Wool Weight Research Articles

Applications of porous flow through electrodes. II. Hydrogen evolution and metal ion removal at packed metal wool electrodes

Packed metal wool electrodes have been used for producing hydrogen electrolytically and for removal of Cu2+ ions from a flowing electrolyte stream. Current-potential relations for the two reactions were measured under various operating conditions. The polarization behaviour of the packed wool electrodes has been characterised and interpreted. The effects of pore electrolyte resistance and bed thickness on the polarization of the hydrogen evolution reaction were evaluated and interpreted in terms of an existing model. The effect of the generated gas bubbles on the pore electrolyte resistance is the underlying reason for the measured excessive ohmic potential drops. It has been shown that wool-packed electrodes perform better than, or at least as well as, particle-packed electrodes (turnings, wirelets, small cylinders). The weight of metal wool needed to achieve these results is only about 10% of the weight of the metal particles. The mass transfer at the packed wool electrode has been analysed.

Effect of breed of dam, type of birth and sex of lamb on efficiency of conversion of food to lamb and wool in Merino, Poll Dorset × Merino and Border Leicester × Merino ewes

The effects of breed of dam (South Australian Merino (M), Border Leicester x Merino (BL x M) and Poll Dorset x Merino (PD x M)), type of birth (single and twins) and sex of lamb (wether and ewe) on the efficiency of the ewe (organic matter intake per unit (liveweight)0.75 and clean wool weight per unit intake) and of the ewe-lamb(s)) unit (liveweight and carcass weight per unit intake) were examined in two pen experiments (PE1, PE2) and a grazing experiment (GE). Each single-born lamb in PE1 and PE2 was slaughtered at weights =32 and =35 kg, respectively, and twin-born lambs when their combined weight doubled that of singles. In GE all lambs were slaughtered on the same day at 35.5 kg mean liveweight. Ewes rearing twins ate 19% more (P < 0.05) organic matter per unit (liveweight)0.75 during lactation than those rearing singles, the other effects of breed and sex were not significant during either late pregnancy or lactation. BL x M ewes grew 32% less (P < 0.001) clean wool per unit intake than did M ewes in PE, whereas the breed difference in GE was not significant, PD x M ewes grew 39% less wool than M ewes in GE (P < 0.001). Ewes rearing twins were 23% less efficient in converting food to wool than those rearing singles in PE, (P < 0.01), the corresponding difference in GE was not significant. There were no significant differences between breeds of dam for efficiency of the ewe-lamb unit when lambs were compared at the same age. However, when lambs were grown to the same liveweight the M ewe-lamb unit produced 14% (P < 0.001) and 8% (P < 0.05) more liveweight and carcass weight per unit intake than the BL x M in PE,. These results include adjustment for the effects of type of birth and sex. In all experiments ewes with twin lambs were about 45-55% and 35-45% more efficient than those with singles on a liveweight and carcass weight basis, respectively (P < 0.001), the effects were independent of whether the lambs were at the same age or the same liveweight. We conclude that efficiency of conversion of food to carcass weight on a flock basis will be largely dependent on variation in reproduction rate and to a lesser extent on breed of dam, and on breed of dam only when lambs are slaughtered at the same liveweight. In contrast, the effects of breed of dam on efficiency of food conversion to wool fibre were large.

Resistance to cold stress in the newborn lamb 2. Role of body weight, birth rank, and some birth coat characters as determinants of resistance to cold stress

Abstract The effects of body weight and birth rank on resistance to cold stress were examined in Romneytype and Nd-type lambs. Twins exhibited lower coat depths than singles and they also appeared to have a lower summit metabolic rate per kg body weight. These effects were, however, small and the greater rate of body cooling experienced by twin lambs was principally a function of their low body weights. Sire of .the lamb exerted a small influence on its body weight and coat depth but these differences were not translated into a corresponding effect on the rate of decline in rectal temperature. Nd-type lambs had significantly greater coat depths and midside wool weights (per unit area of skin) than Romney-type lambs. The metabolic rate required by the lamb to maintain deep-body temperature was significantly related to coat depth (b = - 0.14 W Ikglmm) but not to midside wool weight. Rate of decline in rectal temperature was also low in deep-coated lambs. Most of the difference between Romney-type and Nd-typ...

A novel approach to growth promotion using auto-immunisation against somatostatin. I. Effects on growth and hormone levels in lambs

Nine three-week-old lambs were immunised against somatostatin linked to human serum globulin. Significant antibody titres were obtained in all these lambs. The rate of weight gain was greater in those animals immunised against somatostatin (treated) than in the control animals which were immunised against globulin alone ( P < 0.001). The final height of the treated lambs was also significantly greater ( P < 0.05) as a result of increased height velocity during the period of treatment ( P < 0.01). Evaluation of the animals both before and after slaughter indicated that there was no effect of treatment upon body composition, but rather that there had been proportional growth. The carcass assessments revealed that the treated lambs had a longer leg-length ( P < 0.01) and had a greater warm carcass weight ( P < 0.05) than the control animals, but had similar scores for fat and muscle covering. There was no difference in wool weight between the two groups. No significant difference was found between the groups in the basal levels of either insulin or growth hormone. However, growth hormone release following arginine infusion was greater in the treated animals. There was also a small, but significant, difference ( P < 0.05) in the levels of bioassayable somatomedin activity between the treated and control lambs, the treated lambs having higher somatomedin activity. Histological examination of the pancreas from control and treated lambs revealed an increased incidence of abnormalities (mainly acinar necrosis and loss of beta-cell staining) in the islets of Langerhans in the treated lambs, but it could not be concluded that auto-immunisation against somatostatin produced any specific morphological change in the betacells of the pancreatic islets. The results of this study suggest that somatostatin plays an important physiological role in regulating growth stimulation. Removal of the inhibitory effect of somatostatin (in this case by neutralisation of the effect with antibodies) can result in increased growth. The hormonal changes induced by this treatment have yet to be fully elucidated. Further investigations are required to assess the usefulness of this treatment as an alternative to the more conventional synthetic steroid treatments for growth promotion.

Desenvolvimento e produtividade de algodoeiros sob efeito de reguladores vegetais

Neste trabalho efetuaram-se estudos para determinar os efeitos de reguladores vegetais em algodoeiro Gossypium hirsutum L. cv. IAC-17, através da análise de crescimento e produtividade em plantas submetidas a diferentes dosagens e épocas de aplicação de reguladores vegetais. Para conhecimento do desenvolvimento, produção, características agronômicas dos algodoeiros e características tecnológicas das fibras, sob ação de reguladores vegetais, realizou-se em Piracicaba (SP) na safra 1978/79 um experimento sob condições de campo, em uma área de 1700 m², onde foi implantada a cultura. Trataram-se os algodoeiros com: cloreto -1,1 - dimetil piperidíneo (DPC) nas concentrações de 84, 167 e 250 ppm; cloreto (2-cloroetil) trimetilamônio (CCC) nas concentrações de 250, 350 e 450 ppm e ácido (2 - cloroetil) fosfônico (CEPA) nas concentrações 1670, 3340 e 6680 ppm, sendo cada substância aplicada a 51, 65 e 143 dias após a germinação, respectivamente. Realizaram-se os tratos culturais normais recomendados para a cultura. Os resultados indicam que DPC e CCC tendem a reduzir a altura das plantas e o diâmetro da copa. Aplicações de DPC não afetaram os parâmetros da análise de crescimento do algodoeiro, sendo que CCC 25O ppm reduziu a área foliar e o peso da matéria seca. O índice de área foliar foi diminuído por 28 dias com aplicações de CCC 250 e 350 ppm, sendo que a menor concentração reduziu a eficiência fotossintética nas plantas e as concentrações mais elevadas de CEPA e CCC tenderam a diminuir o número de capulhos e o peso de algodão em caroço. CCC 350 ppm aparentemente aumentou o peso médio do algodão por capulho, enquanto CEPA 6680 ppm tendeu a reduzi-lo. Em cada tratamento, o peso das sementes e a porcentagem de fibras amostradas em 50 g de algodão em caroço,bem como o peso de 100 sementes, não foram afetados pela aplicação de CCC, DPC e CEPA. Também as características tecnológicas das fibras não foram afetadas pela aplicação dos reguladores vegetais.

Investigations on cellulose biodegradation in activated sludge plants

Cellulose is the major carbon substrate entering treatment plants for municipal waste waters. In the present investigation an attempt was made to study its degradation in activated sludge. Cellulolytic micro‐organisms were enumerated in different treatment plants and at one plant they were assessed after different steps over a period of about 1 year. The degradation of cellulose contained in Nylon bags suspended in the mixed liquor was also studied and the activities of cellulase components were assayed. Finally, the concentrations of cellulose and lignin in the suspended solids taken from different treatment steps were determined. The results showed that active cellulolysis occurred in activated sludge. The degradation was mainly bacterial, although no significant enrichment of such bacteria was found in the sludge floc. Cellulase activity, however, showed an increase. Experiments with the Nylon bag indicated that 60% of the weight of cotton wool was degraded in 4–5 weeks. It was concluded that about 60% (w/w) of the cellulose entering the system could be degraded by bacteria during aerobic treatment, while 50–60% of that present in the surplus activated sludge was degraded during anaerobic sludge digestion.

Effect of breed of dam and lamb, and of lamb sex on efficiency of conversion of food to lamb and wool in Merino and first-cross Merino ewes

The effects of breed of dam (Merino (M), Border Leicester x Merino (BL x M) and Poll Dorset x Merino (PD x M)), breed of lamb (Suffolk sired (S)) and sex of lamb (castrate male, female) on the efficiency of the ewe (organic matter intake per unit metabolic weight and clean wool weight per unit intake) and on the efficiency of the ewe-lamb unit (liveweight and carcass weight per unit intake) were examined. The effects of breed of dam and breed of lamb were differentiated by a system of cross-mothering of all lambs at birth. Each lamb was slaughtered at = 35 kg liveweight. The two crossbred types ate less organic matter per unit metabolic weight than did M dams during late pregnancy, but there were no differences during lactation. Compared with the absolute intake of M dams, PD x M and BL x M ewes ate 11 and 18 % more throughout the experimental period (224 days). The conversion efficiencies of food to wool of PD x M and BL x M dams were 59 and 66 % of that of Merinos. There were no significant differences between breeds of lamb or between lamb sexes for either intake per unit metabolic weight or clean wool growth per unit intake of the ewe. There were no significant differences between breeds of dam or between lamb sexes for either lamb liveweight or carcass weight per unit intake. This applied whether the lambs were at the same age or at the same liveweight. Ewes rearing S x (PD x M) and S x (BL x M) lambs had higher carcass weights per unit intake than did those rearing S x M lambs.

Influence of weaning age, management, and slaughter age on export lamb carcass production and slipe wool weights

Abstract A series of five experiments was conducted over a period of 4 years with lambs weaned at 4, 5, 6, 9, 12, 15, or 18 weeks of age. Management treatments included restricted milk intake, creep grazing, rotational grazing, and set stocking. Slaughter ages ranged from 12 to 30 weeks. Early weaning at 4, 5, or 6 weeks caused varying post-weaning growth checks, lasting from 1 to 4 weeks, the most severe following 4-week weaning in the absence of creep grazing. Subsequent growth rates were similar to those for later-weaned lambs. Weaning lambs at 9 weeks of age resulted in similar final live weights to those obtained by weaning at 12 or 15 weeks. The reductions in final slaughter weights caused by early weaning (up to 21%) were associated in some experiments with lower killing-out percentages and reduced carcass fat. In one experiment, where treatments were compared at a common carcass weight of 17.5 kg, 4-week weaning resulted in 2–5% lower levels of chemical carcass fat and up to 4% and 1% higher values for water and protein respectively than in later-weaned lambs. Creep grazing in association with early weaning tended to minimise the growth check. Restricted milk intake before weaning at 5 weeks of age caused a prolonged growth reduction followed by no compensatory growth. Set stocking resulted in heavier weights for both early- and late-weaned lambs. A liberal supply of milk and grass before early weaning and the lack of subsequent compensatory growth are discussed. Favourable reasons for early weaning include reduction of carcass fat and removal of competition by ewes under conditions of feed shortage. The practice can also be used in association with sheep dairy production, accelerated lambing, or progeny test programmes. It is recommended that the conventional lamb weaning age be reduced to about 9 weeks.

Economic comparison of open and closed nucleus breeding schemes for wool production

Returns on investments in open or closed nucleus breeding schemes to improve clean wool production were examined using Hill's approach of examining the flow of genes through the population. Returns on capital in such schemes are competitive with many alternative investments on the farm if predictions of response are correct. For example, for a typical case considered with heritability of wool weight of 0·4, standard deviation of 0·4 kg, 90% lambs weaned per ewe joined from mature ewes, and 250 cents/kg clean, marginal returns on money invested in labour and materials in the breeding programme in excess of 40% were obtained. The return on the extra investment with an open nucleus using 50% of base-born ewes in the nucleus was about 20%. Returns are sensitive to cost, lambing percentage, price and heritability, the extra returns from the open nucleus becoming more attractive as predicted response or price increases. The value of the gains is not very sensitive to numbers of age groups of ewes or rams. Most of the extra returns go to the commercial flocks, so premiums would need to be paid to the nucleus to provide incentives to maintain the breeding programme.

The comparative productivity of five ewe breeds. 2. Hogget wool production

This paper contains information on the fleece characteristics of hogget ewes from five breeds in each of seven years at Temora Agricultural Research Station. Measurements of greasy fleece weight, clean scoured yield and the components of clean fleece weight were made on the following breeds: a Border Leicester x Merino fixed halfbred (BLM), Corriedale, Polwarth, a South Australian strong wool (S.A. Merino) and a medium wool Peppin strain of Merino. Average annual clean fleece weights were 3.53, 3.53, 3.04, 2.77 and 2.70 kg for the S.A. Merino, Corriedale, BLM, Peppin Merino and Polwarth breeds respectively. Average fibre diameters of these breeds were 23.1, 25.1, 27.2, 20.3 and 22.1 pm respectively. An interaction between breeds and years for clean fleece weight was associated with larger differences between the breeds in the years when environmental conditions favoured higher average clean fleece weights. Differences between breeds were large in all the components of clean fleece weight. Within breeds, the contribution of variation in follicle number to variation in clean wool weight was relatively greater in the Polwarth and Peppin Merino breeds than in the Corriedale and S.A. Merino breeds, with the BLM breed intermediate. The converse ranking applied to variation in fibre volume as a contributor to variation in clean wool weight within breeds.

Grazing irrigated pasture with sheep: Effect of winter management on pasture regrowth

Abstract Three systems of rotational grazing, shifting every 2, 4, or 7 days, were compared with ‘ration’ grazing over two winters. The ration-grazed ewes were kept on a run-off and allowed to graze the next paddock for 1/2 h per day in June, 1 h in July, and 2 1/2 h in August. When each paddock had been grazed, it became the run-off while the next paddock was grazed. Pasture residue after grazing in the ration-grazed treatment averaged 220 kg DM/ha compared with a mean of 350 kg DM/ha on the rotation treatments. Winter regrowth over 2 years averaged 10.0 kg DM/ha/day on the ration treatment and 12.8 kg DM/ha/day for the rotation treatments. Wool weights and lamb birth weights were not affected by winter grazing management but in the rotation treatments ewe live-weight gain in winter increased with grazing duration, averaging 5.3 kg, 6.2 kg, and 6.8 kg on the 2, 4, and 7 day shifts respectively. The ration-grazed ewes gained 5.7 kg each winter.

MANAGEMENT CHANGES WITH THE INTENSIFICATION OF FARMING THE PUMICE LANDS OVER THE LAST TEN YEARS

The reasons for the large changes in pumice land farming systems over the last 10 years are outlined and the resultant increases in production presented. The large increases in district milkfat production and milkfat per cow are attributed to management changes such as later calving, shorter lactation, winter management, and the grazing of lucerne. Changes in sheep farm management such as later lambing, earlier weaning, grazing of lucerne, the use of rotational grazing, and a decline in beef cattle are outlined. Lambing percentages have increased, but wool weights are static. Future management changes that farmers should follow are outlined.

Effect of selenium supplementation on survival, liveweight and wool weight of young sheep on Kangaroo Island, South Australia

The responses in liveweight, wool weight and survival, to selenium supplementation, were studied in young sheep from weaning to yearling age. The experiment was conducted over three years. In the first year, one sodium selenite supplementation rate was used (total dose 46.5 mg). During the following two years two supplementation rates were administered (total doses 46.5 mg and 93 mg). Mean concentrations of selenium in whole blood in unsupplemented sheep varied from 0.19-0.56 pmol l-l and from 0.20-0.44 pmol l-1 in the two years in which concentrations were measured. Supplementation, which commenced at lamb marking, increased the selenium concentration in sheep at weaning and thereafter. Selenium supplementation improved the break-of-season weight (P &lt; 0.01) and yearling weight (P &lt; 0.01 ) but not weaning weight (0.05 &lt; P &lt; 0.1 ). Hogget fleece weight was improved (P &lt; 0.01 ) and mortality reduced (P &lt; 0.01) by selenium supplementation. There was a treatment x year interaction in mortality rates (P &lt; 0.01 ). There were no significant differences between the two supplementation rates

Seasonal wool production of Romney, Coopworth, Perendale, Cheviot, and Corriedale wethers

Abstract Seasonal wool production of Romney, Coopworth, Perendale, Cheviot, and Corriedale wethers born in 1969 and 1970 was studied for 4 and 3 years respectively. Weight of clean wool per midside patch at 28- or 56-day intervals, fibre diameter, and live weight were recorded from approximately 20 weeks of age. Live-weight change with season was similar for all breeds. A marked seasonal variation in wool production and fibre diameter on the midside patch occurred after animals reached 1 year of age. Clean wool growth from the patch was 3.3, 3.1, 3.0, 2.8, and 2.7 times greater for Perendale, Coopworth, Romney, Corriedale, and Cheviot respectively in summer than in winter. Summer fibre diameters were 1.3–1.4 times those of the winter diameters. Breed differences for weight of clean wool per patch and fibre diameter were most pronounced in the periods of higher wool growth rates.

Wool and leather production from 15-month-old wethers of different breeds on hill country

Abstract Skins from 120 15-month-old wethers born in two seasons were used in two fellmongering and tanning trials. The breeds represented were Romney, Border Leicester × Romney Perendale, Cheviot, Dorset × Romney, Drysdale, Drysdale × Romney, and Merino × Romney. Differences between breeds were significant in both trials for skin weight and slipe wool weight. Romney gave similar slipe wool weight to Drysdale × Romney and Merino × Romney in trial 1 and similar to Border Leicester × Romney in trial 2. Perendale and Dorset × Romney skins produced less slipe wool than other breeds in trial 2, Cheviot ranking lowest in both trials. Leather of best quality was produced by Romney and Drysdale × Romney in trial 1 followed by Cheviot and Perendale, Drysdale and Merino × Romney producing a poor quality product. In the second trial, raising the liming temperature improved leather quality of Romney, Dorset × Romnty, Border Leicester × Romney, and Perendale skins. Perendale skins showed greatest benefit from the higher liming temperature. As heavier animals produced larger leather areas, any change which resulted in heavier animals would clearly benefit the fellmongering and tanning industries. Drysdale would be an exception because of lower leather quality and Cheviot because of lower wool production.

Wool production of yearling ewes of different breeds on hill country

Abstract Wool production data were obtained from 1303 ewe hoggets (13 months of age) of Romney, Coopworth, Perendale, and Cheviot breeds from 1970 to 1974. All hoggets had previously been shorn as lambs at 3 months of age. Mean greasy fleece weights were: Romney 2.65 kg, Coopworth 2.71, Perendale 2.46 kg, and Cheviot 1.83 kg. Mean fibre diameters were: Romney 30.8 µm, Perendale 31.0 µm, Cheviot 31.1/tm, and Coopworth 32.2 µm. Coopworth had the greatest weight of clean wool per unit skin area followed in decreasing order by Romney, Perendale, and Cheviot; Romney produced the greatest weight of wool per unit body weight followed in decreasing order by Coopworth, Perendale, and Cheviot. Body weights were: Romney 28.2 kg, Coopworth 32.8 kg, Perendale 32.6 kg, and Cheviot 32.1 kg. Hoggets reared as singles were 1.7 kg heavier in body weight and produced 0.09 kg more greasy wool than those reared as twins. Most parameters of wool production increased with age of the hogget at shearing. Returns per sheep from th...

The assessment of air-inlet filters for intravenous infusions in glass bottles

Glass infusion bottles require the influx of air into the containers to replace fluid during administration. A non-absorbent cotton wool plug, situated in the air-inlet set, acts as a filter to remove airborne micro-organisms. an enclosed air space artificially contaminated with viable bacterial spores was used to assess the contamination of intravenous infusions from an airborne source. Only small numbers of spores gained access to the infusion fluids when containers were used with commercially made air-inlet sets. Removal of the filter permitted the entry of spores, the numbers being related to the concentration present in the external air. The efficiency of cotton wool plugs was related to the weight of cotton wool in the air-inlet set. The compression applied to the cotton wool also significantly influenced filter efficiency. Although air-inlet sets were challenged with much higher levels of airborne contamination than would be expected in a hospital environment, results indicate that the air-inlet set should contain sufficient cotton wool. The compression of the filter material should also be considered.

Index selection for both current and future generation gains

ABSTRACTWhen economic returns from current and future generation gains are comparable in magnitude, selection decisions should take account of both sources of gain. A combined selection index is devised to maximize the present value of discounted returns from all sources. The index depends on genetic and phenotypic variances and covari-ances, population structure, discount rate and the relation of annual returns to individual traits. The combined index can be regarded as the sum of separate indices maximizing returns from each source. The method is illustrated with a simple example using wool weight and body weight in sheep.

Response to selection in Australian Merino sheep. VIII.* Further results on selection for high clean wool weight with attention to quality

Results of selection for high clean wool weight per head with control of quality are reported for two selection groups over the period 1966–74. Results for the same experiment for the periods 1950–1959 and 1961–64 were reported earlier. Both groups were selected for high clean wool weight, one (S) with a ceiling on fibre diameter and degree of skin wrinkle, and the other (MS) with a lower limit on staple crimp frequency and a ceiling on skin wrinkle. Genetic progress in clean wool weight was greater in S than in MS over the 1966–74 period (0.12–0.15 lb/annum, compared with 0.06–0.09). This was to be expected from genetic correlations of clean wool weight with fibre diameter (low positive) and staple crimp frequency (high negative). The result supports the previous recommendation that staple crimp frequency is an inefficient way of controlling wool quality while attempting to improve quantity by selection, because its use severely restricts the likely progress in quantity. The actual rate of progress in the S group was similar to that in the period 1950–59, which was followed by a fall in superiority of the selected over the control group animals born during 1961–64. The recovery of response in the 1966–74 period negates the suggestion that the loss of response during the 1961-64 period was due to a 'plateau'. The most likely explanation is that a genotype x environment interaction occurred, such that the genetic gain made in the 1950-59 period could not be expressed in the poorer environments of 1960–65, but reappeared gradually under the improving environment of the 1966–74 period. Attempts to remove this interaction by regression of response on the mean clean wool weight of the unselected control group (as an index of the level of the environment) for each year, were not successful. The interaction is, therefore, not simply a case of all selection groups being equal when the environment is poor. ________________ *Part VII, Aust. J. Agric. Res., 26: 937 (1975).

The use of dyebanding for measuring wool production and fleece tip wear in rugged and unrugged sheep

Forty fine-wool Merinos grazed sown pastures and 40 grazed on weedy unimproved areas for 2 years. The sheep were dyebanded at intervals, and the weight of wool lost from the fleece tip was estimated from sequentially harvested sets of staples. Half the sheep in each group were fitted with woven polyethylene coats. In year 1, an estimated 4.2% of wool grown was lost from the fleece tip of unrugged sheep and 7.0% in year 2; losses from rugged sheep were 1.2 and 1.8 respectively. However, rugging had no effect on the quantity of clean scoured wool harvested each year, as rugged sheep grew slightly but consistently less wool than the controls. Rugging increased the percentage of clean scoured wool obtained from fleeces in the poor environment by 6 percentage points, but did not affect it on good pastures. Little difference in processing attributes was found in wool from rugged and unrugged sheep when assessed in bulk for commercial processing, although rugged wool was valued at 9% higher in one year. The length between bands on staples retained on the sheep for 32 weeks was shorter than between corresponding bands on adjacent staples that were removed from the sheep and stored for 32 weeks. The reduction was 13–22% on unrugged and 3–14% on rugged sheep. Attempts to use length or fibre diameter measurements to predict the weight of wool grown were unsuccessful. Theoretical considerations in the technique of dyebanding are discussed, and details of a recommended procedure are presented as an appendix.