牛隻活重估計法之研究

Dept. of Animal, National Tai-wan University 1. Purpose Dairymen computting the efficiency of fuming feed into milk of their cows from milk production, figuring feed needs for maintenance from feeding standards, and watching growth progress under different conditions, the first thing is to know the body weight of those individuals. Again, all of the animal merchant, feeder, butcher, or someone interesting in cattle husbandry, breeding. and even farmers are Willing to have a useful and simple method to estimate the live’ weight of cattle without the trouble ad expense of actual weighing. Especially because cattle scales are not often equipped at small forms as in China. Hence the purpose of the present study is to bring out a simple formula Which comprises one to three linear measurements of an animal, the estimated weight is easily done by substituting and mathmatical calculating. And if may also be much helpful to the field work of cattlemen. 2. Material A. careful study of 398 sets of live weight to several, measurements records, collected by the present author and coworkers during the post 10 years on catties belonging to the University Farm, these are tabulated as follows: number of sets Breeds sex measured age Holstein ♀ 303 from birth to 6-yr old Holstein ♂ 20 from birth to 8Mos, 3-yr, 6-yr old Jersey ♀ 27 from birth to 8Mos, 3-yr old Jersey ♂ 7 from birth to 5Mos, 3-yr old Browu-Swiss ♀ 3 3.5 yrs old Cross-bred ♀ 5 4-8 Mos old Korean ♀ 10 from birth to 2-yr old Korean ♂ 7 from birth to 6-Mos old Native cattle ♀ 3 at birth, 0.5-yr old Native cattle ♂ 10 from birth to 1-yr o1d Buffalo ♂ 2 4-yr old Buffalo ♀ 1 3.5-yr old Total 398 3: Method a. Derivation of the formula for estination of live weight of cattle Let W be the body weight, G be the heart girth, L be the length of trunk. (from point of shoulder to ischium) S be shin circumference Then, Li. Wt.= mass of the animal body = volume×sp. gr. = area of cross-section at chest × long axis of cattle × Sp. gr. ＝π(G/2π)^2×(L+ another measurement C) ×1……(Supposition) =πG^2/4π^2 × (L+G) =1/4π G^2 × (L+C) =0796 G^2 × (L+C) Therefore the original rational formula is W=.0796G^2×(L+C) If the unit of weight is Kilogram, then it W=.0796G^2×(L+C) If the unit of weight is Kilogram, then it would be W(kg.)=79.6G^2(m)×(L(m)+C(m)) b. Since c value is nearly 12.% of L in Holstein (author, s calculation by the formula C=4πW/G^2-L) therefoe the aboove formula may be changed thus: W(kg.)=79,6×G^2×(L+c) =79.6×G^2×(L+0.125L) =79.6×G^2×L(1+0.125) =79.6×G^2×L×l.125 =89.6×G^2×L 89.6 is the coefficient in this formula, which is named K, by author in this papery c. Again, according to author, s study, the value of c is corresponding to the relation between shin circumfernece and body length. that is, shin circumference is approximately 12.5% of body length in cattle of both sexes and any age. Therefore, a new modified formula with definite coefficient can be established and confirmed by using S instead of c, W(kg,)=79,6 G^2×(L+s)……author, s formula with data un-published, d. Moreover, fortunately, Brody, Habu and many others showed that the relation between live weight to heart girth is closer than that of weight to any other linear measurements, In author,s data, this also be proved, So the formula for common use may be further simplified, if L is changed into G, From author,s study, L is 94,1% of G in Holstein breed and Jersey too, ∴W(kg)=89.6G^2×L=89.6×G^2×,941G=84,3G.^3 The coefficient 84.3 in this Formula is named k by author in this paper, e. In short, the moln topics of this paper are to investigate the value. of kp, and k24 on cattle of different breeds, sexes and ages. 4 Results compared with that of other investigators a. The values of k1 and k2 are variable in different ages, they may be plotted continuously as curves of k1 and k2, b. In one breed, the curves of k1 and k2 have the same tendency, Holstein, Jersey and native cafe, choir curves of k1 k2 seemed in similar manner of tracing, but they are differ in beef breeds, Sind, cross-breds and buffaloes, though the material of latter are too few to be approved c. Former scientists mostly applied their formulae with either definite coefficient or separated one to the dairy cattle, but those arc noteworthily unaccurate if used in other kind of ox. d. Even in dairy cattle, the results of author s study differ somewhat sparcely compare dwith those of others List of comparison (The from abridges) e. It may be regard as significant, when results obtained were over-5to+5% of their real. weight. So that, some of the above mentioned formulae are necessary in further study, particularly on those of different species, breed, and perhaps different localitles (due to different feeding and other conditions affect growth changes directly) otherthen dairy cattle.

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牛隻活重估計法之研究

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