140 



MASS. EXPERIMENT STATION BULLETIN 230 



3. Including in the experiment tlie lieifer calves from the cows in the two 

 groups and keeping them as far as possihle on the same diet as their dams, 

 in order to see if any effects of the treatment are more marked in the second 

 or even in the third generation than in the original animals used. 



4. Observation of the effects of the feeding upon: 



(a) the general condition and weight of the animals, 



(b) growth of heifers, 



(c) milk production, 



(d) composition of the milk, especially its content of calcium and 

 phosphorus, 



(e) reproduction, under which general heading have been observed: 



(1) recurrence of heat, 



(2) difficulties in getting cows bred, 



(3) number of abortions and retained afterbirths, 



(4) condition of the calves at birth and subsequently. 



The Herd 



The station herd is made up of high-grade Holsteins with a few Jerseys, 

 and usually numbers, including young stock, eighteen to twenty head. At 

 present there are nineteen animals included in the experiment, — fourteen 

 milch cows, one two-year-old heifer, and three eight-months-old heifers.' There 

 have of necessity been some changes in the herd since the experiment was 

 started, but of the nineteen individuals originally included, ten are still in the 

 herd. Since the commencement of the experiment in December, 1921, the 

 milking herd has had an average annual production per cow of 8000 pounds 

 of milk, testing 4.21 per cent of fat. 



All cows are given a two months dry period during which time they arc 

 liberally fed, but they are not sent to pasture. They are maintained on dry 

 feed the j'^ear around, except for a period commencing about June 25 and 

 ending about October 10, during which time each cow is fed about 25 pounds 

 daily qf such green soiling crops as oats, millet, sorghum and fodder corn, as 

 a substitute for a portion of their hay. Ensilage, roots or legume hay have 

 not been fed during the experiment. 



Rations Fed 



The rations have purposely been made as poor in mineral matter as a wise 

 choice of feeds, other factors being considered, would permit. The hay has 

 consisted principally of timothy, with some red top, blue grass and orchard 

 grass. 



The grain ration has consisted of the following mixture: 



100 



' All heifer calves are included in the experiment as soon as old enough to subsist 

 on hny and dry grain. The age varies M'ith the calf from five to seven months. 



