The response of broad- and fine-wool Merino wethers to differential grazing of annual pastures during spring

2002 ◽  
Vol 42 (2) ◽  
pp. 117 ◽  
Author(s):  
M. W. Hyder ◽  
A. N. Thompson ◽  
P. T. Doyle ◽  
K. Tanaka
Keyword(s):  
Average Rate ◽  
Fibre Diameter ◽  
Grazing Pressure ◽  
Wool Production ◽  
Wool Growth ◽  
Significant Difference ◽  
Grazing Period ◽  
One Year ◽  
Different Response ◽  
First 90 Days

Two experiments examined the effects of manipulating grazing pressure during spring on the liveweight and wool-growth response of fine- and broad-wool genotypes of Merino wethers grazing annual pastures. One-year-old broad- and fine-wool Merino wethers (Bungaree and Peppin; mean fibre diameter 25.4 v. 20.7 m and 22.1 v. 19.8 m before years 1 and 2, respectively) were grazed on annual pastures maintained near target amounts of green feed on offer (800, 1100, 1400, 2000 and 2800 kg green DM/ha), or set-stocked at the district average of 8 sheep/ha, during the spring of 1992 and 1993. Within the control-grazed treatments, there was no significant difference in the total amount of pasture produced during the experimental periods but more (P<0.05) pasture was produced under set-stocking (7900 v. 5400 kg DM/ha and 7700 v. 5600 kg DM/ha in years 1 and 2, respectively). Liveweight change was linear for most treatments over the first 90 days or so of the spring grazing period, and in both years the average rate of liveweight change was similar for both genotypes. Liveweight change increased (P<0.001) curvilinearly with increasing feed on offer, which explained more than 80% of the variance in liveweight change in both years. A significant (P<0.05) green feed on offer × year interaction indicated a different response to feed on offer between years, with liveweight maintenance occurring at about 500 and 1060 kg DM/ha in years 1 and 2, respectively. Within genotypes, there was no significant (P>0.05) difference in liveweight change during spring for sheep grazing treatments 2000 kg DM/ha or above. Sheep from the broad-wool genotype produced more (P<0.05) wool than those from the fine-wool genotype and, as expected, the wool was also significantly broader at all feed on offer levels. For both broad- and fine-wool sheep, feed on offer and liveweight change were closely correlated with wool growth rate and fibre diameter in both years. The asymptote of the relationships with feed on offer and the intercept of the relationships with liveweight change was greater (P<0.05) for broad- than fine-wool sheep. However, there was no significant difference between genotypes in either size and shape or slope of these relationships. In other words, the wool-growth and fibre-diameter response of broad-wool sheep to decreasing feed on offer in the spring was the same as that for fine-wool sheep. For both genotypes, annual clean-wool production (P<0.001) and mean fibre diameter (P<0.05) increased withincreasing feed on offer during spring. The total amount of wool grown per hectare during spring decreased linearly (P<0.001) with increasing feed on offer. Grazing to about 2500 kg DM/ha more-than trebled the total clean wool produced per hectare compared with set-stocking. Thus, irrespective of sheep genotype, managing feed on offer in spring is a useful tool for manipulating wool characteristics, and increasing pasture utilisation and total wool production per unit area.

Effects of stocking rate in spring on liveweight and wool production of sheep grazing annual pastures

1994 ◽  
Vol 45 (2) ◽  
pp. 367 ◽  
Author(s):  
AN Thompson ◽  
PT Doyle ◽  
M Grimm
Keyword(s):  
Fibre Diameter ◽  
Stocking Rate ◽  
Wool Production ◽  
Wool Growth ◽  
Linear Relationships ◽  
Condition Score ◽  
Grazing Period ◽  
Staple Strength ◽  
Stocking Rates ◽  
Staple Length

Two experiments examined the effects of different stocking rates in spring, and hence the availability of annual pastures, on changes in liveweight and wool production in Merino wethers (Experiments 1 and 2 respectively: age 5 and 2+-year-old; liveweight 63.8 � 0.64 (s.e.m.) kg and 43.8 � 0.34 kg; condition score 3.9% 0.14 and 3.l � 0-08). In Experiment 1, stocking rates were 8, 16, 24, 32 and 40 sheep/ha from 8 August, 1989 f9r 122 days; Experiment 2 involved an additional stocking rate of 48 sheep/ha from 23 August, 1990 for 98 days. Feed on offer (FOO kg DM/ha) declined (P < 0.01) linearly as stocking rate increased. Stocking rate and initial FOO (ranging between 1100 and 7000 kg DM/ha) had no significant effects on pasture growth rate (PGR) through most of spring. Late in spring, increased stocking rates resulted in greater (P < 0.05) PGR. The total amount of pasture produced in the grazing period was not significantly affected by stocking rate (Expt 1, 7530 to 8200 kg DM/ha; Expt 2, 6390 to 6860 kg DM/ha). The relationships between liveweight change (LWC) or wool growth rates (WGR) and FO, during the period until pasture wilting at the lowest stocking rate (83 days in Expt 1; 76 days in Expt 2), were described by Mitscherlich equations. More than 74% of the variation in LWC or WGR was explained by differences in green FOO. In Expts 1 and 2 respectively, more than 90% of the maximum liveweight gain (66 and 192 g/day) was achieved at a FOO of 4000 or 3000 kg DM/ha, and sheep maintained weight at 2000 or 1000 kg DM/ha. More than 90% of the maximum WGR (22.3 and 19.0 g/day) was achieved at a FOO of 3000 or 2000 kg DM/ha. More than 70% of the variation in WGR was explained by LWC in both experiments. The slopes of the linear relationships were 0.047 g wool/g LWC in Expt 1, and 0.024 g wool/g LWC in Expt 2. At liveweight maintenance, sheep produced 15% less (Expt 1) or 25% less (Expt 2) wool than those grazed under conditions which allowed maximum rates of liveweight gain. Fibre diameter (FD) and length of wool grown were affected in the same manner as WGR by increases in FOO and hence LWC. In Expts 1 and 2 respectively, total clean wool weights were reduced by 17 and 9 g, mean FD by 0.05 and 0.02 microns and staple length by 0.35 and 0.13 mm, for each increase of one sheep/ha during the spring treatment periods. The effects of stocking rate in spring on annual wool production, mean FD and staple length were described by linear (P < 0.05 to P < 0.01) relationships. Standard deviation of midside FD (Expt 2), staple strength and position of break (both experiments) did not change significantly with stocking rate. These results indicate that grazing to a lower FOO during spring can be used to manipulate the amount and characteristics of wool produced by Merino wethers grazing annual pastures in Mediterranean climates with 600-700 mm rainfall.

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.

Effects of defaunation of the rumen and supplementation with amino acids on the wool production of housed Saxon Merinos. 2. Methionine and protected methionine

1988 ◽  
Vol 28 (2) ◽  
pp. 179 ◽  
Author(s):  
DJ Cottle
Keyword(s):  
Amino Acids ◽  
Fibre Diameter ◽  
High Energy ◽  
Previous Trial ◽  
Growth Responses ◽  
Wool Production ◽  
Low Protein ◽  
Wool Growth ◽  
Protein Diets ◽  
Ciliate Protozoa

In experiment 1, 6 groups, each of 10 superfine Merino wethers, were individually penned indoors and hand-fed oats, wheat straw and whole lupins, either alone or with 2 g/day of DL-methionine or 6.6 g/day of fatty acid coated methionine (Ketionin) for 23 weeks. Following shearing the 6 groups were hand-fed lucerne-chopped hay in experiment 2 either alone or with hydroxymethyl-methionine (Mepron) or Ketionin for 23 weeks. In both experiments the rations were fed at maintenance level and were offered 3 times a week. Half of the sheep had no rumen ciliate protozoa following treatment in a previous trial. In experiment 1, defaunated sheep produced an additional 6.5%clean wool on the supplemented oats plus lupins rations. Inclusion of Ketionin in the ration of defaunated sheep resulted in an 11% increase in clean wool growth, without affecting wool quality. In experiment 2 defaunated sheep produced an additional 6% clean wool on the lucerne-chopped hay ration. No responses to defaunation occurred on the supplemented rations. Inclusion of both forms of protected methionine in the ration (providing 2 g methionine/sheep.day) resulted in 23% and 13% higher clean wool production in the faunated and defaunated sheep respectively. Fibre diameter of wool was increased by 0.7 pm in sheep receiving Mepron and 0-5 pm in sheep receiving Ketionin. The wool grown by suppiemented sheep remained suitable for the 'Sharlea' trade (< 17.5 �m). It is concluded that wool growth responds more to defaunation on high energy-low protein diets. Wool growth responses to supplementation with protected methionine were greater on 100% roughage diets than on high grain diets. Further study is needed before an optimal ration for superfine wool production is formulated.

Effect of stocking rate on fleece measurements and their relationships in merino sheep

1976 ◽  
Vol 27 (1) ◽  
pp. 163 ◽  
Author(s):  
DH White ◽  
BJ McConchie
Keyword(s):  
Fibre Diameter ◽  
Major Determinant ◽  
Stocking Rate ◽  
Merino Sheep ◽  
Wool Production ◽  
Rate Experiment ◽  
Fleece Weight ◽  
One Year ◽  
Staple Length

The wool characteristics of Merino wethers were measured for 6 years in a stocking rate experiment. The decline in fleece weight due to increasing stocking rate from 4.9 to 12.4 sheep per hectare was usually accompanied by a reduction in fibre diameter and staple length and an increase in staple crimp frequency. The magnitude of these responses differed considerably between years; in one year clean fleece weight was reduced by 50%, with an associated reduction of 5 µm in mean fibre diameter and one of 2 cm in staple length. In four of the six years of the experiment, variation in fibre diameter accounted for at least 50% of the variation in wool production between stocking rate treatments. The relationships between clean fleece weight and fibre diameter were similar between years, mean fibre diameter being reduced by about 1.8 �m for each kilogram reduction in clean fleece weight. Fibre diameter is the major determinant of wool price, and this information should improve the prediction of economic responses to changes in stocking rate.

The influence of protein quality on the effect of flavomycin on wool growth, liveweight change and rumen fermentation in sheep

1990 ◽  
Vol 41 (5) ◽  
pp. 987 ◽  
Author(s):  
PJ Murray ◽  
JB Rowe ◽  
EM Aitchison
Keyword(s):  
Protein Quality ◽  
Rumen Fluid ◽  
Initial Period ◽  
Fibre Diameter ◽  
Experimental Period ◽  
Feed Additive ◽  
Wool Production ◽  
Wool Growth ◽  
The Mean ◽  
Wheat Chaff

The feed additive flavomycin, a glycolipid antibiotic, was evaluated for its potential to improve wool growth in sheep fed two pelleted diets: one based on lucerne chaff and lupin grain and the other on wheat chaff and fishmeal. Seventy-eight weaner ewes, approximately 20 months of age and mean weight of 32 kg (s.e. � 0.3), were placed in individual pens and fed the pelleted diets at a level equivalent to 3.5% of the mean liveweight of the group. The experiment consisted of an initial period (8 weeks) during which all animals received their respective diets with no flavomycin, followed by an experimental period (9 weeks) during which the animals received their diets with flavomycin. Flavomycin was included at three different rates (l0, 20 and 40 ppm) in both diets (nine sheep/level) during the experimental period and twelve sheep were fed each of the unmedicated diets (no flavomycin). Feed intakes were measured daily and animals weighed weekly. Wool growth was measured for the initial and experimental periods by clipping a mid-side patch of about 100 cm2. In sheep fed the lucernellupin based diet, flavomycin increased liveweight gain ( P < 0.05) at 20 ppm but had no effect on wool production, whereas in those fed the hay/fishmeal diet, there was a linear decrease in liveweight gain (P < 0.001) (161, 151, 142, 130 g day-1) and a dose related increase in clean wool production (P<0.01) (12.9, 14.5, 15.2, 15.3 g m-2 day-1) with increasing rates of flavomycin (0, 10, 20, 40 ppm respectively). There was no significant effect of flavomycin on fibre diameter in the sheep fed either diet. The inclusion of flavomycin in both diets significantly increased the molar proportions of propionate in the rumen fluid and in sheep on the hay/fishmeal pellet it reduced the concentration of rumen ammonia. The time animals took to eat their ration was increased with the inclusion of flavomycin in the hay/fishmeal diet.

Grazing management of native pastures in the New England region of New South Wales. I. Pasture and sheep production with special reference to systems of grazing and internal parasites

1959 ◽  
Vol 10 (4) ◽  
pp. 530 ◽  
Author(s):  
R Roe ◽  
WH Southcott ◽  
HN Turner
Keyword(s):  
New England ◽  
Fibre Diameter ◽  
Wool Fibre ◽  
Maximum Diameter ◽  
Late Winter ◽  
Parasitic Infestation ◽  
Wool Production ◽  
Skeletal Size ◽  
Significant Difference ◽  
Sheep Production

In a 4-year grazing experiment with Merino sheep, on a native pasture dominated by Bothriochloa ambigua S.T. Blake, three rates of stocking and continuous v. rotational grazing were compared. The effects of these treatments on the forage available and the botanical composition of the pasture and on sheep liveweights, size of sheep, wool production, wool fibre diameter, and parasitic infestation, both with and without drenching with phenothiazine, mere studied. The effects of seasonal conditions on the above and on the chemical composition of the pasture were also recorded. No consistently significant differences between grazing treatments in their effects on the pasture or on sheep liveweights or parasitic infestation were recorded, although during the final 3 years the total forage available was less under heavy stocking. Seasonal variations in total forage mere not marked, but, production of green forage increased greatly in the spring and declined to a very low level during winter. Similarly, sheep liveweights increased during spring and summer and declined in the winter. These liveweight changes were significantly correlated with the amount of green forage available. Wool fibre diameter showed similar seasonal fluctuations but the maximum diameter was attained earlier than maximum liveweight. Coincident with a spring rise in the amount of green forage there was also an increase in the percentages of crude protein and phosphorus in the green components of the pasture. Liveweight gains of the drenched sheep were significantly greater from the beginning of each experimental year in the late spring (November) to late winter (August) in all stocking treatments. In the spring, when the quality of the pasture improved and worm egg counts were low, drenching had no effect on liveweight gains in three out of four years. Drenching also significantly improved wool production and resulted in an increase in skeletal size of sheep in three out of four years. Drenching reduced egg counts of the parasites Oesophagostomum spp. and Haemonchus contortus (Rudolphi) Cobb but was less effective against Trichostrongylus-Ostertagia spp. For all grazing treatments there was no significant difference in the amount of wool produced per head, but over the 4-year period 56 per cent. more wool per acre was produced from the heavy than from the light rate of stocking.

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.

Factors differentiating between high and low wool producing sheep in western Queensland

1992 ◽  
Vol 43 (6) ◽  
pp. 1367
Author(s):  
DA Pritchard ◽  
PK O'Rourke
Keyword(s):  
Linear Growth ◽  
Phenotypic Expression ◽  
Fibre Diameter ◽  
Live Weight ◽  
Unit Surface Area ◽  
Growth Responses ◽  
Wool Production ◽  
Pasture Quality ◽  
Wool Growth ◽  
Commercial Flock

Four experiments were carried out to examine factors which may influence the phenotypic expression of wool growth. High wool producing sheep (HPS) and low wool producing sheep (LPS) were selected from a commercial flock and studied under grazing and controlled feeding conditions. Results are discussed in relation to management of HPS for increased wool production. In the paddock experiment, advantages to HPS in wool growth per unit surface area were least (7%) when pasture quality was low (11 g N/kg DM) and greatest (20%) when pasture quality was best (21 g N/kg DM). Despite the greater live weight of HPS compared with LPS (16%), the HPS produced 25% more clean wool per unit of live weight. Daily clean wool production was always greater in HPS than in LPS. Values ranged from 9.1 v. 7.5 g/day to 15.1 v. 11.6 g/day. During the period following the peak in nitrogen content of the pasture, HPS produced a greater volume of fibre than LPS (194 v. 167 8m3/dayx103), this difference being primarily associated with the greater fibre diameter of wool from HPS (25.4 v. 24.6 8m). In pen experiment 1, the efficiency of conversion of feed to wool was determined under controlled feeding conditions. Differences in wool growth between HPS and LPS at maintenance (M) and above maintenance (M+) were 21% and 49% respectively. Relative efficiency of conversion of feed to wool was 5% higher for HPS during the period immediately following the change in ration and greatest (38-48%) after sheep had made liveweight gains. Wool growth differences between HPS and LPS in pen experiment 2 could not be attributed to either differences in follicle density (66 v. 64 follicles/mm2) or the ratio of secondary to primary follicles (24 : 1 v. 22 : 1). The efficiency of retention of apparently absorbed nitrogen was similar (21.4 v. 20.8%) for HPS and LPS at below maintenance (M-) but differed at M-t (26.8 v. 11.7%). Rumen dry matter turnover time at M- was faster in HPS than in LPS (29.8 v. 38.4 h) but similar at M+ (30.4 v. 34.4 h). At M-, volumetric fibre production of HPS increased from 79 to 106 ,8m3/dayx 103 and from 59 to 75 ,8m3/day x103 for LPS following the subcutaneous administration of the sulfur containing amino acid methionine. These increases were associated with increases in both fibre diameter (1.5 8m) and fibre linear growth (42 8m/day) in HPS, but only linear growth (52 ,8m/day) in LPS. At M+, when basal wool growth was high, there was little increase in wool growth by either group following supplementary methionine. Wool growth responses to methionine were 25 and 19% for HPS and LPS respectively at M+ in pen experiment 3.

Undernutrition of the Merino sheep and its sequelae. II. The influence of finite periods of arrested growth on the subsequent wool growth, fleece development, and utilization of feed for wool production of lambs

1968 ◽  
Vol 19 (4) ◽  
pp. 639 ◽  
Author(s):  
WG Allden
Keyword(s):  
Recovery Period ◽  
Fibre Diameter ◽  
Normal Diet ◽  
Early Recovery ◽  
Wool Production ◽  
Wool Growth ◽  
Development And Utilization ◽  
Rigorous Treatment ◽  
Experimental Treatments ◽  
Early Recovery Period

Five groups of Merino lambs were subjected to contrasting nutritional regimes during a preparatory period of 400 days. All animals were then restored to a normal diet and during the subsequent 27 months the sequelae to the experimental treatments were measured in terms of wool growth, fleece development, and the utilization of feed for wool production. The most rigorous treatment (growth arrested for 400 days at 15 kg weight) had as its sequel a less dense wool follicle population (adjusted to a standard body weight) and a reduced growth rate of wool during the early recovery period. Total fibre numbers and wool growth per unit of feed intake were also depressed but not significantly so. Fibre diameter, fibre weight, and the ratio of secondary to primary follicles were not affected. The less severe treatments (growth restrictions for 200 days (a) at 15 kg and (b) at 30 kg) influenced none of the parameters under study once a normal diet had been restored. It is concluded that only with extreme under nutrition from early in post-natal life is the wool-producing potential of young sheep likely to be impaired.

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