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Effective lactation yield : A measure to compare milk yield between cows with different dry period lengths
- Source :
- Journal of Dairy Science 99 (2016), Journal of Dairy Science, 99, 2956-2966
- Publication Year :
- 2016
-
Abstract
- To compare milk yields between cows or management strategies, lactations are traditionally standardized to 305-d yields. The 305-d yield, however, gives no insight into the combined effect of additional milk yield before calving, decreased milk yield after calving, and a possible shorter calving interval in the case of a shortened dry period. We aimed to develop a measure that would enable the comparison of milk yield between cows with different dry period (DP) lengths. We assessed the importance of accounting for additional milk yield before calving and for differences in calving interval. The 305-d yield was compared with a 365-d yield, which included additional milk yield in the 60 d before calving. Next, an effective lactation yield was computed, defined as the daily yield from 60 d before calving to 60 d before the next calving, to account for additional milk yield before calving and for differences in calving interval. Test-day records and drying-off dates of 15 commercial farms were used to compute the 305-d, 365-d, and effective lactation yields for individual cows. We analyzed 817 second-parity lactations preceded by no DP, a short DP (20 to 40 d), or a conventional DP (49 to 90 d). Compared with cows with a conventional DP, the 305-d yield of cows with no DP was 7.0 kg of fat- and protein-corrected milk (FPCM) per day lower, and the 305-d yield of cows with a short DP was 2.3 kg of FPCM per day lower. Including additional milk yield before calving in the 365-d yield reduced this difference to 3.4 kg of FPCM per cow per day for cows with no DP and to 0.9 kg of FPCM per cow per day for cows with a short DP. Compared with cows with a conventional DP, median days open were reduced by 25 d for cows with no DP and by 18 d for cows with a short DP. Accounting for these differences in calving interval in the effective lactation yield further decreased yield reductions for cows with no DP or a short DP by 0.3 kg of FPCM per cow per day. At the herd level, estimated 365-d yield losses for cows with no DP or a short DP differed from effective lactation yield losses by 0.4 to -0.8 kg FPCM per cow per day. Accounting for additional milk yield before calving had a major and consistent effect on yield comparisons of cows with different DP lengths. The effect of correcting for calving interval was more variable between farms and will especially be important when calving interval is affected by DP length.
- Subjects :
- 0301 basic medicine
Time Factors
Bedrijfseconomie
Ice calving
WASS
Calving interval
Wiskundige en Statistische Methoden - Biometris
Animal Production Systems
03 medical and health sciences
Milk yield
Animal science
Pregnancy
Business Economics
Lactation
Genetics
medicine
Animals
Adaptatiefysiologie
Mathematical and Statistical Methods - Biometris
Mathematics
Productivity
Dierlijke Productiesystemen
0402 animal and dairy science
food and beverages
04 agricultural and veterinary sciences
Milk Proteins
040201 dairy & animal science
Dry period length
Parity
030104 developmental biology
medicine.anatomical_structure
Milk
Yield (chemistry)
Herd
WIAS
Adaptation Physiology
Animal Science and Zoology
Cattle
Female
Food Science
Subjects
Details
- Language :
- English
- ISSN :
- 00220302
- Volume :
- 99
- Database :
- OpenAIRE
- Journal :
- Journal of Dairy Science
- Accession number :
- edsair.doi.dedup.....acb76a8ce929206f9b14c21b92fe82a3