The Welfare of Cull Holstein Cows in an Abattoir: Testing the Effects of Reduced Noise in the Chute and a Workshop on Humane Handling

Jane Morrigan, 1999 M.Sc. Thesis, Nova Scotia Agricultural College & Dalhousie University

Abstract

During pre-slaughter handling at a commercial abattoir, cattle are exposed to many potential stressors, among them loud noises and electric prodding. Air-relief valves on pneumatic doors that separate small groups of cows in a single file chute produce a sudden, loud hissing noise as they are raised and lowered between cows. Electric prodding of cows is used to manoeuver them from lairage pens into the single file chute leading to the stunning-box, where they are stunned by a captive-bolt pistol prior to exsanguination and death.

Cull dairy cows are a high-risk category of livestock for welfare problems, as they generally arrive at an abattoir in poor body condition. A study was carried out to describe pre-stunning behaviour and characteristics of cull Holstein cows from the Atlantic region.

This study investigated 1) the characteristic features of a population of cull dairy cows at the time of slaughter, 2) the effects of reducing the noise of air-exhaust valves on vertical doors in the single file chute, and 3) the effects of a workshop with abattoir staff aimed at reducing electric prodding of cows. Seven hundred and fifty two (752) cull Holstein cows were observed as they were handled in the stunning-box area just prior to slaughter, at a large abattoir in the region. Ten responses (5 behavioural and 5 physiological) were used as indicators of fear and stress.

Using zero-one sampling across all treatments average frequencies of 58.4% balking, 50% struggling, 29.4% attempting to turn around, 36.6% trembling, and 7.4% vocalizing were observed (n=752). Exsanguinated blood showed an average PCV% of 35.8±0.24 (n=625), 22.2±1.0 ng/ml plasma cortisol (n=209), and 684.7±55.4 U/L creatine phospho-kinase (n=209). The longissimus dorsi muscle of the carcasses showed an average pH of 6.76±0.01 at 45 min post mortem (n=534), and 6.14±0.01 at 72 hours post mortem. Forty-one point eight percent (41.8%) of the cows were emaciated (BCS=1, n=744), 82.4% were lactating, 15.6% were pregnant, and 65% of the carcasses were classified as dark-cutters (pH ultimate > 6.0).

The installation of mufflers to reduce noise of air-relief valves on pneumatic doors in the chute did not appear to make a significant difference in the cows’ behaviour.

A workshop on humane handling of cattle led to a 30% reduction in the use of the electric prod from 96% to 67% (P<0.0001, n=752), and a 20% reduction in the time the cow spent in the single file chute (P<0.0001, n=579) in the six weeks following the workshop. It also led to a 14.2% reduction in balking (P<0.05), a 22.5% reduction in attempts to turn around in the single file chute (P=0.08), a 3.9% decrease in PCV% (P<0.01) due possibly to reduced splenic contractions, no change in cortisol, a 1.5% increase in pH at 45 min post mortem (P<0.0001) due possibly to reduced acute fear, and no change in pH ultimate.

It is suggested that initial training of staff at an abattoir led to small yet positive improvements in the welfare of cull Holstein cows during the immediate pre-slaughter period.

Full paper (PDF, 482 kb)

Posted February 2008