What are Production Diseases, and How do We Manage Them?

Table 10 Contribution to "Not pregnant to first service" and to "days open"

Factor	Incidence or quartile	Contribution to non-pregnancy from 1^st AI	Open Days added
Calving diseases	38.9	6.9	5
Unobserved heat	15.8	7.5*	20*
Fat/Protein ratio before AI^ac	1.110	11.2**	17*
Short rest period^a	75.0	10.0*	-7
High yield at drying off^ad	1563.0	-4.2†	-16*
Long dry period^a	72.0	-0.7	8
Summer calvings^b	2.0	-0.6	-5
Common factors		27.0*
Mean days open (151-d upper limit)			117
Rate of non-pregnancy (model)		58.2
Rate of non-pregnancy (actual)		52.6

†p < 0.1 *p < 0.05 **p < 0.01; ^aUpper or lower quartile of the lactation group. ^bCalving period April through August; ^cChanging fat/protein ratio; ^dHigh FCM yield in the last 120 days before calving.

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