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A simulation study of the effects of the calving interval on milk yields of dairy cows in fixed time periods
Year:
1992
Source of publication :
Animal Production
Authors :
אמיר, שמואל
;
.
גניזי, אברהם
;
.
זרחי, מירי
;
.
שינדלר, חיים
;
.
Volume :
55
Co-Authors:
Genizi, A., Department of Statistics and Operations Research, Agricultural Research Organization, The Volcani Center, Israel
Schindler, H., Institute of Animal Science, The Volcani Center, Agricultural Research Organization, Israel
Amir, S., Institute of Animal Science, The Volcani Center, Agricultural Research Organization, Israel
Eger, S., Extension Service, Ministry of Agriculture, Israel
Zarchi, M., Department of Statistics and Operations Research, Agricultural Research Organization, The Volcani Center, Israel
Foote, R.H., Department of Animal Science, Cornell University, NY, United States
Facilitators :
From page:
309
To page:
314
(
Total pages:
6
)
Abstract:
Multiparous cows were assigned before calving to three calving to first insemination intervals. Records of cows conceiving at first or second insemination, were used to construct a model of the lactation curve which incorporated peak production and the effect of progressing pregnancy. The model was used to simulate milk yield during a 4-year period for three production levels and five calving intervals. The model separated the descending part of the lactation curve into a linearly and an exponentially declining component, with the latter becoming distinct at about 20 weeks after conception. Peak yield was negatively correlated with the slope of the linear decline. Within a simulated 4-year period, cumulative milk yields at fixed time periods after calving depended upon the period chosen and the calving-to-conception interval of the cow. Late conceptions resulted in higher cumulative yields at the end of the 1st year, and in lower yields at the 2nd year end, with respect to early conceptions. Smaller differences were found between the intermediate calving intervals. During the 3rd and 4th years the early conceptions had a distinct advantage. Different rates of the linear decline, obtained for the different production levels, changed the magnitude of the yield differences between the calving intervals but not their relative ranking. The model presented offers a means for the suitable choice of the calving cycle according to the length of the period for which a cow is expected to remain in the herd. © 1992, British Society of Animal Science. All rights reserved.
Note:
Related Files :
calving interval
Dairy cows
Lactation curve
Mathematical models
milk yield
עוד תגיות
תוכן קשור
More details
DOI :
10.1017/S0003356100020997
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
28975
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:43
You may also be interested in
Scientific Publication
A simulation study of the effects of the calving interval on milk yields of dairy cows in fixed time periods
55
Genizi, A., Department of Statistics and Operations Research, Agricultural Research Organization, The Volcani Center, Israel
Schindler, H., Institute of Animal Science, The Volcani Center, Agricultural Research Organization, Israel
Amir, S., Institute of Animal Science, The Volcani Center, Agricultural Research Organization, Israel
Eger, S., Extension Service, Ministry of Agriculture, Israel
Zarchi, M., Department of Statistics and Operations Research, Agricultural Research Organization, The Volcani Center, Israel
Foote, R.H., Department of Animal Science, Cornell University, NY, United States
A simulation study of the effects of the calving interval on milk yields of dairy cows in fixed time periods
Multiparous cows were assigned before calving to three calving to first insemination intervals. Records of cows conceiving at first or second insemination, were used to construct a model of the lactation curve which incorporated peak production and the effect of progressing pregnancy. The model was used to simulate milk yield during a 4-year period for three production levels and five calving intervals. The model separated the descending part of the lactation curve into a linearly and an exponentially declining component, with the latter becoming distinct at about 20 weeks after conception. Peak yield was negatively correlated with the slope of the linear decline. Within a simulated 4-year period, cumulative milk yields at fixed time periods after calving depended upon the period chosen and the calving-to-conception interval of the cow. Late conceptions resulted in higher cumulative yields at the end of the 1st year, and in lower yields at the 2nd year end, with respect to early conceptions. Smaller differences were found between the intermediate calving intervals. During the 3rd and 4th years the early conceptions had a distinct advantage. Different rates of the linear decline, obtained for the different production levels, changed the magnitude of the yield differences between the calving intervals but not their relative ranking. The model presented offers a means for the suitable choice of the calving cycle according to the length of the period for which a cow is expected to remain in the herd. © 1992, British Society of Animal Science. All rights reserved.
Scientific Publication
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