Newborn pups from 4 large litters were allotted to 6 groups to determine effect of time and route of administration on absorption of an alternate source of immunoglobulin. Selective absorption of specific classes of immunoglobulins was also investigated. The alternate source of immunoglobulin consisted of pooled serum that was administered either PO or SC. Control groups were either left with the dam (group C1) or fed milk replacer (group C2). Blood samples were collected from pups at birth and 24 hours. Immunoglobulin (IgA, IgG, IgM) concentrations were determined by use of radial immunodiffusion on samples of pooled serum, colostrum, and pups' serum (birth and 24 hours). Serum IgA concentration was less than the sensitivity of the procedure and was not included in the statistical analysis. Pups fed 8 ml of pooled serum at birth and 12 hours later (group T1) absorbed more (P < 0.05) IgG and IgM than did group-C2 pups, but less (P < 0.05) than did group-C1 pups. Pups fed 8 ml of pooled serum at 12 hours only had significant (P < 0.05) increase of IgG concentration, but no absorption of IgM (P > 0.05) at 24 hours, compared with control pups (group C2). Pups administered 8 ml of pooled serum SC at birth (group SC1) had similar (P > 0.05) absorption of IgG and higher (P < 0.05) absorption of IgM than did pups of group T1. Pups administered 16 ml of pooled serum SC at birth had the highest increase of IgG and IgM concentrations of all treatment groups, but immunoglobulin concentrations were lower (P < 0.05) than those for group-C1 pups. Absorption of IgG was favored, compared with IgM, when pooled serum was fed. Results indicate clearly that intestinal absorption of immunoglobulins is minimal after 12 hours and thus, another route of administration should be used. Pups in groups SC1 and T1 had similar absorption of IgG, despite lower IgM absorption in pups of group T1. This lower IgM concentration in group-T1 pups may have been the result of selective intestinal absorption or the consequence of low number of pups per group. Subcutaneous administration of 16 ml of pooled serum was the most successful alternative to colostrum, with minimal pain to pups if serum was administered slowly. Serum IgG concentration in C1 pups was higher than expected and probably was attributable to the amount of colostrum available to the pups.

Efficacy of sulbactam, a beta-lactamase inhibitor, in combination with ampicillin, was evaluated for treatment of experimentally induced pneumonia caused by beta-lactam-resistant Klebsiella pneumoniae. Infection was experimentally induced in 18 healthy weanling foals that were randomly allocated to 3 treatment groups: sulbactam plus ampicillin (S/A, 3.3 and 6.6 mg/kg of body weight, respectively), ampicillin (6.6 mg/kg), or vehicle only. Foals were treated daily for 7 days; the observer was unaware of treatment status. Compared with ampicillin and vehicle, treatment with S/A resulted in a statistically significant (P < 0.05) decrease in severity of pneumonia, with regard to bronchoalveolar lavage cytologic findings (decreased total cell and neutrophil numbers, and increased lymphocyte numbers) and extent of macroscopic lesions in lung tissue of the noninoculated regions. Marked trends toward improvement of S/A-treated foals were observed for quantitative results of bacteriologic culture of bronchoalveolar lavage fluid samples (P < 0.07), macroscopic pathologic features of the whole lung (P < 0.1), and histopathologic variables (P < 0.07), compared with ampicillin- and vehicle-treated foals. Treatment effects were not observed for radiographic, hematologic, and blood gas abnormalities that resulted from infection. In conclusion, the combination of sulbactam plus ampicillin was found to have synergistic effects in vivo, to reduce the extent and severity of experimentally induced grain-negative lung infection in foals.

Effect of fluoride was assessed on molars during and after mineralization. Two groups of 7 sheep each were dosed orally with 3.5 mg of fluoride/kg of body weight daily for 4 months (from 5 to 9 months after birth). Sheep of the first group were slaughtered immediately after fluoride administration; those of the second group were slaughtered 4 months later at the age of 13 months. Three control groups of 7 sheep each were slaughtered at 5 months (to determine the state of the teeth at the beginning of fluoride administration), and at 9 and 13 months. During fluoride administration, plasma fluoride concentration rapidly increased to about 0.50 micrograms/ml; after fluoride administration, it stabilized at 0.20 micrograms/ml in treated sheep, whereas controls had concentration of 0.10 micrograms/ml (P < 0.01). Parts of the molars that were in the process of mineralization during fluoride administration (mainly second molars) had thinning enamel, with pits, mainly close to the apex, marked decrease in hardness throughout the layer (< 100 Vickers U, compared with 240 Vickers U), and fluoride accumulation twice as high as that in controls (1,000 to 2,500 mg(kg [dry weight]). Fluoride accumulation was higher in dentine (2,700 to 4,200 mg/kg), but hardness was less affected. On parts of the molars that were already mineralized mostly, the first molar), changes in the appearance of enamel and cementum, decreased hardness (less important than in teeth during mineralization) affecting outer enamel more than inner enamel, high fluoride concentration (4,000 to 5,500 mg(kg [dry weight]) in outer enamel extending over 200 Km were observed. Thus, in sheep, fluoride has a substantial postsecretory effect that may be explained by a slower maturation phase of enamel in this species. Because molar wear is correlated to enamel hardness (dentine at the occlusal surface has low resistance--30 Vickers U), abnormal abrasion of molar teeth that have mineralized before and during fluoride intakes can be observed.

The anthelmintic efficacy of ivermectin (IVM) delivered from a sustained-release (SR) bolus was evaluated against natural infections with gastrointestinal tract nematodes in 12 crossbred beef heifers in spring. The 12 calves were randomly allotted to 2 groups of 6 calves each. Group-1 calves were treated with an SR bolus designed to deliver 8 mg of ivermectin/d. Group-2 calves were nontreated controls. Cattle groups were kept in separate concrete-floored pens (grass hay nutrition) and slaughter was performed at 35 days after treatment. Fecal egg counts for group-1 calves remained zero after treatment, except for detection of < 1 egg/g of feces in 1 calf at the time of slaughter; counts in nontreated calves increased. Mean and range of Ostertagia ostertagi inhibited larvae in nontreated calves were 27,093 and 10,622 to 56,368, respectively. Efficacy of the IVM SR bolus was 100% against O ostertagi developing fourth-stage larvae (L4) and inhibited early L4, Haemonchus placei adults, Cooperia punctata and C spatulata adult males, Cooperia spp adult females, Cooperia spp L4, Trichostrongylus colubriformis adults, Bunostomum phlebotomum adults, and Oesophagostomum radiatum adults. Efficacy for O ostertagi and T axei adults was 99.9%. Numbers of nontreated calves infected with C pectinata adult males and Oes radiatum L4 were too low to evaluate efficacy. Calves treated with the IVM bolus gained 10.2 kg, whereas nontreated calves lost 1.8 kg. Abomasal lesions were dearly greater in nontreated calves on the basis of index comparisons of abomasal weight and total live weight and gross pathologic features.

Four shed-lambing operations in western Colorado were monitored during the 1984 spring lambing season to determine the causes and rates of perinatal lamb mortality. The number of lambing ewes per flock ranged from 513 to 1,712, and lambing percentages ranged from 131 to 180%. Overall perinatal lamb mortality ranged from 8.2 to 12.2%. Most lamb deaths occurred during parturition or within 24 hours after parturition. More than 85% of all lamb deaths were in lambs born to ewes having 2 or more lambs. The leading causes of lamb death were starvation, dystocia, stillbirth (unknown cause), and infectious diseases. A wheel model was used to categorize factors causing lamb deaths into 4 groups: physical, social, host, and biological, and to present data on perinatal lamb mortality in a simple visual model. In all flocks, social and biological factors resulted in most of the lamb deaths. On the basis of our findings, we suggest that interventions designed to improve ewe-lamb bonding and to reduce infectious agents and the incidence of prolonged parturition may reduce lamb mortality.

Two nonoverlapping clones, pOH405 and pOH632, containing cDNA inserts in the VP2 coding region of genome segment A were selected from a cDNA library prepared from the double-stranded RNA genome of the OH strain of infectious bursal disease virus (IBDV) of serotype 2. Clone pOH405, which is located in the hypervariable segment of VP2, is 328 base pairs long, has nucleotide sequence homology of 72 to 73%, and amino acid sequence homology of 64 to 67% with IBDV strains of serotype 1. Clone pOH632, which is located in the highly conserved C-terminal part of VP2, is 230 base pairs long, has nucleotide sequence homology of 87 to 88%, and amino acid sequence homology of 100% with IBDV serotype 1. The lower detection limit of 32P-labeled probes prepared from both clones was 10 ng of OH-IBDV double-stranded RNA, using high-stringency conditions of hybridization (54 C, 50% formamide) and washing (55 C, 0.015M NaCl, 0.0015M trisodium citrate, pH 7.0, with 0.1% sodium dodecyl sulfate), and autoradiography for 24 hours. Under these conditions, the dot-blot hybridization assay for detection of serotype 2 IBDV double-stranded RNA was 1,000 times more sensitive, using probe pOH632, but only 10 times more sensitive, using probe pOH405, compared with the assay for IBDV serotype 1, using the same probes. Thus, probe pOH632 could differentiate between the 2 IBDV serotypes by nucleic acid hybridization.