Examination From a Distance
The physical examination begins with examination from a distance, with assessment of behavior, body condition, and stance. Drooping of the head and ears is an early sign of illness.
Sick calves spend increasing amounts of time recumbent and are less inclined to drink. In beef calves, lambs, and kids this may be reflected by udder distention in the dam. With dairy calves the calf feeder reports that the calf requires stimulation to stand and fails to drink. Abdominal contour should be noted, with consideration of the neonate's reported appetite; an abdominal contour that appears normal may actually be abnormal if the calf has not eaten for a couple of days. Observing the neonate navigate its environment provides a simple assessment of vision. From a distance, mentation, posture, vision, abdominal contour, stance, lameness, respiratory rate, breathing effort, characters of nasal and ocular discharge, and spontaneous coughing can be evaluated. Abnormal postures exhibited by patients with respiratory conditions may be recumbency, open-mouth breathing, abnormal extension of the head and neck, head tilt, or reluctance to lie down. Abnormal breathing characteristics include prolongation of the inspiratory or expiratory phase of respiration, an expiratory abdominal press or snap, marked tachypnea, frequent spontaneous coughing, stridor, or inspiratory or expiratory noises. Abnormal mentation of neonatal ruminants may be the result of meningoencephalitis, hypoglycemia, hypoxic ischemic encephalopathy, calving injury, or severe metabolic acidosis. Abnormal posture of the head and neck are exhibited by neonates with respiratory difficulty, but meningoencephalitis, otitis media, hypernatremia, polio- encephalomalacia, congenital defects of the central nervous system, and lasalocid toxicity should be considered.Examination from a distance on-farm also provides an opportunity to assess the neonate's environment. Environmental and/or management-induced compromise in the form of inappropriate stocking density; mixed age-groups; inadequate ventilation or shade; wet, muddy conditions; moldy bedding; inadequate protection from adverse weather; evidence of poor hygiene; inappropriate feed on offer; and excessive fly challenge may all contribute to the risk of disease.
With the increasing use of robotic calf feeders, a plethora of data is available on farms that use this technology to monitor calf behavior. Reductions in drinking speed, unrewarded visits, and milk consumed may be observed 3 to 4 days prior to overt clinical signs of disease.284 The onset of change in these parameters relative to detection of clinical signs is dependent on disease type, with changes observed earlier in association with diarrhea than pneumonia.284