The effects of pregnancy and lactation on wool production and liveweight in Polwarth ewes

1978 ◽  
Vol 18 (90) ◽  
pp. 58 ◽  
Author(s):  
RND Reid
Keyword(s):  
Growth Rate ◽  
Early Pregnancy ◽  
Wool Production ◽  
Wool Growth ◽  
Pregnancy And Lactation ◽  
Fleece Weight

Groups of Polwarth ewes which 1. were barren, 2, were pregnant but aborted with prostaglandins in early pregnancy, 3. lambed and reared a single lamb and 4. lambed but had their single lamb removed soon after birth, were used to estimate the effects of pregnancy and lactation on wool and Iiveweight. Pregnancy plus lactation reduced liveweight (17 per cent), wool growth rate (9 per cent) and clean fleece weight (11 per cent) ; pregnancy alone reduced liveweight (10 per cent), wool growth rate (7 per cent) and clean fleece weight (10 per cent) and its effects were greater than those of lactation in each of the characters studied.

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.

Effects of weaner nutrition on sire and flock rankings: a re-analysis of historical data

2009 ◽  
Vol 49 (12) ◽  
pp. 1100
Author(s):  
B. J. McGuirk
Keyword(s):  
Growth Response ◽  
Historical Data ◽  
Scale Type ◽  
Genetic Merit ◽  
Wool Production ◽  
Log Transformation ◽  
Wool Growth ◽  
Nutritional Effects ◽  
The 1950S ◽  
Fleece Weight

Early work in the 1950s on the wool growth response of sheep from diverse genotypes for wool production in response to varying planes of nutrition at pasture did not show the significant genotype × environment interactions exhibited in later pen studies with the same or very similar genotypes. However, this early study used a log-transformation on all traits to adjust nutritional effects for scale. Re-analysis of the original (i.e. untransformed) data shows that superior genetic merit for clean fleece weight, different sire progeny groups or selection flocks is more apparent when hogget ewes are fed a high plane of nutrition at pasture. However, only in the case of flocks was the interaction statistically significant, and this interaction was insignificant when data were either log-transformed, or when an appropriate test that accounts for scale-type effects was applied. When left untransformed, the data are, thus, in agreement with the subsequent pen studies that examined data on untransformed clean wool production.

Stimulation of wool growth by thyroxine implantation. I. Liveweight changes and wool growth of fine-wool Merino wethers

1964 ◽  
Vol 15 (4) ◽  
pp. 657 ◽  
Author(s):  
LJ Lambourne
Keyword(s):  
Dose Rate ◽  
Fibre Length ◽  
Dual Purpose ◽  
Wool Production ◽  
Wool Growth ◽  
Body Tissues ◽  
Four Seasons ◽  
Lower Body Weight ◽  
Native Pastures ◽  
Fleece Weight

Groups of 20 and 30 fine-wool Merino wethers were treated with L-thyroxine and their subsequent liveweight changes and wool production studied under a variety of grazing conditions for a year. Treatments comprised : (1) Single implantations of 60 mg in autumn, winter, spring, or summer. (2) Repeated implantations at all four seasons of 30, 60, or 90 mg. (3) Weekly subcutaneous injection of 7 mg in aqueous solution. These groups were grazed with untreated wethers on improved native pastures at one to two sheep per acre. (4) Repeated 60 mg implantations at four seasons in wethers grazed on native pasture providing a lower level of nutrition. (5) Repeated 60 mg implantations at four seasons in wethers grazed on sown pasture providing a higher level of nutrition. After every implantation there was a loss of 5–10 lb liveweight — more pronounced and more prolonged in the wethers given greater amounts of thyroxine, and more prolonged in those at lower levels of nutrition. Deaths occurred in several groups, increasing with dose rate or with poorer nutrition up to 30–50% of the group. Wool growth was not increased significantly by repeated 60 mg implants at the lowest level of nutrition, nor by the single 60 mg implant in late spring. Increases of 34% in annual fleece weight resulted from 60 mg implants in autumn and summer. Repeated implantation of 30, 60, and 90 mg in groups on a medium or high plane of nutrition increased annual fleece weight by 8, 14, and 19%, and 7 mg injected weekly by 11%. Increases in fleece weight were due partly to increased fibre length, and partly to an increase in grease and suint which reduced the clean scoured yield by 1–2%. It is concluded that line-wool Merinos, despite their lower body weight and greater specialization for wool production, react to thyroxine treatment in the same way as has been established for "dual-purpose" sheep. The safe maximum dose rate is critically dependent on the current level of nutrition, particularly for young sheep. Repeated implantations without adequate opportunity for recovery of catabolized body tissues may produce no increase in wool growth and may cause death.

Fibre diameter and staple strength of sheep selected for divergent clean fleece weight when subjected to an increase in intake or an increase in intake and diet change

2005 ◽  
Vol 56 (2) ◽  
pp. 195 ◽  
Author(s):  
M. A. Friend ◽  
G. E. Robards
Keyword(s):  
Growth Rate ◽  
Stepwise Regression ◽  
Fibre Diameter ◽  
Dietary Treatment ◽  
Diet Change ◽  
Wool Growth ◽  
Ad Libitum ◽  
Staple Strength ◽  
Fleece Weight ◽  
Ad Libitum Feeding

Merino wethers with a high (fleece plus, Fl+) or low (fleece minus, Fl–) potential for wool growth were offered a restricted intake of either oat grain or lucerne chaff for 8 weeks followed by ad libitum lucerne chaff for 4 weeks. The Fl– sheep that were fed oats then lucerne had a lower (P < 0.05) intake during the first 2 weeks of ad libitum feeding than all other groups. Staple strength of Fl+ sheep (37.5 ± 2.2 N/ktex) was less (P < 0.05) than that of Fl– sheep (44.5 ± 2.4 N/ktex), and dietary treatment did not significantly affect staple strength. Wool growth rate was unaffected by dietary treatment, but was greater (P < 0.001) for Fl+ (6.4 ± 0.2 µg/mm2.day) than for Fl– (4.0 ± 0.2 µg/mm2.day) sheep. Along-fibre variation in diameter was greater (P < 0.001) in Fl+ (15.6 ± 0.5%) than in Fl– (9.9 ± 0.5%) sheep. Between-fibre variation in diameter was greater (P < 0.001) in Fl+ (16.5 ± 0.5%) than in Fl– (13.2 ± 0.5%) sheep, and between-fibre variation in diameter was affected (P < 0.05) by dietary treatment in Fl+ sheep. Staple strength was significantly correlated (P < 0.05) with along-fibre variation in diameter (r = –0.48), and stepwise regression analysis indicated that along-fibre variation in diameter, wool growth rate during early restricted feeding, and minimum fibre diameter explained 63% of the variance in staple strength. The results are discussed in relation to the lower staple strength of Fl+ sheep.

Whole wheat grain feeding of Merino ewes. 3. Influence of level of wheat and vitamin A on wool growth in pregnancy and lactation

1976 ◽  
Vol 16 (78) ◽  
pp. 49 ◽  
Author(s):  
WR McManus ◽  
JA Reynolds
Keyword(s):  
Growth Rate ◽  
Vitamin A ◽  
Fibre Diameter ◽  
Late Pregnancy ◽  
Control Group ◽  
Whole Wheat ◽  
Wool Growth ◽  
Pregnancy And Lactation ◽  
Wool Yield ◽  
The Relationship

In experiment 1, ewes were fed three levels of wheat in pens, with or without vitamin A, from joining to weaning. The wheat levels ranged from 3.4 to 4.6 kg head-1 week-1. Control groups were run on native pasture. In experiment 2 three levels of wheat, which ranged from 3.9 to 7.1 kg head-1 week-1. were fed to ewes from joining to weaning. At each wheat level two groups were fed wheat in pens (wheat/ pen); another group was fed wheat in small paddocks (wheat/paddock). One of the wheat/pen groups received vitamin A. A control group was run at pasture. Vitamin A had no effect on wool traits except on wool yield in experiment 2. Clean wool weight and staple length increased linearly with increasing wheat intakes in both experiments. The relationship between fibre diameter and wheat level was linear in experiment 1 and curvilinear in experiment 2. In experiment 2 there were differences between wheat/pen and wheat/paddock groups in all the wool traits measured. In experiment 1, wool growth rate was reduced by 40 per cent in the wheat groups and by 44 per cent in the pasture groups during late pregnancy and lactation. In experiment 2, compared with early pregnancy, wool growth rate was reduced by 11 per cent and 31 per cent in the wheat groups during late pregnancy and lactation respectively.

Effect of selection for wool growth on seasonal patterns of yield, fibre diameter, and colour in Romney lines

1995 ◽  
Vol 35 (1) ◽  
pp. 27 ◽  
Author(s):  
T Wuliji ◽  
IL Weatherall ◽  
RN Andrews ◽  
KG Dodds ◽  
PR Turner ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fibre Diameter ◽  
Seasonal Patterns ◽  
Control Line ◽  
Wool Growth ◽  
Growth Decline ◽  
Selection For ◽  
Staple Strength ◽  
Fleece Weight

Seasonal wool growth and associated wool characteristics were measured in a Romney line selected for high fleece weight and an unselected control line in 1990 and 1991. Both had a significant (P<0.01) decline in wool growth rate in winter compared with summer. The wool growth rate advantage (P<0.001) of the selected line over the control averaged 19 and 33% for ewes, and 24 and 36% for hoggets, in summer and winter, respectively. Staple strength, yield, and fibre diameter differences were closely associated with wool growth. Colour analysis showed no difference between lines in either brightness (Y) or yellowness (Y - Z). However, both the Y and Z values were lower in spring and summer, while Y - Z was highest in summer. The results suggest that selection for high fleece weight also improves major wool characteristics and reduces the relative winter wool growth decline in Romneys.

Wool production and heterosis by the Merino, the Polwarth, and their reciprocal crosses

1993 ◽  
Vol 33 (4) ◽  
pp. 397 ◽  
Author(s):  
LG Butler ◽  
BJ Horton ◽  
PM Williams ◽  
RG Banks
Keyword(s):  
Maternal Effect ◽  
Reciprocal Cross ◽  
Fibre Diameter ◽  
Similar Amount ◽  
Or Efficiency ◽  
Weaning Weight ◽  
Wool Production ◽  
Wool Growth ◽  
Fleece Weight ◽  
Lower Production

Tasmanian Merinos and Polwarths were mated in each of 2 years to produce 2 drops of Merino, Polwarth, and F1 reciprocal cross progeny. Polwarths had weaning weights similar to Merinos but were 14% heavier as hoggets. Polwarths grew a similar amount of wool of 11% greater (P<0.001) fibre diameter; however, wool production was 9% less efficient based on metabolic weight. Polwarths displayed an advantage in resistance to footrot. There was a marked Polwarth maternal effect of about 16% on weaning weight but no elfect on hogget weight. The Polwarth maternal effect on fleece weight and efficiency was 9% (P<0.001). In a comparison with a single-born male, ewes weighed 5% less at weaning and 7% less at hogget shearing and produced about 6% less wool (P<0.001), although of comparable fibre diameter. Twins weighed 17% less at weaning, but only 3% less at hogget shearing (P<0.001). They grew about 5% less wool, which was of 2% greater fibre diameter (P<0.001) and 5% higher wool score, but efficiency was 2.5% lower. Production was generally lower (except for yield and wool score) in the 1988 drop than the 1987 drop by 3-10%. Differences in productivity between ram sources were of only slightly lesser magnitude than differences between breeds. The number of feet affected by footrot was reduced by 17% in the 1988 drop. Severe footrot affecting more than 1 foot reduced liveweight but did not significantly reduce fleece weight. There appeared to be some heterosis for weaning weight (10%) and hogget weight (6%), but little heterosis in wool growth (2-3%) or efficiency (-2%).

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.

Feed intake, liveweight and wool growth rate in Merino sheep with different responsiveness to low- or high-quality feed

2002 ◽  
Vol 42 (4) ◽  
pp. 399 ◽  
Author(s):  
N. R. Adams ◽  
D. Blache ◽  
J. R. Briegel
Keyword(s):  
Growth Rate ◽  
Feed Intake ◽  
Poor Quality ◽  
The Other ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
High Quality ◽  
Merino Sheep ◽  
Wool Growth ◽  
Fleece Weight

A previous field trial using 30 sheep from each of 3 strains of Merino sheep (designated F, M and B) found that wool growth rate in strain B changed less throughout the year, compared with the other 2 strains. The present study examined components of liveweight loss on dry pasture with low protein and low digestibility to detect underlying relationships with the subsequent responsiveness of wool growth rate to young green pasture. Strain B lost less liveweight when grazed on dry (poor-quality) pasture, but lost more liveweight on sparse green pasture, than the other 2 strains. The rate of liveweight loss was not related to fatness on dry pasture, but was related to fatness on green pasture. The plasma concentration of leptin at the start of winter was related to clean-fleece weight (P<0.01). A second study examined the role of voluntary feed intake in strains M and B, offered low (56%�digestibility) and then high (70% digestibility) quality feed ad libitum in individual pens. Wool growth rate increased (P<0.001) on the better feed and tended to increase more (P = 0.06) in strain M. Feed intake increased (P�= 0.01) more in Strain M when offered good-quality feed. Fatness affected feed intake similarly in both periods. The results indicate 2 mechanisms that differed between feed conditions. First, sheep differed in their capacity to increase wool growth on high-quality feed, associated with the capacity to increase feed intake. Second, fatness was associated with the differential liveweight response to good or poor quality feed, although it was not clear whether it acted through appetite. It is hypothesised that the capacity to increase wool growth rate on good feed may be associated with a greater decrease in protein synthesis rate on poor quality pasture. This may result in a lower drive to eat and so a greater liveweight loss on poor pasture.

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.

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