Responses of wool growth rate and body reserves to nutrition in Merino ewes: a potential biological link between production and fitness

2007 ◽  
Vol 58 (9) ◽  
pp. 913 ◽  
Author(s):  
N. R. Adams ◽  
J. R. Briegel ◽  
J. C. Greeff
Keyword(s):  
Growth Rate ◽  
Body Condition ◽  
Body Condition Score ◽  
Plasma Concentrations ◽  
Genetic Selection ◽  
Fibre Diameter ◽  
Lower Body ◽  
Lower Plasma ◽  
Wool Growth ◽  
Ad Libitum

This study examined whether the low body-fat reserves in sheep with high estimated breeding values (EBVs) for clean fleece weight (CFW) reported previously are affected by nutritional history, and second whether the effect may be related to differences in the variation in fibre diameter (CVfd). Groups of 11 20-month-old Merino ewes with high and low EBVs for CFW and for CVfd were compared in a 2 × 2 design at low bodyweight, then fed ad libitum for 100 days and re-measured. The response of wool growth rate to feed supply (WRF) was estimated as the slope of the regression against time of clean wool mass collected from mid-side patches at intervals of 30–40 days throughout the experiment. High CFW sheep had greater feed intake relative to liveweight and liveweight gain (P = 0.02), but did not differ significantly in other characteristics from low CFW sheep. High CVfd sheep had lower plasma concentrations of insulin (P = 0.02), IGF-1 (P = 0.03), and albumin (P = 0.02) throughout the study, and had less fat when in poor body condition (P = 0.02). The WRF was greater in both the high CFW (P = 0.003) and the high CVfd (P = 0.004) genotypes. When studied in poor body condition, sheep with a high WRF had lower liveweight (P < 0.001), lower body condition score (P < 0.001), lower plasma albumin (P < 0.001), and higher plasma growth hormone (P = 0.02), but these relationships weakened or disappeared after ad libitum feeding. Sheep with high WRF also had lower plasma concentrations of insulin (P = 0.002) and IGF-1 (P = 0.008) throughout the study, which may have brought about the increased responsiveness of protein and energy metabolism to nutrition. The results indicate that genetic selection for wool characteristics can affect the responsiveness of wool growth rate to nutrient supply. Sheep that are highly responsive grow more wool when offered abundant feed, but may have lower body nutrient reserves when on limited feed.

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.

Production by wethers fed oats, wheat, and lupins, with dry annual pasture in north-eastern Victoria

1981 ◽  
Vol 21 (112) ◽  
pp. 480 ◽  
Author(s):  
PA Kenney
Keyword(s):  
Body Condition ◽  
Crude Protein ◽  
Body Condition Score ◽  
Export Market ◽  
Cereal Grains ◽  
Wool Growth ◽  
North Eastern ◽  
Condition Score ◽  
Ad Libitum ◽  
Live Export

An experiment was conducted at Rutherglen Research Institute in autumn 1979 to evaluate various grain supplements for the fattening of 18-month-old Merino wethers intended for the live export market. All sheep had mature, dry pasture, harvested during mid summer, freely on offer. This herbage contained 9% crude protein and was 47% digestible. Wheat, oats or lupins were fed as supplements at 0, 180, 360, 540 g/head.d and ad libitum. Mixed grain rations were also studied: lupins were fed at 0, 90, 180 and 270 g/head.d with either wheat or oats ad libitum. Wethers were fed these rations for nine weeks and fasted liveweight, wool growth, and body condition score were measured. Animals were then slaughtered and carcases weighed. Animal performance was positively related to the rate of grain intake. Ad libitum intakes of wheat and oats were low - 450 and 520 g/head.d respectively, and only maintained liveweights. in contrast, lupins fed ad libitum were consumed at 650 g/head.d, which resulted in significant increases in live and carcase weight - 4 kg and 3.8 kg respectively. Pasture intake was reduced by one third with all ad libitum grain rations. The addition of lupins at 180 g/head.d to wheat or oats increased the ad libitum intakes of the cereal grains to 550 and 650 g/head.d, respectively, with associated liveweight gains of 1.0 and 4.5 kg for the nine week period. Intake of cereal grains was generally low compared with that in other published reports; but all rations containing more than 10% lupins showed promise as supplements for fattening wethers.

scholarly journals Genetics of heifer puberty in two tropical beef genotypes in northern Australia and associations with heifer- and steer-production traits

2009 ◽  
Vol 49 (6) ◽  
pp. 399 ◽  
Author(s):  
D. J. Johnston ◽  
S. A. Barwick ◽  
N. J. Corbet ◽  
G. Fordyce ◽  
R. G. Holroyd ◽  
...  
Keyword(s):  
Growth Rate ◽  
Body Condition ◽  
Reproductive Tract ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
Production Traits ◽  
Northern Australia ◽  
Marbling Score ◽  
Condition Score ◽  
Age At Puberty

A total of 2115 heifers from two tropical genotypes (1007 Brahman and 1108 Tropical Composite) raised in four locations in northern Australia were ovarian-scanned every 4–6 weeks to determine the age at the first-observed corpus luteum (CL) and this was used to define the age at puberty for each heifer. Other traits recorded at each time of ovarian scanning were liveweight, fat depths and body condition score. Reproductive tract size was measured close to the start of the first joining period. Results showed significant effects of location and birth month on the age at first CL and associated puberty traits. Genotypes did not differ significantly for the age or weight at first CL; however, Brahman were fatter at first CL and had a small reproductive tract size compared with that of Tropical Composite. Genetic analyses estimated the age at first CL to be moderately to highly heritable for Brahman (0.57) and Tropical Composite (0.52). The associated traits were also moderately heritable, except for reproductive tract size in Brahmans (0.03) and for Tropical Composite, the presence of an observed CL on the scanning day closest to the start of joining (0.07). Genetic correlations among puberty traits were mostly moderate to high and generally larger in magnitude for Brahman than for Tropical Composite. Genetic correlations between the age at CL and heifer- and steer-production traits showed important genotype differences. For Tropical Composite, the age at CL was negatively correlated with the heifer growth rate in their first postweaning wet season (–0.40) and carcass marbling score (–0.49), but was positively correlated with carcass P8 fat depth (0.43). For Brahman, the age at CL was moderately negatively genetically correlated with heifer measures of bodyweight, fatness, body condition score and IGF-I, in both their first postweaning wet and second dry seasons, but was positively correlated with the dry-season growth rate. For Brahman, genetic correlations between the age at CL and steer traits showed possible antagonisms with feedlot residual feed intake (–0.60) and meat colour (0.73). Selection can be used to change the heifer age at puberty in both genotypes, with few major antagonisms with steer- and heifer-production traits.

scholarly journals Influence of post-calving supplemental protein on calf performance and reproductive efficiency for beef cows fed silage

1999 ◽  
Vol 79 (1) ◽  
pp. 97-106 ◽  
Author(s):  
E. Charmley ◽  
J. A. Small ◽  
K. B. McRae
Keyword(s):  
Milk Production ◽  
Body Condition ◽  
Body Condition Score ◽  
Beef Cows ◽  
Negative Energy ◽  
Protein Supplementation ◽  
Linear Effect ◽  
Calf Performance ◽  
Ad Libitum ◽  
Protein Milk

Protein supplementation for winter-calving beef cows between calving and turnout to pasture was studied in two trials. Changes in cow body weight (BW) and condition and calf BW gains were recorded from calving to weaning in the fall. Reproductive performance was monitored, and in trial 2, milk production was determined. In trial 1, multiparous silage-fed cows were allocated to one of five levels of corn gluten meal (CGM): 0, 200, 400, 600 and 800 g d−1. In the second trial, cows were allocated to either restricted or ad libitum silage feeding in combination with three protein supplements: no protein, 400 g d−1 CGM or 475 g d−1 soybean meal (SBM). In trial 1, cows gained weight during supplementation, but on pasture they lost weight (linear effect, P = 0.10). Calf gains and weights at turnout and weaning showed a quadratic response to protein supplementation (P < 0.05). There was a trend toward a linear decline in days to first service with increasing levels of CGM (P < 0.10). In trial 2, cows on restricted silage feeding lost weight (P < 0.05) and body condition (P < 0.10), whereas those fed ad libitum silage gained weight and condition. On pasture, this pattern of weight change was reversed (P < 0.05). Protein supplementation did not influence BW change but tended to cause a lower body condition score at turnout (P = 0.10). Restricting silage intake to the cow did not affect calf performance, but protein supplementation increased gains both during supplementation and on pasture, thus increasing weaning weights (P < 0.05). When silage was fed ad libitum, SBM was more effective than CGM for increasing calf gain. However, when silage was restricted, CGM was more effective. Restricting silage intake did not impair milk production, but feeding CGM increased milk production (P < 0.05). For ad libitum-fed cows, protein supplementation increased pregnancy rate; restricting feed had the opposite effect. Our data suggest that protein supplementation to silage-fed beef cows in good body condition can increase calf performance; however, the level of supplementation is critical, and possible adverse effects on breeding have to be taken into account, particularly with cows in negative energy balance after calving. Key words: Beef cow, protein, milk production, calf gains, silage

Wool growth regulation by local skin cooling

1967 ◽  
Vol 9 (3) ◽  
pp. 393-397 ◽  
Author(s):  
J. M. Doney ◽  
J. G. Griffiths
Keyword(s):  
Heat Transfer ◽  
Growth Rate ◽  
Blood Flow ◽  
Growth Regulation ◽  
Fibre Diameter ◽  
Systemic Response ◽  
Local Cooling ◽  
Local Skin ◽  
Wool Growth ◽  
Skin Cooling

Local cooling of the skin, produced by exposure to wind was shown to depress the rate of length growth of wool. The depression was associated with reductions in skin temperature and blood flow and with increases in heat transfer in the exposed regions. Fibre diameter did not appear to be affected and there were no indications of a systemic response of wool growth rate to exposure.

The influence of abomasal supplements of methionine on wool growth of wheat-fed sheep

1974 ◽  
Vol 25 (6) ◽  
pp. 919 ◽  
Author(s):  
PJ Reis ◽  
DA Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Blood Plasma ◽  
Fibre Diameter ◽  
Length Growth ◽  
Wool Growth ◽  
Abomasal Infusion ◽  
Mineral Mixture ◽  
In Blood Plasma

Sheep receiving a diet consisting solely of wheat (500 g/day), supplemented with a mineral mixture, were given abomasal infusions of varying amounts of DL-methionine (1.5–6.0 g/day) or of L-cystine (5 g/day). Other sheep received DL-methionine as a supplement to a roughage diet. All levels of methionine infused caused a decrease in the mass of wool grown by sheep consuming the wheat diet. This effect was greatest with 6 g methionine and was due mainly to a considerable depression of fibre diameter. Smaller amounts of methionine decreased fibre diameter and increased length growth rate. The infusion of methionine caused a considerable weakening of the wool grown by most of the sheep, with the result that a 'break' was observed in the fleece after about 1 week of methionine administration. This effect occurred with all levels of methionine but was more pronounced with 6 g/day. The abomasal infusion of cystine (5 g/day) caused little change in the mass of wool grown, but fibre diameter was decreased slightly. There were no appreciable effects on the strength of wool fibres and no wool was shed. Supplementation of the roughage diet (400 g/day) with methionine at 2 g/day stimulated wool growth, whereas with 6 or 10 g/day the mass of wool grown was unchanged but fibre diameter was markedly reduced. The strength of wool fibres was not markedly influenced by methionine infusions on this diet. The levels of amino acids in blood plasma and in abomasal digesta indicated that the mixture of amino acids absorbed was similar with both the roughage and the wheat diets.

scholarly journals Weight estimation and hormone concentrations related to body condition in Icelandic and Warmblood horses: a field study

2019 ◽  
Vol 61 (1) ◽  
Author(s):  
Rasmus Bovbjerg Jensen ◽  
Lucca Louise Rockhold ◽  
Anne-Helene Tauson
Keyword(s):  
Body Weight ◽  
Body Condition ◽  
Body Condition Score ◽  
Plasma Concentrations ◽  
The Body ◽  
Neck Length ◽  
Morphometric Measurements ◽  
Body Weights ◽  
Condition Score ◽  
Correct Determination

Abstract Background The main objectives of this study were to evaluate the accuracy of different body weight formulas for estimating body weight of Icelandic and Warmblood horses, as well as to assess the associations between the variables cresty neck score, body condition score, and plasma concentrations of leptin, insulin and cortisol. A total of 81 adult (≥ 4 years of age) horses (43 Icelandic and 38 Warmblood horses) was included in this study. The following morphological measurements were collected by two examiners simultaneously; body weight; height at withers; neck length; 0.5 neck length; neck circumference; umbilical circumference, two different heart girths, as well as two different body length measurements. The horse’s body weights were measured on a weight scale, and cresty neck scores were rated along with body condition scores using both the 0 to 5 and the 1 to 9 systems. Results In general, the concordance correlation coefficient was high for most formulas, but the mean bias and slope bias deviations varied between formulas. Some simple formulas using only heart girth, or heart girth and length can be used to estimate body weight of Icelandic and Warmblood horses as good as more complex formulas using four morphometric measurements. Plasma concentrations of leptin and insulin were higher (P < 0.001) for the Icelandic than the Warmblood horses, probably reflecting higher body fat content as suggested by the differences in body condition score. Conclusions Body weight formulas only give an estimate of body weight and not a completely correct determination. Some simple and more complex formulas can be used for Icelandic horses even though they are not developed for this breed. Complex formulas using four morphometric measurements were accurate, but simple formulas using only heart girth, or heart girth and length can be used to estimate body weight and thereby be applied to weight tapes and used to estimate the body weight of both Icelandic and Warmblood horses.

Mature body composition of the Gallego sheep breed of Galicia (north-west Spain)

1992 ◽  
Vol 1992 ◽  
pp. 179-179
Author(s):  
M. R. Cropper ◽  
N. Diaz
Keyword(s):  
Body Composition ◽  
Body Condition ◽  
Crude Protein ◽  
Dry Matter ◽  
Growth Parameters ◽  
Body Condition Score ◽  
North West ◽  
Condition Score ◽  
Ad Libitum ◽  
Mature Size

Taylor (1980) indicated the importance of mature size in the description of animals and its usefulness for standardising growth parameters. The mature size and body composition of the Gallego breed, a small meat-producing type first described by Mason (1967), have never been estimated under defined management conditions. Therefore, using the scaling rules and results of Thonney, Taylor, Murray and McClelland (1987) as a guide, a study was made to determine whether the reputation of Gallego lambs for producing lean carcases was borne out in the composition of mature animals.Twenty-one ewes (mean liveweight, LW, 32.7, sd 5.4 kg) and eight rams (LW 47.6, sd 8.6 kg) were selected as cast animals on the basis of age ( >4 years), body condition score (BCS, >1.75), health and teeth status and group-fed on concentrate (180 g crude protein/ kg dry-matter) and hay ad libitum. LW was measured fortnightly. When all animals had a LW and BCS which were stable for 2 months, 3 subgroups were slaughtered monthly. Weights of wool, body organs and hot carcase (HC) were recorded. Dissection of the cold carcase (CC) into commercial joints (Cabrero Poveda, 1984) and total lean, bone and fat.

The use of thyroxine to reduce average fibre diameter in fleece wool when feed intake is increased

2001 ◽  
Vol 41 (5) ◽  
pp. 611 ◽  
Author(s):  
G. J. Lee ◽  
K. J. Thornberry ◽  
A. J. Williams
Keyword(s):  
Saline Solution ◽  
Daily Intake ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Treatment Groups ◽  
Average Fibre Diameter ◽  
Wool Growth ◽  
Average Fibre ◽  
Ad Libitum ◽  
The Difference

An experiment was conducted to determine whether thyroxine injections would control the increases in fibre diameter when the wool growth of Merino wethers is stimulated by an increased supply of feed. Fifty-seven sheep were allocated to 1 of 5 levels of daily intake, ranging from 0.75 maintenance to ad libitum, and injected every third day with 3 mg of L-thyroxine or a saline solution (control). Sheep treated with thyroxine had elevated plasma tri-iodothyronine (T3) levels, which were highest in sheep fed the least (P<0.01). Ad libitum intakes of sheep treated with thyroxine tended to be higher than that of control sheep, particularly in the fifth to seventh weeks of the experiment, and liveweight gain over the initial 4 weeks was significantly (P<0.001) less. Wool growth was increased by thyroxine treatment, although the difference was small in the second half of the experiment at the highest intake levels. Fibre diameter of sheep treated with thyroxine was greater at low intakes, although the difference diminished as intake increased. Fibre length in the second half of the experiment was positively related to intake, but there were no effects of thyroxine. Although the relationships of fibre diameter and length with wool growth did not differ between the treatment groups, length accounted for more of the variation in wool growth in the second half of the experiment in treated wethers than in control wethers (0.376 v. 0.182 of the variation, respectively). Thyroxine did not appreciably reduce the extent of the increase in fibre diameter associated with an increase in the availability and intake of feed.

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