LESS than one percent of cattle passing through Meat Standards Australia grading are submitted via the current MSA saleyard pathway, but new research suggests that the opportunity could be widened to include longer periods between farm and slaughter.

Current regulated timeframes under MSA saleyards pathways mean the the process is not commercially or logistically viable for many beef supply chains.

However a recently completed research project involving the University of New England, saleyards operator Regional Livestock Exchanges and consultant Rod Polkinghorne looked into the eating quality impact of an extended pathway and feeding pathways, to enable an increase in the growth of MSA graded saleyard-sourced cattle that can achieve the necessary eating quality compliance.

The final standard is yet to be signed-off, but industry is expected to be notified about the change in the next month or so, along with the publication of a fact sheet.

Specifically, the project looked at the viability of extending the saleyards pathway to a maximum of 48 hours, as opposed to the current 36 hour limit from farm to slaughter. A second component looked at an on-site feeding pathway, designed to ‘re-establish’ MSA eligibility after feeding saleyard cattle a high quality feed during the post-sale process.

The research looked at four separate saleyard protocols compared to a direct-to-slaughter control group, using cattle sourced from New South Wales and Victoria. Two replicates were conducted using the same experimental design. Each utilised five treatment groups of about 120 mixed sex cattle of different breeds from four properties of origin that were balanced across treatments.

The control treatment group of 24 steers and heifers (six from each property, never mixed) were directly consigned to the abattoir, under a 24 hour control, while the cattle for the other four treatment groups all were penned with their property contemporary group during an auction.

The four saleyard treatments were:

• Extended MSA saleyard pathway (48 hours, not mixed & water only)
• 72 HR (72 hours, one day on feed at saleyard)
• 7 DAY (seven days total, including six days on feed at saleyard) and
• 14 DAY (14 days total, including 13 days on feed at saleyard).

The 72 HR, 7 DAY and 14 DAY groups were mixed contemporary groups post-sale with access to a feed ration and good drinking water.

The impact of treatment on tenderness, juiciness, flavour, overall liking and MSA eating quality score (MQ4) were measured using untrained consumers for striploin and ribeye (grilled) aged for seven days. The effect of muscling, treatment group and their interaction were an analysed. Carcase traits were also included in the models as co-variates and interacted with cut, but were removed if they were non-significant.

At slaughter and boning, the NLIS tag RFID code was read at the knocking box and recorded on the plant IT system following normal plant procedure. Abattoir body numbers were assigned post sticking and indicated by a printed number stuck to the hide until reaching the scale and having final carcase tickets attached.

The trial visual eartag was also entered manually by abattoir personnel.  In addition, as a final backup to ensure failsafe, animal to carcase ID in the event of a misread or system issue, research personnel and an abattoir supervisor removed both the trial visual tag and the NLIS tag after the second leg position and placed them in consecutively numbered Ziplock bags to retain the ability to physically relate body number to both electronic and visual ID.

Key findings

Among the key results, in the combined analysis, the 72 HR re-fed treatment group had improved consumer scores compared to the control (direct consignment) treatment across all sensory attributes of eating quality, tenderness, juiciness, flavour and overall liking – although not significantly different to the other treatment groups.

The 48 HR, 7 DAY and 14 DAY re-fed treatment groups had a negative, but non-significant relationship across all sensory attributes of eating quality, tenderness, juiciness, flavour and overall liking compared to the direct consignment control treatment group.

In the first replicate group, average liveweights of the cattle in the 48 HR (485kg) and 72 HR (503kg) treatments were lower than their on-farm weights but the 7 DAY (518kg) and 14 DAY groups (537kg) of re-fed cattle did not differ from their average on-farm weights (537kg).

The average hot standard carcase weight of the cattle in the 48 HR (266kg), 72 HR (273kg) and 7 DAY (273kg) were lower compared to the 14 DAY (280kg) and the direct kill group (280kg).

Dressing percentage relative to the farm exit weight appeared to be greatest for the direct 24hr group (52.74pc) compared with other treatments. The highest average dressing percentage in relation to the saleyard exit liveweight (54.87pc) was the unfed post sale group (48 HR) which also had the lowest average dressing percentage relative to the farm exit weight (51.81pc) reflecting reduced gut fill at saleyard exit and reduced carcase weight relative to farm weight.

The extension of the current MSA saleyard pathway up to 48 HR (36 hours + 12 hours – water only) had significantly reduced the juiciness, flavour and overall likeness for both cuts used in the sensory analysis work, compared to the direct consignment group, while the MQ4 and tenderness did not significantly differ.

The 72 HR treatment (1 day on feed) group was not significantly different for any consumer sensory trait or MQ4 score to the direct consignment cattle.

The 7 DAY and 14 DAY re-fed treatments had significantly reduced consumer scores across all sensory attributes of MQ4, tenderness, juiciness, flavour and overall liking, compared to the direct (control 24hr) and 72 HR treatment groups – except for juiciness where the 72 HR and 14 DAY treatments did not differ.

The impact of re-feeding on beef eating quality showed a reduction of greater than 5 points across all consumer sensory traits in the 7 DAY and 14 DAY re-fed treatments compared to cattle that were directly consigned.

Surprisingly, this adverse impact was not observed in the 72 HR treatment for any consumer sensory trait or MQ4 score, implying prolonged exposure to stress has greater impact on eating quality than an initial stress event for all the meat quality attributes in the first replicate group.

Cut had a significant impact on all consumer sensory eating quality attributes, with the striploin eating better than the ribeye. The interaction between cut and treatment was insignificant across all sensory attributes. Hump height was the only carcase characteristic found to significantly impact consumer sensory eating quality attributes.

Key findings

Since the eating quality and tenderness in the 48 HR group in the first replicate group were comparable to those of the direct consignment group and neither the second replicate group nor the combined trials significantly differed from the controls, the MSA saleyard pathway could be extended to a maximum of 48 hours following the current MSA saleyard pathway rules, the project suggested. However the 48 HR pathway must involve no mixing of cattle.

Although no significant differences in consumer eating quality factors were observed between the directly consigned group and the 72-hours treatment for each replicate and the combined analysis, it was determined there was insufficient evidence (with only two replicated trial groups) to support the adoption of the 72 hours with re-feed pathway.

Additionally, commercial implementation of a pathway including re-feeding would require additional auditing and strict processes in place at saleyards to ensure the feed quality requirements were met, along with other factors such as frequency of feeding, pen size, suitable feeding equipment and feeder access.

Mob size and its impact on mixing stress would also require further evaluation.

Future research

Although the 72 hours pathway had a positive relationship with all eating quality attributes for both replications, the cattle were provided high-energy feed supplementation for one day at saleyard, further economic analysis related to feed cost and eating quality needs to be conducted.

Additionally, more research is needed to comprehend the management techniques, stress levels in different treatment groups and causes of the different treatment outcomes for the replicates, allowing for the widespread adoption of a particular method for enhancing meat eating quality.

Consistent pH differences between muscles within a carcase are considered highly likely to impact ultimate eating quality, and in particular flavour development, through interactions with muscle structure and composition, packaging, ageing and cooking.

A better understanding of these relationships could have important ramifications for MSA grading.