Lactation curves in dairy goats

"Lactation curves were modeled using a multiphasic function and effects of breed, parity, season of kidding, and level of milk production on the curve were studied. Milk production data on dairy goats were grouped into 90 subclasses: breed (5) by parity (3) by season (2) by level of production (3). Subclass means for three-day groups were smoothed and used to estimate parameters of a diphasic function, sum of two phases. For each phase, characteristics for scale (initial, peak, and 305-d yields) and for shape (time of peak and duration), which are functions of parameters, were analyzed using a linear model including breed, parity, season, and mean level of production as a covariate. Breed had little effect on scale or shape on the curve. Parity affected scale and shape characteristics of second phase of lactation primarily. Season had the most consistent effect on the curve, affecting scale and shape characteristics of each phase. Level of production affected scale and shape characteristics of second phase more than those of first phase. First phase, with its proximity to overall peak and short duration, could be interpreted as a ""peak"" phase. Second phase, affected largely by parity, could be interpreted as a ""persistency"" phase."

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Animal Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Gipson, Terry A.

Contributors dc:contributor

• Grossman, Michael

• Agriculture, Animal Culture and Nutrition

Statement dc:rights

• Copyright 1989 Gipson, Terry A.

Language dc:language

eng

Identifier

AAI8924821
(UMI)AAI8924821

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/20630