MATERIALS AND METHODS
Milk samples were collected from Boer goats reared
under the intensive system in NLBO, Pokhara primarily for
research purpose and up-grading of local breed. The research
site is located within longitude 83° 58' 20.604'' E and
latitude 28° 15' 48.996'' N at an altitude of about 793m
above sea level (Figure 1). Twenty three Boer goats were
lactating at the time of data collection. These therefore
constituted the sample population. All goats were kept under
the same environmental conditions and were provided with
similar care and nutrition. Goats were fed with 600 gm of
concentrate per day. Ipil-Ipil (Leucaena leucocephala), Melia
azadirachta, Ficus semicordata, etc. and Oat (Avena sativa),
Sudan, Berseem, etc. were the major sources of fodder and
forage respectively provided to the goats.
Sample collection procedure
Goats were handled by two individuals in which one
restrains the goat while the other one performs milking
operation by hand.
The teats were washed with clean water and rubbed
with a clean towel to remove excess water.
A total of 10 ml of milk sample was collected from
both teats in a sterile container to analyze the milk
Figure 1 - Map showing livestock development farm in
The teats were cleaned again after milking was
The collected milk sample was then taken to the laboratory located within the farm. The samples were
homogenized before analysis using Akashganga Milk Analyzer, AMA-Mini-40. The data obtained were recorded and
analyzed to determine the effect of lactation length on milk constituents.
Data regarding the age and lactation length was obtained from the recoding system present within the farm. The
obtained data were recorded in an Excel sheet and were analyzed using IBM SPSS version 20 (Amos, 2011). The lactation
length was divided into three categories as 2nd, 3rd, and 4th week of lactation. The relation between lactation length and
milk constituents was analyzed using ANOVA test whereas an Independent sample T-test was used to determine the
relationship between litter size and milk composition.
Effect of lactation length on milk composition
The effects of lactation length on milk composition are shown in Table 1. The study revealed that there was no
significant effect (p=0.232) of lactation length on the fat content of milk during the first month of lactation. The lowest fat
percent was recorded on the 4th week of lactation. Lactation length showed a significant effect (p=0.041) on the Solids
nonfat (S.N.F) content. Solids nonfat slightly decrease in 3rd week but was elevated again on 4th week. The freezing point
showed a significant difference (p=0.041) due to variation in lactation length. The trend in freezing point indicates a
constant decrease with increase in lactation length. A significant effect (p=0.042) of lactation length on the protein
content of milk was also recorded during our study. Protein content was reduced during the 2nd, 3rd, and 4th week of
lactation respectively. The lactose content of the milk was significantly affected (p=0.049) by lactation length. Lowest
lactose content was recorded at 3rd week of lactation based on our study
Effect of litter size on milk composition
Results of our study revealed that fat, S.N.F, protein, and lactose content of milk showed no significant difference
within 1 month of parturition due to variation in litter size (Table 2). All components are weakly correlated (negatively) to
litter size except freezing point. Goat milk from does with two kids showed slightly lower fat, protein, lactose, and S.N.F
content but insignificant compared to a goat with single kids (Table 2). The freezing point of milk showed significant
variation (p=0.043) with the number of kids. The freezing point was negatively correlated (r= -0.424) to litter size similar
to other milk constituents.
Citation: Regmi S, Mahato P, Sapkota KhR (2021). Effect of lactation length and litter size on milk composition of Boer goat within one month of parturition. Online J.