Effect of dietary crude protein concentration on milk productivity traits in early lactation dairy cows
Laen...
Kuupäev
2021
Kättesaadav alates
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
The evaluation and control of nitrogen balance at the farm and its relation to milk
productivity traits are becoming essential in dairy farming. Increasing in milk productivity
farmers tend to increase protein content in feed. The research complied into three (A, B, C) dairy
cow groups (8 cows in each group) with LB and HM breed’s cows in the early lactation period
divided into three phases (I, II, III) from 10 till 30 lactation days and lasting to 90 lactation days.
Each group cows were feeders with total mixed ration (TMR) with different CP content (approx.
17.0%; 16.0%; 15.0% accordingly). The amount of feed consumed by each cow were recorded
and feed samples collected during the study. Feed samples were analysed for CP and other feed
quality descriptive traits. Milk yield ( kg d
-1
) and milk samples were collected at day 21 of each
phase for analysis. Milk samples were analysed for fat (%), total protein (%), casein (%), and
urea content (mg dL-1
). The statistical analyses were conducted using ANOVA and descriptive
parameters. To evaluate the feed CP conversion efficiency estimated part of that in the yield of
milk protein for each cow and on average for the study group in each study phase. The conversion
efficiencies of feed CP in milk were ranged from 28.5% to 40.7% in study phase I, and from
33.0% to 39.9% in phase II, and the differences were statistically significant. In phase III, the
range from 30.4% to 36.3% were not statistically significant.
The objective of this study was to evaluation of feed protein conversion efficiency for dairy cows
in the early lactation phase and define the optimal crude protein (CP) content in the feed.
Kirjeldus
Received: January 30th, 2021 ; Accepted: April 24th, 2021 ; Published: April 29th, 2021 ; Correspondence: diana.ruska@llu.lv
Märksõnad
milk yield, milk total protein, milk urea, feed crude protein, articles