mills is in a brown scale : the traditionnal « frieze » (« bure » in French).By rugging the sheep, the discolouration of black and grey fleeces due to light, is easily prevented however it apparently does not have any effect on the progressive greying of fleeces which was seen in some animals.

Suffolk-sired lambs from Merino, Border Leicester x Merino and Poll Dorset x Merino dams were either mothered to ewes of their own breed of dam or to ewes of one of the other breeds of dam, with the exception that lambs born from Border Leicester x Merino, and Poll Dorset x Merino dams were not fostered between Border Leicester x Merino and Poll Dorset x Merino breeds of dam. Liveweight and lucerne meal consumption of the lambs and milk yields of the dams were determined during the first 100 days of lactation. Lambs reared by Border Leicester x Merino dams were significantly heavier than those reared by Merino dams at 16 and 23 days of age. They maintained this advantage throughout lactation, though differences were not statistically significant. There were no significant differences in liveweight of lambs between Poll Dorset x Merino and Merino dams. Suffolk x (Border Leicester x Merino) lambs were significantly heavier than Suffolk x Merino lambs at birth and when 9 days of age. They maintained this advantage throughout lactation, though the differences were not significant. Suffolk x (Border Leicester x Merino) lambs were also significantly heavier at birth than Suffolk x (Poll Dorset x Merino) lambs. However, the difference decreased with age so that the liveweights of the two breeds were similar by 80 days of age. There were no significant differences due either to breed of lamb or to breed of dam in lucerne meal intake by lambs and ewe milk yield. We conclude that the lamb's genetic potential for growth and maternal environment were of approximately equal importance in determining the superior growth of lambs born and reared by first-cross Merino dams compared with those born and raised by Merino dams.

Thirteen South Australian strong-wool Merino ewes and eight Border Leicester × Merino ewes mated to Poll Dorset rams were fed on lucerne pellets ad libitum during late pregnancy and lactation in pens. Each of their single-born progeny was slaughtered at 33 kg full liveweight. Breeds were compared for efficiency of the ewe (organic matter intake per unit liveweight and clean wool per unit intake), efficiency of the lamb (liveweight and body solids gain per litre of milk), and efficiency of the ewe-lamb unit (liveweight and carcass weight per unit intake). Border Leicester × Merino ewes ate 7% less organic matter per unit liveweight than Merino ewes during lactation; however, there was no significant difference during late pregnancy. In terms of absolute intake 120 Merinos = 100 Border Leicester × Merinos. Border Leicester × Merino ewes were 73% as efficient in converting feed to clean wool as Merino ewes. Merino ewes grew wool of smaller diameter and higher crimp frequency than crossbreds. Lambs from the Merino ewes were as efficient in converting milk into animal tissue as the progeny from Border Leicester x Merino ewes during the first 4 weeks of suckling. Lambs from Merino ewes required on average 25 extra days to grow to the same slaughter weight and ate 110% more organic matter from solid feed than lambs from crossbred ewes. However, the proportion of feed eaten by the lamb was small (10%) compared with that eaten by the ewe. Lambs from crossbred ewes were 23% heavier than those from Merino ewes at the same age. The crossbred ewe-lamb unit, however, consumed 20% more feed and hence was as efficient as the Merino ewe–lamb unit. The Merino ewe–lamb unit was more efficient than the crossbred ewe-lamb unit when the lamb genotypes were slaughtered at the same liveweight (P < 0.05); however, the difference was not significant when expressed as carcass weight per unit intake.

Thirteen South Australian strong-wool Merino ewes and eight Border Leicester × Merino ewes mated to Poll Dorset rams were fed on lucerne pellets ad libitum during late pregnancy and lactation in pens. Each of their single-born progeny was slaughtered at 33 kg full liveweight. Breeds were compared for efficiency of the ewe (organic matter intake per unit liveweight and clean wool per unit intake), efficiency of the lamb (liveweight and body solids gain per litre of milk), and efficiency of the ewe-lamb unit (liveweight and carcass weight per unit intake). Border Leicester × Merino ewes ate 7% less organic matter per unit liveweight than Merino ewes during lactation; however, there was no significant difference during late pregnancy. In terms of absolute intake 120 Merinos = 100 Border Leicester × Merinos. Border Leicester × Merino ewes were 73% as efficient in converting feed to clean wool as Merino ewes. Merino ewes grew wool of smaller diameter and higher crimp frequency than crossbreds. Lambs from the Merino ewes were as efficient in converting milk into animal tissue as the progeny from Border Leicester x Merino ewes during the first 4 weeks of suckling. Lambs from Merino ewes required on average 25 extra days to grow to the same slaughter weight and ate 110% more organic matter from solid feed than lambs from crossbred ewes. However, the proportion of feed eaten by the lamb was small (10%) compared with that eaten by the ewe. Lambs from crossbred ewes were 23% heavier than those from Merino ewes at the same age. The crossbred ewe-lamb unit, however, consumed 20% more feed and hence was as efficient as the Merino ewe–lamb unit. The Merino ewe–lamb unit was more efficient than the crossbred ewe-lamb unit when the lamb genotypes were slaughtered at the same liveweight (P < 0.05); however, the difference was not significant when expressed as carcass weight per unit intake.