GB2276085A

GB2276085A - Enhancing wool production and quality in breeding ewes

Info

Publication number: GB2276085A
Application number: GB9404014A
Authority: GB
Inventors: Ray Johnson
Original assignee: Rhone Poulenc Nutrition Animale SA
Current assignee: Adisseo France SAS
Priority date: 1993-03-04
Filing date: 1994-03-02
Publication date: 1994-09-21
Also published as: FR2702129A1; GB9404014D0; ZA941540B; CN1107288A; IE940193A1; RU94007077A

Abstract

Wool production in breeding ewes, in terms of both quality and quantity, is improved by administration of a protected amino acid, especially methionine or lysine. The amino acid is preferably protected (coated) by a polymer based composition and may be administered as a medicated grain feed supplement.

Description

NETHOD FOR IMPROVING WOOL PRODUCTION AND WOOL QUALITY IN BREEDING EWES The invention relates to a method for improving wool production and wool quality in breeding ewes.

When breeding ewes undergo late pregnancy, parturition and lactation, they suffer both nutritional and physiological stress. Such stress is known to result in both a reduction in wool growth rate and also a transient thinning of wool fibre. Fibre thinning can result in a significant and progressive down grading of the value of the whole fleece if tensile strengths fall below 35N/K tex and in extreme cases, can lead to wool fibre breakage~tender wool or shedding).

At least some of these effects are attributable to the combination of poor nutrient input from sparse dry pasture and the additional requirements for nutrients to support foetal growth and lactation.

A requirement accordingly exists to at least minimise the depression in wool production and wool quality which occurs in breeding ewes around the time of lambing.

The present invention provides a method for improving wool production in a breeding ewe which comprises administering an effective amount of a protected amino acid to the breeding ewe.

According to a feature of the present invention wool quality in a breeding ewe is improved by administering an effective amount of a protected amino acid to the breeding ewe.

Wool production is increased by both an increase in wool fibre length and an increase in the volume growth rate of the wool.

The present invention thus also provides a method for increasing the wool fibre length and volume growth rate of wool in a breeding ewe which comprises administering an effective amount of a protected amino acid to the breeding ewe.

According to yet another aspect of the present invention, the wool fibre tensile strength of a breeding ewe is improved by administering an effective amount of a protected amino acid to the breeding ewe.

The protected amino acid may be administered to single or twin bearing ewes.

Preferably the ewe is a Merino ewe as the wool of such ewes is of a high value. However, it will be appreciated that the wool of other breeds of ewe will also benefit from the effects of the present invention.

The amino acid is preferably methionine or lysine or a mixture of both, more preferably methionine.

The amino acids administered to the ewe may be protected in the following manner using, for example, three types of polymer-based composition.

The first type of polymer-based composition comprises a combination of a basic amino copolymer and a hydrophobic substance of which the melting point is greater than 60"C and/or of a polymer which has limited solubility in water. The basic amino copolymer may be obtained, for example, from the reaction of: - a neutral ethylenic monomer such as methyl acrylate or methacrylate, styrene, acrylonitrile or vinyl acetate; and - a diethylenic monomer having a basic nitrogen containing group such as diethylaminoethyl acrylate or methacrylate, tert-butylaminoethyl acrylate or methacrylate, morpholinoethyl methacrylate or a vinylpyridine.

The hydrophobic substance is preferably a fatty acid, a fatty ester, a fatty alcohol, a paraffin or a natural or synthetic wax. Preferably, the hydrophobic substance is stearic acid. The polymer insoluble in water is generally a cellulose ether or ester such as ethylcellulose or cellulose acetobutyrate, or a polyvinyl ester such as polyvinyl acetate. A composition comprising 85% by weight of amino acid for 15% by weight of coating is preferably employed.

The coating generally contains 10 to 30% of basic amino copolymer and from 70 to 90% of an optional mixture of a hydrophobic substance and a polymer insoluble in water.

The second type of polymer-based composition which can be used comprises a mixture of a natural polymer such as zein, in combination with a hydrophobic substance having a melting point greater than 60"C and/or a polymer which has limited solubility in water.

A composition containing 10 to 90% of zein and 10 to 90% of a hydrophobic substance and/or a polymer insoluble in water is preferably employed.

A third type of polymer-based composition which can be used comprises a mixture of chitosan, in combination with a hydrophobic substance. A composition containing 1 to 5% of chitosan and 95-99% of hydrophobic substance having a melting point over 45"C is preferred.

A plasticizing agent may be added to the above compositions. Plasticizing agents include, in particular, triacetine, propylene glycol, butyl phthalate and sodium oleate.

The coating compositions described above are known, and have been described in European Patent No. 260186 for the first type of composition and in European Patent No.

321337 for the second type of composition.

The protected amino acids are preferably provided in the form of a medicated grain supplement which is fed to the breeding ewes generally over a 2 to 3 month period. The ewes are preferably fed the protected amino acid around late pregnancy and lactation. Preferably about 0.8 to 2g of amino acid, more preferably 1.6g of methionine is administered to the breeding ewe per day with supply of amino acid achieved by feeding 3 times a week.

The present invention is illustrated by the following Examples.

EXPERIMENT DESIGN The experiments were conducted in ewes lambing in Australia in Autumn. The experiments allowed for the assessment of the effects of a single dose rate of protected methionine (2g/h/d average) in two flocks of breeding ewes maintained on average and poor pasture. Two contemporaneous untreated control groups were maintained at the same stocking rate under the same average or poor pasture conditions in adjacent paddocks to the respective groups of treated ewes.

The product was tested on ewes at the "high" and "low" nutrition levels defined by pasture conditions on the Northern and Southern sides of the property, respectively.

Experimental animals (4 groups of 200) were selected from a larger flock of 1453 breeding ewes in order to achieve a balanced representation of 20% non-pregnant ewes, 50% single bearing and 30% twin bearing ewes in each group. The final lambing percentage in each flock was 110 lambs per 100 ewes present.

This group substructure allowed for analysis of effects on a whole flock basis as well as separate analysis of the effects of treatment in ewes with different litter size.1 1 Maximum emphasis and replication was given to the single bearing ewes since this is the predominant litter size in Merino flocks in Australia. While a lambing percentage of 110% is typical under Australian conditions it is generally true that the litter size distribution of a flock within this final lambing percentage would be 10% non pregnant, 70% single bearing and 20% twin bearing.

The litter size distribution used in this study (20:50:30) was to achieve sufficient numbers of ewes in each litter size class for quantitative assessment of effects.

Grain Supplements Ewes in all groups received a supplement of whole oat grain at an average rate of 300gm/h/day premixed with 2% (w/w) molasses binding agent for protected methionine microspheres.

Supplementary feeding was conducted three times weekly with one third of the weekly ration being given on Monday, Wednesday and Friday. On each feed day, a total of 140kg of grain feed was trailed along the ground for each experimental group. This allowed uncrowded access to the grain for all ewes present.

Treatments and Preparation of Medicated Grain Treated groups 2 (high nutrition) and 4(low nutrition) received small (approx. l.Omm diameter) microspheres consisting of cores of DL-methionine mixed with binding agents, which were coated with a pH sensitive copolymer of 2-vinylpyridine/styrene. The spheres consisted of approximately 70% methionine (% weight) and the product was known as Rhone-Poulenc SMARTAMINE-S protected methionine.

The treatment dose rate was 2.0gm/head/day finished of product (average product dose per day per ewe).

The treatment was administered as a medicated oat supplement.

The microspheres were thoroughly mixed with oats using a Universal Feeder Mixer (Wormbat Industries, Queensland) and bound to the grain with 2% liquid molasses added at the time of mixing.

Rations were made up at 2-4 weekly intervals and bagged off into 20-30kg colour coded bags ready for the farmer to feed out to each experimental group.

Control ewes received grain mixed with 2% molasses but without methionine.

No mould or deterioration was seen in any of the grain bags throughout the experiment.

Schdule of Events for Experiment The treatment period of the experiment was conducted during Autumn in Australia (April and May) at which time pasture is usually poor after the dry, hot summer period but also at which time the first Autumn rains can result in rapidly improving pasture conditions with a return to green feed.

The ewes were joined to rams in November of the previous year and were individually ear tagged in December to facilitate selection into the trial groups. Ewes were shorn in February and their pre-experiment fleece weights were recorded.

The ewes underwent pregnancy diagnosis by realtime ultrasonic scanning in late February and 800 selected ewes were allocated to the four experimental groups on 16 March. A dye band was applied to the wool on 16 March (DB1) and again on 8 April (DB2) to allow for analysis of pretreatment fibre growth and quality for all ewes.

Treatment commenced in groups 2 and 4 on 8 April, approximately 4 weeks prior to the mean predicted lambing date of 6 May.

Treatment continued until 14 June (last feed), thus providing a treatment during the first 6 weeks of lactation (on average) and a total duration of treatment for all ewes of 10 weeks.

A third dye band was applied to wool at the end of treatment on 14 June (DB3) and all ewes were observed for one month after cessation of treatment until the last dye band was applied on 26 July (DB4).

The lambs were not individually identified with their respective mothers and the flocks were disturbed minimally during the lambing period, except for 3 time weekly feeding and any routine husbandry.

All of the breeding ewes were weighed and assessed for condition score (scale of 1, lowest to 5, highest) prior to the trial, at allocation, at the commencement of the pre-treatment period (16 March), at the commencement (6 April) and end of treatment (26 June) and at the time of weaning of 16 July.

An assessment of the ewes rearing lambs was made by wet/dry udder scoring on 14 June.

Dye banded mid side wool staples were removed approximately one month after application of DB4 and were taken for linear measurement and tensile strength testing.

Greasy fleece weights were recorded for all ewes at the annual shearing following the trial. Ewes were shorn on February of the year after lambing.

Marking of Wool and Measurement of Length Growth Freshly prepared URSOL-D in hydrogen peroxide was administered to the base (skin level) of a mid flank wool staple on all ewes on 16 March, 6 April, 18 June and 26 July.

Wool length growth was determined as follows:

Inter dye Days Dye band segment Phase of trial band period designation 16 Mar-6 Apr 31 "A" Pre-treatment period 6 Apr-18 Jun 73 "B" Treatment period 18 June-26 Jul 38 "C" Post treatment period Length growth between dye bands (mm) was determined by hand measurement using a Vernier calliper.

Length measurements were taken on unstretched wool staples.

Fleece Weight Ewe fleece weight was recorded at shearing in February. These fleece weights represent fleece growth at 12 month period during which time the ewes underwent treatment, for just 10 weeks.

The Examples will now be described with reference to the accompanying drawings in which: Figure 1 shows the structure of the experiment conducted; Figure 2 shows the schedule of events for the experiment; Figure 3 shows the effect of protected methionine on the liveweight of non-pregnant single bearing and twin bearing ewes; Figure 4 shows the effect of protected methionine on the wool fibre strength in non-pregnant, single bearing and twin bearing ewes; Figure 5 shows the effect of protected methionine on the wool fibre volume growth rate in non-pregnant, single bearing and twin bearing ewes; and Figure 6 shows the effect of protected methionine on the greasy fleece weight of non-pregnant, single bearing and twin bearing ewes.

Example 1 - Effects of Protected Methionine on Body Weight and Condition in Breeding Ewes (a) Single bearing ewes In single-bearing ewes the treated ewes were slightly (1.19,P < 0.02) heavier than controls at the start of treatment. This difference increased during treatment so that by the end of treatment the ewes receiving protected methionine were 3.49% or 1.32kg/h (P < 0.001) heavier than controls. Over this period all pregnant sheep lost approximately 14kg/h due to the combined effects of lambing and lactation and also due to the reduced pasture availability during a very dry and hot Autumn.

Condition score was also higher (P < 0.001) in treated single bearing ewes (c.s. at the end of treatment 1.18 + 0.04) than in controls (c.s. 0.96 + 0.03). These low condition scores (out of a scale of 1-5) are indicative of the extremely difficult nutritional circumstances prevailing during the trial.

(b) Twin bearing ewes Twin bearing ewes also underwent losses of liveweight and condition score due to the foetal and lactational burden. Despite these losses, treatment of twin bearing pregnant ewes with protected methionine resulted in liveweights being 4.178 (1.56kg) higher than controls (P < 0.001) at the end of the treatment period. This effect continued into the post-treatment period.

The mean condition score of treated ewes (c.s. at the end of treatment 0.97), though low overall due to the stress of the season, was higher (P < O.001) than that in the control twin bearing ewes (c.s. 0.77). Significant interactions between methionine treatment and level of pasture were observed in the condition scores of twin ewes at the end of treatment but otherwise the effects of methionine were independent of pasture feed.

(c) Non-pregnant ewes No significant effects of protected methionine treatment were observed in non-pregnant ewes which largely maintained liveweight and condition score over the experimental period.

Overall, the effects of protected methionine on liveweight and condition score in these breeding ewes were small and far outweighed by physiological and nutritional stress of pregnancy and lactation.

Example 2 - Effects of Protected Methionine of Linear Wool Growth, and Wool Growth in Pregnancy and Lactation (a) Single bearing ewes Fibre length growth rate was increased by 4.93% (P < 0.001) by protected methionine during the treatment period but not in the post-treatment period.

This effect on length growth was independent of level of pasture feed; The effect of increased length resulted in an increase of 13.66% (P < 0.001) in the volume growth rate of wool during the treatment period for single bearing ewes given the protected methionine.

(b) Twin bearing ewes In twin bearing ewes, protected methionine treatment resulted in a 7.28% increase (P < 0.001) in length growth rate which persisted to the post-treatment phase (+ 5.49%, P < 0.01).

The effect of treatment on length growth in twin bearing ewes was independent of level of pasture available.

The effect of increased length growth resulted in an 11.43% increase (P < 0.01) in wool volume growth rates during treatment of twin bearing ewes.

This effect persisted (+ 10.54%, P < 0.05) in the post-treatment period.

(c) Non-pregnant ewes Treatment of non-pregnant ewes with protected methionine had a non-significant effect (+ 2.17%, n.s.) on fibre volume growth rate. In summary, while the effects were small in non-pregnant ewes there were increases in fibre growth during both the treatment and post-treatment periods in the pregnant/lambing ewes.

Example 3 - Effects of Protected Methionine on Tensile Strength of Wool from Breeding Ewes Tensile strength was high in both treated (67.2N/Ktex) and control untreated controls (66.98 N/Ktex).

These differences were not significant.

In contrast, fibre strength was improved by 8.8t (P = 0.052) in the single bearing ewes which were treated (52.27 N/Ktex) compared to controls (48.04 N/Ktex) similar effects were seen in the twin bearing ewes which, after treatment, showed an 8.9 increase in tensile strength from 43.97 N/Ktex in control to 47.90 N/Ktex in treated animals.

On a whole flock basis, including non-pregnant, single and twin bearing ewes, the average tensile strength of wool was increased by 5.2% or + 2.79 N/Ktex (P < 0.05) due to treatment with protected methionine.

Surprisingly, despite the generally poor pasture conditions in this trial the wool grown was still of commercially acceptable strength (in the 45-70 N/Ktex range) for 20-21 micron wool.

It is expected that the increase in tensile strength would assume great or commercial significance in situations where penalties would be applied to weaker wool.

Example 4 - Effect of Protected Methionine on Fleeceweight in Breeding Ewes Fleece weights at annual shearing in the season of treatment were slightly higher in single bearing (+1.5% n.s.) and in twin bearing ewes (+2.7%, P < 0.05) and in nonpregnant ewes (+1.8%, n.s.).

Overall, on a whole flock basis, treatment with protected methionine increased greasy fleece weights by an average of +2% (P < 0.025).

Example 5 - Summary of the Results of Examples 1 to 4 Examples 1 to 4 have shown that protected methionine can be used to improve both wool production and wool quality in breeding ewes carrying single or twin foetuses/lambs.

In this case the product was applied in late pregnancy and lactation during a season of particularly poor pasture feed due to a last occurrence of Autumn rains for this property. The responses to treatment were statistically significant on a whole flock basis.

Lamb marking percentages were similar in all groups as follows: High Nutrition Low Nutrition Control 95.4% 80.7% Mothers treated 86.1% 82.5% with pM Since lambs were not identified to individual ewes, no assessment of the survival of singles and twins could be made.

Overall (mean) lamb liveweights at marking on 19 June were slightly higher for lambs from the treated mothers as follows: High Nutrition Low Nutrition Control 11.51kg 10.12g Mothers treated 12.32kg 10.52kg with pM This data suggests that protected methionine is safe for use in breeding flocks at around late pregnancy and lactation.

Claims

1. A method for improving wool production in a breeding ewe which comprises administering an effective amount of a protected amino acid to the breeding ewe.

2. A method for improving wool quality in a breeding ewe which comprises administering an effective amount of a protected amino acid to the breeding ewe.

3. A method for increasing the wool fibre length in a breeding ewe which comprises administering an effective amount of a protected amino acid to the breeding ewe.

4. A method for increasing the volume growth rate of wool in a breeding ewe which comprises administering an effective amount of a protected amino acid to the breeding ewe.

5. A method for increasing the wool fibre tensile strength of a breeding ewe which comprises administering an effective amount of a protected amino acid to the breeding ewe.

6. A method according to any one of the preceding claims, wherein the breeding ewe is a single or twin bearing ewe.

7. A method according to any one of the preceding claims, wherein the breeding ewe is a Merino ewe.

8. A method according to any one of the preceding claims, wherein the amino acid is protected by a polymer-based composition.

9. A method according to Claim 8, wherein the polymer-based composition comprises a combination of a basic amino copolymer and a hydrophobic substance of which the melting point is greater than 60"C and/or of a polymer which has limited solubility in water.

10. A method according to Claim 9, wherein the basic amino copolymer is obtained from the reaction of a neutral ethylenic monomer with a diethylenic monomer having a basic nitrogen-containing group.

11. A method according to Claim 8, wherein the polymer-based composition comprises a mixture of a natural polymer and a hydrophobic substance having a melting point greater than 60 C and/or a polymer which has limited solubility in water.

12. A method according to Claim 11, wherein the natural polymer is zein.

13. A method according to any one of Claims 9 to 12, wherein the polymer having limited solubility in water is a cellulose ether or ester.

14. A method according to Claim 8, wherein the polymer-based composition comprises a mixture of chitosan and a hydrophobic substance.

15. A method according to any one of Claims 9 to 14, wherein the hydrophobic substance is a fatty acid, a fatty ester, a fatty alcohol, a paraffin or a natural or synthetic wax.

16. A method according to Claim 15, wherein the hydrophobic substance is stearic acid.

17. A method according to any one of the preceding claims, wherein the amino acid is methionine, lysine or mixtures thereof.

18. A method according to any one of claims 1 to 16, wherein the amino acid is methionine.

19. A method according to any one of the preceding claims, wherein the breeding ewe is fed the protected amino acid around late pregnancy and lactation.

20. A method according to any one of the preceding claims, wherein the effective amount of amino acid is about 0.8 to 2 grams per day at the rate of 3 times a week.

21. A method according to Claim 20, wherein the effective amount of amino acid is 1.6 grams per day at the rate of 3 times a week.

22. A method according to Claim 1, substantially as hereinbefore described in the foregoing Examples.

23. A method according to Claim 1, substantially as hereinbefore described with reference to the accompanying drawings.

24. Wool whenever obtained by a method according to any one of the preceding claims.