The Mowat Lamb Tailer Reports on Departmental Trials

New Zealand Journal of Agriculture, Volume 72, Issue 1, 15 January 1946, Page 17

The Mowat Lamb Tailer Reports on Departmental Trials

By

T. K. Ewer and J. J. Hancock,

Animal Research Division,

Ruakura.

f I ’HE influence of various methods of castration and tailing of lambs A upon their subsequent growth, as judged by live-weight gains, has been investigated by several workers both overseas and in New Zealand (Garner and Sanders, Journal Agricultural Science, 26: 2, 1936; Ewer, New Zealand Journal of Agriculture, 65: 6, 1942). It was found in each series of experiments that the method of tailing had no significant effect upon subsequent weight gain.

IN the spring of 1944, following a request by the inventor, two trials were carried out, one at the Kirwee Experimental Farm and the other at Mamaku Outstation of Ruakura Animal Research Station, with a docking instrument known as the “Mowat tailer.” It was claimed that with this instrument “post marking” losses were reduced, that blood loss was less, and thus that the lamb fattened more quickly.

THE KIRWEE TRIAL. Method Two hundred lambs were selected from a mob whose dams had been run together throughout the winter. After weighing, the lambs were randomised into two groups' of approximately equal weight. These lambs were from Corriedale ewes by Southdown rams and were approximately 4 to 6 weeks old. It is realised that most lambs in New Zealand are tailed at a younger age than this, but Mr. Mowat claimed that his instrument was of particular value for use with older lambs. Following weighing and division into two groups on October 6, the lambs were castrated and docked on October 9. The method of castration was by the knife and was performed by one man. The lambs docked by the Mowat . instrument were done by the inventor himself. The lambs docked by the knife were done by the officer in charge, Kir wee Experimental Farm. Both operations went on simultaneously. The usual

precautions of cleanliness were adopted.

TABLE I—LIVE-WEIGHT GAINS. Live Weights in lb. . Number Dressed After After After Slaughtered. Weights. Initial. 12 Days. 31 Days. 101 Days. lb. Mowat Group .. 26.8 33.1 43.1 60.9 30 32.95 Knife Group .. 26.9 32.6 42.6 60.2 32 33.7 ' TABLE AVERAGE LIVE WEIGHTS AND LIVE-WEIGHT INCREASES. Live Weights in lb. Total Increase. Initial. Aft Jr 20 Days. After 90 Days. lb. Knife ewe lambs .. 27.4 38.9 68.9 41.5 Knife ram lambs .. 31.4 42.5 74.5 - 43.1 Mowat ewe lambs .. 28.9 40.4 70.3 41.4 Mowat ram lambs ... 31.1 43.6 75.5 44.4

The weather, being still and cool, was suitable for the operation, which was done in a temporary yard especially erected in the corner of a clean paddock. After marking the lambs were allowed to mix with their dams at once. The ewes and lambs were kept together as.one mob until weaning in January. Since any effect upon the lambs’ weight due to the tailing operation is likely to be revealed within 10 days, the first weighing after docking was done on October 18. At the same time an examination of the docking wound of each lamb was made to see the extent of healing. The lambs were subsequently weighed on two occasions approximately 5 weeks and .10 weeks after tailing. Following the last l weighing, a fat lamb buyer went through the lambs and picked those that were fit for the works. The following day these were slaughtered and information on dressed weights collected. Results x It will be seen from Table 1 that there was practically no difference in the behaviour of the two groups: When subjected to statistical analysis the small difference of 0.71 b. in the two groups is shown to be due to chance and not to the method of tailing employed. . When docking wounds were examined at the first weighing after the

operation none of those made by the knife had healed, while 3 of those made by the Mowat instrument had healed over. At the next weighing it was found that 98 per cent, of the Mowat-docked lambs and 82 per cent, of the knife-docked lambs were healed.

THE MAMAKU TRIAL.

Method

Altogether 117 Southdown-Romney X lambs were included in the experiment. Their age range was 38 to 46 days, averaging 6 weeks. Docking operations were carried out on October 20. Weather conditions, due to heavy rain and strong wind, were very bad, and prevented weighing of the lambs at tailing. Mr. Mowat tailed 31 ewe lambs and 27 ram lambs with his patent tailer. The majority of the ram lambs in this group were “cord crush” castrated. The Farm Manager at Mamaku tailed 31 ewe lambs and 28 ram lambs using the knife. Castration of these ram lambs was effected by removal of the testicles. The Mowat ' group contained 35 twins and one triplet and the knife group 33 twins and 2 triplets.

Results

The lambs were weighed three times days, 3 weeks, and 13 weeks after tailing. Table II shows average live weights and the total average liveweight increases during this period. It will be observed that over the initial 20-day period the gains were identical in the two groups of ewe lambs (11.51 b. but slightly in favour of the group of ram lambs tailed by the Mowat instrument (12.501 b. against 11.101 b.). Over the next 70 days the respective gains were slightly higher in the groups tailed by the knife in the case of both ram and ewe lambs. Thus the “knife” ewe lambs gained 30.01 b. against the “Mowat” ewe lambs, 29.91 b. The “knife” ram lambs gained 32.01 b. against the “Mowat” ram lambs, 31.91 b. Over the whole period the ewe lambs tailed by the knife did slightly better in rate of gain than those tailed by the Mowat instrument, while the ram lambs showed a superiority of 1.301 b. average live weight in favour of the Mowat instrument.

These differences, however, are extremely small in each case, and are obviously not consistent. When the detailed data are subjected to statistical analysis the differences are shown to be not significant—that is, they cannot be taken to indicate a real difference in the two methods of castration, differences of the magnitude concerned being more probably due to random or chance differences in the natural growth rate of the individual lambs included in the trial. It can only be concluded, therefore,

that this experiment has not demonstrated any significant superiority of the Mowat instrument over the knife in so far as subsequent rates of growth of the lambs are concerned. . Table 111 shows the number of fat

off the mother, carcass grades, dead and missing, and left on hand.

TABLE NUMBER FAT OFF MOTHER, CARCASS GRADES, DEAD OR MISSING, ETC. Fat Fat Total Lofton Died or Grand Carcass Grade. Ist 2nd Fat Hand Missing. Total. Down. Prime. 2nd. Cut. Cut. Knife ewes .. 20 9 29 2— 31 7 12 10 Knife rams ..16 8 24 22 28 8 8 8 Total ..36 17 53 4 2 59 15 20 18 Mowat ewes ..19 11 j 30 1 31 1 10 13 7 Mowat rams ..16 4 20 4 3 27 8 4 8 Total .. 35 15 50 5 3 58 18 17 15

Discussion These experiments serve to show that the small amount of bleeding which is. inevitable when lambs are docked with the knife does not adversely affect them, and that their weight gains are not significantly lower than those of lambs which are docked in a supposedly bloodless manner. It was noted that actually only a proportion of the lambs docked

by the Mowat instrument did not bleed. The operation was somewhat slower than when the knife was used. Only one lamb (at Kirwee) died within a few days of tailing, which might be attributed to the effects of the operation (this lamb died from blood poisoning and happened to come from the group tailed by the Mowat instrument). Summary In two experiments involving approximately 300 lambs, designed to test the effect of the Mowat tailer upon subsequent lamb fattening, compared with docking by the knife, it was found that 1. There was no significant difference between the live weights subsequently gained by the lambs.

2. Lamb losses were negligible with either method. 3. The number of lambs fattened before weaning was practically the same in both groups. 4. There was no significant difference in carcass grades. In view of these considerations it may be stated that the decision in regard to the use of the Mowat tailer or any other instrument of similar nature should be made solely on whether or not the operator finds it more convenient than the knife.

FENCING MATERIALS For estimating requirements of fencing material the following figures will be found useful: — Plain Wire Gauge. Yds. per cwt. No. 8 566 No. 10 882 No. 12 1333 Barbed Wire No. 12 (3in. barbs) 450 No. 14 725 The “effective” length per cwt. is often quoted and is the actual length of fencing that 1 cwt. of wire will cover, allowing for bends, waste, etc. The effective length of No. 8 wire is 484 yds. per cwt.