scholarly journals Improving the nutrition of Merino ewes during pregnancy increases the fleece weight and reduces the fibre diameter of their progeny's wool during their lifetime and these effects can be predicted from the ewe's liveweight profile

2011 ◽  
Vol 51 (9) ◽  
pp. 794 ◽  
Author(s):  
A. N. Thompson ◽  
M. B. Ferguson ◽  
D. J. Gordon ◽  
G. A. Kearney ◽  
C. M. Oldham ◽  
...  
Keyword(s):  
Western Australia ◽  
Opposite Effect ◽  
Fibre Diameter ◽  
Late Pregnancy ◽  
Wool Production ◽  
Wide Range ◽  
Condition Score ◽  
Pregnancy And Lactation ◽  
Fleece Weight ◽  
Poor Nutrition

Nutrition of ewes during pregnancy can have permanent impacts on the production potential of their progeny. The hypothesis tested in the experiments reported in this paper was that improving the nutrition of Merino ewes during pregnancy and lactation increases the fleece weight and reduces the fibre diameter of their progeny’s wool during their lifetime. In addition, that these effects on the progeny’s wool production can be predicted from the ewe’s liveweight profile. At sites in Victoria and Western Australia in each of 2 years, a wide range in the liveweight and condition score profiles of Merino ewes was generated by varying the amount of supplements fed from joining to Day 100 of pregnancy and the amount of feed on offer grazed from Day 100 to weaning. The site in Victoria was based on perennial pastures and included both single- and twin-bearing ewes whereas the site in Western Australia was based on annual pastures and included single-bearing ewes only. The production and characteristics of wool from the progeny were measured until 51 months of age at the site in Victoria and 33 months of age at the site in Western Australia. The nutritional treatments and the resulting changes in ewe liveweight had significant impacts on the fleece weight and to a lesser extent the fibre diameter of wool produced by their progeny, but there were no consistent effects on other characteristics of progeny fleece wool. The fleece weight of the progeny was related to the liveweight change during pregnancy of their mothers (P < 0.05) and the relationships were similar for the two experiments at each site. At the site in Victoria, a loss of 10 kg in ewe liveweight between joining and Day 100 of pregnancy reduced fleece weight by ~0.2 kg at each shearing until 51 months of age whereas gaining 10 kg from Day 100 of pregnancy to lambing had the opposite effect. The effect of changes in ewe liveweight during late pregnancy on the fleece weight of their progeny at each shearing was of similar magnitude at the site in Western Australia. When evident, the effect of the ewe liveweight profile on the fibre diameter of progeny wool was opposite to the effect on clean fleece weight and the effect of poor nutrition in early to mid pregnancy could be completely overcome by improving nutrition during late pregnancy. Twin-born and reared progeny produced ~0.3 kg less clean wool at each shearing (P < 0.001) that was 0.3-μm broader (P < 0.001) than that from single-born progeny at the site in Victoria. However, the effects of varying ewe nutrition and ewe liveweight change during pregnancy on fleece weight and fibre diameter of progeny wool were similar (P > 0.05) for both single- and twin-born or reared progeny. Overall, these results supported our hypothesis and it is clear that the nutritional management of Merino ewes during pregnancy is important for optimal wool production from their progeny during their lifetime.

scholarly journals The wool production and reproduction of Merino ewes can be predicted from changes in liveweight during pregnancy and lactation

2011 ◽  
Vol 51 (9) ◽  
pp. 763 ◽  
Author(s):  
M. B. Ferguson ◽  
A. N. Thompson ◽  
D. J. Gordon ◽  
M. W. Hyder ◽  
G. A. Kearney ◽  
...  
Keyword(s):  
Fibre Diameter ◽  
Late Pregnancy ◽  
Reproductive Rate ◽  
Breeding Cycle ◽  
Wool Production ◽  
Condition Score ◽  
Pregnancy And Lactation ◽  
Influence Of Food ◽  
Staple Strength ◽  
Fleece Weight

Defining the nature of the relationship between change in liveweight throughout a breeding cycle and ewe wool production and reproduction would be useful for developing management guidelines for Merino ewes. In this paper we tested the hypotheses that (1) feed on offer has variable effects on liveweight profiles of individual ewes; and (2) liveweight profiles of individual ewes can be used to predict their fleece wool production and reproductive performance. At sites in Victoria and Western Australia in 2001 and 2002, pregnant Merino ewes were exposed to 10 nutritional treatments. In each of the four experiments, ewes in average condition score 3 at artificial insemination were fed to achieve either maintenance or loss of a condition score over the first 100 days of pregnancy before grazing one of five levels of feed on offer between Day 100 and lamb weaning. Across all four experiments, the average difference in ewe liveweight between extreme treatments was: 7.0 kg (range 4.7–8.7 kg) at Day 100 of pregnancy; 11.9 kg (range 4.9–17.8 kg) at lambing; and by weaning was 13.9 kg (range 8.8–22.7 kg). Liveweight at joining and liveweight change during pregnancy and lactation of individual Merino ewes were significantly related to their clean fleece weight, fibre diameter and staple length and thus the second hypothesis was supported. Heavier ewes at joining produced more wool that was longer and broader and this effect was consistent across both sites and years. A 10-kg loss in ewe liveweight between joining and mid pregnancy, mid pregnancy and lambing or during lactation reduced clean fleece weight by 0.4–0.7 kg and fibre diameter by 0.5–1.4 um. At the Victorian site, where ewes were shorn in summer, a loss of 10 kg in liveweight between joining and Day 100 of pregnancy reduced staple strength by 5 N/ktex. As expected the influence of food on offer on changes in ewe liveweight was different between years and sites and between late pregnancy and lactation due to a complex group of pasture and animal factors. Therefore, managing changes in ewe liveweight itself rather than feed on offer will achieve more predictable outcomes. A higher liveweight at joining resulted in a predictable improvement in ewe reproductive rate and liveweight at joining was more important than the liveweight profile leading up to joining. This paper has shown that it is possible to predict the differences in wool production and reproductive rate of flocks of Merino ewes if ewe liveweight records at key times are known.

scholarly journals On-farm paddock-scale comparisons across southern Australia confirm that increasing the nutrition of Merino ewes improves their production and the lifetime performance of their progeny

2011 ◽  
Vol 51 (9) ◽  
pp. 805 ◽  
Author(s):  
R. Behrendt ◽  
A. J. van Burgel ◽  
A. Bailey ◽  
P. Barber ◽  
M. Curnow ◽  
...  
Keyword(s):  
Fibre Diameter ◽  
South Australia ◽  
Final Analysis ◽  
Reproductive Rate ◽  
Wool Production ◽  
Condition Score ◽  
Pregnancy And Lactation ◽  
Fleece Weight ◽  
Fat Score ◽  
Progeny Performance

Experiments conducted by Lifetimewool at plot-scale have shown that differences in the maternal liveweight during pregnancy and lactation (liveweight profiles) of individual Merino ewes influences their wool production and reproductive rate as well as the birthweight, survival, weaning weight and lifetime wool production of their lambs in a predictable manner. This study determined whether these impacts of nutrition of the ewe on ewe and progeny performance are measurable on commercial properties across southern Australia at a paddock-scale where ewes were aggregated into flocks with a greater spread of the date of conception and where the liveweight profile of the flocks were managed based on random samples of 100 ewes and liveweight was uncorrected for fleece weight or conceptus. Eighteen paddock-scale experiments at 15 sites were conducted in cooperation with wool producers across Victoria, Western Australia, New South Wales, South Australia, and Tasmania. Each co-operator joined up to 1000 mixed aged adult Merino ewes. The flock was scanned using ultrasound at Day 50 from the start of joining to identify those ewes that conceived during the first 21 days of joining. These ewes were then split at random into two treatments and fed to achieve a target difference in liveweight of 10 kg or ~1 condition score/fat score at lambing. The production of ewes during their year of pregnancy and following their next joining was measured as was the performance of their progeny up to their third shearing. Only the 13 paddock-scale experiments that achieved a difference in liveweight profile at lambing of at least 4 kg were included in the final analysis. In these 13 experiments, increasing the nutrition of Merino ewes during pregnancy clearly increased the clean fleece weight and fibre diameter in ewes and the survival and lifetime wool production of their lambs. In most cases the size of the effect was not significantly different to that predicted by the relationship derived using individual liveweight profiles in the plot-scale experiments. This confirms that managing average ewe liveweight or condition score/fat score profile through better nutrition will lead to predictable increases in the performance of ewes and their progeny performance under commercial conditions and validates the use of the plot-scale relationships in economic analyses.

Lambing performances and wool production of maiden and adult Merino ewes fed different amounts of lupin seed in mid-pregnancy

1992 ◽  
Vol 43 (2) ◽  
pp. 339 ◽  
Author(s):  
RW Kelly ◽  
EJ Speijers ◽  
IG Ralph ◽  
JP Newnham
Keyword(s):  
Birth Weight ◽  
Crude Protein ◽  
Fibre Diameter ◽  
Late Pregnancy ◽  
Maternal Plasma ◽  
Waveform Analysis ◽  
Wool Production ◽  
Glucose Levels ◽  
Lupin Seed ◽  
Pregnancy And Lactation

Maiden (1.5 years old, 42 kg) and adult (4-5 years old, 55-58 kg) Merino ewes were divided into 15 groups of 30 on the basis of ovulation rate (three classes of ewe: maiden = 1, adult = 1 or 2) and fed lupin seed (91% digestible, 33% crude protein) three times per week at rates equivalent to 0, 100, 200, 300, or 400 g head-1 day-1 from day 28 to day 108 of pregnancy (17 December to 6 March). Thereafter the ewes were fed at the same rate (400-500 g head-1 day-1 of lupins, ad libitum oaten hay) until two weeks post lambing. They were grazed on two hectare plots from day 22 of pregnancy until two weeks after lambing; the plots had 1.3 tomes dry matter/ha (54% digestible, 11% crude protein) at the start of grazing. The differential feeding induced changes in liveweight and condition score during mid-pregnancy ranging across the ewe classifications from 8.4 to +5.0 kg and -1.6 to +1.3 units, respectively. In late pregnancy and lactation there were compensatory changes in the ewes, so that at 12 weeks post-lambing the difference between the animals from the mid-pregnancy feeding treatments had been reduced to less than 2 kg. There was a significant relationship (linear P < 0.001) between lamb birth weight and rate of lupin feeding during mid-pregnancy. For every 0.1 kg head-' day-' of lupins fed, lamb birth weight increased by 0.11 kg. There was no significant effect of class of ewe on this relationship. Maternal plasma glucose levels at about day 100 of pregnancy increased with rate of lupin feeding (interaction between class of ewe and feeding treatment P < 0.01). Ultrasound measurements of cotyledon diameters were greater (P < 0.001), and resistance to maternal placental blood flow less (assessed by Doppler arterial waveform analysis, interaction between class of ewe and feeding treatment P < 0.05) at about day 100 of pregnancy in ewes fed 400 g head-1 day-1 of lupins compared with unfed ewes. These findings indicated that in the unfed ewes there was a reduced nutrient supply to the fetus from reduced glucose availability, smaller placentas and less expansion of the placental vasculature. Growth of the lambs to four weeks of age increased with rate of lupin feeding in mid-pregnancy (quadratic P < 0.05), although the actual differences in weight at four weeks of age were small (<1 kg). Annual wool production from the ewes was significantly affected by the differential feeding during mid-pregnancy, with clean fleece weight (linear P < 0.01), staple length (linear P < 0.01) and strength (linear P < 0.001) increasing with increased rate of lupin feeding, and the position of break shifted from the period of pregnancy to after lambing (quadratic P < 0.01). Mean fibre diameter was not significantly affected by any treatment. It was concluded that the ewes at greatest risk from underfeeding in mid-pregnancy, in terms of lamb and wool production, were maiden ewes and adult ewes bearing twins.

Effects on wool production during pregnancy and lactation of twice daily abomasal supplementation with casein or methionine and cystine

1978 ◽  
Vol 18 (90) ◽  
pp. 52 ◽  
Author(s):  
AJ Williams ◽  
RN Tyrrell ◽  
AR Gilmour
Keyword(s):  
Amino Acids ◽  
Fibre Diameter ◽  
Late Pregnancy ◽  
Similar Response ◽  
Early Lactation ◽  
Wool Production ◽  
Wool Growth ◽  
Pregnancy And Lactation ◽  
Sulphur Amino Acids ◽  
Sorghum Grain

The responses in wool production of Merino ewes to abomasal supplements of casein (56 g day-1) and of a mixture of methionine and cystine were measured during late pregnancy and early lactation. The mixed supplement provided equal quantities of the sulphur amino acids as the casein. The ewes were offered sufficient quantities of a diet of sorghum grain/lucerne hay (in the ratio 7 : 3 by weight) to maintain maternal liveweight. During the final four weeks of pregnancy and the first six weeks of lactation, the cassin supplement increased wool growth (826 vs. 639 g cm-2 day-1). A similar response was observed for fibre diameter (1 9.7 vs. 18.5 pm : P < 0.05). Wool production and fibre diameter did not differ between the ewes supplemented with methionine and cystine and the control ewes during this same period. The ewes supplemented with methionine and cystine produced wool with the greatest sulphur content, and this trait was least in the wool from the control ewes (3.84 vs. 3.64 vs. 3.49: P < 0.05). We concluded that the availability of the sulphur amino acids was not primarily limiting wool production in pregnant/lactating ewes.

scholarly journals The birthweight and survival of Merino lambs can be predicted from the profile of liveweight change of their mothers during pregnancy

2011 ◽  
Vol 51 (9) ◽  
pp. 776 ◽  
Author(s):  
C. M. Oldham ◽  
A. N. Thompson ◽  
M. B. Ferguson ◽  
D. J. Gordon ◽  
G. A. Kearney ◽  
...  
Keyword(s):  
Maternal Nutrition ◽  
Late Pregnancy ◽  
Climatic Conditions ◽  
Birth Rank ◽  
Maternal Genotype ◽  
Condition Score ◽  
Pregnancy And Lactation ◽  
Second Year ◽  
Lamb Survival ◽  
Poor Nutrition

The single largest influence on the survival of lambs in the first few days of life is their birthweight. Fetal growth and birthweight are regulated by genotype of the fetus, maternal genotype, maternal nutrition and the external environment. In this paper we report the extent to which the changes in maternal liveweight during pregnancy and lactation (liveweight profile) of Merino ewes can be used to predict the birthweight and survival of their progeny to weaning. At two sites [Victoria (Vic.) ~700 ewes and Western Australia (WA) ~300 ewes] in each of 2 years, a similar experiment used adult Merino ewes to explore effects of nutrition from joining to Day 100 of pregnancy and from Day 100 of pregnancy to weaning. The average difference between extreme treatments at Day 100 of pregnancy were 7 kg in ewe liveweight and 0.7 of a condition score (CS) and at lambing 11.9 kg and 1.3 of a CS. This resulted in average birthweights of progeny from different treatments ranging from 4.0 to 5.4 kg and survival to weaning ranging from 68 to 92%. Across the four experiments between 68 and 85% of all lamb deaths to weaning occurred within 48 h of birth. Lambs born to ewes in CS 2 at Day 100 of pregnancy were lighter (P < 0.05) in both years at the Vic. site than those from ewes in CS 3 at Day 100 of pregnancy. Lambs born to the ewes grazing a feed on offer of 800 kg DM/ha during late pregnancy were also lighter than those from other levels of feed on offer between 1100 and 3000 kg DM/ha at the Vic. site in both years and at the WA site in 1 year (P < 0.001). Lambs from the 800 kg DM/ha treatment during late pregnancy at the Vic. site had a lower survival than other treatments, especially in the second year. There were no significant effects of treatments on lamb survival at the WA site; however, the results were in the same direction. The birthweight of individual lambs was significantly related to the liveweight profile of their mothers. Their liveweight at joining, change in liveweight to Day 100 of pregnancy and change in liveweight from Day 100 to lambing all contributed (P < 0.05) to the prediction of the birthweight of their lambs. The responses were consistent across experimental sites and years, lamb birth rank and sex, and confirmed that the effects of poor nutrition up until Day 100 of pregnancy could be completely overcome by improving nutrition during late pregnancy. At the Vic. site, survival to 48 h was most influenced by the birthweight of the lamb and survival was significantly higher in single- than twin-born lambs and female than male lambs after adjusting for differences in birthweight. A higher chill index during the 48 h after birth reduced survival of both single and twin lambs to a similar extent, but reduced survival of male lambs more than female lambs. There were no effects of birthweight or chill index on lamb survival at the WA site where most lambs weighed more than 4 kg at birth and climatic conditions during lambing were less extreme. Overall, these results supported our hypothesis that improving the nutrition of Merino ewes during pregnancy increases birthweight and this leads to improved survival of their progeny.

Reproduction effects on annual fleece production, liveweight and body condition of grazing Merino ewes

2000 ◽  
Vol 40 (7) ◽  
pp. 931 ◽  
Author(s):  
C. M. Waters ◽  
K. A. Coelli ◽  
G. J. Lee ◽  
K. D. Atkins
Keyword(s):  
Body Condition ◽  
Reproductive Cycle ◽  
Fibre Diameter ◽  
Production Capacity ◽  
Major Effect ◽  
Wool Production ◽  
Merino Wool ◽  
Condition Score ◽  
Fleece Weight ◽  
Reproductive Cycles

This study sought to confirm the long-term consequences of current and previous reproductive cycles on liveweight, body condition and wool growth over the lifetime of Merino ewes (2–6 years of age). Liveweights and body condition scores at 4 stages of the reproductive cycle, and annual fleece weights (greasy and clean), fibre diameter and yield were analysed to determine the effects of the previous and current reproductive performance (birth-type or rearing-type categories) using records from about 3300 Merino ewes collected between 1977 and 1989. The major effect of current reproduction on liveweight and wool production was associated with fertility, although both birth and rearing types also contributed. Ewes that lambed in the current year weighed 5.2 kg less at weaning and grew 0.4 kg less clean wool annually than dry ewes, while ewes that reared a lamb to weaning weighed 4.3 kg less than ewes that lost their lamb(s). The effects on condition score followed those of liveweight. The effects of previous reproduction on liveweights and condition scores were large and, although diminishing with time, lasted for at least 10 months, whereas any effects on annual fleece weight and mean fibre diameter were small. The results suggest that many ewes may enter the next reproductive year before recovering from the reduction in either liveweight or body condition associated with the previous reproductive cycle. Since Merino ewes are required to produce both wool and replacement sheep, the changes in a ewe’s production capacity associated with reproduction are important to Merino wool production enterprises as their profitability may be influenced.

Lamb mortality and growth to weaning in commercial Merino flocks in Western Australia

1992 ◽  
Vol 43 (6) ◽  
pp. 1399 ◽  
Author(s):  
RW Kelly
Keyword(s):  
Western Australia ◽  
Fibre Diameter ◽  
Mortality Rates ◽  
Unit Change ◽  
Condition Score ◽  
Average Condition ◽  
The Mean ◽  
Staple Strength ◽  
Fleece Weight ◽  
Highly Correlated

Eighteen farm flocks of four-tooth Merino ewes (average of 371 ewes at lamb marking, range 278 to 511) were studied in 1987/88 ( n =8 ) and 1988/89 (n=10) over the period from 2 to 4 weeks pre-joining until 12 weeks post-lambing. All farms were located in the south-west of Western Australia, and the flocks started lambing between mid-April and mid-July. The average liveweights of ewes pre-joining ranged over 40.2 to 61.8 kg, and average condition scores ranged from 2.2 to 4.2. Mean liveweight changes of the ewes ranged over losses of up to 8.5 kg to gains of up to 10.4 kg between consecutive recordings at 2 to 3 month intervals up to 12 weeks post lambing, and condition score changes ranged over minus 1.2 to plus 1.2. The greatest losses in liveweight and condition score in many flocks corresponded with the period from mid-pregnancy to marking, the time of greatest nutrient demand of the ewe. There was considerable variation between flocks in the percentage of dry ewes (2.9 to 17.7%), lambs born per ewe present at marking (83.0 to 147.3%), lambs alive per ewe present at marking (66.3 to 123.2%), and lamb deaths as a percentage of total lambs born (10.9 to 29.8%). For single and twin-born lambs, the percentage of lamb deaths between flocks ranged from 6.0 to 19.9% (mean = 11.0%) and 19.1 to 63.2% (mean = 33.1%) respectively. Of the ewes giving birth to twins, an average of 9.6% lost both lambs. The mean birthweights were 4.4 kg (range 3.6 to 5.1 kg) for singles and 4.0 kg (range 3.3 to 4.5 kg) for twins, and were highly correlated (r = 0 - 74, n = 13 flocks, P<0.01). Lamb growth to marking averaged 232 g head-1 day-1 and 205 g head-1 day-1, and from marking to weaning 198 g head-1 day-1 and 193 g head-1 day-1 for single and twin-born lambs respectively. The mortality rates of both single and twin-born lambs were highly correlated with mean liveweight of the ewes at mid-pregnancy (r = -0.64, P<0.01; r = -0.75, P<0.001; respectively). A kilogram increase in mean liveweight at mid-pregnancy was associated with declines in the mortality rates of single-born lambs of 0.7% units (s.e. = 0.23), and of twin-born lambs of 2.2% units (s.e. = 0.57). Mortality rates of the singles were highly correlated with that of twins (r = 0.86, P<0.001), with a 1% unit change in death rate of singles being associated with a 2.5% (s.e. = 0.41) unit change for twins. Mortality rates of twins were associated with mean cotyledon diameter measured in mid-pregnancy (r = -0.48, n = 13, P<0. l0), and mean umbilical resistance to blood flow (r = 0.78, n = 9, P<0.02). Growth from birth to weaning of single-born lambs was associated with the mean liveweight of the flock in mid-pregnancy (r = 0.72, P<0 .001). Clean fleece weight and mean fibre diameter of the fleeces from single.bearing and rearing ewes were correlated with mean ewe liveweight in mid-pregnancy (r = 0.56, P<0.05; r = 0.70, P<0.01; respectively). Staple strength was correlated with mean ewe liveweight at marking for both single and twin producing ewes (r = 0.72, n = 18, P<0.01; r = 0.74, n = 9, P<0.05; respectively). It was concluded that liveweight of the ewe in mid-pregnancy, which represents the sum of starting liveweight and liveweight change, is the most important single and practical criterion that can be used by a farmer to set the goals for nutritional management of the flock over pregnancy to improve lamb survival.

Ewe nutrition during pregnancy and birthweight of lambs has minimal impact on fat and eye muscle depth in Merino progeny

2013 ◽  
Vol 53 (6) ◽  
pp. 509 ◽  
Author(s):  
B. L. Paganoni ◽  
C. M. Oldham ◽  
M. B. Ferguson ◽  
A. N. Thompson ◽  
P. E. Vercoe ◽  
...  
Keyword(s):  
Western Australia ◽  
Eye Muscle ◽  
Minimal Impact ◽  
Sheep Industry ◽  
Wide Range ◽  
Pregnancy And Lactation ◽  
Australian Sheep

The hypothesis tested in this experiment was that Merino lambs with lower birthweights, due to poor ewe nutrition during pregnancy, would have more fat and less muscle than Merino lambs with higher birthweights. At two sites (Victoria and Western Australia) in each of 2 years, a wide range in the liveweight profiles of ewes was generated during pregnancy and lactation by varying the amount of supplements fed and feed on offer grazed. Progeny had fat and muscle depth at the C-site measured at various ages from 8 to 28 months of age. Across the four experiments, there were differences of 0.5 kg in birthweights and 8 kg in weaning weights between extreme treatments. The effects on the depth of fat and muscle were very small with fat depth increasing by 0.1–0.2 mm (5–7%) and muscle depth increasing by 0.2–0.7 mm (1–3%) when birthweights decreased by 1 kg. The effects of birthweight on fat depth are consistent with our hypothesis whereas the effects of birthweight on muscle depth are in contrast to our hypothesis. Nevertheless, the impacts of birthweight on the depth of fat and muscle measured at the C-site of progeny from Merino ewes, is unlikely to be of any commercial significance within the range of nutritional scenarios during pregnancy and lactation that are likely to be experienced within the Australian sheep industry.

Effect of time of joining and rate of stocking on the production of Corriedale ewes in southern Victoria. 3. Wool growth and the composition and availability of pasture

1975 ◽  
Vol 15 (73) ◽  
pp. 159 ◽  
Author(s):  
PA Kenney ◽  
IF Davis
Keyword(s):  
Fibre Diameter ◽  
Late Pregnancy ◽  
The Other ◽  
Early Lactation ◽  
Stocking Rate ◽  
Wool Production ◽  
Wool Growth ◽  
The Mean ◽  
Brome Grass ◽  
Stocking Rates

A study was made during a three year period (1 968-1 970) of wool production by a flock of 540 ewes grazing annual pasture at Werribee, Victoria. The ewes were stocked at three rates (5, 7 1/2 and 10 ewes ha-1) and lambed between July 6 and August 20 or between September 10 and October 29 each year. Fibre diameter and length of wool samples were measured in 1968, 1969 and 1970 ; in 1970 growth of greasy wool was calculated from staples of dye-banded wool. Wool growth was reduced in all ewes during late pregnancy and early lactation but was not affected during late lactation in ewes lambing in September. The proportion of tender fleeces from all ewes was greater in 1970 and the weight of fleeces from only those ewes bearing single lambs was less in all years for ewes lambing in July than for ewes lambing in September. More ewes were barren and fewer ewes had twins in July and consequently the mean fleece weights of all ewes from both groups were similar. Fleeces from ewes stocked at 10 ha-1 were lighter, shorter and finer than fleeces from ewes stocked at 5 and 7 1/2 ha-1, but the proportion of tender fleeces did not differ between the groups. Wool production of ewes stocked at 5 and 7 1/2 ha-1 increased from 1968 to 1970, whereas that of ewes at 10 ha-1 did not. This was associated with differences in pasture availability and composition. At 10 ewes ha-1 less pasture was present in winter and spring in 1970 than in 1968, whereas at the other stocking rates it was greater. In 1970 the density of weeds in autumn was greater and in spring more silver grass (Vulpia spp.) and less brome grass (Bromus spp.) was available at the high stocking rate.

Assessing Wiltshire Horn-Merino crosses. 1. Wool shedding, blowfly strike and wool production traits

1994 ◽  
Vol 34 (6) ◽  
pp. 717 ◽  
Author(s):  
KA Rathie ◽  
ML Tierney ◽  
JC Mulder
Keyword(s):  
Fibre Diameter ◽  
The Other ◽  
Wool Fibre ◽  
Production Traits ◽  
Wool Production ◽  
Phenotypic Correlations ◽  
Fleece Weight ◽  
Head Neck

Wiltshire Horn-Merino (WH-M) crosses of 1/2, 5/8 and 3/4 Merino content were compared over 10 years for wool shedding, blowfly strike frequency and wool production traits. Merinos and 1/2 Merino WH-M were compared over 4 years. For wool production traits, 1/2 and 5/8 Merino WH-M ewes were compared to Border Leicester-Merino (BL-M) ewes over 2 years. Shedding increased with age for all WH-M genotypes, with 3/4 Merinos showing less shedding than 1/2 Merinos at all ages. At 1 and 2 years of age, 5/8 Merinos were intermediate between the other 2 WH-M genotypes, but at later ages they were similar to 1/2 Merinos. All genotypes showed less shedding at the belly site than the head, neck and breech as lambs, but not at older ages. Phenotypic correlations between sites on the same sheep were high, averaging 0.85. Repeatability estimates for each site ranged from 0.26 to 0.45. Shedding increased most with age in the 1/2 Merinos, and least in the 3/4 Merinos. Little or no shoulder and back wool was shed by most sheep. All 1/2 and 5/8 Merinos and most 3/4 Merinos had bare legs and points. Blowfly strike incidence was far higher in Merinos than 1/2 Merinos, in all years. Among WH-M, blowfly strike incidence increased as Merino content increased, in all years. All WH-M were far inferior to both Merinos and BL-M in total greasy wool weight and all its components, and also in clean fleece weight, with their level of inferiority increasing as their Merino content declined. Wool fibre diameter for all WH-M was coarser than for Merinos, but was a little finer than for BL-M. Fibre diameter increased in the WH-M as their Merino content declined. All WH-M had lower wool yields than the Merinos or BL-M. In some years the 314 Merinos had lower wool yields than the 1/2 and 5/8 Merinos, which were similar in all years. Shedding caused numerous genotype x age interactions in wool weight and its components, as Merinos and BL-M did not shed, and with the WH-M shedding increased most with age in the 1/2 Merinos, and least in the 3/4 Merinos. Due to preferential shedding from the belly and other low-value areas, the WH-M inferiority in total wool weight was less severe for fleece weight. Winter shearing succeeded in harvesting some wool from WH-M that would be shed before a summer shearing, but not enough to alter rankings among genotypes. All WH-M genotypes have wool too coarse, and not enough of it, to compete as a wool sheep with the Merino at current wool prices under usual Australian pastoral conditions. In areas where mustering is difficult or blowfly strike unusually severe, WH-M genotypes may find a niche.

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