Effects of Intermittent Electrical Shock on Responses Related to Milk Ejection

Abstract

Electrical shock is perceived to be a problem on many dairy farms. Thirteen cows were subjected to intermittent electrical shock (5 s on, 25 s off) at a.m. and p.m. milkings for 7 days. Seven cows were subjected to 3.6 mA shocks starting with preparation (1 min udder wash and dry) and six cows to 6.0 mA. One additional cow initially in the 6.0 mA group had to be removed from the study because of severe behavioral responses to shock. Compared to 5-day preshock and postshock periods, milk yield, milking time, and Wisconsin Mastitis Test scores were not affected by shock. Maximum rate of milk flow increased slightly. The number of behavioral events such as lifting legs during milking increased with a greater increase in the 6.0 mA group. Heart rate was elevated (+3 beats/min) only in response to shock during preparation (initial shock). For selected days, time to peak oxytocin response was delayed in the 3.6 mA group, and peak prolactin and area under prolactin response curves increased similarly for both groups during shock. There were significant a.m.-p.m. differences in milk yield, milking time, maximum rate of milk flow, heart rate, and responses of oxytocin and prolactin. We think that milk yield can be maintained, at least in the short term, in cows subjected to electrical shock due to power-line problems if dairy producers take exceptional care to accommodate behavioral responses.

Scientific report on the effects of farming systems on dairy cow welfare and disease

“…Cows that were shock at currents of 12 mA were unapproachable (Lefcourt et al, 1985). In the study, electric prod caused more reactions but only the sound of an electric prod was enough to elicit movement in calves.…”

Conséquences de faibles courants électriques sur le bien-être de bovins laitiers. Prise en compte de la variabilité individuelle

“…Ces résultats sont en accord avec ce qui est généralement observé dans la littérature (Lefcourt et al 1985). Après huit semaines d'exposition, une adaptation comportementale a été mise en évidence avec une diminution du lapement (qui expose la langue, organe conducteur et sensible à l'abreuvoir sous tension), permettant probablement de diminuer l'intensité du stimulus électrique, alors que la fréquence d'exposition au stimulus électrique restait élevée (entre cinq et sept expositions par jour).…”

Les courants électriques parasites en élevage

“…Lefcourt (1982) définit la «réponse comportementale modérée» par la manifestation de tressaillements de la peau ou de vocalisations auxquelles peuvent s'ajouter, selon les auteurs, des levers intempestifs de pattes ou bien une «danse» d'une patte sur l'autre, de la crispation musculaire et des mouvements soudains de la tête (Gustafson et al 1985, Lefcourt et al 1986, Brugère 2002. La «réponse comportementale sévère» se traduit par des sauts, des courbements de dos et des coups de pattes (Lefcourt et al 1985, Aneshansley et al 1992.…”