Follicle productivity and wool production in Romney ewes

1962 ◽  
Vol 13 (5) ◽  
pp. 924 ◽  
Author(s):  
DA Ross
Keyword(s):  
Linear Relationship ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Spatial Relationship ◽  
Length Change ◽  
Fibre Volume ◽  
Cross Sectional ◽  
Wool Production ◽  
Absolute Length ◽  
Relationship Of

Fibre diameter and fibre length arrays of monthly samples of 10 mature Romney ewes were each subdivided into seven groups such that group 1 contained the coarsest or longest 15% of fibres and group 7 the finest or shortest 15% of fibres. A study was made of the relation between the characteristics of these seven groups and the level of wool production over a period of 18 months.There was a linear relationship of the form y = a + bx between fibre cross-sectional area d², fibre length per day l , or fibre volume per day d²l (y), and the level of wool production (a), at each of the seven levels within the array. A similar linear relationship held between the change in d², l , or d²l associated with a change in the level of wool production and the corresponding value of d², l, or d²l on which this change was based. In three of the 10 ewes the change in fibre length associated with a change in wool production was constant over the array; in the other ewes the absolute length change increased in the faster-growing fibres. In all ewes the percentage change in d², l , or d²l decreased with increasing fibre size. In four of the five ewes whose wool was free from medullation the change in fibre volume per unit area of fibre cross section associated with a change in the level of wool production was a constant over the array. Some aspects of follicle efficiency and follicle competition are discussed. It is concluded that in mature ewes all follicles have the same "efficiencies" and do not compete for fibre substrate. The spatial relationship of the follicles did not, affect wool production. The concept of a "basic pattern" of wool production is introduced and discussed.

Fleece characters and their influence on wool production per unit area of skin in Merino sheep

1958 ◽  
Vol 9 (3) ◽  
pp. 363 ◽  
Author(s):  
SSY Young ◽  
RE Chapman
Keyword(s):  
Unit Area ◽  
Fibre Diameter ◽  
Fibre Volume ◽  
Cross Sectional Area ◽  
The Body ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fibre Density ◽  
Wool Production ◽  
Staple Length

The variations in fleece characters and the dependence of wool production per unit area of skin on these characters were studied with 15 sheep in both a medium and a strong-wool strain of Merino. Small but significant differences in staple length and fibre diameter were found between regions on the body, whereas differences in density were large. The variation in density was about three times as large as those in staple length and fibre diameter. Distinct dorsoventral and anteroposterior gradients over the body existed for fibre density, but not for staple length and fibre diameter. The influences of the fleece characters on wool production per unit area were somewhat different in the two strains, and changed with level of production. Among the medium-wool sheep, fibre density had the largest effect on production, with staple length less and mean fibre cross-sectional area least. Among the strong-wool sheep, length was more important than density, which in turn was more important than fibre cross-sectional area. The combined data indicated that as mean wool weight per unit area increased, the influence of density rose to a maximum and then diminished, whereupon mean fibre volume became the main contributor to wool weight. For different positions on the body of individual sheep, the dependence of wool production per unit area on the fleece characters was found to be similar in the two strains. Fibre density had the major effect in determining the level of production, whereas the influences of staple length and fibre area were negligible.

Methods of analysis and the influence of fleece characters on unit area wool production of Romney lambs

1960 ◽  
Vol 11 (5) ◽  
pp. 851 ◽  
Author(s):  
AE Henderson ◽  
BI Hayman
Keyword(s):  
Unit Area ◽  
Fibre Length ◽  
Fibre Volume ◽  
Cross Sectional Area ◽  
The Body ◽  
Skin Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Wool Production ◽  
Fibre Number

Investigation has been made of the influence of fibre number per unit area (N), cross-sectional area of fibre (A), and fibre length (L), on wool production per unit area of skin (W). The influence of the compound characters fibre volume (V) and proportion of skin area occupied by fibre (0) has also been considered. Methods are given whereby the significance of the variation associated with any one of these interacting components can be assessed. Data from four groups of lambs were analysed, each group having been subjected to a different nutritional regime. Slightly more than three-quarters of the variation induced in W by these treatments was due to variation in L, with N and A having negligible effects. No evidence was found that the relative influence of the components changed with change in level of production. Differences in W between lambs on the same nutritional level were influenced almost equally by variation in N and L, with A again having a negligible effect. Of the variation in W between positions on lambs, approximately 50 per cent. was accounted for by variation in N, 40 per cent. by variation in A, and 10 per cent. by variation in L. Variation of the compound character O accounted for nearly 90 per cent. of the variation in W over the body.

The influence of selection and plane of nutrition on the components of fleece weight in Merino sheep

1958 ◽  
Vol 9 (6) ◽  
pp. 802 ◽  
Author(s):  
RB Dun
Keyword(s):  
Fibre Diameter ◽  
Fibre Length ◽  
Small Contribution ◽  
Cross Sectional ◽  
Single Character ◽  
The Mean ◽  
Low Levels ◽  
The Difference ◽  
Fleece Weight ◽  
High Level

The components of clean fleece weight were examined in five experimental flocks of medium-wool Peppin Merinos. Four single-character selection groups – clean fleece weight plus, clean fleece weight minus, crimps per inch plus, and crimps per inch minus – were examined by measuring fleece production in 18-month-old ewe progeny. Measurements were also made on progeny from the "nucleus" flock, which was selected for clean fleece weight with subsidiary selection for crimps per inch and against fold score. Data were collected in 1952 and 1954. The 1954 figures were obtained from a nutrition experiment in which sheep mere grown from weaning to 18 months on a high and on a low plane of nutrition. The mean measurements of the components of clean fleece weight (W) were compared between flocks using the "percentage deviation" technique. Four comparisons were made: (1) Nucleus/Fleece minus; (2) Fleece plus/Fleece minus; (3) Crimps minus/Crimps plus; (4) high nutritional plane/low nutritional plane. In comparisons (1) , (2), and (3), difference in weight of wool per unit area of skin (w) accounted for nearly all the difference in W. Body weight (S) made a small contribution while difference in fold score (R) was negligible. Fibre density (N) accounted for +86 per cent., and fibre cross-sectional area (A) for –28 per cent., of the difference in W in comparison (1). In comparison (2) the figures were N +47 per cent., A +21 per cent., while the figures for comparison (3) were N –26 per cent., A +121 per cent. The increase in fleece weight was invariably accompanied by a decrease in crimps per inch. In all three comparisons primary density (P) was the major cause of change in N. Fibre length (L) made a uniform contribution of approximately +15 per cent. in the three comparisons.The relative importance of the components of fleece weight was similar at both high and low levels of nutrition.The effect of a high level of nutrition was to produce large increases in A, L, and S. The increase in S was compensated by an equal decrease in P. The increase in fibre diameter was not associated with any change in crimps per inch.

Wool yield and characteristics of Dorset, Leicester and Sunffolk breeds and their ‘DLS’ cross

1977 ◽  
Vol 88 (3) ◽  
pp. 651-653 ◽  
Author(s):  
M. H. Fahmy ◽  
J. A. Vasely
Keyword(s):  
First Generation ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Wool Production ◽  
Average Fibre Diameter ◽  
Average Fibre ◽  
Wool Yield ◽  
Fleece Weight

SUMMARYGreasy fleece weight (12 months growth) and wool samples from hip and shoulder regions were taken on 15 Dorset, 20 Leicester, 20 Suffolk and 17 DLS ewes (a cross of ½ Dorset, ¼ Leicester, ¼ Suffolk obtained by mating DL rams to DS ewes and DS rams to DL ewes). The purpose of the study was to compare wool production and characteristics of the first generation of DLS with that of the three breeds of origin. Wool production of DLS was 3·58 kg, 8·8 and 14% higher than that of Suffolk and Dorset, but 11% lower than that of Leicester (P< 0·01). The percentage of clean wool was highest in Leicester (78·3%), followed by DLS, Dorset and Suffolk (76·1, 74·3 and 70·5%, respectively). The average fibre diameter of the DLS and Leicester was 38 /m, 4 /m thicker than that for Suffolk and Dorset (P < 0·01). Average fibre length was 15 cm in DLS and Dorset, 6 cm shorter than in Leicester, and 3 cm longer than in Suffolk (P < 0·01). The variability in fibre diameter and length was highest in Leicester, followed closely by DLS.

Follicular determinants of the length and diameter of wool fibres. 2. Comparison of sheep differing in thyroid hormone status

1994 ◽  
Vol 45 (6) ◽  
pp. 1149 ◽  
Author(s):  
PI Hynd
Keyword(s):  
Thyroid Hormone ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Fibre Volume ◽  
Concomitant Change ◽  
Wool Growth ◽  
Root Sheath ◽  
Inner Root Sheath ◽  
Hormone Status ◽  
Dividing Cells

The thyroid hormone status of Corriedale sheep was manipulated in order to produce a change in the rate of fibre elongation (L) with no concomitant change in the diameter (D) of the fibres, to allow the follicular factors responsible for fibre L to be determined. Thyroidectomy resulted in a 60% decrease in wool growth per unit area of skin and a 40% decrease in the rate of fibre volume output, due largely to a decline in fibre L from 412 ,8m/day to 277 8m/day ( P < 0.0001) while fibre D was unchanged (23.9 8m v. 21.9 pm, P > 0-05). Elevation of plasma thyroxine levels to 250% of Control values had no significant effect on fibre L and D, but patch wool growth was increased ( P < 0.05). A high proportion (22.9%) of the follicles in the hypothyroid sheep was inactive in comparison to the low levels of inactivity in the control (1.2%) and hyperthyroid animals (0.1%). The rate of division of follicle bulb cells was depressed by hypothyroidism and increased by hyperthyroidism (P < 0.0001), but there was no effect of thyroid status on the size of the cortical cells released from the wool fibres. Hypothyroid sheep had slightly smaller follicle bulbs and dermal papillae than the control and hyperthyroid animals. The proportion of dividing cells entering the fibre cortex (estimated from cortical cell volume, rate of fibre volume growth and rate of cell division) was depressed by thyroidectomy suggesting that relatively more dividing cells entered the inner root sheath in the follicles of hypothyroid sheep. This is supported by the lower production ratio (ratio of area of fibre to area of fibre-plus-inner root sheath) of the hypothyroid sheep. It is concluded that the rate of fibre elongation is depressed in hypothyroid sheep as a result of both a reduction in the rate of division of cells in the follicle bulb and fewer of these dividing cells entering the fibre cortex. This mechanism allows rapid changes in the rate of fibre elongation to occur with little change in the size of the follicle bulb, and may account for a number of scenarios in which fibre length changes rapidly with no concomitant change in fibre diameter. Fibre diameter, on the other hand, appears to be closely related to the dimensions of the follicle bulb, and by association, to the rate of bulb cell production. Selection of sheep with small follicle bulbs and at the same time, high production ratios, may be means of increasing fibre length whilst maintaining low fibre diameter.

EMI Shielding Effectiveness of Copper/Epoxy Composites

2005 ◽  
Vol 13 (7) ◽  
pp. 657-668 ◽  
Author(s):  
Robert C. Wetherhold ◽  
Joseph M. McManaman
Keyword(s):  
Volume Fraction ◽  
Surface Condition ◽  
Fibre Volume Fraction ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Fibre Volume ◽  
Shielding Effectiveness ◽  
Emi Shielding Effectiveness ◽  
Ni Powder ◽  
Phase Interference

Samples of shaped and treated copper (Cu) fibre/brittle matrix composites have been fabricated with a variety of fibre shapes, treatments, diameters, and powder inclusions and tested for shielding effectiveness (SE) using the ASTM standard D4935-99 method over the frequency range 200 to 1500 MHz. A small amount of nickel (Ni) powder was included in some specimens to evaluate the effect of magnetic permeability on SE. Most tests were conducted at constant (15 vol%, “v%”) fibre volume fraction. Results show that a smaller fibre diameter results in significant SE improvements. SE was also substantially improved by relatively minor fibre shaping (which changes along the fibre length) or by fine-scale roughening via chemical treatment. Addition of small amounts of Cu powder leads to major improvements in SE. Most of the improvements are presumably due to the establishment of conductive networks, although fibre shaping or treatment allows greater scattering and thus more internal reflections with attendant absorption. The smaller diameter fibres consistently gave better SE. When a continuous fibre mesh was used, high SE resulted, showing the dominance of fibre connectivity for such materials; the surface condition of the mesh is relatively unimportant. The improvements in SE can be achieved with essentially identical mechanical properties, leading to an effective multifunctional material, although most of the SE values achieved so far are modest. Ni powder results in overall improvement in SE as well as a cyclic dependence of SE on frequency, which indicates phase interference at a scale of particle size not previously seen.

scholarly journals Performance of crossbreds of Polish Merino dams with F1 rams: Finnsheep X Polish Merino. A. Semi-intensive fattening of ram-lambs up to 40—45 kg

1988 ◽  
Vol 60 (6) ◽  
pp. 540-545
Author(s):  
M. Osikowski ◽  
B. Borys ◽  
M. A. Osikowski
Keyword(s):  
Body Weight ◽  
Energy Consumption ◽  
Weight Gain ◽  
Body Weight Gain ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Carcass Quality ◽  
Wool Production ◽  
Ram Lambs ◽  
Fleece Weight

The investigations were carried out to evaluate fattening ability, carcass quality and wool production of semi-intensively fattened ram lambs the progeny of F1 rams: Finnsheep (F) x Polish Merino (PM) mated to PM ewes. Two experiments were performed, on a total of 73 crossbreds and 73 purebred PM lambs. The lambs were housed together in a shed and fed farm-produced roughages, supplemented by commercially available concentrates. The crossbred lambs under semi-intensive feeding were found to have similar fattening ability as the purebreds: daily gains F x PM x PM 196 g and PM 191 g, energy consumption per 1 kg of body weight gain 26.1 and 27.0MJ, respectively. Crossbreeding did not affect slaughter value, but the commercial evaluation of live lambs was poorer in the crossbred groups. The tested crossbreds had generally better wool performance: their clean fleece weight was 1.09 kg, while that of the purebreds was 0.98 kg, rendement respectively 59.3 and 53.0 %, fibre length 6.7 and 5.4 cm, while fibre diameter was similar in the both groups.

The effect of previous and current nutrition on wool production in southern Victoria

1962 ◽  
Vol 2 (6) ◽  
pp. 160 ◽  
Author(s):  
MJ Sharkey ◽  
IF Davis ◽  
PA Kenney
Keyword(s):  
Fibre Diameter ◽  
Fibre Length ◽  
Initial Increase ◽  
Nutritional Treatment ◽  
Wool Production ◽  
Wool Growth ◽  
Short Period ◽  
The Mean ◽  
Fleece Weight ◽  
Autumn And Winter

The effect of different planes of nutrition on the wool production of Corriedale wethers at pasture was studied between August 1959 and December 1960. The plane of nutrition was controlled by rate of stocking. The effect of previous nutritional treatment on wool production was slight. It affected wool weight and fibre length for 160 one month and fibre diameter for two months. The differences in current nutritional treatment were accompanied by large differences in wool production except during the spring months. On the highest plane of nutrition the wool production showed little seasonal variation, apart from an initial increase in production during the autumn. On the medium and low planes of nutrition wool growth declined substantially in autumn and winter and increased again in spring. The mean fibre diameter of the wool that was clipped frequently was greater than that of fleece wool obtained from the opposite midside at shearing. Further, in the groups on medium and low planes of nutrition estimates of fleece weight based on the combined weight of periodical clippings were greater than actual fleece weights. It is concluded that, in the dry Victorian summer, wool production is influenced by the plane of nutrition in the previous spring for a short period only, and that in autumn and winter it is dependant almost entirely on the feed immediately available.

Variation in mohair staple length over the lifetime of Angora goats

2013 ◽  
Vol 53 (6) ◽  
pp. 479 ◽  
Author(s):  
B. A. McGregor ◽  
K. L. Butler ◽  
M. B. Ferguson
Keyword(s):  
Fibre Diameter ◽  
Fibre Length ◽  
Cross Sectional ◽  
Genetic Origins ◽  
Age Cohort ◽  
Likelihood Model ◽  
Biological Determinants ◽  
Angora Goats ◽  
Fleece Weight ◽  
Staple Length

Previous work has shown that, within an Angora goat flock, clean fleece weight is proportional to fleece-free liveweight (FFLwt)2/3 and for goats of the same age and cohort, the mean mohair fibre diameter is proportional to FFLwt1/3. This indicates that fibre length might not be related to the size of animals. This study examines how mohair staple length (SL) is related to FFLwt of Angora goats of different genetic origins over their lifetime and how the relationship varies with other lifetime factors. Measurements were made over 11 shearing periods on a population of Angora goats representing the current range and diversity of genetic origins in Australia, including South African, Texan and interbred admixtures of these and Australian sources. Records of breed, sire, dam, date of birth, dam age, birthweight, birth parity, weaning weight, liveweight, fleece growth and fleece quality were taken for castrated males (wethers) (n = 94 animals). FFLwt were determined for each goat at shearing time by subtracting the greasy fleece weight from the liveweight recorded immediately before shearing. The average of the FFLwt at the start of the period and the FFLWt at the end of the period was calculated. Liveweight change (LwtCh) was the change in FFLwt over the period between shearings. A restricted maximum likelihood model was developed for SL, which allowed the observations of the same animal at different ages to be correlated in an unstructured manner. Average SL differed from ~12.0 to ~14.5 cm, depending on age. There were no consistent effects of season. At any age, an increase of 10 kg LwtCh between animals results in about a 0.34 (s.e. = 0.087) cm increase in SL. There was no evidence of an effect of FFLwt on SL. The results confirm our hypothesis that within a single age cohort of Angora goats, there is very little, if any, relationship between the liveweight and SL of individual animals. This implies that the biological determinants of size of fibres related to cross-sectional area are substantially different to the size determinants of fibre length.

Maternal and genetic influences on follicle and fleece development in Lincoln and Welsh Mountain sheep—a study involving egg transfer

1965 ◽  
Vol 7 (3) ◽  
pp. 333-345 ◽  
Author(s):  
G. Wiener ◽  
J. Slee
Keyword(s):  
Post Partum ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Maternal Environment ◽  
Maternal Influences ◽  
Wool Production ◽  
Secondary Follicle ◽  
Specific Effects ◽  
Fibre Growth ◽  
General Average

SUMMARYBy mean of egg transfer, lambs of a large breed of sheep (Lincoln) were born out of dams of a small breed (Welsh Mountain) and vice versa. One breed was approximately twice the weight of the other. The effects of this contrast in maternal environment upon the development of the wool follicles and upon subsequent wool production are described in this paper. These effects are compared with differences between singles and twins.Data were obtained from skin and wool samples taken at birth and at 84 days post-partum.Genetic differences were the largest single source of variation for most of the component characters of the skin and fleece.Strong maternal influences were in evidence. These were shown to have affected both Lincoln and Welsh lambs in a general (average) way and also to have had different, specific effects on each genotype as shown by genotype-environment interactions. Differences in maternal environment following egg transfer, clearly affected follicle density, primary/secondary follicle ratio, fibre medullation, fibre diameter and fibre length. Wool production was not affected, apparently because reduced follicle density was associated with increased fibre length.In the comparison between singles and twins the latter appeared to suffer a post-natal rather than a pre-natal restriction of secondary follicle development, and in the absence of extra fibre growth there was reduced wool production at 84 days.

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