Wool Yield Research Articles

Differential expression of genes and proteins associated with wool follicle cycling.

Sheep are valuable resources for the wool industry. Wool growth of Aohan fine wool sheep has cycled during different seasons in 1 year. Therefore, identifying genes that control wool growth cycling might lead to ways for improving the quality and yield of fine wool. In this study, we employed Agilent sheep gene expression microarray and proteomic technology to compare the gene expression patterns of the body side skins at August and December time points in Aohan fine wool sheep (a Chinese indigenous breed). Microarray study revealed that 2,223 transcripts were differentially expressed, including 1,162 up-regulated and 1,061 down-regulated transcripts, comparing body side skin at the August time point to the December one (A/D) in Aohan fine wool sheep. Then seven differentially expressed genes were selected to validated the reliability of the gene chip data. The majority of the genes possibly related to follicle development and wool growth could be assigned into the categories including regulation of receptor binding, extracellular region, protein binding and extracellular space. Proteomic study revealed that 84 protein spots showed significant differences in expression levels. Of the 84, 63 protein spots were upregulated and 21 were downregulated in A/D. Finally, 55 protein points were determined through MALDI-TOF/MS analyses. Furthermore, the regulation mechanism of hair follicle might resemble that of fetation.

Characteristics of the Doba-lek 82 line in Kazakh dromedary NAR

Zootechnical characteristic of camel sires is presented for the Doba-lek 82 line bred at the Taushyk farm of the Kazakh NAR breed of meat-milk productivity. Average live weight of females in that line was 589.3 kg, 4.2 kg wool yield, 93.4% output of net fiber, and 3650.5 kg milk yield with fat content 4.4%.

Dose–response of supplementing marine algae (Schizochytrium spp.) on production performance, fatty acid profiles, and wool parameters of growing lambs1

Microalgae are the original source of docosahexaenoic acid (DHA; 22:6n-3) in the marine food chain, and its inclusion in animal feeds has been considered as a means of increasing the DHA level in foods of animal origin. As such, this study aimed to investigate the effects of supplementing an algal meal, high in DHA derived from Schizochytrium spp. (DHA-G), in the diet of Canadian Arcott lambs, on growth, carcass characteristics, wool production, and fatty acid (FA) profiles of subcutaneous adipose tissues (SAT), perirenal adipose tissues (PAT), and skirt muscle (SM). Forty-four lambs were randomly assigned to dietary treatments. Diets consisted of a pelleted, barley-based finishing diet with DHA-G supplemented at 0, 1, 2, or 3% DM as a replacement for flax oil and barley grain. Feed deliveries and orts were recorded daily. Lambs were weighed weekly and slaughtered once they reached ≥ 45 kg live weight. Carcass characteristics, ruminal pH, and liver weights were determined at slaughter. Wool yield was determined on mid-side patches of 100 cm(2) shorn at d 0 and on the day before slaughter (d 105 or 140). Dye bands were used to determine wool growth, fiber diameter, and staple length. Adipose tissues and SM samples were taken at slaughter and analyzed for FA profiles. Data were analyzed using mixed procedure in SAS with orthogonal contrasts testing for linear, quadratic, or cubic responses to increasing levels of DHA-G. Daily DMI, ADG, and G:F were similar as were wool quality and yield (P > 0.05). Carcass characteristics were generally unaffected (P > 0.05), except for body wall thickness (mm), which showed a quadratic response (P = 0.01) with increasing DHA-G. The concentration of eicosapentaenoic acid (EPA; 20:5n-6; mg/100 g fresh tissue) linearly increased (P < 0.001) with DHA-G in both adipose tissues and responded quadratically in SM (P = 0.05). Similarly, DHA (mg/100 g fresh tissue) increased linearly (P < 0.01) with DHA-G in all tissue types (P < 0.001). Supplementing DHA-G decreased (P < 0.001) the n-6:n-3 ratio in all tissues. No effects (P ≥ 0.05) on PUFA or SFA were observed across the 3 tissues, with no response (P ≥ 0.10) in the SFA:PUFA ratio in either SM or SAT; however, the SFA:PUFA ratio linearly decreased in PAT (P = 0.01) as DHA-G increased. These results indicate that DHA-G can be successfully included in the diets of growing lambs, up to 3% DM, with the potential to improve carcass characteristics and the FA profile of adipose tissue and muscle.

Responses to betaine and inorganic sulphur of sheep in growth performance and fibre growth

Sulphur-containing amino acids (SAA) are essential and usually the first limiting amino acids for growth, milk and wool production. The keratin fibre that grows from epidermal tissue is rich in SAA. The rate of fibre growth and its S content are influenced by the availability of SAA. Betaine is a dietary source for a labile methyl group and actively participates in methionine metabolism by donating methyl groups for the remethylation of homocysteine to methionine. Ruminants are capable of synthesizing SAA from inorganic S sources, and most bacteria in the rumen can use inorganic S to meet their requirements for growth. The objective of this study was to examine whether betaine and an inorganic sulphur supplement could provide methyl groups and sulphur amino acids in a way that growth performance and wool production of ewes and lambs are improved. Treatments performed included betaine supplementation, sulphate supplementation and betaine plus sulphate supplementation with five replications for each treatment. The dry matter intake of the ewes was affected by betaine plus sulphate supplementation (p < 0.05). In the ewes, betaine plus sulphate supplementation increased (p < 0.05) the wool growth rate, wool yield, staple length and wool sulphur concentration, while decreasing wool wax and wool yellowness (p < 0.05). In the lambs, wool growth rate, wool yield, fibre diameter, staple length, staple strength, wool sulphur concentration, wool wax and fibre percentage did not differ (p > 0.05) between treatments. In the ewes, plasma methionine concentration increased (p < 0.05) with betaine plus sulphate treatment. No corresponding difference (p > 0.05) was observed in plasma methionine concentration in the lambs. It can be concluded that betaine plus sulphate supplementation has the potential to change wool characteristics in the ewes, while these compounds were without any effect on growth and wool production of the lambs. Combining the two supplements was advantageous.

Incidence and effects of diseases in sheep in Uttar Pradesh

The present study was undertaken to analyze the incidence and effects of diseases in Sheep. The prevalence of specific diseases (42.0%) (FMD 11.7% and HS 30.30%) were more prominent followed by parasitic diseases (18%) digestive diseases (18%) and respiratory diseases (18.0%). while reproductive and other diseases (enterotoxaemia, skin infections) were also prevalent at lower morbidity rate (2.0%) in the study area. Lambs were highly affected by parasitic diseases (41.67%). In young stocks the highest proportional morbidity rate was observed due to digestive diseases (26.32%) while in adults other diseases (4.0%) had high morbidity. Males were affected more by specific diseases (48.72%) followed by parasitic diseases (23.08%). But in females, highest proportional morbidity rate was observed due to respiratory diseases (22.95%). The highest mortality was due to specific diseases (41.86%) followed by parasitic diseases (20.93%) and digestive diseases (20.93%). The analysis of the data on the effect of disease on wool yield in sheep did not reveal any significant difference in wool reduction due to pasturellosis and circling diseases. Overall wool reduction due to both diseases was (44.88%) but pasturellosis had higher effect (44.94%) than circling disease (44.76%) on wool production in sheep.

Survey and Performance Evaluation of Malpura Sheep in Farmers’ Flocks of its Native Tract

Data on growth, wool and milk yield of Malpura sheep maintained under farmers’ flocks in its native tract were recorded and analyzed. In breeding tract of Malpura sheep, more than 80 percent farmer's family members were found illiterate. The average weight of adult rams was 49.17 ± 0.53 kg and of the lactating ewes was 34.36 ± 0.18 kg. Location significantly affected body height in the all age groups, while for other traits an erratic trend was noticed. The least squares means of body weight at weaning and hoggets stage were 13.09 ± 0.15 and 22.55 ± 0.34 kg, respectively. The wool yield of animal was higher (P<0.01) in March clip (755 g) followed by that in September – October (481 g) and was lowest in July (444 g). The week of lactation significantly affected (P<0.01) daily milk yield and maximum milk yield was in 4th week of lactation. The overall performance of Malpura in farmers’ flock was found satisfactory under prevailing harsh climatic conditions of semi-arid tropics.

Comparing methane emissions from different sheep-keeping systems in semiarid regions: A case study of Syria

Sheep husbandry represents a significant source of methane (CH4) in semiarid grassland regions such as Syria. However, the contribution of sheep to CH4 emissions in Syria is still unknown. This study was designed to quantify CH4 emissions and identify possible mitigation strategies for their reduction. Methodology developed by the Intergovernmental Panel on Climate Change (IPCC) was used to estimate CH4 emissions. A survey was conducted on 64 farms from different locations in Syria in 2009. Data were collected concerning sheep-keeping systems (SKSs), body mass, milk and wool yield, farm locations, feed rations, periods of grazing on the Steppe, the duration of pasturing on agricultural residuals and time periods when sheep were kept in stables. Using a linear statistical model, the influence of SKS, geographical region and sheep body mass on emitted CH4 were analysed. The results showed that the geographical region, SKS and sheep body mass had significant effects (P<0.05) on CH4 emissions. According to the model, the mean values of estimated CH4 emissions from extensive, semi-intensive and intensive SKSs were 26±0.9, 22.5±1.3 and 13.5±1.7kg/sheepyear, respectively. In comparing differences between the least square means of CH4 emissions, the extensive and semi-intensive SKSs produced 92% and 66% higher CH4 emissions compared to intensive SKS. The differences in CH4 emissions within the distinct SKSs were attributed to dietary composition. Extensive SKS used a less concentrated feeding regime (98±17day/year) than semi-intensive SKS (114±47day/year), and intensive SKS employed concentrated feeding year round. Furthermore, it was observed that sheep with the same body mass produced higher CH4 emissions in extensive SKS than in semi-intensive and intensive SKSs. Moreover, the semi-intensive SKS occupied more natural pastures than extensive SKS, which caused an overuse of the Steppe. Therefore, an effective mitigation strategy involves the use of more digestible feed, which would be accomplished by increasing the quantity of concentrated feed. Owing to unfavourable farming conditions, low-cost nonconventional feeds such as the residuals of wheat and cotton should be used to improve sheep management practices to reduce Steppe overgrazing in the extensive and semi-intensive SKSs of Syria and other semiarid areas.

Effects of crude glycerin supplementation on wool production, feeding behavior, and body condition of Merino ewes1

The increasing availability of crude glycerin from the biodiesel industry has led to an interest in its use as an energy source in ruminant diets. However, its effects on ruminal fermentation patterns and methane (CH4) production are unclear, and there are no reports on the effect of its inclusion in the diet on wool production or growth of Merino sheep. Thus, the objectives of this study were to determine the effects of increasing levels of crude glycerin on in vitro ruminal fermentation and CH4 production and DMI, BW, feeding behavior, and wool growth and quality in Merino ewes. Crude glycerin (99.2% pure, colorless, odorless, viscous liquid) replaced whole wheat grain in completely pelleted diets at levels of 0%, 6%, and 12% DM in both in vitro and in vivo studies. For in vitro studies, diets were dried and ground through a 1-mm screen and incubated on 2 different days for 24 h. Modified McDougal's buffer and rumen liquor were mixed 3:1, and gas production and CH4 concentration was measured after 6, 12, and 24 h of incubation with pH and IVDMD measured at 24 h. Cumulative gas (mL/g DM) and methane (mL) production was similar (P ≥ 0.35) among dietary treatments. In vitro dry matter disappearance (%) increased (P < 0.01) with increasing concentrations of crude glycerin. For the in vivo study, 39 Merino ewes were randomly assigned to 3 treatments (n = 13 ewes/treatment). Pelleted diets were available continuously for a 10-wk period through the use of automatic feeders. Ewes were weighed every 7 d. Wool yield was determined on mid-side patches of 100 cm(2) shorn at d 0 and d 70. Dye bands were used to determine wool growth and fiber length. Intake and ADG were similar among treatments (P = 0.59). Neither wool yield, length, spinning fineness, nor fiber diameter (μm) were affected after supplementation with crude glycerin (P ≥ 0.13). This study indicates the potential for crude glycerin to be included in the diets of Merino sheep at up to 12% DM without negatively affecting wool yield and quality.

The Effect of Some Environmental Factors on Dirty Wool Yield in Daglic Sheep.

The Effect of Some Environmental Factors on Dirty Wool Yield in Daglic Sheep.

Greenhouse gas emissions profile for 1 kg of wool produced in the Yass Region, New South Wales: A Life Cycle Assessment approach

The use of Life Cycle Assessment (LCA) to determine environmental impacts of agricultural production, as well as production by other industry sectors has increased. LCA provides an internationally accepted method to underpin labelling and marketing of agricultural products, a valuable tool to compare emissions reduction strategies and a means to identify perverse policy outcomes. A single-issue LCA focussing on greenhouse gas emissions was conducted to determine the emissions profile and carbon footprint of 19-micron wool produced in the Yass Region on the Southern Tablelands of New South Wales. Greenhouse gas emissions (in carbon dioxide equivalents; CO2-e) from the production of all enterprise inputs and from the production of wool on-farm were included. Total emissions were found to be 24.9 kg CO2-e per kg of greasy wool at the farm gate, based on a 4941 breeding ewe enterprise on 1000 ha, with a total greasy wool yield of 65.32 t per annum. The co-products included 174 t sheep meat as liveweight from wethers and cull ewes plus 978 maiden ewes sold off-farm as replacement stock. Total emissions from all products grown on 1000 ha were 2899 t CO2-e per annum. The relative contribution of greenhouse gas emissions from different components of the production system was determined. Direct emission of methane on-farm (86% of total) was the dominant emission, followed by nitrous oxide emitted from animal wastes directly (5%) and indirectly (5%), and decomposition of pasture residue (1%). Only 2% of total emissions were embodied in farm inputs, including fertiliser. The emissions profile varied according to calculation method and assumptions. Enteric methane production was calculated using five recognised methods and results were found to vary by 27%. This study also showed that calculated emissions for wool production changed substantially, under an economic allocation method, by changing the enterprise emphasis from wool to meat production (41% decrease) and by changing wool price (29% variability), fibre diameter (23% variability) and fleece weight (11% variability). This paper provides data specific to the Yass Region and addresses broader methodological issues, to ensure that future livestock emissions calculations are robust.

Influence of simulated body condition score on growth, physiological responses and blood metabolites of native Malpura ram

The effect of simulated body condition score (BCS) on body weight, wool yield, respiration rate, pulse rate and rectal temperature was evaluated in native Malpura ram. The rams were randomly divided into group 1 (2.5 BCS; n= 7), group 2 (BCS 3.0–3.5; n=7) and group 3 (BCS 4.0; n=7). Apart from grazing for 8 h a day, the rams were provided with concentrate mixture @ of 100 g, 300 g and 500 g to group 1, 2, and 3, respectively, to attain their respective BCS. The body weight (kg), heart girth (cm) physiological responses i.e. respiration rate (RR, breath/min), pulse rate (PR, beat/ min) and rectal temperature (RT °C) were recorded at fortnightly interval. The wool yield was recorded at 6 monthly interval clipping. The blood samples were also collected at fortnightly interval and analyzed for packed cell volume (PCV, %), hemoglobin (Hb, g/dl) and glucose (mg/dl). The animals of G1 had significantly lower (P&lt;0.05) RR and RT than the other 2 groups of rams. A significant decrease in the body weight, HG and wool yield was observed in G1 rams as compared to G2 and G3 rams. The PCV, Hb and glucose values were significantly higher in G2, G3 animals than that of G1 animals.

Comparative performance of different regional native sheep in Bangladesh

This study was undertaken to investigate the performance of native sheep in Bangladesh. Data were collected during 2004-2010 from sheep of the Barind, Jamuna and Coastal areas. The phenotypic characteristics did not differ significantly, but ears were shorter in Barind than in Jamuna and Coastal sheep. The coat colour was 45% white, 26% brown, 24% white brown and 3% black brown in Barind and Jamuna sheep, but white (70%) and white brown (30%) in Coastal sheep. Differences were not significant for age at first heat, age at first pregnancy and age at first lambing. Days open and post-partum ewe weight were significantly (P&lt;0.01) different. Onset of post-partum heat, lambing interval, gestation length, number of services per pregnancy, litter size and placental weight did not differ significantly. Birth weight was significantly (P&lt;0.05) higher in Coastal sheep than in Barind and Jamuna. Higher (P&lt;0.05) wool yield was obtained in Coastal sheep and in the summer. Though the wool was coarse and hairy, wool from Coastal sheep had more (P&lt;0.05) bends per inch, and was finer. Diarrhoea, pneumonia in lambs and skin diseases were the most common diseases in all sheep. Though sheep from the different areas had similar performance, better reproductive performance was obtained in the Barind sheep.DOI: http://dx.doi.org/10.3329/bvet.v28i2.10692Bangl. vet. 2011. Vol. 28, No. 2, 85 – 94

Effects of betaine and sulfate supplementation on milk and wool production of Naeini ewes

Twenty lactating Naeini coarse wool ewes (45±3.2kg BW, approximately 35 months of age), were studied in a completely randomized design during a three-month experimental period in order to investigate the effect of betaine and sulfate supplementation on milk and wool characteristics. Treatments included, betaine supplementation, sulfate supplementation and betaine plus sulfate supplementation, along with control group. Ewes were randomly distributed in individual pens with five replications for each treatment. Isonitrogenous and isocaloric diets were twice offered to the ewes on a daily basis according to the NRC recommendation. The level of betaine used on the TMR was 5gkg−1 betaine, and basal diet contained 0.17% DM organic sulfur. Dry matter intake (DMI) was altered by betaine and sulfate supplementation (P<0.05). No significant effect of betaine and sulfate supplement was detected on body weight (P>0.05). Milk yield and milk fat percentage were increased by betaine and sulfate supplementation (P<0.05), whereas percentages of milk protein, lactose, ash and SNF were not significant by supplements (P>0.05). Betaine and sulfate supplementation significantly increased the daily growth rate of the wool, and the wool yield was compared with that of the control group (P<0.01). Mean fiber diameter was not affected by betaine and sulfate supplementation (P>0.05). Staple length was affected by the type of supplements (P<0.001). For the staple strength, a higher value was observed in the betaine plus sulfate treatment (P<0.05). Betaine plus sulfate supplementation significantly increased the concentration of wool sulfur (P<0.01). In contrast, wool wax and wool yellowness significantly decreased by the betaine and sulfate supplementation (P<0.05). Although there was an increase in the plasma cysteine concentration, it was not a significant one (P>0.05). In addition, no effects of betaine and sulfate supplementation were observed on plasma copper concentration. In conclusion, these data indicated that betaine plus sulfate supplementation had positive effects on milk and wool production of Naeini ewes.

Assessment of Grewia oppositifolia leaves as crude protein supplement to low-quality forage diets of sheep

In the tropical arid and semi-arid regions of many developing countries, sheep are predominantly grazed on low-quality pastures and stall-fed on crop residues. This study evaluated the potential of Grewia oppositifolia tree leaves as crude protein (CP) supplement to the low-quality diets of sheep in comparison with cottonseed cake (CSC). Changes in the chemical composition of the leaves with progressive maturation (December to March) were studied. The leaves maintained a high CP content (>164 g/kg dry matter (DM)) during the prolonged maturation in the winter feed scarcity period. The leaves were rich in Ca (41 g/kg DM) and K (89 g/kg DM). The rate of degradation and effective degradability of CP were consistently higher (P < 0.001) in CSC than in G. oppositifolia. A balance trial in a 4 × 4 Latin square design with four mature Ramghani wethers showed that DM intake, DM and CP digestibility, and N retention did not differ with the substitution of CSC with G. oppositifolia leaves, as a supplement to a basal diet of sorghum hay. Body weight (BW) gain and wool yield responses to the supplements were examined with 36 lambs (27 ± 3 kg BW; age 11 ± 1 months) for 15 weeks. The lambs were only grazed on local pasture (control group) or supplemented with CSC, G. oppositifolia leaves, and their mixture on iso-N basis. Addition of the supplements increased (P < 0.05) BW gain and wool yield, and the leaves were as effective as CSC. These results demonstrated that G. oppositifolia leaves provide good quality green fodder during the prolonged winter feed scarcity period, and that the leaves can be efficiently utilized as a CP supplement to the low-quality diets of sheep.

ESTIMATION OF PHENOTYPIC CORRELATIONS AND REPEATABILITY OF SOME ECONOMIC TRAITS IN AWASSI AND HAMDANI EWES

This study included two flocks of Awassi (106) and Hamdani (73) ewes belongs to the Animal Resources Department College of Agriculture and Forestry at Mosul University. and another flock of Awassi ewes (127) belongs to the Animal Husbandry Station General Directorate of Applied Agriculture Researches at Rashidia Region during 2005-2006 and 2006-2007 seasons. The studied traits were daily milk yield (DMY) and some of its physical traits at fixed intervals 15 days post lambing for 5-6 months. Also wool yield (WY) and some of its physical traits were studied during the two seasons. The results revealed a highly positive significant correlation (p≤ 0.01) between (DMY) and ewe weight. a highly positive significant correlation (p≤ 0.01) between fat percentage with both protein and lactose percentage. between protein and lactose percentage in Awassi ewes. There was a positive significant correlation (p≤ 0.05) between (DYM) and ewe weight. and a highly significant correlation (p≤ 0.01) between fat and protein percentage. between protein and lactose percentage in Hamdani ewes. While the rest of the relationships were negative or non significant in both breeds. There were a highly significant correlations (p≤ 0.01) between greasy fleece weight (GFW) and all wool traits and ewe weight. also between clean fleece weight (CFW) with all wool traits. between clean wool (CW) with both staple length (SL) and fibre length (FL). between (SL) and (FL) in Awassi ewes. In Hamdani ewes all the relations were non significant except for (GFW) with both (CFW) and (CW). between (CFW) and (CW). between (SL) and (FL) were highly significant (p≤ 0.01). Repeatability estimates for milk traits in Awassi ewes were low to high (0.015-0.785) while in Hamdani ewes were low to moderate (0.052-0.400). Repeatability estimates for wool traits were low to high in Awassi and Hamdani ewes (0.013-0.785) and (0.206-0.749) respectively.

Evaluation of Genetic Parameters of Milk Yield and some of its Composition with Wool Yield and some of its Physical Traits in Two Breeds of Iraqi Sheep

Evaluation of Genetic Parameters of Milk Yield and some of its Composition with Wool Yield and some of its Physical Traits in Two Breeds of Iraqi Sheep

Estimation of Genetic Parameters for Wool Traits in Angora Rabbit

Different genetic parameters for weaning weight and wool traits were estimated using restricted maximum likelihood (REML) in Angora rabbits. Total wool yield of first (I), second (II) and third (III) clips were taken as a separate trait under study. The records from more than 2,700 animals were analysed through fitting six animal models with various combinations of direct and maternal effects. A log likelihood ratio test was used to select the most appropriate model for each trait. Direct heritability estimates for the wool traits were found to be moderate to high across different models. Heritability estimates obtained from the best model were 0.24, 0.22, 0.20 and 0.21 for weaning weight, clip I, II and III; respectively. Maternal effects especially due to permanent environment had higher importance at clip I and found to be declining in subsequent clips. The estimates of repeatability of doe effect on wool traits were 0.44, 0.26 and 0.18 for clip I, II and III; respectively. Weaning weight had moderately high genetic correlations with clip I (0.57) and II (0.45), but very low (0.11) with clip III. Results indicated that genetic improvement for wool yield in Angora rabbit is possible through direct selection. Further, weaning weight could be considered as desirable trait for earliest indirect selection for wool yield in view of its high genetic correlation with wool traits.

Medullated fibres and fleece characteristics in Corriedale hoggets from two flocks in Uruguay

The incidence of medullation in 549 Corriedale hoggets from two experimental flocks, its association with other characteristics of the fleece, and the sire effect were evaluated. The investigation was carried out during 2005–06 in hoggets from the Faculty of Agriculture and Faculty of Veterinary Science experimental flocks. Fleeces were weighed and samples were taken at shearing by picking 104 staples from fleeces to measure medullation. A mid-side wool sample was taken to determine wool characteristics (fleece weight, wool yield, mean fibre diameter, staple strength and length). A Dark Fibre Detector was used to identify total medullated fibres and fibre type: medullated fibres (med) and kemp, which were confirmed by light microscope. Mean total medullated fibres, med and kemp content per 10 g of clean wool were 4.2 ± 11.2; 2.0 ± 8.9 and 2.3 ± 4.9, and median values were 0.9, 0.0 and 0.7, respectively, in 549 fleeces. A high variability between samples and a higher proportion of hoggets with kemp fibres than those with med were observed. There were significant differences between sire families for total medullated fibre content/10 g, med fibre content/10 g and kemp fibre content/10 g, but there were no significant effects between flocks, years or interaction between them. Phenotypic correlations between medullated fibre content and wool characteristics were generally low (less than 0.19). In conclusion, medullated fibre content was highly variable between samples and was not strongly correlated with other fleece characteristics. Medullation varied between sire groups, suggesting genetic variation, which could be exploited to improve wool quality.

Effect of substituting groundnut cake for different levels of rice bran on growth and wool production of German Angora rabbits.

An experiment was conducted on 72 German Angora rabbits (42 youngs and 30 adults) divided into three groups to assess the effect of three experimental diets (T1, T2 and T3) with different levels of groundnut cake replaced by rice bran on their growth performance, wool yield, quality, and digestibility of nutrients. The inclusion rate of groundnut cake was decreased from 20 to 15 to 10% and that of rice bran increased from 13 to 18 to 23% in T1, T2 and T3, respectively. The same diets presented 16.1, 15.1 and 14.0% DM of crude protein and 11.3, 11.1 and 10.9 MJ/kg DM of digestible energy, respectively. All animals were kept under similar housing and management conditions and the experiment was continued for a period of 225 days (3 shearings). No significant effects of the experimental diets on body weight gain, wool yield and wool attributes were observed in young and adult rabbits. However, the wool yield at the 2nd shearing was higher in the T1 group (P&lt;0.05) indicating the positive effect of a diet higher in protein and energy on the wool production at an early stage of growth. Voluntary intake both of concentrates and roughages were not affected by the dietary treatment. The digestibility coefficients of dry matter and crude fibre were increased both in young and adult rabbits with the reduction of groundnut cake, while those of crude protein and ether extract were decreased in young rabbits only. From this experiment it can be concluded that groundnut cake can be safely replaced with rice bran in adult feeds at rates of up to 10% of the total content, while in young rabbits it may not be advantageous to go above a 5% level of replacement to avoid a substantial reduction in protein concentration, and the impairment of growth and wool production.

ADAPTABILITY OF RUSSIAN ANGORA RABBITS IN SEMI ARID TROPICS

Russian Angora rabbits raised under semi arid conditions during 1982-1985 had average kindling % of 58.7. The average litter size at birth and at weaning (6 weeks) were 5.68 and 3.62 respectively. Body weight al birth 6, 12 and 24 weeks were 55 g, 536 g, 1.17 kg and 2.61 kg and 54 g, 536 g, 1.19 kg and 2.64 kg. The first group of data corresponds to males and the second to females. The wool was clipped firstly at 3 months of age and then at quarterly intervals. The wool yield showed steady increase with the age and was highest in the fourth clip: 40g/clip at 3 months and 60g/clip for adults on average. The wool yield in young as well as in adult rabbits was lowest in June clip (-36%/general mean). The influence of age, years and season of clip were significant (P 0.01) while the sex difference were non significant. The breeding of Russian angora rabbits was discontinuad after 1985 due to appearance of a genetic disorder "Retarded Wool Syndrome" which cause significant loss in wool yield. lt was probably due to inbreeding in a small population coupled with adversa effect of hot climate.