U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Norman, Hitem
                                            Van Tassell, Curtis

                                                         - *Curt*item
                                            Vanraden, Paul
  Submitted to: American Forage and Grassland Conference Proceedings
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 6/14/2004
                                    Publication  Date: 6/16/2004
                                    Citation: Norman, H.D., Van Tassell, C.P., VanRaden, P.M. 2004. Optimum genetic choices for dairy producers using grazing practices [abstract]. Proceedings of 2004 Conference of the American Forage and Grassland Council 13:20, 219.Interpretive Summary:
                                Technical Abstract: The decline in cow fertility has had a negative financial impact on all dairy producers, especially those who practice pasture-based dairying (grazing) and seasonal calving. Two breeding approaches that have been tried by some US grazers to obtain cattle with better fertility or other desired characteristics are 1) use of bulls from countries that practice grazing (such as New Zealand and Ireland) and 2) use of bulls of a breed different from that of the cows to strengthen characteristics desired in the herd. This study compared performance of US daughters of New Zealand artificial-insemination (AI) Holstein bulls and daughters of other (predominantly US) AI Holstein bulls in the herd; no AI Holstein bulls from Ireland had US daughters of milking age. Herds were required to have at least five daughters of New Zealand bulls; cows were required to have calved from December 2001 through December 2003 and to have had an opportunity to express the performance trait. Data included records from 163 daughters of New Zealand bulls and 1966 daughters of other bulls in 19 herds. Mean milk and protein yields were lower by 1572 and 24 lbs, respectively, for daughters of New Zealand bulls than for daughters of other bulls, but mean fat yields were equal. Daughters of New Zealand bulls had higher mean somatic cell scores (indicator of mastitis susceptibility) than did daughters of other bulls (3.1 versus 2.8) and shorter mean productive life (longevity) by 3.6 mo. Mean pregnancy rate (fertility measure) for daughters of New Zealand bulls was 29.7%; mean DPR for daughters of other bulls was 27.9%. Grazer breeders may have focused more than other breeders on improving reproductive efficiency as the mean pregnancy rate for US Holsteins that calved from 2002 through 2003 was only 25.8%. Selecting bulls entirely on reproductive performance would not be warranted because other traits have economic value as well. A better choice for breeders who want more emphasis placed on reproductive traits is to use an index with more weight on daughter pregnancy rate than is recommended for the majority of the US dairy cattle industry.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov