Table 3.

Effect of supplemental Zn in late gestation on farrowing performance of sows

	Treatment
Item	CON1	INT2	HI3	SE	P-value
No. of sows	112	112	115	—	—
No. of litters	108	104	110	—	—
No. of piglets	1,565	1,424	1,525	—	—
Parity	2.9	3.0	2.9	0.2	0.92
Days fed supplemental Zn	35.8	36.0	36.1	0.4	0.70
Gestation length, d	115.2a	115.2a	115.6b	0.1	<0.01
Lactation length, d	22.4	21.9	22.3	0.3	0.45
Days to service	6.9	7.1	5.8	0.9	0.43
Sows mated within 7 d postweaning4, %	85.9	83.3	89.8	—	0.48
Body condition score5
Day 85 gestation6,7	14.9a	15.5b	15.5b	0.2	0.03
Prefarrow8	13.1	13.3	13.3	0.6	0.68
Weaning	11.4	11.8	11.8	0.4	0.32
Farrowing performance
Total pigs born/litter	14.7	13.8	14.2	0.4	0.23
Pigs born alive/litter	14.0	13.1	13.4	0.4	0.25
Pigs weaned/litter	10.7	10.3	10.7	0.3	0.26

^abMeans within a row with different superscripts differ (P < 0.05).

¹Diets containing 125 ppm supplemental Zn as AvailaZinc and ZnSO₄·H₂O.

²Diets containing 365 ppm supplemental Zn as Control + ZnSO₄·H₂O.

³Diets containing 595 ppm supplemental Zn as Control + ZnSO₄·H₂O.

⁴Calculated as: (number of sows mated within 7 d of weaning/total sows at weaning) × 100; Chi-square = 1.46, df = 2.

⁵Body condition scores evaluated at last rib via caliper.

⁶Initiation of dietary treatments.

⁷Initial body condition score was included as a covariate in the statistical model for subsequent body condition scores.

⁸One day before expected farrowing date.