Angora Goats Research Articles

The effect of different levels of inorganic sulphur on the rumen parameters of Raini goat

Added sulphur (S) in the diet of ruminants has an equivocal effect on the ruminal fermentation. For example, Hegarty et al. (1994) reported an increased total VFA concentration in the rumen of sheep fed a high S diet versus those offered a low S diet (<0.25%, DM basis). Moderated high percentages of S (0.4-0.6%) in the diet of sheep have generally had no effects on ruminal VFA and ammonia-nitrogen concentrations (deOliveira et al., 1996). Working with Angora goats, Qi et al. (1992) noted that total ruminal fluid VFA concentration ranged from 76.7 to 79.1 mM and was not affected by added S (0.16-0.4%). There is limited information related to the influence of supplemental S on the metabolic responses in the rumen of Cashmere goat. Therefore, an experiment was conducted with an Iranian native breed of Cashmere producing goat, Raini, to evaluate the metabolic responses in rumen parameters to S supplementation.

Effects of bovine somatotropin and thyroid hormone status on hormone levels, body weight gain, and mohair fiber growth of Angora goats.

Forty-eight Angora goats (24 wethers and 24 doelings; 5 mo old; 16 +/- 0.5 kg initial BW) were used in an experiment with a 2 x 3 factorial treatment arrangement (n = 8) to evaluate effects of recombinant bovine somatotropin (bST) administration and thyroid hormone status (euthyroid, hypothyroid, and hyperthyroid) on hormone levels, ADG, and mohair fiber growth. The bST was a slow-release zinc-based suspension, with sustained delivery (100 microg/[kg BW x d]) over a 14-d period. Hyperthyroidism was maintained by daily treatment with thyroxine (T4; 150 microg/[kg BW x d]), and hypothyroidism was achieved by feeding 6 mg/(kg BW x d) of propylthiouracil. The experiment was conducted in July to September and consisted of a 2-wk pretreatment period and 8 wk of bST treatment. Goats were given ad libitum access to a diet with 15% CP and 2.54 Mcal/ kg ME (DM basis). Concentrations of T4 and T3 were greatest (P < 0.01) among treatments for hyperthyroid-bST and hyperthyroid-control (T4: 38.6 and 38.0 microg/dL; T3: 406 and 385 ng/dL, respectively); similar among euthyroid-control, euthyroid-bST, and hypothyroid-bST (T4: 11.1, 11.5, and 9.8 microg/dL, respectively; T3: 232, 252, and 226 ng/dL, respectively); and lowest (P < 0.01) for hypothyroid-control (T4: 5.1 microg/dL; T3: 144 ng/dL). Plasma concentration of insulin-like growth factor-I was greatest (P < 0.01) for euthyroid-bST (596 ng/mL) and hypothyroid-bST (618 ng/mL); however, concentration for hyperthyroid-bST was similar to those for euthyroid-control, hypothyroid-control, and hyperthyroid-control (188, 178, 187, and 191 ng/mL, respectively). Dry matter intake was greatest (P < 0.05) for euthyroid-bST (794 g/d), similar among hypothyroid treatments (693 and 703 g/d for control and bST, respectively) and euthyroid-control (681 g/d), and lowest for hyperthyroid groups (554 and 518 g/d for control and bST, respectively); ADG for hyperthyroid goats (11 g/d) was lower than with hypothyroidism and euthyroidism (72 and 73 g/d, respectively); and mohair fiber growth was greater (P < 0.01) for hyperthyroidism (0.133 g/[100 cm2 x d]) than for hypothyroid and euthyroid goats (0.102 and 0.104 g/[100 cm2 x d], respectively). Hyperthyroidism also increased mohair length growth rate by 15% and decreased fiber diameter by 7.8% (P < 0.01). These results demonstrate interactions between growth hormone administration and thyroid hormone status, although these influences had limited effects on ADG and mohair fiber growth.

Kidding, Mortality and offtake rates of Angora goats in the mountains and Lowlands of Molimo-Nthuse area in Lesotho

Kidding, Mortality and offtake rates of Angora goats in the mountains and Lowlands of Molimo-Nthuse area in Lesotho

Effects of season on fleece traits of Angora does in the US

Twenty nonpregnant Angora does were used to determine seasonal effects on fleece traits, including fiber growth and follicle activity. Does grazed pastures and were supplemented with a 50% concentrate diet at a level near that required for BW maintenance. Clean fiber growth rate was greatest ( p<0.05) among seasons in summer and lowest ( p<0.05) in winter (1.13, 0.85, 0.98 and 1.20 mg/cm 2 per day for autumn, winter, spring and summer, respectively); seasonal differences in fiber diameter were similar (34.9, 31.7, 33.7 and 36.5 μm for autumn, winter, spring and summer, respectively). Fleece fiber medullation was greatest ( p<0.05) in summer (0.48, 0.32, 0.40 and 0.76%), and medullated fiber diameter was greater in spring and summer than winter (69, 65, 73 and 71 μm for autumn, winter, spring and summer, respectively). Primary follicle activity varied with season more than did activity of secondary follicles (primary: 74, 23, 79 and 99%; secondary: 97, 86, 94 and 99%; for autumn, winter, spring and summer, respectively). In summary, Angora goats in the US appear to exhibit seasonal follicle and fiber growth cycles, the knowledge of which may improve future nutritional management for efficient feed use in mohair production. The optimal time of shearing US Angoras for minimal contamination with medullated fibers may be just before spring and autumn equinoxes when it is likely that medullated fibers have been recently shed.

Effects of dietary level of Leucaena leucocephala on performance of Angora and Spanish doelings

Thirty Angora (16±2 kg initial body weight) and 20 Spanish doelings (19±2 kg initial body weight), approximately 8 months of age, were used in an 10 week experiment to evaluate effects of dietary level of Leucaena leucocephala on body weight (BW) gain and fiber growth. The control diet (CS) included 9% dry matter (DM) of formaldehyde-treated casein; other diets consisted of 15, 30, 45 or 60% DM of leucaena leaf meal (0.75% mimosine; 15, 30, 45 and 60 l, respectively). Diets were formulated to be 2.13 Mcal metabolizable energy/kg DM, and ranged in crude protein from 10 to 14% of DM. DM intake was greater ( P<0.05) for 45 l than for CS and 15 l (710, 648, 815, 899 and 811 g per day for CS, 15, 30, 45 and 60 l, respectively) and similar ( P>0.05) between Angora and Spanish doelings. BW gain was similar ( P>0.05) among diets (48, 28, 38, 34 and 26 g per day for CS, 15, 30, 45 and 60 l, respectively) and between breeds. Mohair growth rate was lower ( P<0.05) for 60 and 30 l than for CS (1.34, 1.18, 0.94, 1.16 and 0.88 mg cm −2 per day, and mohair diameter was greatest ( P<0.05) for CS and lowest ( P<0.05) for 60 l (27.7, 25.9, 25.1, 25.0 and 23.8 μm for CS, 15, 30, 45 and 60 l, respectively). Cashmere growth rate and fiber diameter for Spanish goats were similar among diets, and primary and secondary follicle activities for both Angora and Spanish goats were not affected by dietary treatments ( P>0.05). Diet affected ( P<0.05) plasma concentrations of urea, threonine, arginine, valine, phenylalanine, isoleucine, leucine and lysine, with concentrations increasing as dietary level of leucaena increased. In conclusion, diets of moderate to high levels (e.g., 45%) of leucaena with 0.75% mimosine can be fed to goats without adverse effects on BW gain or fiber growth. However, further study of the composition of leucaena-based diets appears necessary to achieve most efficient utilization.

Protein and sulphur amino acid nutrition of hair fibre-producing Angora and Cashmere goats

The results from a number of studies are presented which investigated responses in fibre production of British Cashmere and Angora goats to variation in protein and sulphur amino acid nutrition under conditions of active fibre growth. Requirements for amino acids were considered in the context of the concentration of amino acids, including cysteine and methionine, in rumen microbial protein and in dietary protein supplements compared with the amino acid composition of hair fibre. Increases in fibre yield and diameter were consistently observed in Angora goats given good quality protein supplements or rumen-protected intestinally-available methionine (Smartamine™M, Rhône-Poulenc). Cashmere yield was not influenced by urea or white fishmeal supplementation but responded positively (in contrast to other studies in the literature) to additional dietary methionine. While responses in cashmere production have been recorded in response to protein supplementation at sub-maintenance levels of nutrition, it is suggested that one component of the absent or reduced response at above maintenance may be the smaller quantitative synthesis of this fibre compared with mohair production by Angora goats. The results are considered in the context of studies from the sheep literature in which protein and amino acid supplementation were shown to stimulate proliferation of hair forming cells in the wool follicle and to increase deposition of protein fractions containing high concentrations of sulphur-containing amino acids. Results from an in vitro study suggested that methionine could support cashmere fibre growth (approximately 0.75) in the absence of cysteine and cystine, providing evidence that methionine is essential for fibre production and that transulphuration occurs in isolated hair follicles. However, cysteine and cystine were also required to produce maximum growth. In the context of competition between the hair follicle and other body tissues, data are presented which illustrate the increases in nitrogen retention and/or anabolic growth response to protein or protected-methionine supplementation in non-integumental tissues of Cashmere and Angora goats also, despite the presence of lower concentrations of sulphur-containing amino acids in these tissues. The results confirm the value of a good quality protein supplement or more targeted supply of rumen-protected intestinally-available methionine to correct a frequently apparent deficiency in sulphur amino acid supply for (a) growth of hair fibre by Angora goats and, less consistently, by Cashmere goats and (b) other body tissues in both genotypes.

Variation of mohair quality over the body in Angora goats

Forty female Angora goats were selected at random from the experimental nucleus of the National Institute of Agricultural Technology (Pilcaniyeu, Argentina), with the aim of analyzing the variability of main fleece characteristics of the Angora goats and establishing an optimum sampling site. Samples were taken at the first and second shearings (12 and 18 months of age) from the following parts of the fleece: neck, midrib, back, britch, belly and shoulder. For each sample the following determinations were made: oven-dry yield (YLD); average (AFD); standard deviation (SDAFD) and coefficient of variation (CVAFD) of fiber diameter; percentage of medullated fibers (MFT); characterization of three types of medullated fibers: continuous (MFC), interrupted (MFD) and kemp (KEMP) by estimating their proportion, average fiber diameter, standard deviation and coefficient of variation of fiber diameter; wax (WAX); suint (SUINT); humidity (HMD); staple length (STAPLE); degree of brightness (Y) and degree of yellowness (Y–Z). All variables studied showed statistically significant variability among to the sampling position ( P < 0.05), except of Y–Z, proportion of FMC, average fiber diameter of MFD and KEMP, and standard deviation of fiber diameter of KEMP at 12 months of age, at 18 months old for STAPLE and standard deviation of fiber diameter of MFD, and for CVAFD at the two ages of shearing ( P > 0.05). The results showed that sampling from the midrib of Angora goats gave adequate representation for most of the fleece variables analyzed.

Ruminoreticulum bypass in goats and its possible effect on the efficacy of oxfendazole against resistant gastrointestinal parasites

Ruminoreticulum bypass was observed in 9–12-month old Angora goats using video-taped fluoroscopy. For experimental purposes, ruminoreticulum bypass was stimulated by yarding animals for 19–24 h before drenching, or by yarding and oral premedication with 2% cobalt sulphate solution. When bypass occurred, 50–100% of the drench was deposited in the abomasum. Ruminoreticulum bypass had no apparent effect on the faecal egg count reduction of benzimidazole resistant Ostertagia spp. following drenching with a standard dose of 5 mg/kg of oxfendazole, although the low frequency of bypass prevented any firm conclusions from being made. The importance of ruminoreticulum bypass to the efficacy of benzimidazole anthelmintics in goats may have been overemphasised.

Carcass traits and retail display-life of chops from different goat breed types.

Four groups of goats, Boer x Spanish, straightbred Spanish, Spanish x Angora, and straightbred Angora were slaughtered at a constant age according to accepted industry procedures. At 24 h postmortem, various carcass yield and quality measurements were taken. At 48 h postmortem, one side from each carcass was fabricated into major wholesale cuts for dissection into percentage lean, bone, and fat. Rib chops from the opposite side were fabricated, packaged, and displayed in a retail case. Trained panelists evaluated the rib chops over 4 d of retail display for lean color, surface discoloration, and overall appearance; packages were opened and analyzed for off-odor on d 4. When slaughtered at constant ages, Angora goats had lighter (P < .05) live and hot carcass weights than all other breed types, and Boer x Spanish goats had heavier (P < .05) live and carcass weights than Spanish goats. Live and carcass weights for Boer x Spanish and Spanish x Angora goats did not differ (P > .05). Carcasses from Angora goats had considerably smaller (P < .05) longissimus muscle areas than all other breed types. Carcasses from Spanish goats had lower (P < .05) carcass conformation scores than carcasses from Boer x Spanish goats but did not differ (P > .05) from carcasses of the other two breed types. Carcasses from Angora goats had smaller (P < .05) leg circumferences than the carcasses from Boer x Spanish and Spanish x Angora breed types. In general, carcasses from Boer x Spanish and Spanish goats possessed higher (P < .05) percentages of lean and lower (P < .05) percentages of fat for the side than did carcasses from Spanish x Angora and Angora goats. When the Spanish x Angora carcasses were compared to the Angora carcasses, it seemed that the addition of the Spanish breeding tended to increase lean and decrease fatness for most side or primal comparisons. There were no (P > .05) breed type or breed type x day effects for lean color, surface discoloration, overall appearance or off-odor; however, day of display did influence (P < .05) these traits. Crossing Spanish with Angora goats may be an option to improve carcass characteristics over that of straightbred Angora.

Single daily intramuscular injections of low quantities of recombinant ovine interferon-tau extends luteal life-span in Angora goats.

The objective of this study was to determine whether single, daily intramuscular injections of low amounts of ovine interferon-tau (ovIFN-tau) would extend luteal life-span in nonpregnant Angora goats. Female goats were assigned randomly to receive a single daily injection of 1) PBS (control; n = 11), 2) 125 microg/d ovIFN-tau (n = 11), or 3) 500 microg/d ovIFN-tau (n = 11) from d 14 to 20 after estrus. Luteal life-span was defined as the number of days from the synchronized estrus until serum progesterone (P4) declined (< 0.5 ng/mL) and was of normal duration in controls (19.4 +/- 0.3 d) but was increased (P < 0.05) in goats receiving 125 microg/d (23.2 +/- 1.3 d) and 500 microg/d (25.5 +/- 1.2 d) ovIFN-tau. Injection of either ovIFN-tau dose caused an initial decrease (P < 0.05) in serum P4 concentrations relative to controls but did not differ from controls thereafter. Rectal temperatures increased (P < 0.05) following ovIFN-tau treatment until d 18 for goats given the lower dose and throughout the treatment period for those given 500 microg/d. In summary, injections of as little as 125 microg/d of ovIFN-tau extended luteal life-span in goats. This dose caused a transient reduction in serum P4 concentrations and induced hyperthermia.

Oncostatin M induces leukocyte infiltration and cartilage proteoglycan degradation in vivo in goat joints.

To evaluate the effect of intraarticular injections of recombinant human oncostatin M (rHuOSM) in the goat joint. One milliliter of endotoxin-free normal saline (vehicle) containing either 40 ng, 200 ng, or 1,000 ng of rHuOSM was injected into the right radiocarpal joints (RCJs) of 12 male angora goats, while the left RCJs were injected with an equivalent volume of vehicle alone. In subsequent studies, the right and left RCJs of 8 male angora goats were injected with 200 ng of rHuOSM, and 1 hour later, the right RCJs were injected with either 5 microg of recombinant murine leukemia inhibitory factor binding protein (rMuLBP) or 1 mg of recombinant human interleukin-1 receptor antagonist (rHuIL-1Ra) in 1 ml of vehicle, while the left RCJs received 1 ml of vehicle alone. Goat joints were examined for clinical features of inflammation, and synovial fluid (SF) was aspirated on day 0 (before injection) and at days 2 and 6 postinjection. Injections of rHuOSM stimulated dose-dependent increases in the carpal:metacarpal ratio, SF volume, and SF leukocyte numbers, and stimulated dose-dependent decreases in the cartilage proteoglycan (PG) content ex vivo and PG synthesis. No significant changes were observed in the control joints that received saline alone, or between RCJs that were injected with 200 ng rHuOSM followed by 5 microg rMuLBP and RCJs that were injected with 200 ng of rHuOSM alone, except in respect to synovial fluid keratan sulfate concentrations, where a modest statistically significant reduction was observed in the joints injected with the combination of rHuOSM and rMuLPB. In contrast, RCJs injected with 200 ng rHuOSM followed by 1 mg of rHuIL-1Ra had significantly lower SF volumes (P<0.0001) and a significantly higher rate of ex vivo PG synthesis (P<0.0001). These results indicate that rHuOSM stimulates inflammation and modulates cartilage PG metabolism in vivo. Some of the effects of rHuOSM in vivo appear to be due, in part, to elaboration of IL-1. Even at very high doses, however, the rHuIL-1Ra did not attenuate OSM-mediated cartilage PG resorption. Thus, OSM has the potential to contribute to synovitis in vivo and can stimulate cartilage PG resorption in vivo, independent of IL-1.

A note on defleecing of Angora and Spanish goats using Leucaena

A note on defleecing of Angora and Spanish goats using Leucaena

Repeatability and heritability of objective and subjective fleece traits and body weight in South African Angora goats

The repeatability and heritability of body weight, greasy fleece weight and mean fibre diameter, as well as various subjective fleece traits of South African Angora goats were estimated. The first of two data sets analysed, was collected through the Angora goat performance testing scheme (AGPTS), while the second comprised data collected on the experimental flocks kept at the Jansenville Experimental Station (JEF). The following traits were assessed subjectively on a linear scale ranging from 1 to 50 at the second, third and fourth shearings, namely fullness of face covering, fullness of the neck, fullness of belly and points, style, character, evenness of fleece, softness of face and ears, pigmentation in the face and on the ears, and kemp and medullated fibres. Heritability and repeatability estimates were obtained by fitting repeatability animal models under a DFREML programme. Heritability for body weight was higher in the JEF (0.47 ± 0.01) than in the Angora studs (0.35 ± 0.05), while the same heritabilities were estimated for fleece weight (0.22 ± 0.04) and fibre diameter (0.30 ± 0.05) in both data sets. The repeatability of body weight was higher in the JEF (0.63) than in the studs (0.53), but it was lower for fleece weight (0.27 vs. 0.41) and fibre diameter (0.35 vs. 0.68) in the JEF. Heritability and repeatability estimates for all subjectively assessed traits, with the exception of face cover in the JEF and pigmentation in both data sets, were moderate to low. Due to the fact that young bucks in South Africa are sold at 14–16 months of age with their full third fleece, performance testing has to be done at 8–9 months of age at the second shearing. As fleece weight had the lowest repeatability of the three production traits, it was recommended the fleece weight be left out of the selection index. The possible inclusion of style in the selection index needs to be investigated further. As far as the other subjectively assessed traits are concerned, it is recommended any selection for the further improvement of these traits should be based on independent culling levels and they should not be included in the selection index.

Faecal egg counts in Angora goats following natural or experimental challenge with nematode parasites: within-flock variability and repeatabilities

Phenotypic variation in faecal worm-egg count (FEC) was studied in 100 Angora goats between 6 months and 2 years old as part of a wider investigation into the potential use of FEC as a selection trait in breeding goats for improved natural resistance to nematode infection. Shortly after weaning at 4–5 months old the goats were subjected to a procedure involving successive natural and experimental challenges, which was continued at 6-monthly intervals until the goats were 2 years old. Experimental challenges consisted of Trichostrongylus colubriformis infective larvae administered orally at a dose rate of 1000 larvae/kg liveweight. FECs resulting from both natural and experimental infections varied considerably between individual goats as well as between different sampling times. Mixed model analysis of variance of natural infections confirmed that a significant component of this variation was attributable to differences between individual goats ( P < 0.01) as opposed to other potential sources of variability, indicating that although generally deemed to be more susceptible than sheep, Angora goats do nevertheless vary in their ability to resist nematode infection. Rank correlations between pairs of FECs derived from the same infection were relatively high for both natural and experimental infections ( r = 0.63–0.70 and 0.54–0.79, respectively; all P < 0.01). However, those between mean FECs measured on successive 6-monthly sampling occasions were considerably lower and more variable ( r = 0.01–0.41 and 0.19–0.62 for natural and experimental infections, respectively). Nevertheless, FECs resulting from natural infections showed moderate correlations with those from corresponding experimental infections ( P < 0.01) on all except the first sampling occasion ( r = 0.23–0.61). Correlations were marginally higher when FECs from experimental infections were adjusted for infecting dose size ( r = 0.32–0.63). FECs resulting from experimental infections were significantly higher on the first sampling occasion (at 6 months) than on subsequent occasions ( P < 0.01) suggesting that some degree of resistance to nematode establishment had developed in the goats by 12 months old. On the basis of unadjusted FECs there appeared to be no marked increase in resistance beyond that age, although analyses based on FECs adjusted for infecting dose size suggested an increase in acquired resistance up to 18 months of age. FECs following natural challenge in goats which had also received experimental infections were not significantly different from those exposed only to natural challenge, indicating that the drench-abbreviated experimental infections had had no immunizing effect. Does that had given birth and were lactating at 24 months had significantly higher FECs than ‘dry’ does in the flock ( P < 0.01), suggesting that like sheep, goats exhibit a post-parturient relaxation of immunity. The use of FECs as potential indicators of resistance status in goats and as a criterion for the selection of breeding animals is discussed.

Effects of zinc-methionine on performance of Angora goats

Effects of supplementation with zinc-methionine (Zn-Met), a source of potentially rumen protected methionine and zinc (Zinpro 40, Edina, MN), on mohair growth, BW gain and blood metabolites were investigated in Angora goats. Forty yearling Angora goats (20 wethers and 20 doelings) were offered a basal diet (11.2% CP, 22 ppm Zn, 2.3 Mcal/kg DM) at 4% BW of DM for 120 days. The treatments (1–5) were: 1, 3 and 5 g/day of Zn-Met, 150 mg/day of zinc oxide and control (no supplementation). Supplementation of the diet with Zn-Met (1, 3 and 5 g/day of Zn-Met) increased ( P < 0.07) ADG (65.5 versus 55.9 g/day for control). ADG for goats receiving ZnO was lower ( P < 0.04) than for goats receiving a similar amount of Zn from 3 g/d Zn-Met (50.5 versus 62.9 g/day), although Zn-Met inclusion in the diet numerically ( P = 0.13) increased clean mohair production, which also changed quadratically ( P < 0.09) as Zn-Met level increased (1.59, 1.51, 1.62, 1.60 and 1.59 kg in 120 days) for treatments 1, 2, 3, 4 and 5, respectively. Supplementation of the diet with Zn-Met increased ( P < 0.03) plasma Zn concentration (0.92 versus 0.72 mg/l for control); there were no differences in plasma Zn concentration between goats receiving the ZnO supplement and goats receiving a similar amount of Zn from Zn-Met (0.87 versus 0.92 mg/l; P > 0.56). Plasma methionine concentration was not affected by Zn-Met supplementation ( P > 0.53). In summary, supplementation of a Zn-adequate diet with Zn-Met increased ADG by yearling Angora goats regardless of level of Zn-Met added. Supplementation of 1 g Zn-Met may have positive effect on ADG and mohair growth when diet contains about 20 ppm Zn.

Effects of mimosine on plasma amino acid concentrations in Angora goats

Effects of mimosine intravenously infused for 2 days or orally dosed on plasma amino acid concentrations in Angora goats were determined. In one experiment, 20 mature Angora wethers (36 ± 1.9 kg BW) were infused for 2 days with 79, 102 and 135 mg/(kg BW/day) of mimosine, 90 mg/(kg BW/day) of 2,3-dihydroxypyridine (2,3-DHP) or saline; plasma was sampled before infusion and 24 and 48 h later. At 7 days after infusion began, fleece shedding was observed in all goats receiving mimosine, but not in any goats infused with 2,3-DHP or saline. Mimosine depressed ( p < 0.05) plasma concentrations of Gly, Thr, Arg and Lys, with mimosine level having no effect. Conversely, amino acid concentrations in goats infused with 2,3-DHP were similar ( p > 0.10) to levels in Control goats. In another experiment, Angora bucklings (23 ± 0.5 kg BW) were orally dosed with 400 or 600 mg/kg BW of mimosine; plasma samples were collected before dosing and 22 and 46 h later. At 9 days after oral doses of mimosine, no fleece shedding was noticeable; however, at 31 days changes in fleece status of some goats were observed. For Thr and Arg, mimosine dosing decreased plasma concentrations at 22 h compared with concentrations before dosing ( p ≤ 0.05), and for Thr, Arg and Lys mimosine dosing increased amino acid concentrations at 46 h ( p ≤ 0.05). The increase in Val concentration due to mimosine dosing was greater than 0 for 400 mg/kg BW of mimosine ( p < 0.05) and at 46 h ( p < 0.01), and was greater ( p < 0.05) at 46 than 22 h. The increase in Leu concentration due to mimosine dosing differed from 0 for 400 ( p < 0.05) and 600 mg/kg BW of mimosine ( p < 0.05) and at 46 h ( p < 0.01), and was greater ( p < 0.05) at 46 versus 22 h. In conclusion, 2-day infusion of mimosine to defleece altered plasma concentrations of some amino acids.

Effects of level of feed intake on body weight, body components, and mohair growth in Angora goats during realimentation

Sixteen Angora wethers (14 months of age and 33 ± 1.3 kg BW) consumed a 14.7% CP, 70% concentrate diet for 40 days at 51%, 65%, 83%, and 100% of ad libitum intake (severe restriction, moderate restriction, low restriction, and ad libitum intake, respectively), followed by 41 days of realimentation with ad libitum consumption, to evaluate mohair growth and BW change. BW change in the last 21 days of the realimentation phase increased linearly ( p = 0.07) as the level of feed intake during the restriction phase decreased (87, 31, 36, and 14 g/day for severe restriction, moderate restriction, low restriction, and ad libitum intake, respectively SE 23.6). Clean fiber growth rate in the last 20 days of the restriction phase decreased linearly ( p = 0.08) as level of feed intake decreased (15.2, 16.0, 15.8, and 18.1 g/day for severe restriction, moderate restriction, low restriction, and ad libitum, respectively; SE 0.99), as also occurred ( p = 0.07) in the last 21 days of the realimentation phase (14.7, 13.2, 17.1, and 17.2 g/day for severe restriction, moderate restriction, low restriction, and ad libitum intake, respectively; SE 1.30). BW change and clean fiber growth rate within the latter period of restriction or realimentation phases were not correlated ( p > 0.10). In conclusion, the level of feed intake can have a more prolonged effect on mohair growth than BW change.

Resistance of field isolates of Trichostrongylus colubriformis and Ostertagia circumcincta to ivermectin

Twelve Romney lambs and 10 Angora goats were infected with 7000 infective third-stage larvae (89% Trichostrongylus, 11% Ostertagia) collected from goats suspected of harbouring ivermectin-resistant nematodes. On 28 days p.i., the lambs and goats were divided into treatment and control groups of six and five animals, respectively. The animals in the treatment groups were treated with ivermectin (0.2 mg/kg) and necropsied 35 days p.i. Faecal egg counts were estimated on days 28 and 35 p.i. and larval development assays (LDAs) were conducted on 22, 24, 26, 28, 30, 32, 34 and 35 days p.i. The ivermectin treatment reduced Trichostronglus colubriformis burdens by 39% and 13% and Ostertagia circumcincta by 33% and 0% in lambs and goats, respectively. When compared with a susceptible strain, the LDAs indicated a resistance factor before treatment in lambs for T. colubriformis of 2.6 and 1.5 with ivermectin and avermectin B 2, respectively, which rose to 3.4 and 2.0 after treatment. The LD 50 values of the two control groups were relatively constant throughout the experiment. Prior to ivermectin treatment the LD 50 values of the treated groups were similar ( P>0.05) to the control groups but following ivermectin treatment their LD 50 values increased steadily until the animals were killed on 35 days p.i. The LD 50 values for ivermectin and avermectin B 2 of sheep were always slightly higher and significantly different ( P<0.01) than those of goats indicating a host effect on this parameter. The greater reduction in worm counts in goats suggests a difference in the efficacy of ivermectin between lambs and goats. This is the first confirmed report of ivermectin resistance in a field strain of T. colubriformis.

Variation in fibre and fleece characteristics between and within South African, New Zealand, and South African x New Zealand Angora goat genotypes

Twenty Angora goats of each of three genotypes, South African, New Zealand, and South African × New Zealand (Crossbred), were sampled prior to their third shearing at 18 months of age. Fibre samples were taken at six sites, neck, shoulder, midside, britch, belly, and back. Staple length, yield, fibre diameter, variation in fibre diameter, medullation, and kemp levels measured on each sample. Genotype, site, and genotype × site effects were significant (P < 0.01) for all traits except mean fibre diameter. South African and Crossbred fibre was longer and length was less variable than in New Zealand fleeces. There was no difference (P ≥ 0.05) in mean fibre diameter between genotypes but coefficient of variation of fibre diameter was significantly higher (P < 0.01) in New Zealand than Crossbred and South African fleeces. Medullation and kemp levels were low in South African fleeces, less than 1% medullation and 0.5% kemp, with little difference between sites. Medullation and kemp levels were significantly higher (P < 0.01) in New Zealand than Crossbred fleeces, with similar trends in variation between sites for both genotypes. Quality of mohair from South African and Crossbred goats at 18 months of age was better than from New Zealand goats, with South African fibre also superior to Crossbred fibre for some characteristics.

Intake of Ashe Juniper and Live Oak by Angora Goats

Angora mutton goats (Capra hircus) were fed diets of either live oak [Quercus virginiana (Small) Sarg. var. fusiformis], alfalfa hay (Medicago sativa L.), Coastal bermudagrass hay (Cynodon dactylon (L.)Pers.) or female ashe juniper (Juniperus ashei Buchholz) plus Coastal bermudagrass hay during the spring and fall of 1991 in a digestion/metabolism study. Nitrogen concentration of Coastal bermudagrass hay was nearly equal to that of alfalfa hay; nitrogen concentration of ashe juniper and live oak were much lower than those of the hays, and were higher in fall than spring. Dry matter intake and dietary nitrogen were highest for alfalfa hay, intermediate for Coastal bermudagrass hay, and lower for ashe juniper and live oak. Goats retained more nitrogen when consuming alfalfa and Coastal bermudagrass hays than juniper or live oak during fall, but differences were smaller (P > 0.10) during spring. Nitrogen balance was negative for goats consuming live oak in the spring. Nitrogen balance was positive for live oak in the fall and positive for ashe juniper for the spring and fall. Animals fed hay diets had higher levels of urine output than those fed juniper or live oak. Dry matter digestibility of juniper and live oak diets was less in fall than in spring. During fall, dry matter intakes of juniper and live oak were significantly lower than those of alfalfa and Coastal bermudagrass hays. We conclude that both ashe juniper and live oak foliage can provide nutrients for goats but only as portions of diets.