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PRINT: ISSN 2221-1896
ONLINE : ISSN 2223-0343
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Effects of multiple births on gestation length of Iranian
Holstein dairy cows
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Ali Kheirandish1, Saeed Khalajzadeh1*
and Jafar Yadi2 |
1Department
of Animal Science, College of Agriculture, Saveh Branch, Islamic Azad
University, Saveh, Iran; 2Department of Veterinary Science,
College of Agriculture, Saveh Branch, Islamic Azad University, Saveh,
Iran
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Abstract |
The present study was conducted to investigate the effect of multiple
(twin and triplet) birth on gestation length (GL) of Holstein cows in
four large-scale dairy herds in Iran. A total of
56,559 records within 7 parities from 21,644 pure breed
Holstein
dairy cows calved from 2002 through 2012 were used. Factors affecting GL
including herd (H), calving year (CY), calving month (CM), parity (P),
birth type (single and multiple births), calf sex, birth type within
parity and H×CY interaction were examined using generalized
linear model (GLM) procedure. Of the factors examined in this
research, the primary ones affecting GL were calving month, birth type
and calving year respectively. Mean GL was calculated 278.54±4.88 d
varied by herd from 278.17 to 278.79 d. Multiple rates increased with an
increase in parity number ranging from 0.4 to 3.54% across parities.
Gestation length was 4.74 d shorter (P<0.001) for multiples than singles
ranging from 4.37 to 4.97 d between herds. The shortest and longest GL
were observed, respectively, in parity 1 and 7 in both categories
(277.59 vs 279.72 d in singles, 273.76 vs 275.23 d in multiples,
P<0.01). Least square means showed GL in multiples were 3.83, 4.79,
4.62, 4.88, 5.04, 5.16 and 4.49 d shorter (P<0.001) than singles from
first to seventh parity. It seems a comprehensive study to identify
factors affecting GL can lead to more precise prediction of parturition
date in dairy cows.
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Keywords:
Gestation length; birth type; parity; dairy cows |
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To cite this article:
Kheirandish A, S Khalajzadeh and J Yadi,
2014.
Effects of multiple births on gestation length of Iranian Holstein dairy
cows.
Res.
Opin. Anim. Vet. Sci., 4(9): 508-511. |
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