GROWTH in Performance Improvement:

Hutterville Colony maintains its improvement in weaning pigs per litter in its 513-sow herd over twelve months to December 31, 2007:

	Ave	T1	T2	T3
Ave total pigs per litter	13.5	13.6	13.5	13.5
Ave live pigs per litter	13.0	13.0	13.0	13.0
Pigs weaned per litter	12.3	12.3	12.3	12.4
Pigs weaned/mated female	30.0	31.0	28.4	30.7
Pre-wean mortality %	3.8	4.0	3.5	3.8

Welcome to Kingdom Farms on its purchase of Trailblazer boars as contributors to its AI breeding program.

Thanks all of our clients for your replacement boar and gilt purchases!

(Reprinted from V5,No6 PEAK of Performance News! by the late Dr. Frank Aherne. This series will continue for nine episodes.)

In previous articles we showed how to match herd size to suit available facilities and discussed the importance of meeting breeding targets. The next important job is to ensure the bred sows and gilts perform efficiently.

Number of pigs weaned per inventoried female (p/s/y) or per mated female are widely used as criteria of breeding herd efficiency. The average p/s/y is a product of number of litters/sow/year and the number of pigs weaned/sow/litter. Each contributes equally, so both criteria must be reviewed when troubleshooting problems of herd productivity.

Litters per sow per year

The number of litters produced per sow per year is dependent upon average gestation length, average lactation length and the average number of days that the sows are non-productive.

Litters/sow/year = 365 – non-productive days / gestation length + lactation length

Average gestation length will vary only by a few days (113-115 days) and therefore litters/sow/year is influenced mainly by lactation length and non-productive days.

Lactation length

In recent years, shorter lactations of 16 to 24 days (compared to 28-35 days) have become increasingly common. Lactation length of 16 to 24 days does not have much influence on pigs/sow/year. Any slight reduction in litter size caused by reducing lactation length from 24 to 16 days is made up by the increase in litters/sow/year.

However, for lactation lengths of less than 16 days, subsequent litter size is reduced (0.06 piglets/day), weaning-to-service interval is increased and farrowing rate may be reduced. It must be realized that if average weaning age is 16 days, then 50% of the lactations are less than 16 days and probably these range from 12 to 16 days. The negative effects of lactation length tend to get very significant at 15 days and less. Also, piglets weaned at 15 days of age and less do not perform as well as do older piglets of lower weaning weight. So manage very early weaned pigs (less than 15 days of age) as you would the lightest piglets that are weaned at older ages. It has been shown that the negative effects of early weaning on subsequent sow performance can be very significantly reduced if sow lactation feed intake is in fact high, at least 5.5 kg/sow/day.

Influence of non-productive days on percentage of inactive sows

Non-productive Days	37	45	55	65
% Inactive Sows	10	12	15	18

Because lactation length of 16 to 24 days is fixed by available facilities and does not have a very significant influence on pigs/sow/year, it leaves non-productive days as the most important factor influencing pigs/sow/year, followed by (b) total born litter size and (c) pre-weaning mortality. Average non-productive days in Canadian herds are about 60 days and about 37 days for the top 10% of producers. This means that, for average herds, about 17% of the herd is inactive each year (60/365 days).

For an average herd, an increase in non-productive days of 1day results in pigs/sow/year of 0.06 piglets as well as a reduction in litters/sow/year of 0.006. So a reduction in non-productive days of 10 days will increase pigs/sow/year by 0.6 pigs. Of the common measures of sow productivity, including pre-weaning mortality and litter size, non-productive days is the best indicator of breeding herd efficiency.

In the next article, we will discuss non-productive days and the factors contributing to non-productive days.

Site Design:  Summit Solutions Ltd.