The issue of piglet castration has become a major animal welfare concern in many European Countries. Some supermarket chains have decided to only sell products from pigs that have not been physically castrated from 1 January 2011 onwards. As a result of this a European wide approach has been drawn up to meet both animal welfare and market demands:
• As a first step, from 1 January 2012, surgical castration of pigs, if carried out, shall be performed with prolonged analgesia and/or anaesthesia with methods mutually recognised.
• As a second step and in the long term, surgical castration of pigs should be abandoned by 1 January 2018.
One of the main contributing factors to boar taint (odour) is the level of androstenone present in the carcass of entire (non-castrated) male pigs. The levels of androstenone are related to slaughter weight/age (maturity of the pig) and other factors. Trials were carried out to determine whether the levels of androstenone are lower in the fast growing Hermitage Maxgro™ breed when compared with other commercially available terminal lines (Duroc and Pietrain), and also to determine if the Hermitage Maxgro™ non castrated male pigs reach slaughter weights without deleterious boar taint problems.
The research was carried out by
Dr. Paul Allen, Principal Research Officer in th Department of Food Chemistry and Technology at the
Teagasc Food Research Centre, Ashtown, Dublin, Ireland and
Dr. Patrick Varley, Research and Development coordinator at
Hermitage Genetics Ltd.
Ninety purebred boars were selected (Hermitage MaxgroTM, Pietrain and Duroc); all boars were fed on identical diets and slaughtered at approximately 112 kg. Growth performance was monitored throughout the finishing period and belly fat samples were collected from each pig at slaughter to determine the concentration of androstenone present. The trial was repeated to confirm the results. The results from these trials show that the Hermitage MaxgroTM achieved slaughter weight faster than the Duroc and Pietrain breeds, thereby demonstrating its superior growth and its ability to reach slaughter weight quicker and at a younger age than other breeds. As a direct result of this faster growth, the concentration of androstenone detected in the belly fat samples from the Hermitage MaxgroTM were significantly lower than those detected in the Duroc pigs. In fact the average level of androstenone measured in the Maxgro™ pigs were over 3.6 times lower than the level detected in the Duroc pigs and although not significant Maxgro pigs had 22% lower average androstenone levels than the Pietrain pigs. The Maxgro™ pigs were on average 6 kg per pig heavier than the duroc pigs at slaughter and approximately 20 days younger. Full results are detailed in the table below.
|
Breed
|
Duroc
|
Maxgro
|
Pietrain
|
SEM
|
Significance
|
|
Age at slaughter (days)
|
176.5a
|
156.7b
|
166.9c
|
2.141
|
***
|
|
Days to 100 kg
|
160.7a
|
142.4b
|
148.9c
|
1.815
|
***
|
|
Body weight (kg)
|
108.3a
|
114.4b
|
112.2ab
|
1.580
|
*
|
|
Carcass weight (kg)
|
81.4a
|
87.2b
|
85.2ab
|
1.523
|
*
|
|
Kill out (%)
|
75.2
|
76.1
|
75.9
|
0.678
|
ns
|
|
Lean (%)
|
61.1
|
61.9
|
62.1
|
0.319
|
ns
|
|
Androstenone (ug/kg,ppb)
|
1793.6a
|
494.2b
|
631.6b
|
128.8
|
***
|
a,b,c Means with different superscripts are significantly different (P < 0.05).
Threshold values
Androstenone (ug/kg,ppb)
< 500 low
500 to 1000 medium
>1000 high