Seasonal variation in fibre diameter and length in wool of grazing Merino sheep with low or high staple strength

Schlink, AC; Mata, G.; Lea, Jim M.; Ritchie, Andrew J.

doi:10.1071/ea98131

Cited by 24 publications

(6 citation statements)

References 20 publications

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“…Wool growth during the pre-treatment covariate period and between days 81 and 123 was determined from mid-side patches 17 . LW was recorded at approximately 3-weekly intervals throughout the experiment.…”

Section: Experimental Methodsmentioning

confidence: 99%

Reponses of sheep to a vaccination of entodinial or mixed rumen protozoal antigens to reduce rumen protozoal numbers

et al. 2007

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Two rumen protozoa vaccine formulations containing either whole fixed Entodinium or mixed rumen protozoa cells were tested on Merino sheep with the aim of decreasing the number and/or activity of protozoa in the rumen. Negative control (no antigen) and positive control (Tetrahymena corlissi antigens) treatments were also included in the experiment. Blood and saliva were sampled to measure the specific immune response. Protozoal numbers in the rumen were monitored by microscopic counts. Vaccination with protozoal formulations resulted in the presence of specific IgG in plasma and saliva, but saliva titres were low. Titres after secondary vaccination were higher (P,0·05) than after primary vaccination. There was a moderate (r 2 0·556) relationship (P, 0·05) between plasma and saliva titres for the rumen protozoal vaccine formulations. Rumen protozoa were not decreased (P. 0·05) by the vaccination and there was also no difference (P.0·05) between treatments in rumen fluid ammonia-N concentration or wool growth. In vitro studies investigated the binding ability of the antibodies and estimated the amount of antibody required to reduce cell numbers in the rumen. The studies showed that the antibodies did bind to and reduced protozoa numbers, but the amount of antibody generated by vaccination was not enough to produce results in an in vivo system. It is suggested that the vaccine could be improved if specific protozoal antigens are determined and isolated and that improved understanding of the actions of protozoa antibodies in rumen fluid and the relationships between levels of antibodies and numbers of protozoa in the rumen is needed. Antigens: Antibodies: Rumen protozoa: SheepThe rumen is populated with many types of micro-organisms, which degrade and ferment the feed eaten by the animal. However, from a production point of view, not all the micro-organisms present in the rumen are essential or provide efficient conversion of feed to protein 1 . Many studies have shown that if protozoa are removed from the rumen, a process known as defaunation, wool growth can be increased due to increased microbial protein outflow to the small intestine 1 -3 . However, successful defaunation methods can be laborious and impractical in normal animal husbandry settings and chemical-based methods can be detrimental to animal health 3,4 . Also, unless defaunated animals remain segregated from faunated animals, or are regularly re-treated with defaunation chemical, the ciliated protozoa are able to re-establish themselves in the rumen. An immunological approach to manipulating rumen microbial populations, specifically rumen ciliates, was investigated by Gnansampanthan 5 . Serum antibodies raised to rumen ciliates were shown to have an immobilizing effect on a mixed rumen ciliate population in vitro, which decreased the ciliates' predatory activity on bacteria 6 . Until now there has been no in vivo examination of the effects that protozoal vaccines have on the numbers of ciliate protozoa in the rumen. The aim of the present experiment w...

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Section: Experimental Methodsmentioning

confidence: 99%

Reponses of sheep to a vaccination of entodinial or mixed rumen protozoal antigens to reduce rumen protozoal numbers

et al. 2007

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“…Fiber diameter is a major determinant of wool quality and price and is usually infl uenced by nutrition in a similar manner to fi ber length, such that the ratio of fi ber length to FD is generally constant in sheep housed in pens as they are provided with a consistent supply of the same diet (Aitchison et al, 1989b;Schlink et al, 1999). As such, the lack of effect of crude glycerin on fi ber diameter is consistent with prior notions of the relationship between DMI and wool production.…”

Section: In Vivo Studymentioning

confidence: 99%

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

Meale

Chaves

Ding

et al. 2013

Journal of Animal Science

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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.

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“…This result could be attributed to the improvement in fiber diameter uniformity during autumn as presented in (Table 2). Total diameter variation has a strong negative phenotypic association with staple strength (Ritchie and Ralph, 1990;Reis, 1992;Schlink et al, 1999). The majority of variations in staple strength were thought to be based on differences in intrinsic fiber strength (Gourdie et al, 1992) and fibers stretching ability (Holman and Malau-Aduli, 2012).…”

Section: Wool Productionmentioning

confidence: 99%

“…The majority of variations in staple strength were thought to be based on differences in intrinsic fiber strength (Gourdie et al, 1992) and fibers stretching ability (Holman and Malau-Aduli, 2012). According to Schlink et al (1999), staple strength was most highly correlated to within staple variations in fiber diameter.…”

Section: Wool Productionmentioning

confidence: 99%

Wool Production and Characteristics, Physiological and Haematological Parameters and Level of some Metabolic Hormones in Barki Ewes Shorn in Autumn as Alternative of Spring Shearing

Taha

Abdel-Khalek

Khalil

et al. 2018

Journal of Animal and Poultry Production

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This study was conducted under the semi-arid desert conditions of the northwest coastal belt of Egypt to evaluate the effect of autumn vs. spring shearing on wool production, some wool traits, physiological responses, thermal gradients, haematological, biochemical parameters and hormonal profile of thyroxin (T4) and cortisol of adult Barki ewes. Results show that autumn shearing reduced (P<0.01) body weight loss; resulted in heavier (P<0.05) greasy fleece weight with lower fiber diameter (P<0.05) and improved the uniformity of wool fiber diameter, point of staple break (P<0.05) and wool staple elongation rate (P<0.01) compared with spring shearing. Spring shearing resulted in higher skin temperature (P<0.05) and thermal gradient between rectal and skin temperature (P<0.01), elevated (P<0.05) serum globulin concentration and declined (P<0.05) albumin/globulin ratio. Serum T4 and cortisol profiles were not affected by shearing in spring or autumn. These results indicated that altering shearing time of Barki sheep from spring to autumn may be safely conducted without negative effects on wool production, physiological responses, blood constituents and animal homeostasis. The reduction in body weight due to shearing suggests the necessity of providing additive food supplementation after shearing to avoid weight loss particularly in autumn.

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Seasonal variation in fibre diameter and length in wool of grazing Merino sheep with low or high staple strength

Cited by 24 publications

References 20 publications

Reponses of sheep to a vaccination of entodinial or mixed rumen protozoal antigens to reduce rumen protozoal numbers

Reponses of sheep to a vaccination of entodinial or mixed rumen protozoal antigens to reduce rumen protozoal numbers

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

Wool Production and Characteristics, Physiological and Haematological Parameters and Level of some Metabolic Hormones in Barki Ewes Shorn in Autumn as Alternative of Spring Shearing

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