Management and Feeding in Winter 59 



tained, she should gain as much during the breeding and 

 gestation periods as she loses in farrowing and the sub- 

 sequent nursing period. The loss of weight during these 

 times will depend chiefly on the number of pigs farrowed 

 and the ability of the sow as a milker, and cannot be pre- 

 dicted. The most prolific and heavy milking sow in the 

 herd, however, will usually make a gain during the pre- 

 vious months considerably in excess of the average. 



It is probably true that every brood sow, as well as 

 every other breeding animal, has a best weight which 

 varies during the year according as the nature of her 

 work as a producer changes. The diagram in Fig. 3 

 represents what is believed to be the best approximate 

 weight curve for a sow a little above the average in pro- 

 lificacy and weighing 325 pounds in thin flesh at the 

 beginning of the breeding season. The variations in 

 weight shown from breeding to weaning time are based 

 on average figures obtained from a study of the weight 

 records of a herd of twenty sows through several breed- 

 ing seasons. This study has led to the conclusion that 

 the herd of mature sows that is thin to start with will, 

 if made to gain 75 to 85 pounds during the breeding and 

 gestation periods, be approximately of the same weight 

 and condition of flesh at the time of weaning their pigs 

 as they were when the breeding season began, when 

 properly fed. 



According to this curve, the sows should make most 

 of their gains during the last six weeks of the pregnancy 

 period. This is natural, for the reason that the pigs in 

 embryo make practically 75 per cent of their growth 

 during this time. If the sows make a gain, on the aver- 

 age, of one-third of a pound daily for the first sixty days 

 of pregnancy, one pound daily in the next thirty days, and 



