Maprelin, which contains a new active molecule, Peforelin, is a gonadotropin releasing hormone (GnRH). A single, low volume injection of the ready-to-use solution induces oestrus in sows after weaning, and in sexually mature gilts where oestrus has been synchronised with Regumate Porcine.
According to the company, it works by selectively inducing the release of the animal's own follicle stimulating hormone (FSH), leading to follicle growth - critical to successful reproduction - and the stimulation of oestrus. Conventional GnRHs, because of their mode of action, are used mainly to induce ovulation.
Janssen says Maprelin is the next step in its pig reproduction programme, named Syncoris. Cornerstone of this programme is Regumate for gilt synchronisation.
Trials have shown that with the use of Maprelin (compared with control groups of breeding animals) the number of gilts and sows showing oestrus within six days of treatment increased by about 15 percentage points (Table 1). For first-litter sows the figure was more than 8 percentage points. The duration of oestrus was not affected.
Gilts came on heat two days faster than with Regumate alone, and the weaning to oestrus interval with sows achieved similar statistically significant reductions.
Farrowing rate increased by over 5 per cent for sows, by 6 per cent for first-litter sows and just on 8 per cent for gilts.
Added to those benefits, for each 100 inseminations sows produced an extra 104 piglets, first-litter sows 105 and gilts an even more impressive 158. All gilt groups in the trials, including the control groups, were synchronised with Regumate. With unsynchronised gilts it is not possible to predict the correct time to inject Maprelin.
Phil Macdonald, the company's UK pig and poultry business manager, says the objective of every producer is profitable pigmeat production. "In the UK and other EU states the costs of feed, housing and labour are considerably higher than in other major pig-producing sectors of the world.
"This makes it important for UK producers to optimise management of the reproductive process. Maprelin is a valuable tool that can help with this objective."
The precision injection gun with Maprelin enables accurate delivery of the small amounts required. Gilts require a 2.0 ml dose 48 hours after their last Regumate treatment, first-litter sows a 0.5 ml dose 24 hours after weaning and multi-litter sows 2.0 ml 24 hours after weaning. Injections are intramuscular.
The solution requires no mixing, reducing the possibility for errors. Opened vials have a shelf life of 28 days and unopened vials a shelf life of two years. Sows and gilts need only one injection per parity, and the withdrawal period for meat and offal is zero days.
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