Abstract :
The lactation curve of Murciano-Granadina goats was studied by using records collected
between 2004 and 2010 under its Official Dairy Recording program, which includes three
milking control programs (Granada, Almeria and Cordoba). A total of 518,557 test-day
records corresponding to 69,330 lactations by 38,039 does in 130 herds were included
in the analyses. Different mathematical models were fitted, and average curves for region
of production, parity, kidding season and type of kidding were estimated. A quadratic spline
function gave the best fitting performance and provided a good description of the Murciano-
Granadina lactation curve. All the factors studied affected both the scale of the lactation
curve and its shape, with more distinct curves in first lactations, goats kidding in the summer
and those producing singletons. When compared with later parities, first-parity does
had a lower initial level of production, later and lower peak yield, and a smaller decline in
milk production after the peak. Goats kidding in the Summer had a steep increase in milk
yield up to the peak, which occurred earlier and with a higher yield than in other seasons,
but seasonal effects differed slightly among regions. The lactation curve was flatter and
with a later peak in goats producing single kids, and a steeper increase in yield up to the
peak was observed as the number of kids increased.
