Influence of various climatic factors on milk production and related traits in Mpwapwa cattle and their crosses
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Date
1994
Authors
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Journal ISSN
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Publisher
Sokoine University of Agriculture
Abstract
A study was carried out to examine the influence
of various
climatic factors on milk production in Mpwapwa breed cattle and their
crosses in Livestock Production Research Institute in Mpwapwa
Central Tanzania. It was based on daily milk yields and weather
information recorded from 1964 to 1989.
Milk yields of individual
cows were accumulated for periods of 28 days and related to average
weather records for the same periods and or the preceding period.
A
short term supplementary study was used to investigate reaction of
different genetic groups of the cattle, in terms of daily milk yield,
milk components, and rectal temperature, to weather conditions.
Over the study period, daily maximum and minimum temperatures
averaged 26.2°CS and 14・5°C, while average daily temperature-humidity
index was 68.5 and 74.1 (morning and afternoon), and annual rainfall
averaged 785 mm.
Least squares means for 28-day milk yield (kg) were
123.8, 179.1, 175.5, 213.3, 131.1, respectively for Mpwapwa and
Jersey, Ayrshire, and Friesian crosses, and Backcross.
All were
significantly different (P<0.05), except between Jersey and Ayrshire
crosses.
The studies revealed that several of the weather variables had a
significant influence on milk yield during the same or the subsequent
period.
However, the magnitude and sign of the partial regression
coefficients were inconsistent and erratic.
In most analyses
concurrent rainfall showed a positive relationship with milk as might
be expected from the effect of rain on pasture growth.
But,
surprisingly, some of the temperature variables were also positively
related to milk yield.
Separate analyses of the data of each of the
five genetic groups failed to demonstrate distinct differences
between groups in reaction to the climatic factors studied.
In the supplementary study daily milk yield and yield of various
milk components did not appear to be influenced by concomitant
weather variables.
Rectal temperature was however, significantly
influenced by weather variables recorded at the same time.
The
genetic groups did not differ significantly in rectal temperature.
The lack of conclusive results might have partly been caused by
the close association between some of the weather variables.
Inclusion of previous milk in most of the analyses, in an effort to
increase precision, may have complicated the interpretation of the
results also.
Further investigation on the nature of the relationships suggested by trends revealed by the study was
recommended. Changes were recommended in the breeding programme to
exploit the more productive
Description
Thesis
Keywords
Milk production, Cattle, Mpwapwa