Slaughtering of Water Buffalo (Bubalus bubalis) with and without Stunning: A Focus on the Neurobiology of Pain, Hyperalgesia, and Sensitization

Abstract

The slaughter process in livestock is considered a stressor where the transport and handling of animals, as well as the selected stunning and bleeding methods, can cause acute pain, distress, and suffering. In water buffaloes, although stunning is known to be performed before bleeding to induce unconsciousness, no emphasis is made on the nociceptive events during this process. Particularly, current mechanical stunning methods applied to cattle are unsuitable for water buffaloes due to anatomical differences in the skull from other large ruminants. Furthermore, although very high-pressure pneumatic (200–220 psi) may be effective in the frontal position for lighter-weight water buffalos, for heavier animals, it is less likely to be effective. The present review aims: (1) to analyze the anatomical particularities of water buffaloes to discuss the importance of selecting a stunning method suitable for buffaloes, and (2) to revise the potential pain-related consequences, such as hyperalgesia and sensitization, and the signs to assess the stun quality and death to comprehend the relevance of a proper technique according to the species.

Evaluation of Anatolian Water Buffalo Carcass Weights Based on a Slaughterhouse Data Collection

“…For instance, other studies have shown that the feeding regime is a significant factor that affects the carcass weights of animals [ 26 ]. Moreover, the animals’ welfare condition before the slaughtering process, i.e., stress, anxiety, fear, and/or discomfort, is likely to impact their carcass weights [ 27 , 28 ]. In our study, the analysis did not include factors related to nutrition information or animals’ welfare conditions before slaughter.…”

Stunning Compliance in Halal Slaughter: A Review of Current Scientific Knowledge

“…The presence of rhythmic breathing immediately after stunning and other signs of vocalization and spontaneous blinking are signs of ineffective stunning [27][28][29][30][31]. Grandin et al [11] summarized various vital indicators of consciousness in buffalo as attempts to regain posture and collapse failure, head raising, eyelid and corneal reflexes with blinking and full eyeball rotation, and respiratory rhythm.…”

“…Nociceptors are activated during improper preslaughter handling and slaughter, such as neck cuts, injury, sticking, electric prods, and a sharp knife, thereby generating electric impulses that are transmitted along the neuronal axon to the spinal cord-brain stem-thalamus-cortex for further processing as pain [8,9]. The prolonged activation of nociceptors due to improper stunning can cause hyperalgesia and peripheral sensitization (increase in the sensitivity of afferent neurons to stimulations) or central sensitization due to the release of neuropeptides and upregulating the existing receptors [10,11]. The central and peripheral sensitization before slaughter also increases the nociception perception during slaughter [11][12][13].…”

“…The prolonged activation of nociceptors due to improper stunning can cause hyperalgesia and peripheral sensitization (increase in the sensitivity of afferent neurons to stimulations) or central sensitization due to the release of neuropeptides and upregulating the existing receptors [10,11]. The central and peripheral sensitization before slaughter also increases the nociception perception during slaughter [11][12][13]. During animal slaughter without stunning, the cutting of soft tissues (muscle, tissue, and viscera) of the neck induces the nociceptive nerve fibers to generate electric impulses, which are transmitted to the higher center of the nervous center for its interpretation as pain [14,15].…”

Movements after Captive Bolt Stunning in Cattle and Possible Animal- and Process-Related Impact Factors—A Field Study

“…However, due to the increasing use of modern stun boxes with tight head restraints and the development of more powerful captive bolt devices (especially pneumatically powered devices), stunning effectiveness at European cattle abattoirs has improved significantly in recent years [1,12]. This also applies to other bovines [13].…”