The benefits of split-sexing finishing pigs

A by-product of Hermitage Genetics’ progeny testing programme has been the production of useful data on the relative finishing performance of boars and gilts

Hermitage Genetics has increased the testing capacity at its Freneystown and Muckalee nucleus farms in Ireland to the extent that between both farms it can now put more than 5,500 animals through an individual test system annually. Freneystown has just completed its first full year of testing in the company’s new MLP Feed Registration Stations. In addition, at nucleus level, the company also individually measures growth, back fat, loin muscle depth and lean meat percentage on a further 30,000 pigs annually.

In the individual feed test station pens, feed recording commences on both male and female groups of animals from about 50kg and continues until approximately 110kg. Each pen and feed station has the capacity to feed 15 pigs, and every pig in the group is tagged with a unique coded ear tag transponder. Every visit to the feed station by each pig is recorded. The duration of the test period is a minimum of 40 days, and the groups on test are categorised by sex and breed.

The system operates on the principle that when the pig is finished eating at the station and withdraws from the trough area, the electronic system records the difference between the pre- and post-visit trough weight and the data is then stored in a file with the pen number, the pig’s identification number, and the date and the time of entry and exit. The recorded data is used to calculate the individual feed intake.

Pigs are weighed at the start of the test period and at the end of the test period, and this, in combination with daily feed intake data, allows the feed conversion efficiency (FCE) to be calculated. FCE is then used in combination with other traits of economic importance for both maternal and terminal lines to select the top-performing replacement breeding boars for the Pig Genetics AI stud and the best replacement breeding females for Hermitage’s nucleus farms.

The results to date (see Table 1) clearly demonstrate the significant advantages of split-sexing entire boars and gilts, and grading for size prior to commencing the finishing period. Separating the sexes has several benefits. Boars and gilts grow at different rates and utilise feed differently, and boars tend to have a higher lean meat percentage than gilts when they reach slaughter weight.

On-farm observations also show that groups of separately penned boars and gilts show less aggressive behaviour within the group, therefore less fighting; exhibit less competition for feed; and demonstrate more uniform gains, therefore less variation within a group.

As a result, less time is required in sorting pigs at point of sale. This system allows for the marketing of more uniform groups of pigs, which can result in a higher return at the abattoir. If there’s less variation in a group, this means a higher portion of the group will be able to meet the specific carcase specifications, therefore optimising grading results by size and reducing the possibility of financial penalties.

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