Does Selection for High PD Cause Lowered Reproductive Efficiency? |
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C6opcr'o l rv" EI>./ension
OCT 2 t \9B\
NEW ,
December, 1975
DOES SELECTION FOR HIGH PO CAUSE 1.(X..'ERED REPRODUCTIVE EFFICIENCY?
E. W. Holtz
For sometime dairymen have been asking if there is 11 relationship between
the level of production and the breeding efficiency of dairy cOW's. Does the use
of high plus PO bulls have any detrimenta l effect on reproductive efficiency?
To find sOTIle answers, Califomia DHIA, The League of Califo~ia Milk Producers
, Bnd the California DR! Registry Advisory Committee provided funds for a
study. Mr. E. W. Holtz, Dairy Fa!1ll Advisor, Sonoma County, California, spent
five months at U[eh State University 'Working with Dr. R. C. Lamb, Dairy Research
Leader, ARS, and Dr . R. D. Plowman, Area Director, ARS.
The raw data consisted of 318,000 complete records from California dairy
herds on production test from January 1970 through March 1975. After editing
and eliminating unuseable records, the final results came from an analysis of
61,109 records ot COIoIS that conceived and calved again in 107 herds .
Many dairymen have always felt that production in the earl y stages of
lactation has a l arge effect on a cow's breeding efficiency. Based on results
of this study , dairy production has no appreciative effect on the breeding efficiency
of dairy cows. COW's prodUCing at a high level during the first four test
periods were bred back as early and conceived as ",ell as 10\l'er producers.
There uas no correlation between uhcn a cOW" uas first bred and the number
of breedings it took to settle the cOW". Based on these results cows can be bred
45-50 days after calving regardless of production leve l during early l actation.
This assumes that a cow has a healthy reproductive tract.
The average number of days from calving to first breeding was 84 days. It
required an average of 1.85 services per conception. The average calving interval
was 390 days and the average number of days open was 110.
The resul ts of this study shOW"ed that ·there is no re l ationship between PO
and reproductive efficiency. Thus, a dairyman need not be concerned that selection
for high pl us PD mllk is going to lead to reproductive problems.
;ubli,"",d--;;" d"r";b::;~~.::h::~«.,f ,h. ,o..~ "f Con' ....... f "'I., • an"dJ .. " . JO, i~,;.
by Ih. ,o..~<"h" •• J E""fUion s..-,..i< • .,f N_ M ... i,o S, ... U" ..... i' ,. Philip Lf).nd..., ~ ... ,
di ........ , . "dlh.U.S.O.p ... "'",'of 'O"..,..;<..J ...... . oop ... 'inl.
Object Description
| Title | Dairy Herd Improvement Notes, December, 1975 |
| Series Designation | Dairy Herd Improvement Association Monthly Report |
| Description | The monthly report of the Dairy Herd Improvement Association (DHIA) was initiated by E.E. Anderson, Extension Dairyman in the 1940s. From the 1960s forward a cooperative report had been prepared jointly by staff members of the NMSU Dairy Department, Agricultural Engineering, Agronomy, Veterinary and sent primarily to dairy herds on test (OS, DHIA, DHIR), County Extension Agents, and Instructors of Vocational Agriculture. The publication of the DHIA report was overseen by Philip Leyendecker, a director of the NMSU Agricultural Extension Service in cooperation with U.S. Department of Agriculture. The title of the report had changed over time; it had a couple of variations, New Mexico Dairy Herd Improvement and Dairy Improvement Notes. This digital collection includes historical issues published between 1961 and 1980. |
| Subject | dairy cattle (NAL); dairy farming (NAL); dairy industry (NAL); Dairy cattle--New Mexico; Dairying--New Mexico; Dairy cattle--New Mexico--Periodicals; Milk and milk products; |
| Creator | Ells, Borden; |
| Contributors | Holtz, E. W.; Huber, J. T.; |
| Date Original | 1975-12 |
| Digital Publisher | New Mexico State University Library |
| Rights | Copyright, NMSU Board of Regents |
| Collection | NMSU Cooperative Extension Service and Agricultural Experiment Station Publications |
| Digital Identifier | UAAPdhi197512 |
| Source | Call number J87.N6 X313.99 D13; http://libcat.nmsu.edu/vwebv/holdingsInfo?bibId=556737 |
| OCLC number | 35302385 |
| Type | Text |
| Format | application/pdf |
| Language | eng |
Page Description
| Title | Does Selection for High PD Cause Lowered Reproductive Efficiency? |
| Series Designation | Dairy Herd Improvement Association Monthly Report |
| OCR | C6opcr'o l rv" EI>./ension OCT 2 t \9B\ NEW , December, 1975 DOES SELECTION FOR HIGH PO CAUSE 1.(X..'ERED REPRODUCTIVE EFFICIENCY? E. W. Holtz For sometime dairymen have been asking if there is 11 relationship between the level of production and the breeding efficiency of dairy cOW's. Does the use of high plus PO bulls have any detrimenta l effect on reproductive efficiency? To find sOTIle answers, Califomia DHIA, The League of Califo~ia Milk Producers , Bnd the California DR! Registry Advisory Committee provided funds for a study. Mr. E. W. Holtz, Dairy Fa!1ll Advisor, Sonoma County, California, spent five months at U[eh State University 'Working with Dr. R. C. Lamb, Dairy Research Leader, ARS, and Dr . R. D. Plowman, Area Director, ARS. The raw data consisted of 318,000 complete records from California dairy herds on production test from January 1970 through March 1975. After editing and eliminating unuseable records, the final results came from an analysis of 61,109 records ot COIoIS that conceived and calved again in 107 herds . Many dairymen have always felt that production in the earl y stages of lactation has a l arge effect on a cow's breeding efficiency. Based on results of this study , dairy production has no appreciative effect on the breeding efficiency of dairy cows. COW's prodUCing at a high level during the first four test periods were bred back as early and conceived as ",ell as 10\l'er producers. There uas no correlation between uhcn a cOW" uas first bred and the number of breedings it took to settle the cOW". Based on these results cows can be bred 45-50 days after calving regardless of production leve l during early l actation. This assumes that a cow has a healthy reproductive tract. The average number of days from calving to first breeding was 84 days. It required an average of 1.85 services per conception. The average calving interval was 390 days and the average number of days open was 110. The resul ts of this study shOW"ed that ·there is no re l ationship between PO and reproductive efficiency. Thus, a dairyman need not be concerned that selection for high pl us PD mllk is going to lead to reproductive problems. ;ubli"",d--;;" d"r";b::;~~.::h::~«.,f ,h. ,o..~ "f Con' ....... f "'I., • an"dJ .. " . JO, i~,;. by Ih. ,o..~<"h" •• J E""fUion s..-,..i< • .,f N_ M ... i,o S, ... U" ..... i' ,. Philip Lf).nd..., ~ ... , di ........ , . "dlh.U.S.O.p ... "'",'of 'O"..,..;<..J ...... . oop ... 'inl. |
