FLUSHING TO INCREASE LAMB YIELDS. 3 



mum lamb yields: (1) The ewes that are in the best nourished condi- 

 tion and therefore more likely to produce two ova are also those 

 first to come in heat and get in lamb, or, (2) the feed and pasturage 

 are more nutritious early in the season and cause production of more 

 ova by the ewes bred at that time. 



In the Bureau of Animal Industry experiments the use of rams 

 began about September 7 to September 10, but in most cases only 

 one or two ewes were bred during the first 10 days. It therefore 

 seems that the ewes ordinarily bred first are those that owing to 

 their better physical condition first come in heat at the beginning 

 of the breeding season, and that their condition is at once the cause 

 of their showing heat earlier and their producing twins. 



An overfat condition may derange the normal action of the ova- 

 ries even more seriously than a thin condition. It seldom occurs 

 except in stock fitted for show or in ewes that have missed getting in 

 lamb and grown fat while running dry. In our experiments there 

 have been some rather fat dry ewes which got in lamb as readily as 

 other ewes. They were not allowed grain, however, and had plenty 

 of exercise. 



RESULTS OF EXPERIMENTS IN FLUSHING EWES. 



GENERAL PLAN OF THE EXPERIMENTS. 



The experiments were made with purebred Southdown ewes, all 

 of which had been bred in the Bureau of Animal Industry flocks. 

 The number of animals was 302, divided into 17 lots, of which Lots 

 1, 2, 5, and 6 were at the Morgan Horse Farm, Middlebury, Vt., 

 and Lots 3, 4, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, and 17 at the bureau 

 farm, Beltsville, Md. The ewes were usually in good condition com- 

 pared with general farm flocks, which it is thought would tend to 

 lessen the effect of flushing. 



In all the tests the lots of ewes were divided with careful regard to 

 age, number of lambs dropped in previous years, gain in weight prior 

 to experiment, and the rams to which bred. As it was necessary to 

 use a number of different rams in each flock, hand breeding 3 was 

 followed, which with the use of teasers 4 made it possible to record 

 the date of each service and at the same time mate each ewe to the 

 ram desired. Approximately the same number of ewes in each lot 

 were bred to each of the rams used that season. In one case the 

 proportion was disturbed because one of the rams was not a sure 

 breeder and some of the ewes booked to him did not get in lamb. 

 Such cases were eliminated from the experiment. The data given 

 are in all cases for ewes having lambs. The matter of dry ewes and 

 the influence of rams upon the lamb yield are discussed separately. 



3 "Hand breeding" is a term applied to the individual mating of a ram and ewe outside the flock. 



4 "Teaser" applies to a ram used in a flock for the purpose of indicating the ewes which are in heat. Copu- 

 lation is prevented by an apron tied around the ram's body. 



