Photoperiodicity of Seasonal Rhythm of Wool Growth in Sheep

Nature ◽  
1961 ◽  
Vol 190 (4770) ◽  
pp. 102-103 ◽  
Author(s):  
L. R. MORRIS
Keyword(s):  
Seasonal Rhythm ◽  
Wool Growth

Seasonal variations in wool growth and heat tolerance of sheep. I. Wool growth

1960 ◽  
Vol 11 (1) ◽  
pp. 75 ◽  
Author(s):  
M Wodzicka
Keyword(s):  
Body Weight ◽  
Day Treatment ◽  
The Other ◽  
Seasonal Rhythm ◽  
Group Iii ◽  
Wool Growth ◽  
Group I ◽  
The Mean ◽  
Group Ii ◽  
The Difference

The monthly wool growth of three groups of rams was studied at Beltsville, Maryland. Group I received natural daylight (at 38° 53' N.) and was shorn monthly. Group II had a 7:17 hours of daylight to hours of darkness rhythm and was shorn every 6 months, once in winter and once in summer. Group III received natural daylight and was likewise shorn every 6 months. The rams of all groups produced more wool in summer than in winter. This difference was significant (P<0.001). The mean body weight and food intake were both greater in the winter months, which indicated that the seasonal rhythm of wool growth was not a consequence of poorer feeding in winter. The rams which were shorn monthly (group I) grew considerably more wool than the other two groups, but the difference was not statistically significant. The short-day treatment of group II did not increase the annual wool production nor decrease the seasonal rhythm of wool growth. The balance of evidence from this and other experiments indicates that temperature rather than light controls the seasonal rhythm of wool growth.

The fleece of the Scottish Blackface sheep. IV. The effects of pregnancy, lactation and nutrition on seasonal wool production

1964 ◽  
Vol 62 (1) ◽  
pp. 59-66 ◽  
Author(s):  
J. M. Doney
Keyword(s):  
Marked Effect ◽  
Weight Maintenance ◽  
Live Weight ◽  
Physiological Status ◽  
Seasonal Rhythm ◽  
Wool Production ◽  
Wool Growth ◽  
Nutritional Conditions ◽  
Pregnancy And Lactation

Pre-mating, pregnancy and lactation periods correspond approximately with summer, winter and spring and any effects either of physiological status or nutritional conditions are confounded with the natural rhythm of wool growth. Within this framework, barren ewes produced slightly more wool than in-lamb ewes in winter and considerably more during the period of lactation. Improved nutrition during winter produced no increase in wool production, although it had a marked effect on live-weight maintenance. During lactation, improved nutrition resulted in an increase in wool production. The implications of the nutritional and seasonal rhythm of wool productions are discussed in relation to the adaptation of the breed to its environment.

Wool growth as affected by nutrition and by climatic factors

1953 ◽  
Vol 43 (4) ◽  
pp. 456-472 ◽  
Author(s):  
I. E. Coop
Keyword(s):  
Environmental Temperature ◽  
Climatic Factors ◽  
Constant Composition ◽  
Seasonal Rhythm ◽  
Wool Growth ◽  
Nutritional Conditions ◽  
Fundamental Cause ◽  
Pregnancy And Lactation ◽  
Low Levels ◽  
Fleece Weight

The weight, length and quality (fineness) of wool produced at different times of the year and under different nutritional conditions has been determined over a period of three years by clipping at monthly intervals the wool grown on delineated skin areas of sheep. The treatments consisted of(a) wet ewes, grazing on pasture all the year, subjected to high and low levels of feeding during the ‘dry’, pregnancy and lactation periods;(b) dry ewes and lambs fed differentially on grazing during the winter and spring;(c) wet ewes fed in stalls on a diet of constant composition at rates sufficient to maintain constant effective body weight (i.e. making allowance for pregnancy increase and fleece weight increase). A small number of these ewes was also subjected to increased environmental temperature during the winter.The experiments have shown the existence of a marked seasonal rhythm in wool growth having a maximum in January (midsummer) and a minimum in July (midwinter). Changes in weight of wool grown are caused by sympathetic changes in both length and diameter. At the same level of feeding the rate of wool growth in midwinter is about onethird of that in midsummer.The nutritional demands of pregnancy reduce the rate of wool growth in winter and those of lactation delay the rise in production in spring. Nutrition also plays an important part in determining the time of the maximum and minimum. In dry sheep the maximum tends to occur before midsummer when pasture growth is at its best, but lactation in wet sheep prevents the expression of a maximum early in the summer, so that in these ewes it generally occurs after weaning, and therefore after midsummer. The level of nutrition also determines within limits the magnitude of the maximum and minimum.The fundamental cause of the seasonal rhythm of wool growth remains obscure. Nutrition, pregnancy and lactation can modify the rhythm, but it exists strongly even when variations due to these are eliminated. The seasonal rhythm of solar radiation has recently been shown to influence rate of wool growth, particularly during winter, and though this is undoubtedly one factor it is not the only one. Temperature has been suggested elsewhere as a possible cause, but the experiments described do not support the theory that environmental temperature has any direct effect on wool growth. It is suggested, however, that the seasonal rhythm of temperature may be a second factor.

Supplementary feeding of Merino wethers grazing weed-free stubble pastures

1981 ◽  
Vol 21 (110) ◽  
pp. 272 ◽  
Author(s):  
LG Butler
Keyword(s):  
Drinking Water ◽  
Field Trial ◽  
Compensatory Growth ◽  
Supplementary Feeding ◽  
Control Group ◽  
Apparent Digestibility ◽  
Wool Production ◽  
Wool Growth ◽  
Wheat Stubble

A field trial was conducted in the Wimmera region of Victoria to investigate the effect of several supplements on 4-year-old Merino wethers grazing a weed-free wheat stubble for 3 months, The four treatments were: a control (no supplement), urea/molasses block, 100 g/head day-1 of lupin grain, and 2 g urea plus 0.5 g Na2SO4 l-1 in the drinking water. Twenty sheep per treatment were used, and liveweight change and wool growth were measured. Although all groups lost weight, the lupin group lost only 0.5 kg per head over the 3 months of the trial, and was 3.8 kg heavier (P <0.01) than the control group, while the urea/molasses group was 2.2 kg heavier (P <0.01) than the control group. There was no effect of the urea plus sulfur supplement in the drinking water on liveweight or wool production. The urea/molasses block did not affect wool production but lupin grain stimulated wool production by 0.08 kg (P <0.05). The sheep were weighed and shorn four and a half months after the trial (August), during which time all groups grazed together on green feed. The experimental liveweight differences had disappeared, apparently due to compensatory growth. In addition, a digestibility trial was conducted in an attempt to explain some of the field results. The treatments were designed to simulate those used in the field. Lupin grain stimulated intake by 129 g day-1 (P <0.05) but had no effect on apparent digestibility of straw. The treatment simulating the urea/ molasses block (urea plus sulfur plus sucrose in the drinking water) stimulated intake by 159 g day-l (P <0.05) and tended to increase digestibility (P > 0.05). It was concluded that supplementary feeding of Merino wethers grazing weed-free stubble is unlikely to be an economic farm practice.

Ectopic expression of FGF5s induces wool growth in Chinese merino sheep

Gene ◽  
2017 ◽  
Vol 627 ◽  
pp. 477-483 ◽  
Author(s):  
Wen-Rong Li ◽  
San-Gang He ◽  
Chen-Xi Liu ◽  
Xue-Mei Zhang ◽  
Li-Qin Wang ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Merino Sheep ◽  
Wool Growth

scholarly journals Effects of Growth Hormone Administration on Wool Growth in Merino Sheep

1988 ◽  
Vol 41 (2) ◽  
pp. 177 ◽  
Author(s):  
PC Wynn ◽  
ALC Wallace ◽  
AC Kirby ◽  
EF Annison
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Energy Intake ◽  
Nitrogen Balance ◽  
Daily Administration ◽  
Maintenance Energy ◽  
Merino Sheep ◽  
Growth Hormone Administration ◽  
Hormone Administration ◽  
Wool Growth

The effects of daily administration of 10 mg of highly purified ovine growth hormone (GH) for a period of 4 weeks on wool growth have been measured in 12 Merino ewes fed either a calculated maintenance energy intake or 1�6 times this amount (six on each ration). Concentrations of hormones, glucose, urea, a-amino N and amino acids in the blood were monitored and faeces and urine collected for measurement of nitrogen balance.

The performance of pregnant and lactating Merino ewes and their lambs fed survival rations of wheat grain and sawdust

1978 ◽  
Vol 18 (90) ◽  
pp. 34 ◽  
Author(s):  
RA Hunter
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Survival Rate ◽  
Wheat Grain ◽  
Term Survival ◽  
Feeding Level ◽  
Wool Growth ◽  
Eucalyptus Maculata ◽  
Maintenance Ration

Merino ewes were mated at pasture and then fed in pens either a maintenance or an 80 per cent maintenance ration of wheat grain three times a week. Half the animals at each feeding level were offered Spotted Gum (Eucalyptus maculata) sawdust. Addition of sawdust to the ration did not affect liveweight change and the wool growth rate of ewes or the birth weight and growth rate of lambs. It did, however, affect the long-term survival rate of ewes. Of the ewes that died after three months of survival feeding, four were in groups fed wheat alone and one in a group fed sawdust with the wheat. The survival rate and growth rate of lambs in all treatments were poor.

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