EFFECT OF SUPPLEMENTATION OF RUMEN PROTECTED CHOLINE AND METHIONINE IN EARLY LACTATING DAIRY COWS
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Date
2021-11-30
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COLLEGE OF VETERINARY & ANIMAL SCIENCES MANNUTHY, THRISSUR
Abstract
A feeding trial was conducted for a period of 90 days to assess the effect
of supplementation of rumen protected choline (RPC) and methionine (RPM) in
early lactating dairy cows. Fifteen crossbred dairy cows in early lactation (within 10
days of calving) were selected from University Livestock Farm and Fodder Research
and Development Scheme, Mannuthy, and were divided into three groups of five
animals each. Rumen protected forms of choline and methionine were purchased
from local market. The animals were allotted randomly to one of the three dietary
treatments, T1 (Control)- Containing CP- 20%, TDN- 68% , T2- T1+20g RPM and
20g RPC, T3- Containing CP- 17%, TDN- 68% + 20g RPM and 20g RPC. All the
experimental animals were fed as per ICAR feeding standard (ICAR, 2013). The average body weight, dry matter intake and milk production of
lactating cows maintained on dietary treatments T1, T2 and T3 were found to have
no significant difference between the groups. The digestibility of crude fibre
(65.53±1.03 per cent) and the neutral detergent fibre (69.33±1.08 per cent) was
significantly higher (p<0.05) for T2, whereas, digestibility of ether extract
(87.26±0.58 per cent) was significantly higher (p<0.05) for T3, when compared
with the other treatments. The dry matter, crude protein, nitrogen free extract and
acid detergent fibre digestibility did not show any significant difference between
the treatment groups. Among the milk constituents, T3 had significantly higher
milk fat (4.03±0.15 per cent, p<0.05), milk solids not fat (8.04±0.06 per cent,
p<0.05), milk protein (2.92±0.04 per cent, p<0.05) and milk total solids
(12.53±0.12 per cent, p<0.01) composition than T2 and control. The milk urea
nitrogen levels did not show any significant difference among the treatment
groups and the values were within the normal range. The serum biochemical
parameters such as serum glucose (74.11±1.09 mg/dL, p<0.01) and total protein
(7.66±0.14 g/dL, p<0.05) levels were significantly higher for T1 and the blood
urea nitrogen level (15.60±1.16 mg/dL, p<0.05) was significantly lower for T3 on
comparison with the other treatments. The serum albumin levels remained
unaffected with the treatment, but the values were within the normal range. There
was no significant difference between the three treatment groups for reproductive
parameter such as postpartum oestrous. Cost per kg milk production was
Rs.27.13±1.80, 29.78±3.81 and 29.63±2.22, respectively for T1, T2 and T3 and the
results suggested that dry matter intake, body weight, milk production, health and
reproductive status of animals in the treatment groups supplemented with rumen
protected choline and methionine were not significantly different from that of the
control group. Moreover, an effective improvement in the milk composition was
noticed in the supplemented group compared with the control, which was more
significant in the treatment group having a lower dietary protein level. Since, the
lactating cows fed with the experimental ration containing lower crude protein
content had comparable results with that having higher crude protein content, it
can be inferred that in medium producing cows having a capacity of 10-12 L/day
milk production can be maintained on a ration containing a low dietary protein
level.
Description
Submitted in partial fulfilment of the requirement for the degree of
MASTER OF VETERINARY SCIENCE in Animal Nutrition