Original scientific paper
ESTIMATION OF DAILY AND LACTATION MILK YIELD FROM ALTERNATIVE MILK RECORDING SCHEME
Sonja Jovanovac
; Zavod za zootehniku, Poljoprivredni fakultet Sveučilišta J.J. Strossmayer u Osijeku, Hrvatska
Vesna Gantner
; Zavod za zootehniku, Poljoprivredni fakultet Sveučilišta J.J. Strossmayer u Osijeku, Hrvatska
K. Kuterovac
; Ministarstvo poljoprivrede, ribarstva i ruralnog razvoja, Zagreb, Hrvatska
Marija Klopčič
; Biotehniška fakulteta, Univerza v Ljubljani, Oddelek za zootehniko, Domžale, Slovenia
M. Cassandro
; Dipartimento di Scienze Zootechniche, Università di Padova, Padova, Italija
Abstract
Statistical methods were to developed and evaluated for the estimation of daily and 305-day lactation milk yield of dairy cattle from alternative milk recording scheme. Data included 7,815 individual test-day milk yield records collected according to the A4 milk recording method on 769 cows reared on 15 family farms. Daily milk yield was estimated using five different methods. The 305-day lactation milk yields were calculated from estimated daily milk yields using the Test Interval Method. The correlation between estimated and true milk yields, as well as the basic statistics of difference between estimated and true milk yield were used as the evaluation criteria for estimation methods. The linear regression of daily to partial milk yields with taking into account the interval between successive milkings proved to be the most accurate one in estimating daily milk yield, either from morning or evening records. The doubling of morning or evening milk yield highly overestimated and underestimated the daily milk yield, respectively. When 305-day lactation milk yields were compared no notable differences between evaluated methods were found.
Keywords
Dairy cattle; Alternative method; Daily yield; Lactation yield; Estimation
Hrčak ID:
24333
URI
Publication date:
15.3.2008.
Visits: 1.154 *