Congratulations to our twelve client herds able to produce as many or more than 25 pigs weaned/sow/year in 2007.

Hutterville Colony		30.0 p/s/y
Big Sky Colony, MT		326.7 p/s/y
Milford Colony		26.1 p/s/y
Miltow Colony		26.0 p/s/y
White Lake Colony		26.0 p/s/y
Bench Colony, SK		25.9 p/s/y
Roseglen Colony		25.8 p/s/y
Starbrite Colony		25.4 p/s/y
Willow Creek Colony		25.1 p/s/y
Newell Colony		25.0 p/s/y
Peace View Colony, BC		25.0 p/s/y
Parkland Colony		25.0 p/s/y

The Trailblazer boar sent to Devine Swine is breeding 5-6 times/week; they have noticed bigger piglets born from their Trailblazer.

50 Years of Lacombes in Canada.
Great underlines on Lacombes

Lacombe gilts averaged 134 Sire Line Index and 133 Dam Line Index on 42 pigs probed on June 4 at our Bloomsbury Farms. High indexing gilt had a 192 SLI with a 166 DLI.

The Role of the Gilt

A brief recap is in order before we talk about the role of the gilt. We have suggested that:

Meeting breeding targets and farrowing rate are the most important factors affecting number of pigs weaned per sow per farrowing group or per year. Proper sizing of the herd to match facility capacity, and of the gilt pool to meet weekly breeding targets, is essential to meeting weaner pig targets. Although the number of weaned sows returning to estrus within an acceptable period after weaning (say 6 days) is the most important factor affecting the number of females served per week; this number will vary from week to week because of voluntary and involuntary culling. Therefore, the major control on meeting breeding targets is provided by proper sizing and management of the gilt pool. However, the quality of the gilts entering the gilt pool and their nutrition and management can have a very significant influence on the reproductive performance and longevity of the gilts.

Sizing the gilt pool

The size of the gilt pool will depend on (1) replacement rate, (2) the culling rate of the gilts received, (3) how frequently you receive gilts and (4) the expected entry-to-service interval. For a herd of 1250 sows, with a 45% replacement rate, a weekly farrowing schedule and an entry-to-service interval of 35 days, the following are the calculations of gilt pool size.
The number of gilts to be served per week is calculated as:

Sow inventory x replacement rate = Number farrowing groups/year

1250 x 0.45 = 52

11

But gilts only cycle every 21 days and so expect only one-third on heat any one week, so you need 33 (11 x 3) to get your 11 estrus gilts. But not all are selected so take 4 times requirement i.e. 11 x 4 = 44. Also, some gilts are held for a time before being served so we must allow for that. The extra gilts required because of this delay is calculated as:

No. gilts served/group x no. days to service
No. days between service groups

For this farm serving 11 gilts/wk and with an entry-to-service interval of 35 days and a weekly service schedule the calculation is:

11 x 35 = 55 7

So total in gilt pool is 44 + 55 = 99 or about 8% of the herd.
The number to be delivered each month (30 days) to this farm should be:
No. to be served/wk x 30 days
No. days between farrowings
= 11 x 30/7 = 47

So 47 gilts should be delivered each month.

Thoughts on Raising Gilts

Most of us buy replacement gilts, so we have little control on how they are raised before we receive them. However, I think we should have some appreciation as to how the gilts previous feeding and management can influence its lifetime performance.

The following are some ideas and suggestions as to how gilts should be raised: (1) there is some evidence that cross-fostering of gilts has a negative effect on age at puberty and conception rate. Little effort is made to ensure that females that have the potential to be selected as future breeding stock are not fostered or that if gilts are fostered they are not later selected as breeding replacements. (2) there is some evidence that gilts raised in small litters (<10) reach puberty earlier and have better subsequent reproductive performance than gilts reared in larger litters. However, this strategy is rarely considered.
(3) clearly mark all female pigs that had ‘splay-leg’ or were lame and ensure they are not subsequently selected as replacement gilts. (4) heavier pigs at weaning have better appetites in the nursery and grow faster in the first month after weaning than do smaller piglets. (5) there is evidence that growth rate and nutrition of gilts in the grower period may have a greater influence on subsequent reproductive performance than they do in the finishing period.