Utilization and reproductive performance of gilts in large-scale pig farming system with different production levels in China: a descriptive study

Table 2 Average estrus information of 100,811 estrus out of 112,157 gilts in 1540 gilts’ batches

	High-performing pig farms (n = 26)	Intermediate-performing pig farms (n = 53)	Low-performing pig farms (n = 26)
	Mean ± SEM	Mean ± SEM	Mean ± SEM
Number of gilts’ batches	235	948	357
Total number of estrus¹	21,198	44,917	34,696
Proportion of first estrus²	62.4%^a	92.7%^b	91.7%^b
Proportion of second estrus³	21.0%^a	5.1%^b	4.7%^b
Proportion of third or more estrus⁴	16.6%^a	2.2%^b	4.6%^b
Total estrus rate⁵	77.2% ± 2.2%^a	78.1% ± 1.2%^a	66.3% ± 2.1%^b
Average times of estrus⁶	1.2 ± 0.05^a	0.9 ± 0.01^b	0.9 ± 0.03^b
Average age of first estrus⁷	209 ± 5.79^a	224 ± 3.18^b	213 ± 5.32^b

¹Total number of estrus: The total number of gilts with estrus from introduction to pre-mating
²Proportion of first estrus: Average proportion of gilts with once estrus in all estrus gilts of each gilts’ batch
³Proportion of second estrus: Average proportion of gilts with twice estrus in all estrus gilts of each gilts’ batch
⁴Proportion of third or more estrus: Average proportion of gilts with three times or more estrus in all estrus gilts of each gilts’ batch
⁵Total estrus rate = Number of gilts in estrus/Total number of estrus
⁶Average times of estrus: Average estrus times of gilts before mating in each gilts’ batch
⁷Average age of first estrus: Average age of first estrus age before mating in each gilts’ batch
^a,b Bars with different letters differ significantly (P < 0.05)

ISSN: 2055-5660