MILK-PRODUCTION AND CONCENTRATIONS OF FAT AND ENERGY IN THE MILK OF SOWS IN DEPENDENCE OF DIETARY METHIONINE SUPPLY .2. CONTRIBUTION TO THE REQUIREMENT OF SUCKLING SOWS FOR S-CONTAINING AMINO-ACIDS

In order to investigate the requirement of suckling sows for S-containing amino acids the effects of dietary methionine supply on milk production and the contents of fat and energy in sows' milk were examined. For the experiment 61 multiparous DL-sows were observed for a total of 96 lactation periods. The sows, divided into 7 groups (I to VII), got a lactation feed containing between 0.21% and 0.84% methionine/cystine so that the average daily intake of met/cys amounted from 9.6 g to 39.5 g. At day 10, 11, 17, and 18 of lactation milk production was messured using the ''weigh-suckle-weigh''-method. The contents of milk fat and energy were determined in hand milked milk samples. In the average of all observation days milk production increased significantly from 6500 to 8500 g/day, when met/cys-supply increased from 9.6 to 29.2 g/day. Higher met/cys-supply showed no response. Milk production also increased in all the groups from day 10/11 to day 17/18 averaging 7500 and 8200 g/sow and day resp. The contents of fat and energy in the sows' milk did not respond to the dietary methionine supply but decreased from day 10/11 to day 17/18. In a total of all groups and all days the contents of fat and energy in 100 g milk amounted to 8.3 g fat and 0.5 MJ. The requirement of lactating sows for S-containing amino acids was determined using milk production data and different statistical models. In regard of the present milk yield the daily requirement of a suckling sow for S-containing amino acids might be estimated to be 31 g met/cys.