1Jr. veL. j. ( 197 7) , 133, 48 3

AN I NEXPENSIVE METABO LIC HARNESS FOR FEMALE SHEEP By A. R. MICHELL

Department oj Medicine, Royal Veterinary College, N. Mimms, Hatfield, Herts

SUMMARY

The detailed construction, from inexpensive materials, of a harness suitable for bu lk collection of urine and faeces from female sheep over extended periods is described. Objectively and subjectively there appears to be little adverse effect on the sheep. Some minor problems are discussed.

I

TRaDUCTION

During a study requiring simultaneous observations of sodium excretion in seven sheep over an extended period economy precluded the use of metabolism cages. Periodic samples were rejected because of circadian rhythms and chronic catheterization raises problems of infection and its potentially serious consequences. Such difficulties are discussed by Nottle & Armstrong (1966) and Beal & Budtz-Olsen (1968 ). There are few available designs for ewes (Basset, 1952; Owen & Ingleton, 1961 ), that of Nottle & Armstrong (1966) using urine/faeces separators mainly influenced this one. It incorporates several original features, uses inexpensive materials and causes little important inconvenience to the sheep.

MATERIALS AND METHODS

The basis was a Stevenson ewe truss (RY 550, Portland Plastics, Hythe, Kent), resting securely and unobtrusively in channels shorn in the fleece (Fig. 1). The hind quarters and tail were also shorn. The backstrap needed shortening and the tail aperture enlarging. The ventral edge of the latter was replaced by a tape forming the dorsal edge of a wir.dow cut in the truss. This gave access to the vulva, resting within the treated sponge pad (I) of the urine/faeces separator (Fig. 2). The separator was steadied by strong elastic straps (2) fastened to a waist band, itself attached to the backstrap (Figs. 2 and 3). The elastic was kept tense, pressure being born by the sponge pad, and it was fastened by locking quick-release studs (Tenax, Lillywhites, London ) (3). Additional vertical stability and adjustment of the separator came from tapes

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BRITISH VETERINARY JOURNAL , 133, 5

secu ring its arch to the truss (4), and a tab on each side (5) attached to the truss via press stu ds with a range of sockets (6). The separator was polythene and the tubing and connectors were standard laboratory equ ipment, fixed with wire. The shelf (7 ) above the urine inle t combined a turn ed edge minimizing vulval trauma, with an angle allowing clearance or faeces. A posterior ridge (8) a llowed anchorage of bulldog clips fixing th e disposable faeces bags (8 in x 12 in , 250 gauge polythene). They were a lso attached to the separator arch (9) by stap led tabs carrying a press stud; these were re-used . The tail rested with in the bag but generally above the faeces. Initially the sheep shake their tails, but th ey soon settle. The anchorage of the faeces bags would have been improved by a small vertical plate at each end of the ridge (8), preventing the clips from sliding and protecting th em fi-om impact. The separator shelf rested as low as possible above the vu lva because the urinatio n posture tends to ease the chamber upwards . Above the outlet in the chamber Ooor was a thin horizontal polythene rod to stop stray faecal pellets forming a seal. The 90 ° bend in the o utlet tube was not ideal but curved corrugated tubes proved more vulnerab le during recumbency and harder to clean; a wider bore and a more ob lique angl e might have been better . The outlet tube terminated in a connector (10) which tied to one on the inlet tube of the urine bag (J I, Fig. I). This was a polythene wine bag with a tap bearing the inl et tube; the tap was switched off wh en bags were changed . The bag, slung by front and rear tapes rested flush below the abdomen. The exposed surface was reinforced with self-adhesive plastic which, together with waterproof adhesive tape, anchored the suspend ing tapes . Fo ur bags per sheep a ll owed routine washing, drying and repairs. They were very well to lerated and, being collapsible, needed no air-bleed. Their drawback is the difficulty in drying; the taps need to be removed and the bags pulled into an inflated sh ape in a 100°C oven . Periodically the bags need to be collapsed and reinflated to expel humid air.

RESULTS A N D DISCUSSION

After 12 weeks with the Stevenson truss, the sheep showed no sign of decubitus. Sample bags fU1d separators were o n six days in 10 to allow modifications or repairs on a routine basis. Samples were collected and inspections made at II a.m. and 4 p.m.; these inspections would have been easier with a tra nsparent separator. The truss had no effect on the sheep and the addition of the full metabolic harness had no significant e ffect. Food intake actually rose (779 ± 67 to 854 ± 60 g/day ± s.e. mean) and water intake fell slightly (J ·39 ±0 · 13 to 1·09 ±0 · 13 lIday). Sodium preference was unaffected (48 · 7 ± 11· 2 and 47·8%± 8· I), the sheep showing no change in the percentage of their total fluid intake which they selected from sodium solutions available as alternatives to water. The main problems were occasional minor vulval bruising, and blockage of the separator by faeces. The impregnated sponge pad tended to absorb urine and a silicone coating might have been useful. Without tests in a metabolic cage, it is difficult to estimate losses caused, for example, by malposition of the chamber or kinks in the outlet tube. During a six-week period the urine volume averaged 400 ± 19 ml (± s.e.

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METABOLIC HARN ESS FOR EWES

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mean) on days when absolu tely no such problems were noted (70%). On remaining days inspection of the harness suggested that some urine loss might have occurred although bulk urine samp les had successfull y accumu lated in the maj ority of instances. Similarly, on 93% of occasions the faecal co llection appeared satisfactory a nd averaged 530 ± 22 g. Th e sheep drank 1·5 to 2 I and Duthie (I 96 J) fo und urine o utputs of 0·4 to 2 I in sheep drinking comparably. Th e sod ium recovered in urine a nd faeces during the six weeks accounted for 68% of the calculated inta ke from chaff, concentrates, and solutions compared with th~ control data of English (I 96 7) showing 83% recovery using metabolism cages. Sodium retention due to growth was trivial, average weight gain per 10 days being 0·14 kg/s heep. With minor modifications, this harness cou ld attain a high degree of reliability not restl-icted to indoor experiments providing that fenc ing or penning is reasonab ly fi·ee of projections. Allowing for price increases the equipment would now cost about £ I 0 per sheep excl uding labo ur. Although the harness req ui res m ore tim e in ma in tenance and supervision than a metabo lic cage, it is very much less expens ive and thus allows th e sim ultaneous study of more animals . It also p ermits the sheep much greater Ireedom to b ehave naturally. The harness therefo re provides a useful a lterna tive method lo r th e co llection of urine and faeces from ewes, particularl y where the emphasis is o n bu lk sampling thro ughout th e 24 h period rather than on abso lu te balance studies. ACKNOWLEDG EM ENTS

Th is work was supported by the Agricultural Research Council a nd Clem ent Stephenson Trust a nd was part of a doctoral dissertation (University o f Lo ndon ) executed under the helpful supervision of Professor F. R. Bell. The separator was constructed by V. C. Tindley of the Dept. of Physiology, Royal Veterinary Coll ege. Photography by A. J. Wagstaff. REF ERE NCES

BASSET, E. G. ( 1952 ). N.Z.}. Sci. Technol. 3 4, 76. BEAL, A . M . & BUDTZ -O LSEN, O . E. ( 1968 ). Awt.}. agric. Res. 19, 11 3. D UTH IE, j. A . (196 I). Ph .D. Thesis, University of Aberdeen. ENGLISH, P. B. ( 1967 ). Br. vet .}. 123, 118. NOTTLE, M. C. &ARMSTRONG,j. M. (1966 ). Awt.}. agric. Res. 17, 165. OWEN,j. B. & i NGLETON, j. W. (1 961). Anim. Prod. 3 , 63.

(Accepted jor publication 26 October /9 76)

An inexpensive metabolic harness for female sheep.

1Jr. veL. j. ( 197 7) , 133, 48 3 AN I NEXPENSIVE METABO LIC HARNESS FOR FEMALE SHEEP By A. R. MICHELL Department oj Medicine, Royal Veterinary Coll...
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