Abstract:
This is an analytical study undertaken to investigate the effect of age, stage of
lactation and production level on the chemical composition of milk. It was
conducted at Sudan University Farm College of Veterinary Medicine during
March and April 2018 .19 mature healthy non pregnant lactating cows were
used .They were grouped according to their age (>6), (6-8) and (8-10) year.
According to their stage of lactation they were grouped into early stage middle
stage and late stage of lactation and according to the milk production level into
low production (6-8), middle production (8-10) and high production level (10-
12) pound.
The milk samples were collected in the evening in sterile glass tubes and then
kept in ice box and transferred immediately to the dairy laboratory for analysis
by a lactoscan milk analyser ) 40-9305(to determine their moisture, total solid
,solid not fat, fat, protein, lactose, ash, Ca, P contents and density.
The collected data were analysed by ANOVA test using Statistical Package for
Social Science (SPSS16.0).
The result showed that the age of cows has a significance effect on Ca, the highest
Ca level (12.2±0.4) mg/100ml by age (6-8) year, then (12.1±0.3) mg/100ml by
age (8-10) year and the lowest Ca level (11.4± 0.8) mg/100ml b yage (>6) year.
The age also affected significantly P level, the highest P level (6.6±0.4)
mg/100ml by age (6-8) year, then (6.4±0.3) mg/100ml by age (8-10) year and the
lowest P level (6.2±0.3) mg/100ml by age (>6) year. The highest fat level
(3.7±0.2) % in (>6) year. And the middle fat level by (8-10) year and the lowest
level (3.4±0.1) % by middle age (6-8) year.
The stage of lactation did not affect milk production, density chemical
composition.
The production level has significant effect on Ca, the highest Ca level (12.3±0.4)
mg/100ml in middle production (8-10), and the lower Ca level (11.7±0.2)
mg/100ml in highest production and the middle Ca level in between them
