This paper is only available as a PDF. To read, Please Download here.
ABSTRACT
Data from 69,145 Holstein cows that calved in 2005 were evaluated to determine the
influence of age at first calving (AFC) on first lactation and lifetime production
in commercial dairy herds. A DHI database was divided into 4 herd management criteria
(HMC). The 4 HMC were 1) 3X milking and rolling herd average (RHA) = 12,750 kg (3X-H),
2) 3X milking and RHA = 11,250 kg (3X-M), 3) 2X milking and RHA = 11,250 kg (2X-M),
and 4) 2X milking and RHA = 9,250 kg (2X-L). For all HMC, a universal loss in first-lactation
milk, fat, and protein yield was observed when AFC was <23 mo. Compared with 24 mo, first-lactation milk yield was decreased, 166, 369, and
654 kg for heifers calving at 22, 21, and 20 mo, respectively. In contrast, AFC ×
HMC interactions were observed for all herd-life and lifetime production criteria.
In 3X-H and 3X-M herds, herd-life and lifetime DIM increased with decreasing AFC.
In 2X-M and 2X-L herds, herd-life and lifetime DIM increased when AFC was reduced
from 30 to 24 mo, but herd-life and lifetime DIM were not increased when heifers calved
<24 mo. In 2X-M and 2X-L herds, the combined effect of reduced first-lactation milk
yield and with no corresponding benefit in lifetime DIM resulted in reduced lifetime
milk, fat, and protein yields when AFC was <23 mo. In contrast, increased lifetime milk, fat, and protein yields were observed
in 3X-H and 3X-M herds when AFC was <23 mo. Data suggest HMC alters the relationship between AFC and lifetime milk, fat,
and protein production in commercial dairy herds.
Key words
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe toAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
LITERATURE CITED
- An overview of experiences of Wisconsin dairy farmers who modernized their operations.J. Dairy Sci. 2001; 84: 717-729
- Impact of age at calving on lactation, reproduction, health, and income in first-parity Holsteins on commercial farms.J. Dairy Sci. 2004; 87: 2130-2135
- Trends in calving ages and calving intervals for dairy cattle.J. Dairy Sci. 2006; 89: 365-370
- Effect of accelerated postpubertal growth and early calving on lactation performance of primiparous Holstein heifers.J. Dairy Sci. 1996; 79: 2024-2031
- Applied dynamics of dairy replacement growth and management.J. Dairy Sci. 1992; 75: 2504-2516
- Effects of early and late breeding of heifers on multiple lactation performance of dairy cows.J. Dairy Sci. 1988; 71: 2735-2743
- SAS System for Linear Models.3rd ed. SAS Inst. Inc., Cary, NC1991
- Effect of age at first calving on some productive and longevity traits in Iranian Holsteins of the Isfahan Province.J. Dairy Sci. 2004; 78: 2130-2135
- The use of two distance measures as a modified multiple comparison technique for obtaining response surface differences.MS Thesis. Univ, Nevada, Reno1993
- Effect of age at first calving on production traits and difference between milk yield returns and rearing cost in Italian Holsteins.J. Dairy Sci. 2000; 83: 603-608
- SAS User’s Guide: Statistics.SAS Inst. Inc., Cary, NC2001
- Effects of three prepuberty body growth rates on performance of Holstein heifers during first lactation.J. Dairy Sci. 1998; 81: 527-538
- Implementation of a routine genetic evaluation for longevity based on survival analysis techniques in dairy cattle populations in Switzerland.J. Dairy Sci. 2001; 84: 2073-2080
- Investigation of factors affecting voluntary and involuntary culling in expanding dairy herds in Wisconsin using survival analysis.J. Dairy Sci. 2003; 86: 1482-1486
Article info
Identification
Copyright
© 2013 American Registry of Professional Animal Scientists. Published by Elsevier Inc. All rights reserved.