Assessment of progesterone profiles and postpartum onset of luteal activity in spring calving Hereford beef suckler cattle

Table 4 Multiple relationships between natural logarithm of days open and explanatory variables

Variable	Group	n	β-value	SE	F-value	P-value
Calf 200-d weight		81	-0.003	0.001	11.25	0.001
Calf birth weight	1^st quartile	21	-0.356	0.127	4.25	0.01
	2^nd quartile	22	-0.285	0.085
	3^rd quartile	19	-0.224	0.100
	4^th quartile	19	0.000	0.000
Luteal phase pattern	Normal	84	-0.370	0.089	17.19	<0.001
	Irregular	24	0.000	0.000
Natural logarithm of onset of luteal activity		103	0.263	0.067	15.21	<0.001
Parity	1^st	23	0.261	0.097	3.73	0.03
	2^nd	19	0.001	0.097
	>2^nd	67	0.000	0.000

ISSN: 1751-0147