In­ject­ing to de­lay the on­slaught of pu­berty

As an­i­mal wel­fare cam­paign­ers in Europe con­tinue to push for a ban on boar cas­tra­tion, Liz Shank­land con­sid­ers a vac­ci­na­tion which some pro­duc­ers be­lieve could be the an­swer to boar taint

Country Smallholding - - Liz Shankland Pigs -

How­ever you feel about the cas­tra­tion of piglets reared for meat, those who do it rou­tinely know that some­time in the fu­ture they will have to con­sider the al­ter­na­tives. As re­ported in last month’s Coun­try Small­hold­ing, the tar­get date for an end to the prac­tice of phys­i­cally cas­trat­ing with­out anaes­the­sia or anal­ge­sia in Europe has been ex­tended to the end of 2018. Wel­fare cam­paign­ers have long ar­gued that this type of cas­tra­tion — car­ried out in the first week of life to guard against any risk of boar taint ( See box, right) — is painful, in­hu­mane and med­i­cally risky. Ma­jor pro­duc­ers in sev­eral coun­tries across Europe have al­ready made vol­un­tary changes in the way they op­er­ate, ei­ther aban­don­ing phys­i­cal cas­tra­tion al­to­gether, or car­ry­ing out the pro­ce­dure with the aid of lo­cal anaes­thetic and/or painkillers.

The first part of this two-part fea­ture ( Coun­try Small­hold­ing, Oc­to­ber) looked at ways in which the risk of taint could be min­imised by bet­ter hus­bandry and care­ful stock se­lec­tion, but, for an in­creas­ing num­ber of pro­duc­ers, vac­ci­na­tion seems to be a prac­ti­cal an­swer.

As al­ready dis­cussed, not all boars will pro­duce tainted meat; some breeds — and some blood­lines within cer­tain breeds — will be more sus­cep­ti­ble than oth­ers. Hus­bandry and en­vi­ron­men­tal is­sues can also be fac­tors. How­ever, to re­duce the risk of cus­tomer dis­sat­is­fac­tion, the ma­jor­ity of butch­ers still pre­fer meat from gilts (young fe­males) or from phys­i­cally-cas­trated boars.

Phys­i­cal cas­tra­tion can only be car­ried out within the first week of life by a breeder; any later and it must be done by a vet­eri­nar­ian us­ing a lo­cal anaes­thetic and anal­ge­sia. Cas­tra­tion per­formed in this way can re­duce the risk of taint, but there is grow­ing op­po­si­tion to cas­tra­tion, which not only car­ries wel­fare con­cerns and health risks, but can also have a detri­men­tal ef­fect on growth ( Coun­try Small­hold­ing, Oc­to­ber).

One al­ter­na­tive ap­proach which is be­ing used with ex­cel­lent re­sults is im­muno­cas­tra­tion. At the mo­ment, there is only one vac­cine li­censed for use for im­muno­cas­tra­tion — Im­provac®. It is im­por­tant to stress that this vac­cine is not a form of chem­i­cal cas­tra­tion — a phrase which of­ten sets alarm bells ring­ing. Im­provac® works by tem­po­rar­ily sup­press­ing tes­tic­u­lar func­tion (in­clud­ing testos­terone pro­duc­tion). In ef­fect, it de­lays pu­berty, while al­low­ing the pig to grow as nor­mal in all other re­spects.

Take up in the UK has been rel­a­tively slow, but in the United States, where more than 95% of pigs are cas­trated be­cause pro­duc­ers take their pigs to much higher weights, in­ter­est is in­creas­ing.

Larry Ru­eff, a vet from Greens­burg, In­di­ana, who owns his own pig farm and uses it as a teach­ing fa­cil­ity, has been a pi­o­neer in per­suad­ing oth­ers to use im­muno­cas­tra­tion in­stead of phys­i­cal cas­tra­tion. He has been us­ing Im­provac® for more than four years and has car­ried out de­tailed tri­als with nu­mer­ous batches of pigs — with im­pres­sive re­sults. Cen­tral to his re­search is his long-held be­lief (backed by sci­en­tific stud­ies) that en­tire boars pro­duce bet­ter, leaner car­casses and bet­ter value for money than those who have been phys­i­cally cas­trated.

“Im­muno­cas­tra­tion lets boars be boars,” he in­sists. “The re­al­ity is that we some­times for­get that per­for­mance in un­cas­trated boars is so much bet­ter, from a feed con­ver­sion and growth rate point of view, than when they are cas­trated.”

Al­though Im­provac® is now be­ing used ex­ten­sively in some parts of Europe, its us­age in the United States is still lim­ited, largely be­cause of con­cerns over food safety.

“We have be­come very con­cerned about our food,” Larry ex­plains. “Here in the US we have the safest food in the world, but some of the gen­eral pub­lic are still sus­pi­cious about what they’re buy­ing.”

Larry be­lieves that con­cerns about ge­net­i­cally-mod­i­fied prod­ucts are partly to blame for con­fus­ing con­sumers; there is a gen­eral mis­con­cep­tion, he says, that any­thing which in­volves sci­en­tific in­ter­ven­tion must be bad.

“When you say im­muno­cas­tra­tion, peo­ple think hor­mones,” he says. “They think it’s some­thing that will make the pork un­safe. That’s just not true. Quite sim­ply, an­drostenone and ska­tole, which are the com­pounds that the male pig nat­u­rally pro­duces when it is in­tact, are the things which can give the pig’s meat taint. All that im­muno­cas­tra­tion does is to block the phys­i­o­log­i­cal process that al­lows those prod­ucts to be made. It makes the body shut the process off, just as your im­mune sys­tem re­acts when you vac­ci­nate for some­thing, such as, in the pig in­dus­try, my­coplasma or cir­covirus. It just uses the body’s nat­u­ral im­mune sys­tem to turn things off.”

Ac­cord­ing to stud­ies car­ried out, while the main rea­son for us­ing im­muno­cas­tra­tion is to de­lay pu­berty and re­duce the risk of boar taint, it also helps to re­duce ag­gres­sion when boars are reared to­gether. Larry Ru­eff says he rou­tinely keeps 25 young boars in a pen — of­ten boars mixed from dif­fer­ent lit­ters — with­out any prob­lems, right up to slaugh­ter weight. When fin­ished, the pigs’ car­casses are leaner than their cas­trated coun­ter­parts and they have con­sumed less food.

Ac­cord­ing to stud­ies car­ried out, while the main rea­son for us­ing im­muno­cas­tra­tion is to de­lay pu­berty and re­duce the risk of boar taint, it also helps to re­duce ag­gres­sion when boars are reared to­gether

The risk of taint could be min­imised by bet­ter hus­bandry and care­ful stock se­lec­tion, but vac­ci­na­tion is also a prac­ti­cal an­swer

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