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EFFECT OF SUBCLINICAL KETOSIS ON DAILY MILK YIELD AND MILK COMPONENTS OF SLOVENIAN HOLSTEIN CATTLE
Vesna Gantner
; Poljoprivredni fakultet Sveučilišta J. J. Strossmayera u Osijeku, Osijek, Hrvatska
Klemen Potočnik
; Univerza v Ljubljani, Biotehniška Fakulteta, Domžale, Slovenija
Sonja Jovanovac
; Poljoprivredni fakultet Sveučilišta J. J. Strossmayera u Osijeku, Osijek, Hrvatska
Nikola Raguž
; Poljoprivredni fakultet Sveučilišta J. J. Strossmayera u Osijeku, Osijek, Hrvatska
Sažetak
The objective of this study was to determine the effect of subclinical
ketosis on daily milk yield and milk components in Slovenian Holstein cows using monthly test day records. Data provided by the Agricultural Institute of Slovenia consisted of 1,299,630 test-day records of milk, fat, and protein from 73,255 Slovenian Holstein cows collected from January 2000 to December 2005. Cows were reared on 5,333 farms in Slovenia. The subclinical ketosis was indicated by the fat to protein ratio higher than 1.5 in cows that yielded between 33 to 50 kg per day (Eicher, 2004). Only the first occurrence of upper
defined criteria was considered in this study. The ketosis index was defined in relation to the timing of subclinical ketosis detection to the subsequent measures of test-day milk yields. The effects of subclinical ketosis on test day milk yield and milk components were studied separately for each parity using mixed model analysis. Statistical model included fixed effect of ketosis index, calving year-month, lactation stage and random effect of animal. Negative
effect of subclinical ketosis on daily milk yield, daily fat content as well as on daily fat and protein yields was determined in each parity. Decrease was determined within 35 days after the detection of subclinical ketosis and continued in subsequent milk controls. When daily protein content was analysed, increase was determined in subsequent milk controls after detection. The research results show that test-day records could be used as a tool for early detection of subclinical ketosis.
Ključne riječi
dairy cows; daily milk yield and milk components; subclinical ketosis; test-day records
Hrčak ID:
32680
URI
Datum izdavanja:
22.12.2008.
Posjeta: 1.389 *