REQUIREMENTS OF ANIMALS 585 



ler and associates. ''^^ Harper and co-workers^""* cited somewhat higher 

 values for the quail, namely, 1222 I.U./IOO g. food for liver storage, and 777 

 I.U./IOO g. food for growth and survival. Although Wolbach and Heg- 

 g^g(jioo5 demonstrated that the duck requires vitamin A, the exact quantity 

 of \dtamin A needed was not determined. 



(g) Swine. The requirement of swine for vitamin A is in the same range 

 as that of other animals, but varies according to the criterion under investi- 

 gation. The smallest amount is required to prevent night bhndness (18 

 to 24 I.U./kg. body weight), ^^^ and somewhat more for growth (22 I.U./kg. 

 body weight).'^" Guilbert and Loosh^^^ indicated that 66 I.U./kg. body 

 weight is sufficient for growth and reproduction, as well as for providing a 

 safety factor. Carotene is much less efficiently utihzed by swine as a 

 source of Antamin A than is the preformed \dtamin A.^*^ Thus, 25 to 39 

 fig. /kg. body weight are necessary to prevent night blindness, 40 jug. are 

 needed for growth, and 125 to 195 fig. are required to assure satisfactory 

 lactation and growth. The deficiency symptoms in the swine include night 

 blindness, diarrhea, infertility of sows, muscular incoordination, and an un- 

 thrifty appearance. 



(h) Cattle. Cattle exhibit the vitamin A deficiency symptoms described 

 by Guilbert et aU°°^ and by Lewis and Wilson. ^""^ These include night 

 blindness, severe xerophthalmia, keratinization of the epithelium and, in 

 the case of pregnant cows, the birth of weak or dead calves. To prevent 

 night bhndness, 21 to 27 LIT. of vitamin A, or 26 to 33 ng. of carotene/kg. 

 body weight are necessary.^*^ The following figures for vitamin A have 

 been reported for older calves: growth and deficiency signs, 32 I.U./kg. 

 bod}'- weight j-^""^ optimum growth, 64 I.U./kg. body weight;'""^ growth and 

 liver storage, 250 I.U./kg. body weight ;^°°'' and maximum blood concen- 

 tration of \atamin A, 512 I.U./kg. body weight. ^""^ In the case of dairy 

 cattle, Guilbert and Loosli^®^ report the vitamin A figm-e as 66 I.U./kg. 

 body weight on the basis of growth, reproduction, plus a safety factor, or 

 132 fig. as ;S-carotene/kg. body weight. Thus, the requirement for caro- 

 tene is 6.6 times as much for carotene as for vitamin A. Baker et al.^'^* 

 reported that a carotene intake of 130 /xg./kg. body weight was insufficient 

 to maintain Hver stores of vitamin A or constant Adtamin A values in the 

 plasma. On the other hand, an intake of 730 jug./kg. body weight of /3- 



loo" T. A. Harper, R. V. Boucher, and E. W. Callenbach, Poultry Sci., 31, 273-283 

 (1952). 



'"OS S. B. Wolbach and D. M. Hegsted, Arch. Pathol, 54, 548-563 (1952). 



"»6 H. R. Guilbert, R. F. Miller, and E. H. Hughes, /. Nutrition, 13, 543-564 (1937). 



«»' J. M. Lewis and L. T. Wilson, /. Nutrition, 30, 467-475 (1945). 



