N-[5-(4-Aminophenoxy)pentyl]phthalimide as a potential defleecing agent and its effect on wool growth

Merino sheep, offered feed at two levels of intake, were given an oral dose of N-[5-(4-am1nophenoxy)- pentyllphthahmide at rates varying over 100-800 mg/kg body weight. Consistent defleecing was obtained at dose rates of 400 nig/kg and above. Feed intake did not Influence defleecing activity. lntravenous infusion of smaller amounts also allowed defleecing. Wool growth rate following dosing was not affected by a dose of 100 mg/kg, but doses of 200 and 400 mg/kg caused depressions of c. 15 and c. 70% respectively in the rate of wool growth in the 2 weeks after dosing. Blindness was observed In one sheep dosed at 400 mg/kg and In all sheep dosed at higher rates

The Relation Between the Responses of Wool Growth and Body Weight to Changes in Feed Intake

Australian Journal of Biological Sciences ◽

10.1071/bi9620720 ◽

1962 ◽

Vol 15 (4) ◽

pp. 720 ◽

Cited By ~ 12

Author(s):

KA Ferguson

Keyword(s):

Growth Rate ◽

Body Weight ◽

Feed Intake ◽

Weight Change ◽

Productive Efficiency ◽

Intake Rate ◽

Body Weight Change ◽

Growth Responses ◽

The wool growth responses to changes in feed intake are related to the changes produced in body weight. The relation is expressed by the equation W = Ei-kG, where W = wool growth rate, i = feed intake rate, G = rate of body weight change, and E and k are constants. The ratio of E to k in sheep of different productive efficiency was found to be constant.

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

10.1071/ea01105 ◽

2002 ◽

Vol 42 (4) ◽

pp. 399 ◽

Cited By ~ 7

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.

Seasonal fluctuations in wool growth in south Western Australia.

10.1071/ea9610085 ◽

1961 ◽

Vol 1 (2) ◽

pp. 85 ◽

Cited By ~ 8

Author(s):

AM Stewart ◽

RJ Moir ◽

PG Schinckel

Keyword(s):

Growth Rate ◽

Body Weight ◽

Western Australia ◽

Seasonal Fluctuation ◽

Seasonal Fluctuations ◽

Merino Sheep ◽

Wool Production ◽

Wool Growth ◽

Climatic Environment

The growth rate of wool was measured at monthly intervals for a period of two years in four groups totalling forty Merino sheep, maintained under typical farm conditions in a Mediterranean climatic environment. Marked seasonal fluctuation in wool growth was found in all sheep. The highest level of clean wool production, 85 attained in the spring months, was nearly three times that of the lowest level, which occurred in the autumn. The rate of wool growth fluctuated independently of body weight. Wool growth fell steep4 while bob weight was maintained; wool growth subsequently rose sharply while body weight increased relatively slowly. The factors responsible for the observed fluctuation in the rate of wool growth are discussed and the conclusion reached that lack of useful energy and protein, in the summer and autumn grazing is probably the principal cause of the decline in rate of wool growth in these months.

The efficiency of conversion of feed to wool in Merino flocks selected for and against fleece weight

10.1071/ea9630269 ◽

1963 ◽

Vol 3 (11) ◽

pp. 269 ◽

Cited By ~ 6

Author(s):

W Ahmed ◽

RB Dun ◽

RJ Winston

Keyword(s):

Body Weight ◽

Feed Intake ◽

Relative Importance ◽

Merino Sheep ◽

Wool Growth ◽

Cent Increase ◽

The Difference ◽

Fleece Weight

The efficiency of conversion of feed to wool was measured in three jocks of Peppin Merino sheep, namely : Fleece Plus-Selected for nine years on high clean fleece weight ; Fleece Minus-Selected for nine years on low clean fleece weight ; Random-An unselected, control flock. Ten 18 month old ewes from each of these flocks were individually housed and fed ad lib on hammer-milled lucerne hay for 54 weeks. Highly significant differences between flocks were observed in feed intake, wool growth, and efficiency of conversion of feed to wool. The relative productive levels for the Fleece Plus, Random and Fleece Minus flocks were-for feed intake, 108 : 100 : 88-for clean fleece weight, 118 : 100 : 70-and for efficiency 109 : 100 : 79. The correlation between efficiency and daily feed intake was very highly significant and negative within each flock, (-0.918, -0.929 and -0.924, for Fleece Plus, Random and Fleece Minus flocks respectively), whereas the correlation between jocks was significantly positive, r = 0.997. The relative importance of the factors determining the 18 per cent increase in clean fleece weight of the Fleece Plus over the Random flock was : efficiency, 55 per cent and feed intake, 45 per cent-and comparing the Random to the Fleece Minus flock : efficiency, 60 per cent and feed intake, 40 per cent. Approximately half the difference in feed intake was independent of body weight.

Body composition of Romney-Southdown cross and Merino sheep foetuses at a constant age and a constant body weight

Animal Science ◽

10.1017/s0003356100022108 ◽

1964 ◽

Vol 6 (3) ◽

pp. 309-319 ◽

Cited By ~ 1

Author(s):

S. K. Stephenson

Keyword(s):

Growth Rate ◽

Body Composition ◽

Body Weight ◽

Muscle Tissue ◽

Hind Limb ◽

Body Shape ◽

Carcass Composition ◽

The Body ◽

Merino Sheep ◽

Australian Merino

1. Body shape and carcass composition have been measured in a dated series of Romney-Southdown cross and Australian Merino sheep foetuses.2. Large differences in shape exist between the two breed groups and these result from growth rate differences in certain components of the bone and muscle tissue.3. Carcass composition at any particular foetal weight, however, is more uniform. In relation to body weight, the Merino has a higher proportion of bone in the body but the proportion of muscle is the same in both breed groups. Nevertheless, the distribution of muscle tissue is changed as there s i a higher proportion of muscle in the hind limb of the Romney-Southdown cross.

The Growth and Composition of Wool V. Stimulation of Wool Growth by the Abomasal Administration of Varying Amounts of Casein

Australian Journal of Biological Sciences ◽

10.1071/bi9690745 ◽

1969 ◽

Vol 22 (3) ◽

pp. 745 ◽

Cited By ~ 21

Author(s):

PJ Reis

Keyword(s):

Growth Rate ◽

Body Weight ◽

Sulphur Content ◽

Wool Growth ◽

Stimulation Of

In a series of five experiments, varying amounts of casein (60~200 gjday) were given to sheep, in the diet or via the abomasum, as supplements to various diets at several levels of intake (400~1200 gjday). Effects on growth rate and sulphur content of wool and on body weight were investigated.

Selection for weaning weight in Merino sheep. 3. Maintenance requirements and the efficiency of conversion of feed to wool in mature ewes

10.1071/ea9670117 ◽

1967 ◽

Vol 7 (25) ◽

pp. 117 ◽

Cited By ~ 5

Author(s):

WA Pattie ◽

AJ Williams

Keyword(s):

Body Weight ◽

Feed Intake ◽

Weaning Weight ◽

Gross Efficiency ◽

Wool Growth ◽

Body Weights ◽

Unit Body Weight ◽

Selection For ◽

Feed Costs ◽

Maintenance Requirements

Net and gross efficiencies of wool growth have been estimated for ewes from three Trangie selection flocks, one selected for high weaning weight (Weight Plus), one for low weaning weight (Weight Minus), and a random control flock. Weight Plus ewes had 15 and 11 per cent heavier body weights than Weight Minus ewes at maintenance and unlimited levels of feeding respectively. At each level, feed intake was proportional to body weight both between and within flocks. In addition, the feed costs of a unit gain and loss of body weight were the same for each flock at each level of feeding. The Weight Plus ewes grew 7 and 10 per cent more wool than Weight Minus ewes at maintenance and unlimited levels of feeding. Consequently, there was only a small difference between the flocks in efficiency of conversion of feed to wool at maintenance, and there was no difference on unlimited intake. These results indicate that there is no genetic correlation between weaning weight and efficiency of conversion of feed to wool. At the three levels of controlled feeding (543, 725, 902 grams of dry matter a day) there were no differences in gross efficiency of wool growth, either between flocks or between levels within flocks, despite differing changes in body weight. During unlimited feeding, gross efficiency of wool growth was lower than that during controlled feeding. This was due to a reduced response in wool growth, as feed costs per unit body weight change were constant. As both production and feed intake changed in proportion to body weight, it is concluded that attention to weaning weight has little place in a Merino breeding program aimed at increasing wool production. However, selection for high weaning weight may be a useful tool in selecting ewes for crossbreeding because of the associated increases in milk production and lamb growth rate.

The influence of dietary supplements of DL-methionine on the growth rate of wool

Australian Journal of Agricultural Research ◽

10.1071/ar9750337 ◽

1975 ◽

Vol 26 (2) ◽

pp. 337 ◽

Cited By ~ 10

Author(s):

PT Doyle ◽

PR Bird

Keyword(s):

Growth Rate ◽

Dietary Supplements ◽

Dry Matter ◽

Nitrogen Retention ◽

Growth Responses ◽

Merino Sheep ◽

Dietary supplements of DL-methionine (0, 1.9, 3.8, 7.7 and 15.4 g per day) were given to five groups of 15-month-old Merino sheep (five per group) over an 8-week period. The roughage ration given (c. 840 g dry matter per day) comprised oaten chaff (78%), lucerne chaff (20%) and minerals (2%). Significant wool growth responses were obtained (18% above controls) when 3.8 g supplemental methionine per day was given. Changes in the rate of wool growth were paralleled by changes in nitrogen retention. Nitrogen retention was significantly increased above controls when 3.8 g supplemental methionine per day was given. Supplemental methionine did not affect liveweight gains.

Adaptation of growing pigs to changes in environmental temperature

Animal Science ◽

10.1017/s0003356100029421 ◽

1971 ◽

Vol 13 (1) ◽

pp. 51-57 ◽

Cited By ~ 27

Author(s):

S. R. Morrison ◽

L. E. Mount

Keyword(s):

Growth Rate ◽

Body Weight ◽

Respiratory Rate ◽

Temperature Change ◽

Water Intake ◽

Rectal Temperature ◽

Feed Intake ◽

Environmental Temperature ◽

Growing Pigs ◽

Ad Libitum

SUMMARYPigs fed ad libitum were exposed to changes from 22 to 33°C and from 33 to 20°C. Responses were investigated in two groups of animals kept for three successive periods of four weeks at 22°, 33° and finally 20°C.Twenty-four hr after the first change, from 22 to 33°C, there was a decline in body weight; after the second change, from 33 to 20°C, there was a large increase. After the change to 33°C, feed intake by the second day and growth rate for the first week were about the same as at the end of the four weeks, but about 12 days were required for water intake, rectal temperature and respiratory rate to reach steady values.After the change from 33 to 20°C, steady values for respiratory rate and rectal temperature were reached in one and 12 days respectively. The rate of gain in weight increased to reach a peak nine days following the temperature change and then declined.

The description and analysis of wool growth

Australian Journal of Agricultural Research ◽

10.1071/ar9770737 ◽

1977 ◽

Vol 28 (4) ◽

pp. 737 ◽

Cited By ~ 12

Author(s):

BN Nagorcka

Keyword(s):

Growth Rate ◽

Body Weight ◽

Linear Regression ◽

Least Squares ◽

Ordinary Least Squares ◽

Time Dependent ◽

Recursive Least Squares ◽

Growth Time ◽

Body Weight Change ◽

Analyses of experimental estimates of the wool growth rate as a function of intake have previously been based on time-independent equations and linear regression with ordinary least squares. Some of these results are reanalysed with the assumption that the sheep is a dynamic system; hence a time-dependent description of wool growth is proposed. A recursive least squares technique has been used, and the results demonstrate that there is a 3½ week lag between intake and wool growth. Time-independent descriptions have not taken account of this and have led to the misconception that efficiency is a function of body weight change.