No change to Alliance male lamb policy

10-02-2010 | Gerard Hall

Alliance Group has no intention of altering its policy of accepting ram and cryptorchid lambs up to twelve months old.

Results of the farmer owned co-operative's study during the past year confirm there is no difference in the eating quality of the meat from 17kg-19.5 kg carcaseweight (CW) entire, cryptorchid or wether (castrated males) lambs.

As a result, Alliance will continue to make no distinction between carcases of different sexes or castration status in its lamb schedule or the contract supply options it offers its shareholder suppliers.

Provided they are in the required and preferred weight ranges, payments to Alliance suppliers will remain the same regardless of whether their lambs are male, female, wethers (castrated males) or induced cryptorchids.

Alliance Group group livestock manager Murray Behrent says the trial was set up in response to perceived but unfounded concerns surrounding the eating quality of meat from ram lambs, specifically in relation to its taste and aroma.

Country-Wide informally tested the perception among a few southern sheep farmers seeking out some sun while holidaying in Central Otago. Several expressed some surprise, but were pleased with the findings of Alliance's study. A few suggested it was about time an old wives' tale was finally put to rest.

Behrent says Alliance has not received any concerns or complaints from its in-market customers. The company did not believe leaving male lambs entire had a detrimental effect on meat quality if they were killed under a certain age and weight but was keen for independent science to back their position.

It is a view supported in the international literature and also among the conclusions contained in a comprehensive review last year by Massey University's Roger Purchas and Nick Schreurs in their report on the issue to Meat & Wool New Zealand.

Keen to further examine the issue, Alliance commissioned independent science providers AbacusBio Ltd to determine what effects, if any, the castration status might have on the meat quality of lambs up to 13-months-old.

AbacusBio's Dunedin-based scientist Dr Anna Campbell found the main difference in meat quality among ram, cryptorchid and wether lambs relates to their pH and time of kill. In the trial, ram and crypt lambs had significantly higher pH levels at nine and 11 months of age than wether lambs.

However, the pattern was not consistent as there were no significant differences in pH levels in the meat of the lambs when they were killed at 13 months or at six and eight months.

While differences in meat tenderness were detected across the different slaughters they were not related to the castration status of the lambs.

Campbell says these differences show much of the variation in meat quality occurs from production and or pre-slaughter handling of the animals.

Campbell started the Alliance study more than a year ago when the company purchased a line of 200 single male lambs as stores from one farm and moved them to an Alliance-owned property. The lambs were all sired by Perendale rams and out of Perendale ewes.

A mix of entires, crpytorchids and wethers, they were slaughtered at five different ages - six, eight, 10, 11, and 13 months - with a balance of entire, cryptorchid and wether lambs in each of the drafts.

The short loins from each lamb were vacuum packed, chilled (-1oC) and assessed for pH and colour stability eight weeks later using a Minolta chromameter.

The second loin was frozen (-20oC) before being assessed for tenderness using a MIRINZ pneumatic tenderometer.

Taste and aroma traits of each loin were also assessed using trained taste panelists with experience of identifying "male flavours" in meat.

Samples of each loin were presented to the panelists in a series of "triangle tests".

These tests are widely used in the food industry as a powerful way to see if there are differences among samples. They are used to determine if consumers can detect differences between brands of same or similar products. The Alliance trial involved giving each panelist a series of tests with each test consisting of one piece of meat from an entire, cryptorchid or wether lamb, plus two pieces from one of the two remaining groups.

The panelists were told two of the samples came from the same group and that one was from a different group.

They had to identify the piece of meat they believed was most different in flavour.

These tests were then analysed to determine if the number of correctly identified samples were different to what would have been selected by chance alone.

Campbell says the results clearly show the panelists could not distinguish whether the meat they were tasting was from an entire, cryptorchid or wether lamb. This was the same for lambs from each age group.

The overall mean CW of the 200 lambs involved in the study was 17.7kg, the mid range of Alliance' most preferred 17kg-19.5kg weight range.

Campbell's results show both slaughter and castration status had a significant effect on hot CWs and their ViaScan saleable meat yield. The entire ram lambs had a significantly higher yield than their wether lamb mates. The ViaScan yields of the cryptorchid lambs fell midway between the entire and wether groups. The pH levels of the meat ranged from 5.58 to 6.5 (mean 5.82) and the effect of castration status was inconsistent at the different ages.

However the redness of the meat was significantly affected by pH, slaughter date and castration status. Interestingly, Campbell says the colour of the meat from the wether lambs was the fastest to deteriorate, while there was no difference between the entire and cryptorchids. The castration status had no effect on the brightness/whiteness of the meat.

With values ranging from 2.8 to 17.5 kgF (shear force), and a mean of 9.9, tenderness was significantly influenced by pH and slaughter date, but not related to castration status.

Behrent says the science confirms Alliance's current position relating to the slaughter of entire lambs.

"It clearly shows there is no "taint" in the meat from ram or cryptorchid lambs being supplied by our commercial sheep farmers in our preferred 17-19.5 kg CW range. This includes those being supplied through the winter months."

However, he warns there will be instances when 22kg and 24kg CW-plus ram lambs killed late in the season or during the winter might show ram characteristics. They are likely to be downgraded.

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