ANIMAL HUSBANDRY. lOQ 



monly fed to pigs, such as grains, wheat offals, bye-products 

 from margarine factories, &c., are all deficient in bases, such as 

 lime, and contain an excess of acids. It was found that when the 

 mineral matter of the food was adjusted to the requirements of 

 the animal by the addition of certain salts the disease did not 

 occur; but when these food stuffs were fed in the natural 

 condition without any adjustment of mineral matter, the disease 

 invariably occurred under all conditions. These results con- 

 firm and explain the experience of pig breeders, who are troubled 

 Avdth the disease particularly in cases where pigs have to be fed in 

 styes, and have no yard or garden in which they can roam. 

 If the pig is able to root up and consume earth, he is probably 

 able to supply himself with sufficient mineral matter, such as 

 lime, to ward off the disease. If he cannot do this, he is likely 

 to develop the disease unless his ration contains some quantity 

 of the required mineral matter. 



Reproduction. 

 We may now consider some valuable work which is being 

 done at Cambridge on the subject of the physiology of reproduc- 

 tion, particularly with reference to the milk supply of the cow. 

 It is a frequent cause of complaint amongst dairy farmers that 

 they are unable to get young heifers in season in the months of 

 December and January, to come in for the subsequent autumn 

 and winter's milk supply. If a heifer cannot be put to the bull 

 tiU the spring she wiU be too late for the following winter's milk 

 supply, so that a cow calving in April or May is worth less than 

 one calving in the late autumn. Further, an examination of 

 the milk records of several societies in different parts of the 

 country, especially in the west of England, shows that cows 

 calving in November and December are yielding more milk per 

 annum than those calving from April to July. Sterility, too, is 

 extremely high in cows; probably upwards of 15% of cows in 

 any season are sterile for a whole season, and in a much larger 

 percentage there is an apparently sterile condition for more or 

 less prolonged periods. Unfortunately, these sterile periods 

 usually occur about December or January, that is, at precisely 

 the time when it is most important that a cow should be put to 

 the bull. The experimental work at Cambridge has therefore 

 largely taken the form of a close study of the periods of " heat " 

 in young heifers, and for some time past observations have been 

 made at two-hour intervals throughout the day and night, 

 The main practical facts that have emerged are that the period 

 of " heat " varies considerably with different animuls and 



