Evaluation of a commercial bovine colostrum replacer for achieving passive transfer of immunity in springbok calves (Antidorcas marsupialis)

Successful assisted rearing and reintegration of a blue wildebeest calf into a managed herd prior to weaning

The blue wildebeest (Connochaetes taurinus; Burchell, 1823) is an African ungulate that is notoriously difficult to hand-rear and reintegrate into managed herds. The following case report is of a female wildebeest neonate that was orphaned, bottle-reared, and successfully reintroduced into a herd at a zoological facility. Since blue wildebeests are a highly precocial and herd-oriented species that calve synchronously in the wild as a reproductive strategy to maximize survival, early release of assist-reared neonates into managed herds before weaning may be an effective strategy for increasing the chance of acceptance. Wildebeest calves can also be easily trained for bottle-feedings in the field to facilitate early release. Due to a lack of literature on the assisted rearing and reintegration of wildebeest calves into managed herds, this case report provides useful techniques for the feeding, training, and releasing of bottle-reared wildebeests that may also be applicable to other assist-reared herd species at zoological facilities.

EVALUATION OF PASSIVE TRANSFER IN NINE SPECIES OF CERVIDAE

The reliability of packed cell volumes (PCV), total solids (TS), blood glucose (BG), γ-glutamyl transferase (GGT), and glutaraldehyde test in determining passive transfer of colostral immunoglobulins was investigated in nine species of cervids: axis deer (Axis axis), hog deer (Axis porcinus), sika deer (Cervus nippon), tufted deer (Elaphodus cephalophus), Père David's deer (Elaphurus davidianus), pudu (Pudu puda), sambar deer (Rusa unicolor), barasinga deer (Rucervus duvaucelli), and Eld's deer (Rucervus eldii). Individually the parameters evaluated were significant though imperfect predictors of passive transfer status in cervids. Interpreted collectively as a panel along with neonate condition, these tests were clinically helpful in diagnosing failure of passive transfer (FPT). Collectively interpreting test results as a panel along with clinical assessment of the animal is recommended. Some species-specific variations in TS, GGT, and glutaraldehyde test results were identified.

NEONATAL INTENSIVE CARE OF 10 HOSPITALIZED GIRAFFE CALVES (GIRAFFA CAMELOPARDALIS) REQUIRING HAND-REARING

This retrospective case series describes the clinicopathologic findings, diagnoses, treatment, and outcomes of 10 hand-reared newborn giraffe (Giraffa camelopardalis) calves admitted to a university teaching hospital for intensive care. Ten calves (five males, five females; nine reticulated giraffes [Giraffa camelopardalis reticulata], one Masai giraffe [G. c. tippelskirchi]), were admitted under 2 days of age. Inadequate transfer of passive immunity was suspected in 5 of 10 calves based on assessment of serum total solids and globulin values. These calves were treated with oral frozen bovine colostrum and/or intravenous hyperimmune bovine plasma. Diarrhea occurred in 6 of 10 calves and was managed with supportive care, fecal microbiota transplantation, and limiting milk intake (offering 10% body weight [BW] in milk per day, while feeding <2 L per meal at 2- to 4-hr intervals). Less common diagnoses included pneumonia (n = 3) and mycoplasma-associated septic arthritis (n = 1). Eight calves received systemic antimicrobial therapy. Hyperlactatemia (lactate > 5 mmol/L; n = 8) and hypercreatininemia (creatinine > 2.0 mg/dl, n = 7) were the most common presenting laboratory abnormalities, which resolved with intravenous fluid therapy. All neonatal giraffes survived to discharge after a median hospitalization of 9.5 days (range, 5-37 days) and were successfully hand-reared at their place of birth. In conclusion, neonatal giraffe calves can be intensively managed in a hospital environment. Diarrhea was a common clinical problem and can be related to feeding regimens. Intravenous hyperimmune bovine plasma infusion was well tolerated to manage failure of transfer of passive immunity in calves with inadequate colostrum administration. The current study supports that compromised neonatal giraffe calves may carry an excellent prognosis after early, intensive intervention.

VALIDATION OF IMMUNOCRIT AS A DIAGNOSTIC TEST TO DETECT FAILURE OF PASSIVE TRANSFER OF IMMUNITY IN HAND-REARED NONDOMESTIC RUMINANT NEONATES

Domestic and nondomestic ruminant neonates with failure of passive transfer of immunity (FPI) have an increased risk of morbidity and mortality. Hand-reared individuals often have a higher incidence of FPI compared with those that are dam-reared. Hand-reared, nondomestic ruminant neonates raised at zoological establishments are often fed a commercially available bovine colostrum replacer. Consequently, it is desirable to monitor for FPI using a single test that performs well across a wide range of species. The immunocrit test method has been reported to have acceptable diagnostic sensitivity for detecting FPI in dairy calves. Advantages of the immunocrit are that it is inexpensive, quick, easy to perform, non-species-specific, and only precipitates immunoglobulins. This study evaluated the ability of immunocrit to predict serum immunoglobulin levels and FPI via comparison with radial immunodiffusion (reference method). The study used 100 serum samples collected from hand-reared ruminant neonates from 29 nondomestic species, 12-120 hr old, that were fed a commercial bovine colostrum replacer at a zoological institution. Sensitivity, specificity, and likelihood ratios for FPI were determined using receiver operating characteristic (ROC) curves. The immunocrit cutoff point of 14% maximized sensitivity at 88.6% (95% CI, 78.7-94.9%) and specificity at 83.3% (95% CI, 65.3-94.4%). The area under the ROC curve was 0.92 (95% CI, 0.87-0.98; P < 0.001). This research demonstrates that the immunocrit test has acceptable performance in detecting FPI in a wide variety of nondomestic hand-reared ruminant neonates. Use of the immunocrit test will help improve the identification of FPI neonates and aid in the management of colostrum feeding practices of nondomestic ruminant species in captivity.

PARAMETERS FOR IDENTIFYING FAILURE OF PASSIVE TRANSFER IN SITATUNGA (TRAGELAPHUS SPEKII)

Failure of passive transfer of immunity (FPT) leads to increased calf morbidity and mortality and requires intensive, time-sensitive, and often expensive management for nondomestic ruminants. Without species-specific information with which to make informed decisions, neonatal data from domestic ruminants are often extrapolated to nondomestic zoo-housed species. To date, there have been no studies evaluating FPT in sitatunga (Tragelaphus spekii). The goal of the present study was to establish parameters to characterize adequate passive transfer in sitatunga calves and compare them to published reference intervals in other species. Medical records of 22 sitatunga calves (12 female, 10 male) were reviewed. Seventeen of these calves were defined as "healthy," having survived at least 60 days without colostrum administration or a plasma transfusion. Calf weight, serum glucose, serum gamma-glutamyl transferase (GGT), total protein (TP), globulin concentrations, and results of a zinc sulfate turbidity test (ZSTT) were noted where possible. Mean birth weight of healthy calves at 24 hr was 4.5 kg (range: 3.76.5 kg, n = 12). The mean blood glucose in healthy calves was 152 mg/dl (range: 80-182, n = 16), mean serum TP concentration was 5.9 g/dl (range: 4.9-7.5, n = 16), mean serum globulin concentration was 3.3 g/dl (range: 1.7-4.7, n = 17), and mean serum GGT concentration was 466 U/L (range: 91-1901, n = 16). A ZSTT was performed for 10 healthy calves, resulting in four negative ZSTT results despite having no clinical signs of FPT and the calves having been observed nursing before testing. Sitatunga appear to have lower values for normal FPT parameters than those developed for domestic cattle. This study illustrates the difficulty of cross-species comparisons, as even closely related species can vary greatly in biologic parameters.