686 



EXPERIMENT STATION RECORD. 



12 or more j'ears the station has kept a record of sheep-breediug operations. For the 

 first years this included only the ear-tag number of the service ram and ewes, the 

 date of service, and the date of birth of the lambs. "The record was gradually 

 perfected until during the past four years it included the nmnber of lambs dropped 

 and their sex, the weight and condition of lambs at birth, the apparent milking qual- 

 ities of the ewes, and the weights of the ewes and the service rams used." 



The general deductions drawn from the recorded data follow: 



" From the breeding records of 514 ewes at this station we conclude that for such 

 animals and conditions as ours the normal i)eri(xl of gestation ranges from 144 to 150 

 days after the date of service, and that more ewes will laml) 146 days after service 

 than at any other time. 



"There is no appreciable difference in the period of gestation for male and female 

 offspring in sheep. There is an apparent relation between the duration of the period 

 of gestation and the period required for reaching maturity. Quick-maturing breeds 

 appear to carry their young for a shorter period than those breeds requiring more 

 time to mature. Large lambs are on the average carried in view for an appreciably 

 longer jieriod than small or medium lambs. Lambs dropped before the 144tii and 

 after the 149th day of pregnancy are lacking in strength and vitality at birth. 



"Shropshire ewes were more prolific than any of the other breeds and cro.sses 

 except the fourth cross of Shropshire rams on a Merino ewe foundation. From the 

 data presented it is apparent that twins are the normal increase for ewes of the 

 mutton type. 



"One-year-old rams are not so prolific as those 2 or 3 years old. Ewes also aver- 

 age a larger percentege of increase in lambs after they reach full maturity at 3 

 years of age until after they are 6 years old, when the rate of increase diminishes. 

 The amount of service required of the ram in breeding has an influence on the per- 

 centage increase in off sjjring of the ewes that produce lambs. Ewes bred early in 

 the season of mating to a single ram dropped a larger pen-entageof lambs than those 

 near the latter end of the season." 



The naaintenance ration of sheep, W. AV. Cooke {Pennsylvania Sta. Rpl. 1901, 

 pp. 238-294)- — Cooperating with tlie State department of agriculture, a number of 

 experiments were conducted to learn the amounts required by sheep for mainte- 

 nance, on a ration of timothy hay alone, and of timothy hay and corn in the propor- 

 tionof 2:1 and 1:2. The total weight of the feed in the 3 cases, which itwas estimated 

 would suffice for sheep weighing 50 kg., was 1.21 kg., 1.06 kg., and 0.94 kg., respec- 

 tively. These A^alues are based on a deduction from experiments with steers, that 

 11 lbs. digestible mitrients from corn is equivalent to 13 lbs. digestible nutrients 

 from timothy hay. The estimated amounts proved to be very nearly correct. Sheei^ 

 1 and 2, each weighing not far from 50 kg. at the beginning of the trial, were fed the 

 full amounts mentioned. Sheep 3, weighing not far from 30 kg., was fed 70 per 

 cent of the amounts given the other sheep, as it was estimated that the surface area 

 of this animal was 70 per cent of that of a sheep weighing 50 kg. 



The feeding periods were of 10 days' duration. The sheep were kept in specially 

 constructed crates, with devices for conveniently collecting the excreta. The food 

 and excretory products were in every case weighed and analyzed. On an average 

 the 3 rations were found to have the following i-oetlicients of digestibility: 



Average coefficients of digestibility — Experiments with sheep. 



