40(5 Orojrf/i and DiKclopiiK nl of Breeds and Crosses of Pigs 



Earhj Maturiti/. In order to obtain an estimate of the rate of maturity 

 of an animal it is necessary to consider three factors. Jn the first place 

 maturity so far as live weight is concerned is the rate at which an animal 

 attains its mature weight. This factor is seen in Table IX for the various 

 breeds, the weights at different ages being shown as a percentage of the 

 weight at 1 1 months. This table shows that the Middle White is the most 

 early maturing breed with the Berkshire following closely behind it. 

 Figures for the other breeds are somewhat fragmentary but indicate that 

 the Large White and Tamworth come Axt while the Lincolnshire Curly 

 Coated and Large Black are last in this respect. 



The second factor by which the rate of maturity may be measured is 

 that of the carcase percentage at different ages. A breed which matures 

 early forms bone, muscle, and fat early, and so the proportion of the 

 t^arcase rises, that is, the age changes of low to high carcase percentage 

 .uo hastened. Miiller(io) believes that the changes causing early maturity 

 are controlled by the glands of internal secretion. Fig. 4 shows the carcase 

 percentages of the breeds af different ages (see also Table VII). At 

 3 and 5 months old the Berk.shire has the highest carcase percentage 

 followed by the Middle Wiite, Large White and Large Black in the 

 order named. At 7 and 9 months the Middle AMiite overtakes the Berk- 

 shire, but the other breeds remain in the same relative order, although 

 they tend more nearly to approach one another. 



Another method of estimating the rate of maturity of different parts 

 of the body is shown in Table X; the weights of parts at dift'erent ages 

 are shown as a percentage of the weights of the parts at 11 months old. 

 Considering the averages of the four breeds, whereas at 3 months old the 

 alimentary canal etc. has made 40 per cent, of its ultimate growth the 

 carcase has made only 23 per cent., the pluck 34 per cent, and the body 

 as a whole 27 per cent. 



The two breeds in which the figures are significant (Berkshire and 

 Large White) stand in the same relative order as given above. If the 

 Live Weight figures in this table for "Carcase Classes" are compared 

 with those given in Table IX for the "Live Classes" it will be seen 

 that the ratio is higher in the Carcase Classes ; the reason has been pointed 

 out above, namely, that the Carcase Class animals e.xhibited at the older 

 ages are not so fat (and heavy) as those of the Live Classes and so the 

 early maturity ratio is liighcr. For the same reason the ratio for 

 Tamworths at 9 months in Table IX is probably rather high on 

 account of the relatively small amount of fat this breed puts on at the 

 older a<res. 



