S. Kracmar et al., CHANGES IN AMINO-ACID-COMPOSITION OF EWE MILK DURING THE FIRST MONTH OF LACTATION, Czech Journal of Animal Science, 43(8), 1998, pp. 369-374
In sheep of the breed Tsigai at the 2nd and higher lactations, changes
in milk amino acid composition from the 5th to 33rd days of lactation
were examined. In amino acids serine, aspartic acid, alanine, glycine
, histidine, arginine and cystine, a slow and even decrease occurred d
uring the whole period of examinations. In tyrosine and proline, a slo
w decrease was registered, and in glutamic acid, a sharper drop occurr
ed by the 19th day of lactations, followed by a slow increase by the e
nd of the period of examinations. In leucine and lysine, the drop was
sharper during the first 12 days of lactation, during subsequent days,
the decrease was slow. The valine and methionine contents were stagna
nt by the 12th day, from the 12th to the 19th days, a sharper drop occ
urred followed by a slow decrease. In isoleucine and threonine, a slow
decrease was found by the 19th day of lactation, a sharper drop occur
red during the period from the 19th to the 26th days, followed by a sl
ow decrease from the 26th day. In phenylalanine, a sharper drop was re
gistered by the 19th day of lactation, followed by increase. In non-es
sential amino acids during the respective period, the decrease ranged
6.41-10.65%, in essential amino acids it ranged 4.12-10.83%, and in Si
gma Met + Cys 3.81-13.96%. In the sum of essential amino acids (EAA) a
nd sum of Met + Cys, the decrease was slow and regular. In the sum of
non-essential amino acids (NEAA) during the period from the 5th to the
19th days of lactation, a clear rise with subsequent decrease were in
dicated.