Skin folds and Merino breeding. 9. Efficiency of conversion of food to wool

1976 ◽  
Vol 16 (80) ◽  
pp. 361 ◽  
Author(s):  
GE Robards ◽  
CH Davis ◽  
DG Saville
Keyword(s):  
Surface Area ◽  
The Other ◽  
Or Efficiency ◽  
Wool Production ◽  
Skin Fold ◽  
Significant Difference ◽  
Ad Libitum ◽  
Ad Libitum Intake ◽  
Ad Libitum Feeding ◽  
Reduced Surface

This paper reports a study of the efficiency of wool production, liveweight change and ad libitum intake of 60 hogget ewes from flocks selected for 15 years for skin wrinkle (Folds Plus), against skin wrinkle (Folds Minus) and randomly selected as a control (Random). Initially, under restricted feeding ewes from each genetic flock consumed 594, 750, 951 or 1097 g DM day-1 of a lucerne pellet ration. The mean efficiency of clean wool production of Folds Minus ewes (8.47 g CW/kg D.M.I.) was less (P < 0.05) than that of either Random (9.38) or Folds Plus (10.18) ewes, which did not differ significantly. During the following ad libitum feeding period, the Folds Minus ewes again produced less wool than either of the other groups and their wool production was less efficient even though they consumed significantly less feed than either Random or Folds Plus ewes. The significant difference in intake between Random and Folds Minus ewes remained when the n takes were corrected for liveweight (kg), metabolic body size (kg0.73) or surface area based on liveweight alone (kg0.67). However, when fold score (FS) was included in the surface area estimate as LW0.67 + FS0.2 the intake difference between flocks became very small. The experimental results and components analyses of the pre- and post-shearing data showed that selection for skin fold had not changed wool growth rate or efficiency of wool production, but had reduced staple length. On the other hand, the lower wool production of Folds Minus ewes was due to both reduced surface area and lower wool production per unit area.

Efficiency of conversion of food to wool. III. Wool production of ewes selected for high clean wool weight and of random control ewes on restricted and unrestricted food intakes in pens

1968 ◽  
Vol 19 (6) ◽  
pp. 1009 ◽  
Author(s):  
CHS Dolling ◽  
LR Piper
Keyword(s):  
Wool Fibre ◽  
Group Differences ◽  
Energetic Efficiency ◽  
Restricted Feeding ◽  
Significant Group ◽  
Wool Production ◽  
Phenotypic Correlations ◽  
Significant Difference ◽  
Ad Libitum ◽  
Ad Libitum Feeding

The clean wool production (W), gross energy intake (I), and body weight (B) of individually fed medium Peppin ewes representative of two groups, one (selected, S) genetically superior in W to the other (control, C), have been measured under restricted and ad libitum feeding of lucerne chaff in pens. Differences in favour of the S group were observed for W and W/I under both regimes, the respective relative values of S/C being under restricted feeding 110/100 and 112/100, and under ad libitum feeding 113/100 and 112/100. Of these between-group differences, only W/I on restricted feeding was significant (P < 0.05). Differences between groups for B and I were small and not significant. On restricted feeding the S/C values were 98/100 for both; on ad libitum feeding they were 99/100 for B and 101/100 for I. When the data from the two feeding regimes were combined, the between-group differences in both W and W/I were significant (P < 0.05), but no significant group x nutritional level interaction was observed in any character. The two levels of nutrition in the pens yielded wool production rates similar to those observed contemporaneously on natural pastures. There were large positive phenotypic correlations between net efficiency (W/I under restricted feeding) and gross efficiency (W/I under ad libitum feeding), and between net efficiency and W under both regimes. There were also positive phenotypic correlations between I and both W (moderate) and B (large) under ad libitum feeding. W/I accounted for 92% of the between-group (genetic) and 70% of the within-group (phenotypic) variation in W. There was no significant difference in plasma protein-bound iodine (PBI) between S and C ewes, while correlations between W and PBI were not significant within either group. The energetic efficiency of the wool production process is discussed; in this experiment no more than 1.5% of the energy consumed appeared as energy in the form of wool fibre.

Growth of sheep to the age of three years after a severe nutritional check in early post-natal life

1997 ◽  
Vol 128 (4) ◽  
pp. 479-494 ◽  
Author(s):  
D. I. KRAUSGRILL ◽  
N. M. TULLOH ◽  
D. L. HOPKINS
Keyword(s):  
Body Weight ◽  
The Other ◽  
Semitendinosus Muscle ◽  
Protein Ratio ◽  
X Ray ◽  
Wool Production ◽  
Significant Difference ◽  
Ad Libitum ◽  
Grazing Sheep ◽  
Free Body

At Mount Derrimut Field Station from 1982 to 1985, growth and body composition was studied in three groups of wethers from the same flock. A control group (C) and a restricted group (R) were housed from the age of 1 day until slaughtered. The first slaughter was at the age of c. 1 year (reported elsewhere) and the second at the age of c. 3 years. Apart from the first 36 days, when group R was fed a severely restricted ration, both groups were fed a high quality diet ad libitum throughout the experiment. At the end of the second year, a group of 2-year-old wethers (G) was introduced, to compare the growth of these sheep with those in groups C and R. Group G sheep were reared on their dams, kept as grazing animals and killed at the second slaughter.At the age of c. 3 years there was no significant difference between groups C and R for mean fleece-free body weights, but the sheep in group G were significantly lighter (P<0·01) in spite of reaching mature size for grazing sheep in the general flock.After the age of 7 months there was no significant difference between groups C and R in rate of wool production. Rate of wool production in group G sheep was not significantly different from that of sheep in the other groups except during the last 6 months, when they produced significantly less wool (P<0·05).Regression analyses for surface and X-ray measurements against fleece-free body weight (independent variable) showed no differences between groups C and R, except for width of metacarpal (X-ray measurement). In this case, the regression coefficients were different (P<0·01) but, at slaughter, actual bone measurements were the same. Both X-ray measurements and those at dissection showed that the metacarpals of group G were significantly (P<0·05) longer and narrower, and had a narrower cortex, than those in the other two groups (P<0·05).There were no significant differences between groups C and R in mean weight and chemical composition of the parts and tissues examined; however, the carcass fat content of sheep in group G was significantly less (P<0·01) than in the other two groups. The sheep in group G had higher weights (P<0·01) for the brain, the digestive tract (DT), kidneys and liver than those in groups C and R.Cell size in the semitendinosus muscle, as indicated by the protein[ratio ]DNA ratio, increased (P<0·01) between the first and second slaughters. There were no differences between groups in protein[ratio ]DNA ratios, but the DNA and protein contents were significantly higher (P<0·05) in the kidneys and liver in group G than in the other groups. Although the weights of the semitendinosus muscle were heavier (P<0·01) in groups C and R than in group G, on a fat-free basis, there were no significant differences between treatments in muscle weight or in DNA and protein contents.It is concluded that sheep will make a complete recovery after a severe nutritional check in early post-natal life if given the opportunity to do so. Even though large differences in body weight may develop between sheep, this appears to have little effect on mature skeletal dimensions. However, at maturity, with grazing sheep that grow relatively slowly, the metacarpals are likely to be narrower and longer than those of the same genotype fed to grow faster. Even with sheep fed ad libitum throughout life, the use of X-ray and surface measurements in young sheep at a particular body weight are unlikely to be useful for the accurate prediction of mature body weight.

Daily changes in food availability, but not long-term unpredictability, determine daily torpor-bout occurrences and frequency in stripe-faced dunnarts (Sminthopsis macroura)

2015 ◽  
Vol 63 (1) ◽  
pp. 12 ◽  
Author(s):  
Alexandra M. Leslie ◽  
Mathew Stewart ◽  
Elizabeth Price ◽  
Adam J. Munn
Keyword(s):  
Food Availability ◽  
Control Period ◽  
Daily Torpor ◽  
Torpor Bout ◽  
Effect Of Food ◽  
Rapid Adjustment ◽  
Sminthopsis Macroura ◽  
Ad Libitum ◽  
Ad Libitum Intake ◽  
Ad Libitum Feeding

Daily torpor, a short-term reduction in body temperature and metabolism, is an energy-saving strategy that has been interpreted as an adaptation to unpredictable resource availability. However, the effect of food-supply variability on torpor, separately from consistent food restriction, remains largely unexamined. In this study, we investigated the effect of unpredictable food availability on torpor in stripe-faced dunnarts (Sminthopsis macroura). After a control period of ad libitum feeding, dunnarts were offered 65% of their average daily ad libitum intake over 31 days, either as a constant restriction (i.e. as equal amount of food offered each day) or as an unpredictable schedule of feed offered, varied daily as 0%, 30%, 60%, 100% or 130% of ad libitum. Both feeding groups had increased torpor-bout occurrences (as a proportion of all dunnarts on a given day) and torpor-bout frequency (average number of bouts each day) when on a restricted diet compared with ad libitum feeding, but torpor frequency did not differ between the consistently restricted and unpredictably restricted groups. Most importantly, torpor occurrence and daily bout frequency by the unpredictably restricted group appeared to change in direct association with the amount of food offered on each day; torpor frequency was higher on days of low food availability. Our data do not support the interpretation that torpor is a response to unpredictable food availability per se, but rather that torpor allowed a rapid adjustment of energy expenditure to manage daily fluctuations in food availability.

Effect of grain or silage supplementation on meat quality attributes of cryptorchid lambs grazing lucerne or annual grass-clover pastures

1995 ◽  
Vol 35 (4) ◽  
pp. 461 ◽  
Author(s):  
DL Hopkins ◽  
PJ Holst ◽  
DG Hall
Keyword(s):  
Meat Quality ◽  
Shear Force ◽  
The Other ◽  
Carcass Weight ◽  
Annual Grass ◽  
Eye Muscle ◽  
Mean Values ◽  
Significant Difference ◽  
The Mean ◽  
Ad Libitum

Objective and subjective tests for quality were performed on the meat from 40 cryptorchid second-cross lambs fed lucerne only (L; n = 8), lucerne plus an oat grain supplement ad libitum (LO; n = lo), lucerne plus wilted lucerne silage ad libitum (LS; n = 11), or an oat-lupin grain (3:1) supplement at 90% of ad libitum while grazing dry summer annual pasture (OL; n = 11). All carcasses complied with the Elite lamb specification of weight >22 kg and GR measurement 6-15 mm. There was no significant difference between groups for hot carcass weight, the mean (� s.e) values being 25.1 0.43, 25.2 � 0.36,25.2 � 0.38, and 25.3 � 0.36 kg for L, LS, LO, and OL groups, respectively. When the GR and fat depth over the eye muscle at the 12th rib were adjusted to a common carcass weight of 25.2 kg there was no significant difference between groups. There was no significant difference between groups for pH, or the colour values a*, b*, and L* of the M. longissimus thoracis et lumborum (a* is relative redness, b* relative yellowness, and L* relative lightness). The shear force values for the loin muscle were significantly (P<0.05) greater for lambs from group OL than for those from group LO. Cooking loss for the loin muscle was significantly (P<0.05) greater for OL lambs than all other groups. A comparison of the mean values for aroma and flavour showed the lambs from group OL produced meat that was considered significantly (P<0.05) less desirable for these characteristics, with other groups being similar. Meat from OL-fed lambs was considered oilier and less meaty than meat from lambs fed the other diets. There was a significant (P<0.05) difference in absolute scores between panellists, but their ranking was not affected and there was no panellist x sample interaction. Because many producers use grain supplements such as oats and lupins for finishing lambs on dry forages, further study is recommended that focuses on the interaction between supplement and the base forage.

Effect of the liveweight of caged sheep and the amount of feed on offer on estimates of digestibility and ad libitum intake

1976 ◽  
Vol 16 (82) ◽  
pp. 656 ◽  
Author(s):  
H Jeffery
Keyword(s):  
Field Data ◽  
Dry Matter ◽  
Significant Positive Correlation ◽  
The Other ◽  
Great Care ◽  
Dry Matter Digestibility ◽  
Cent Increase ◽  
Kikuyu Grass ◽  
Ad Libitum ◽  
Ad Libitum Intake

Three experiments were conducted in which the amount of feed offered to caged sheep was varied. Fresh kikuyu grass (Pennisetum clandestinum) was fed in one experiment and hays in the other two. Within each experiment a significant correlation between dry matter digestibility and liveweight occurred; no differences were detected between the slopes found with the various diets (slope = 0.34 per cent increase in digestibility per kg liveweight). Up to 60 per cent more kikuyu grass was offered to sheep than they could consume. Over this range a significant positive correlation was found between the ratio of the unconsumed to consumed feed and digestibility. This result indicates that great care should be exercised if the results of sheep digestibility experiments are used to interpret field data.

Responses to supplements by weaned lambs grazing mature pasture or eating hay in yards

1985 ◽  
Vol 25 (2) ◽  
pp. 289 ◽  
Author(s):  
M Freer ◽  
H Dove ◽  
A Axelsen ◽  
JR Donnelly ◽  
GT McKinney
Keyword(s):  
Substitution Rate ◽  
Poor Performance ◽  
Sunflower Meal ◽  
Wool Production ◽  
Grazed Pasture ◽  
Significant Difference ◽  
Ad Libitum ◽  
Stocking Rates ◽  
Daily Gain ◽  
Supplement Intake

Weaned crossbred lambs grazing mature pasture in summer at stocking rates of 14, 28 or 42 lambs/ha were supplemented for 60 days with 0, 400, 600 or 800 g/day of either sunflower meal or a 1:1 mixture of sunflower meal and oats. Mean daily gains in fasted weight without and with supplement were - 51 and 62 g, respectively, with no significant difference between the three feeding levels. Greasy wool production increased from 4.7 g/day without supplement to 9.9 g/day at the 600 or 800 g level but the composition of the supplement had no effect. Stocking rate had no effect on animal performance. It was estimated that pasture intake increased slightly with the first 400 g of supplement but fell sharply as the level increased further, with a substitution rate of 1.3. In two experiments, yarded lambs were offered oaten or lucerne hay ad libitum and mixtures of sunflower meal and oats at levels from 400 g/day to ad libitum. Mean daily gain in fasted weight increased from about 140 to about 190 g/day over this range of supplementation and greasy wool production from about 9 to about 10 g/day. In one experiment weight gain and wool production were significantly lower with a 1:6 mixture of sunflower meal and oats than with a 1:2 mixture and the same trend was shown in the other experiment. Measurements of intake showed that the substitution rate for both types of hay was only about 0.5. Comparisons of the animals' estimated requirements and intake in all three experiments indicated that the relatively poor performance of grazing animals was due to the very high substitution rate for grazed pasture at levels of supplement intake above 400 g/day.

Formaldehyde as a silage additive. II. The chemical composition and nutritive value of lucerne hay, lucerne silage, and formaldehyde and formic acid-treated lucerne silages

1973 ◽  
Vol 24 (6) ◽  
pp. 939 ◽  
Author(s):  
SC Valentine ◽  
DC Brown
Keyword(s):  
Formic Acid ◽  
Dry Matter ◽  
Nutritive Value ◽  
Similar Degree ◽  
Fresh Weight ◽  
Wool Production ◽  
Wool Growth ◽  
Ad Libitum ◽  
Ad Libitum Intake

Formaldehyde-treated silage, formic acid-treated silage, formaldehyde-formic acid-treated silage, untreated silage, and lucerne hay were made from a lucerne sward and offered to Merino wethers. The formaldehyde was applied at a rate of 0.9 % of the weight of the dry matter and formic acid at 0.5 % of the fresh weight of the lucerne. Formaldehyde-treated silage and formaldehyde-formic acid-treated silage had significantly lower concentrations of ammonia nitrogen and total and individual organic acids than untreated silage. Formic acid-treated silage had a similar degree of fermentation to untreated silage, but more acetic acid and less lactic acid were produced than in untreated silage. However, when formic acid was applied in combination with formaldehyde, the ensiling fermentation was inhibited more than when formaldehyde was applied alone. There was some apparent protection of protein by the formaldehyde treatment. Treatment with formic acid significantly increased the in vivo digestibility of both nitrogen and dry matter, but did not increase ad libitum intake or wool growth by sheep offered this silage. Compared to untreated silage, treatment with formaldehyde significantly reduced the in vivo digestibility of nitrogen, produced a non-significant increase in intake, and significantly increased wool growth. The treatment of lucerne with both formaldehyde and formic acid significantly increased in vivo digestibility of dry matter, ad libitum intake, and wool growth compared with untreated silage. The treatment of lucerne with a mixture of formaldehyde (0.9% of the dry matter) and formic acid (0.5% of the fresh weight) was a suitable method of controlling the ensiling fermentation in order to increase the ad libitum intake of lucerne silage by sheep and their subsequent wool production. However, the intake and wool production of sheep offered such silage was still significantly less than that of sheep offered lucerne hay.

scholarly journals Novel energy-saving strategies to multiple stressors in birds: the ultradian regulation of body temperature

2016 ◽  
Vol 283 (1839) ◽  
pp. 20161551 ◽  
Author(s):  
Glenn J. Tattersall ◽  
Damien Roussel ◽  
Yann Voituron ◽  
Loïc Teulier
Keyword(s):  
Body Temperature ◽  
Multiple Stressors ◽  
Energetic Cost ◽  
Short Term ◽  
Ad Libitum ◽  
Key Sites ◽  
Ad Libitum Feeding ◽  
Reduced Surface ◽  
Internal Body

This study aimed to examine thermoregulatory responses in birds facing two commonly experienced stressors, cold and fasting. Logging devices allowing long-term and precise access to internal body temperature were placed within the gizzards of ducklings acclimated to cold (CA) (5°C) or thermoneutrality (TN) (25°C). The animals were then examined under three equal 4-day periods: ad libitum feeding, fasting and re-feeding. Through the analysis of daily as well as short-term, or ultradian, variations of body temperature, we showed that while ducklings at TN show only a modest decline in daily thermoregulatory parameters when fasted, they exhibit reduced surface temperatures from key sites of vascular heat exchange during fasting. The CA birds, on the other hand, significantly reduced their short-term variations of body temperature while increasing long-term variability when fasting. This phenomenon would allow the CA birds to reduce the energetic cost of body temperature maintenance under fasting. By analysing ultradian regulation of body temperature, we describe a means by which an endotherm appears to lower thermoregulatory costs in response to the combined stressors of cold and fasting.

A comparative study of Hereford and Friesian steers. 2. Carcass characteristics and meat quality

1982 ◽  
Vol 33 (1) ◽  
pp. 157 ◽  
Author(s):  
DG Taylor
Keyword(s):  
Comparative Study ◽  
Meat Quality ◽  
Carcass Characteristics ◽  
Fat Content ◽  
The Other ◽  
Bone Content ◽  
Retail Meat ◽  
Ad Libitum ◽  
Dressing Percentage ◽  
Ad Libitum Feeding

Two trials, each involving four Hereford and four Friesian steers, were finalized with the slaughtering of the animals and comparison of their carcass characteristics and meat quality. One trial involved hand-feeding the animals to achieve a constant liveweight gain of 0.68 kg/day from 6 months of age to slaughter at 15 months of age; the other trial used animals of the same age, but on ad libitum feeding. Carcass data substantiated the subjective observation that the Friesian carcasses were longer, less compact and displayed less desirable 'beef type' conformation than those of the Hereford. The dressing percentage of the Friesians was significantly (P < 0.01) lower than that of the Herefords. The Hereford carcasses had a significantly greater fat content than the Friesians, but lower percentages of both muscle and bone. The Hereford produced the greater yield of boneless retail meat (not fat trimmed), which could be attributed to their greater carcass fat and lower carcass bone content. The meat from both breeds was of equivalent palatability when assessed subjectively for tenderness, juiciness and flavour, and objectively for tenderness.

The digestion of chopped and ground roughages by sheep. I. Movement of digesta through the stomach

1967 ◽  
Vol 18 (5) ◽  
pp. 789 ◽  
Author(s):  
RH Weston ◽  
JP Hogan
Keyword(s):  
Retention Time ◽  
Metabolizable Energy ◽  
Water Soluble ◽  
Ad Libitum ◽  
Ad Libitum Intake ◽  
Ad Libitum Feeding

Digestion studies were conducted with lucerne hay and wheaten hay prepared for feeding either by chopping or by grinding and pelleting. The sheep were offered food every 3 hr. The rates of flow of water and the rumen volumes were measured by reference to a water-soluble marker. The replacement of a diet of chopped roughage by an equal amount of ground roughage caused a decline in the rate of flow of water from the rumen. With wheaten hay this decreased flow was accompanied by a decline in rumen volume, the retention time of the marker in the rumen remaining constant; with lucerne hay the rumen volume remained constant and the retention time of the marker increased. When the quantity of ground roughage feed was increased, rates of flow from the rumen and abomasum were enhanced and marker retention time in the rumen decreased. Under conditions of ad libitum feeding, the sheep consumed 75% more chopped lucerne hay than chopped wheaten hay; grinding was accompanied by an increase of 50% in the consumption of each hay. When levels of feeding were approximately 90% of the ad libitum intake, it was found that: (i) the rate of flow from the rumen appeared to be independent of diet and method of preparation of the feed; (ii) the rate of flow from the abomasum was higher with the ground roughage; (iii) rumen volume with ground lucerne hay was higher than with chopped lucerne hay or ground wheaten hay; it was also higher with chopped wheaten hay as compared with ground wheaten hay. Sheep spent less time ruminating and eating when the roughages were ground. The amount of metabolizable energy available for production from 1000 g of ground lucerne hay was 950 kcal; it was calculated that this would have declined by 9% if the sheep ruminated for the same time on this ground hay as on the chopped hay.

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