| Show A talc nir variation in BU butterfat tests testa nothing unusual the purebred pure bred dairyman as well as aft the commercial dairyman Is interested in tho the tests tor for butterfat upon their cattle quite frequently these testa are made either cither upon the entire herd or upon individuals of bf the herds when these tests are compared with tests testa made previously a wide variation 0 or r fluctuation Is noted there are tim times es when these tests teata are arc i made within a few days of each oth other er and the variation Is surprising such stich flue fluctuations tuat lons are often looked upon with suspicion while it should be realized that it Is quite natural for cows to vary in their tests testa fo for r butterfat in fact w when li enthis this point Is investigated it Is found that cows vary more in their tests than Is commonly thong thought some years ako ago the michigan aari agricultural college published a special bulletin containing the he w ork of anderson upon the variations in the percentage of butterfat of single mil bilkings kings of cows u upon pon test tile the seven day tests of cows handled under ordinary herd conditions were studied edas as well as similar records upon 2000 cows ed entered in the advanced registry of their re respective spec tive breeds any conclusions reached by these investigations can be looked upon as being indicative of the real condition as the number of milk ings studied Is large enough to warrant this it may be expected that 30 per cent of the cows in a herd will vary in the percentage of butterfat in the milk produced at individual mil bilkings kings in a seven day period 1 per cent or less fifty per cent ok of tho the cows coah during a like period will vary in their tests from II 11 11 to 2 per cent 14 per cent will vary from 21 per cent to 8 3 per cent white while the remaining 0 6 per cent will show a variation between of more than 3 per cent from these facts we may conclude that it Is not ing to have a cow test S 8 per cent at one in milking Ilkin gand and test iest 0 per cent at atthe the next milking I 1 have actually seen a cow test 18 per cent in the morning and test over 6 per cent in thearter the afternoon in a herd cows cheaver the average dge variation of the entire herd test would be per cent based upon these figures B W fairbanks colorado rado agricultural college |
