Evaluation of a serum ELISA for detection of bovine leukemia viral antibodies in milk samples

Bovine leukemia virus (BLV) infection has worldwide distribution in both dairy and beef herds. Our study was initiated in order to encourage control of BLV infection by using milk samples, in lieu of serum samples, to readily test lactating animals prior to dry-off and calving. Two Holstein dairy herds (A and B), with known status of BLV infection as determined by serology, were sampled by the collection of serum and fresh milk samples. Selected samples were tested using a USDA-licensed BLV antibody ELISA kit (Bovine leukemia virus antibody test kit; VMRD, Pullman, WA) for serum. Forty-one lactating cows from each herd were sampled. Herd A was confirmed to have endemic BLV infection; herd B was confirmed to be free of BLV infection. The milk ELISA results demonstrated 100% identification of positive and negative animals compared with the serum results. The correlation of the ELISA values between serum and milk samples was 97%, which supports the use of this BLV ELISA on milk samples.

Neonatal vitamin A injection promotes cattle muscle growth and increases oxidative muscle fibers

Background

Vitamin A and its metabolite, retinoic acid (RA), are important regulators of cell differentiation and organ morphogenesis. Its impact on beef cattle muscle growth remains undefined.

Method

Angus steer calves were administrated with 0 (control) or 150,000 IU vitamin A (retinyl palmitate in glycerol, i.m.) per calf at birth and 1 month of age. At 2 months of age, a biopsy of the Biceps femoris muscle was obtained to analyze the immediate effects of vitamin A injection on myogenic capacity of muscle cells. The resulting steers were harvested at 14 months of age.

Results

Vitamin A administration increased cattle growth at 2 months. At 2 months of age, Vitamin A increased PAX7 positive satellite cells and the expression of myogenic marker genes including PAX7, MYF5, MYOD and MYOG. Muscle derived mononuclear cells were further isolated and induced myogenesis in vitro. More myotubes and a higher degree of myogenesis was observed in vitamin A groups. Consistently, vitamin A increased Latissimus dorsi (LD) muscle fiber size at harvest. In addition, vitamin A increased the ratio of oxidative type I and type IIA fibers and reduced the glycolic type IIX fibers. Furthermore, we found that RA, a key bioactive metabolite of vitamin A, activated PPARGC1A promoter, which explains the upregulated expression of PPARGC1A in skeletal muscle.

Conclusion

Vitamin A administration to neonatal calves enhanced postnatal muscle growth by promoting myogenesis and increasing satellite cell density, accompanied with a shift to oxidative muscle fibers.

Vitamin A administration at birth promotes calf growth and intramuscular fat development in Angus beef cattle

Background

Marbling, or intramuscular fat, is an important factor contributing to the palatability of beef. Vitamin A, through its active metabolite, retinoic acid, promotes the formation of new fat cells (adipogenesis). As intramuscular adipogenesis is active during the neonatal stage, we hypothesized that vitamin A administration during the neonatal stage would enhance intramuscular adipogenesis and marbling.

Methods

Angus steer calves (n = 30), in a completely randomized design, were randomly allotted to three treatment groups at birth, receiving 0, 150,000, or 300,000 IU of vitamin A at both birth and one month of age. A biopsy of the biceps femoris muscle was collected at two months of age. After weaning at 210 d of age, steers were fed a backgrounding diet in a feedlot until 308 d of age, when they were transitioned to a high concentrate finishing diet and implanted with trenbolone/estradiol/tylosin mixture. Steers were harvested at an average of 438 d of age. All diets were formulated to meet nutrient requirements.

Results

Weaning weight and weight during the backgrounding phase were linearly increased (P <  0.05) by vitamin A level, though no difference in body weight was observed at harvest. Intramuscular fat of steers at 308 d of age, measured by ultrasound, quadratically increased (P <  0.05) with vitamin A level from 4.0±0.26 % to 4.9±0.26 %. Similarly, carcass marbling score in the ribeye quadratically increased (P < 0.05).

Conclusion

Administration of vitamin A at birth increased weaning weight and enhanced marbling fat development. Thus, vitamin A administration provides a practical method for increasing marbling and early growth of beef cattle.

Development and Pilot Randomized Control Trial of a Drama Program to Enhance Well-being Among Older Adults

OBJECTIVE

Develop a novel theatre-based program and test its feasibility, tolerability, and preliminary efficacy for improving empathy/compassion and well-being among older adults.

METHOD

Thirteen older adults were randomized to a 6-week Drama Workshop (DW) program or time-equivalent Backstage Pass (BP) control condition. Pre- and post-treatment measures included empathy, compassion, and mood scales. Additional post-treatment measures included self-rated change in empathy/compassion, confidence, and affect. Participants also rated their mood/affect after each session.

RESULTS

The program was successfully completed and well-liked. No pre-to-post-treatment changes in empathy/compassion or mood symptoms were found in either group. Compared to BP, DW weekly ratings indicated higher levels of anxiety and lower happiness; however, the DW program had higher self-ratings of positive change in self-esteem, confidence, and happiness post-treatment.

DISCUSSION

While the DW may not promote empathy/compassion and was personally challenging during the program, engagement in dramatic exercises and rehearsing and performing a dramatic piece was seen by participants as a positive growth experience, as indicated by the post-treatment ratings of enhanced self-esteem, confidence and happiness. Thus, such a program might be useful for counteracting some of the potential negative aspects of aging, including reduced self-efficacy due to physical limitations and negative affect due to losses.

Recognition of Highly Diverse Type-1 and -2 Porcine Reproductive and Respiratory Syndrome Viruses (PRRSVs) by T-Lymphocytes Induced in Pigs after Experimental Infection with a Type-2 PRRSV Strain

Background/Aim

Live attenuated vaccines confer partial protection in pigs before the appearance of neutralizing antibodies, suggesting the contribution of cell-mediated immunity (CMI). However, PRRSV-specific T-lymphocyte responses and protective mechanisms need to be further defined. To this end, the hypothesis was tested that PRRSV-specific T-lymphocytes induced by exposure to type-2 PRRSV can recognize diverse isolates.

Methods

An IFN-gamma ELISpot assay was used to enumerate PRRSV-specific T-lymphocytes from PRRSV_SD23983-infected gilts and piglets born after in utero infection against 12 serologically and genetically distinct type-1 and -2 PRRSV isolates. The IFN-gamma ELISpot assay using synthetic peptides spanning all open reading frames of PRRSV_SD23983 was utilized to localize epitopes recognized by T-lymphocytes. Virus neutralization tests were carried out using the challenge strain (type-2 PRRSV_SD23983) and another strain (type-2 PRRSV_VR2332) with high genetic similarity to evaluate cross-reactivity of neutralizing antibodies in gilts after PRRSV_SD23983 infection.

Results

At 72 days post infection, T-lymphocytes from one of three PRRSV_SD23983-infected gilts recognized all 12 diverse PRRSV isolates, while T-lymphocytes from the other two gilts recognized all but one isolate. Furthermore, five of nine 14-day-old piglets infected in utero with PRRSV_SD23983 had broadly reactive T-lymphocytes, including one piglet that recognized all 12 isolates. Overlapping peptides encompassing all open reading frames of PRRSV_SD23983 were used to identify ≥28 peptides with T-lymphocyte epitopes from 10 viral proteins. This included one peptide from the M protein that was recognized by T-lymphocytes from all three gilts representing two completely mismatched MHC haplotypes. In contrast to the broadly reactive T-lymphocytes, neutralizing antibody responses were specific to the infecting PRRSV_SD23983 isolate.

Conclusion

These results demonstrated that T-lymphocytes recognizing antigenically and genetically diverse isolates were induced by infection with a type 2 PRRSV strain (SD23983). If these reponses have cytotoxic or other protective functions, they may help overcome the suboptimal heterologous protection conferred by conventional vaccines.

Enhanced mitogenesis in stromal vascular cells derived from subcutaneous adipose tissue of Wagyu compared with those of Angus cattle

Japanese Wagyu cattle are well known for their extremely high marbling and lower subcutaneous adipose tissue compared with Angus cattle. However, mechanisms for differences in adipose deposition are unknown. The objective of this paper was to evaluate breed differences in the structure of subcutaneous adipose tissue, adipogenesis, and mitogenesis of stromal vascular (SV) cells between Wagyu and Angus cattle. Subcutaneous biopsy samples were obtained from 5 Wagyu (BW = 302 ± 9 kg) and 5 Angus (BW = 398 ± 12 kg) heifers at 12 mo of age, and samples were divided into 3 pieces for histological examination, biochemical analysis, and harvest of SV cells. Adipogenesis of SV cells was assessed by the expression of adipogenic markers and Oil Red-O staining, while mitogenesis was evaluated by an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium dromide) test, phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (PKB; AKT). Based on histological analysis, Wagyu had larger adipocytes compared with Angus. At the tissue level, protein expression of peroxisome proliferator-activated receptor γ (PPARG) in Wagyu was much lower compared with that of Angus. Similarly, a lower mRNA expression of PPARG was found in Wagyu SV cells. No significant difference was observed for the zinc finger protein 423 (ZNF423) expression between Wagyu and Angus. As assessed by Oil Red-O staining, Wagyu SV cells possessed a notable trend of lower adipogenic capability. Interestingly, higher mitogenic ability was discovered in Wagyu SV cells, which was associated with an elevated phosphorylation of ERK1/2. There was no difference in AKT phosphorylation of SV cells between Wagyu and Angus. Moreover, exogenous fibroblast growth factor 2 (FGF2) enhanced mitogenesis and ERK1/2 phosphorylation of SV cells to a greater degree in Angus compared with that in Wagyu. Expression of transforming growth factor β 3 (TGFB3) and bone morphogenetic protein 2 (BMP2) in Wagyu SV cells was lower than that of Angus, providing potential clues for breed differences on proliferation of SV cells in these two cattle breeds. The results of this study suggest that subcutaneous adipose-derived SV cells of Wagyu possess a lower trend of adipogenesis but higher mitogenesis compared with those of Angus.

Safety and Immunogenicity of a Mycoplasma ovipneumoniae bacterin for domestic sheep (Ovis aries)

BACKGROUND

Mortality from epizootic pneumonia is hindering re-establishment of bighorn sheep populations in western North America. Mycoplasma ovipneumoniae, a primary agent of this disease, is frequently carried asymptomatically by the domestic sheep and goats that constitute the reservoir of this agent for transmission to bighorn sheep. Our long-term objective is to reduce the risk of M. ovipneumoniae infection of bighorn sheep; one approach to this objective is to control the pathogen in its reservoir hosts.

METHODS

The safety and immunogenicity of M. ovipneumoniae for domestic sheep was evaluated in three experimental immunization protocols: 1) live M. ovipneumoniae (50 ug protein); 2) killed M. ovipneumoniae (50 ug whole cell protein) in oil adjuvant; and 3) killed M. ovipneumoniae (250 ug whole cell protein) in oil adjuvant. Immunogenicity was assessed by two serum antibody measures: competitive enzyme-linked immunosorbent assay (cELISA) (experiments 1-3) and serum growth inhibition (Experiment 3). Passive immunogenicity was also assessed in the third experiment using the same assays applied to blood samples obtained from the lambs of immunized ewes.

RESULTS AND CONCLUSIONS

Adverse reactions to immunization were generally minor, but local reactions were regularly observed at immunization sites with bacterins in oil adjuvants. No evidence of M. ovipneumoniae specific antibody responses were observed in the first or second experiments and no resistance to colonization was observed in the first experiment. However, the ewes in the third experiment developed strong cELISA serum antibody responses and significant serum M. ovipneumoniae inhibition activity, and these responses were passively transferred to their lambs. The results of these trials indicate that immunization with relatively large antigenic mass combined with an adjuvant is capable of inducing strong active antibody responses in ewes and passively immunizing lambs.

The effects of exposure of susceptible alpacas to alpacas persistently infected with bovine viral diarrhea virus

Reports of bovine viral diarrhea virus (BVDV) infections in alpacas have been increasing in recent years but much is still unknown about the mechanisms of disease in this species. This report characterizes the transmission of BVDV from persistently infected (PI) alpacas to BVDV naïve alpacas, documents shedding patterns, and characterizes the disease effects in both PI and transiently infected alpacas. Two PI alpacas shed BVDV Type 1b virus in most body fluids, and commonly available diagnostic tests verified their status. Bovine viral diarrhea virus Type 1b transient infections produced only mild signs of disease in BVDV naïve alpacas. Viremia was detected in whole blood, but viral shedding during the acute phase was not detected and antibody appeared to be protective upon re-exposure to the virus.

Disseminated Bovine Viral Diarrhea Virus in a Persistently Infected Alpaca (Vicugna Pacos) Cria

Bovine viral diarrhea virus (BVDV) is an emerging infectious pathogen of concern to the alpaca industry. A 4-month-old, intact, male alpaca cria was diagnosed as persistently infected with BVDV on the basis of repeated positive antemortem polymerase chain reaction (PCR) and virus isolation (VI) assays and negative serologic titers to BVDV. Immunohistochemistry, real-time reverse transcription PCR, and VI performed on tissues collected at necropsy demonstrated disseminated BVDV-1b infection. Virus was detected in multiple tissues, including parotid salivary gland, testes, prostate, kidneys, skin, and gastrointestinal tract. Demonstration of BVDV in previously unreported tissues suggests additional potential routes of BVDV transmission in alpacas.

A fungal granuloma of the frontal sinus in a llama

A 12-year-old, castrated male llama (Lama glama) presented with a 12-cm diameter cranial mass. Computed tomography and postmortem examination revealed that the mass invaded the calvarium and compressed the rostral part of the brain. Light microscopic examination confirmed a fungal granuloma.

Biosecurity and biocontainment in alpaca operations

Biosecurity on South American camelid operations involves both external and internal measures to prevent the introduction and spread of disease. External biosecurity involves practices and techniques directed at the prevention of entry of new diseases into a group of animals. Internal biosecurity or biocontainment, involves practices and techniques that are directed at the prevention or spread of disease within an existing group of animals. External biosecurity is particularly important in North America camelid operations due to the extensive movement of animals for breeding or show purposes. Internal biosecurity typically involves this the prevention and treatment of failure of passive transfer, maintenance of proper nutrition and housing, and the implementation of an appropriate vaccination program for endemic or relevant diseases. Attention to appropriate cleaning and disinfection procedures related to housing, feeding, and treatment equipment is important for the maintenance of both internal and external biosecurity practices. This paper discusses various risk factors associated with the control of infectious disease in the context of external and internal biosecurity measures in camelids operations.

Age-related innate immune response in calves to Babesia bovis involves IL-12 induction and IL-10 modulation

There is a strong innate immunity in calves to infection with Babesia bovis. Interleukin (IL)-12 and IL-10 have been shown in vitro to be important immunoregulatory cytokines. Here we demonstrate in vivo that the protective innate response in young calves to infection with virulent B. bovis involves the early appearance of IL-12 and interferon-gamma (IFN-gamma) transcripts in the spleen. In contrast, IL-12 and IFN-gamma mRNA expression in the spleens of adult cattle that succumbed to the infection was delayed and depressed and occurred within the context of IL-10 expression. Also in contrast with calves, there was no detectable antibody response before death in adults. A vigorous CD8+ T-cell expansion occurred in the spleens of both calves and adults.

IL-4 and IL-10 inhibition of IFN-gamma- and TNF-alpha-dependent nitric oxide production from bovine mononuclear phagocytes exposed to Babesia bovis merozoites

The requirement for IFN-gamma and/or TNF-alpha as co-stimulants with Babesia bovis merozoites for nitric oxide (NO) production was examined, as well as the regulatory role of IL-4 and IL-10. Purified B. bovis merozoites did not induce the production of NO in undifferentiated monocytes without addition of exogenous IFN-gamma and TNF-alpha unless the monocytes taken ex vivo were producing TNF-alpha endogenously. Under the latter condition, the NO production resulting from merozoite stimulation remained IFN-gamma-dependent. There was no evidence for endogenous synthesis of TNF-alpha in monocyte-derived macrophages (MDM), and merozoites alone were incapable of inducing TNF-alpha mRNA in MDM. However, while merozoites plus IFN-gamma induced TNF-alpha mRNA expression in MDM, NO was not produced. Both IL-4 and IL-10 inhibited expression of iNOS and production of NO in merozoite-stimulated monocytes.

Bovine neonatal immunology

The majority of early, in utero immune development occurs independent of antigen exposure. Only later during development can a fetus respond to antigens, and even then the response depends on the stage of fetal development and the nature of the antigen. At birth, the neonate is rapidly exposed to large numbers of potential pathogens. Although immunocompetent, the neonate is immunonaive and dependent on passively acquired maternal immunoglobulins, immune cells, and other substances from colostrum for protection. Neonates that suffer failure of passive transfer of maternal immunoglobulins may be at increased risk for disease; however, many other factors interact in conjunction with the level of passively acquired immunoglobulin to determine the occurrence of disease. These include, but are not limited to, management, environment, hygiene, infection pressure, virulence of organisms, and antibody specificity. In addition to immunoglobulins, colostrum contains large numbers of immune cells and cytokines. It is thought that the primary role for the cellular component of colostrum is to interact with the development of local immunity and to modulate active immunization of the neonatal intestine. In particular, T lymphocytes are thought to transfer immune functions and secrete cytokines. Although most of the major cytokines have been identified in colostrum and milk, their biologic effects on the neonate have yet to be determined.

The age-related immunity in cattle to Babesia bovis infection involves the rapid induction of interleukin-12, interferon-gamma and inducible nitric oxide synthase mRNA expression in the spleen

Young calves possess a strong innate immunity against Babesia bovis infection that lasts for approximately 6 months after birth and is abrogated with the removal of the spleen. This immunity is characterized as cellular involving a soluble mediator. Nitric oxide has been implicated by virtue of its babesiacidal affects in vitro, but questioned to be as effective in vivo, due to its ability to downregulate type-1 immunity. Spleen cells were obtained from 4-month-old calves and adult steers and processed for monitoring cytokine and inducible nitric oxide synthase (iNOS) mRNA expression during the response to initial B. bovis infection. The data provided evidence of a transient role for nitric oxide in innate immunity, characterized by brief iNOS induction in the spleen of calves that was not detectable in the spleens of adults. The iNOS message followed the early induction of interleukin (IL)-12 and interferon (IFN)-gamma message in calves. The induction of IL-12 and IFN-gamma message in adults was delayed until IL-10 message was induced. Transformation growth factor-beta mRNA expression levels were greater in spleen cells from adults early in infection and then declined, whereas expression levels increased in spleen cells from calves later in the infection process. Together, the data support the concept of 'first come, first serve' cytokine influence over cellular activities, the importance of a type-1 response in the control of an initial infection and the need for tight regulation in order to prevent pathology associated with over production of nitric oxide and inflammatory cytokines.

Effects of tallow on the energy metabolism of wethers fed barley finishing diets

A balance trial was conducted to titrate the effects of tallow on the energy metabolism of wethers fed barley finishing diets. Six dietary levels of tallow (0, 2, 4, 6, 8, or 10%) in a barley finishing diet were fed to six crossbred wethers (35+/-1.1 kg) in a randomized complete block design. Diets were 73% barley, 10% tallow and(or) bentonite, 10% alfalfa pellets, and 7% supplement. There was no effect of tallow level on OM intake (1,103.1+/-51 g/d), OM digestibility (84+/-0.9%), GE digestibility (83+/-1.1%), or cell solubles digestibility (84.2+/-1.2%). The level of tallow quadratically decreased ADF digestibility (P < 0.05), methane emissions, and methane energy as a percentage of GE P < 0.01). There were linear increases in dietary GE (megacalories per kilogram of OM [P < 0.01]), dietary DE (megacalories per kilogram of OM [P < 0.05]), and dietary ME (megacalories per kilogram of OM [P < 0.01]), as dietary tallow increased. Numbers of ruminal protozoa (Entodinium spp. and Polyplastron sp.) decreased linearly (P < 0.05) with increased level of tallow. The energy value of tallow (calculated by difference) was low. The total-tract fatty acid digestibility of tallow was calculated by linear regression, without intercept, after accounting for the fatty acids digested from the base diet (0% tallow fed to a wether in a period). Fatty acids of the same carbon length were pooled for the regression analysis. All linear regressions were significant (P < 0.10) indicating no effect of tallow level on fatty acid digestibility. Lauric acid had low digestibility. The high digestibility of all C16 (89%) and C18 (104%) fatty acids suggests an effect of tallow on endogenous and microbial fatty acid excretion. Fatty acid digestibility was probably a minor contributor to the low energy content of tallow, calculated by difference, in these diets.

Thyroid hormone coordinates respiratory control maturation and adenine nucleotide translocator expression in heart in vivo

BACKGROUND

The signal transduction mechanism linking mitochondrial ATP synthesis with cytosolic ATP utilization in heart changes during postnatal development in vivo. This maturational process occurs in parallel with accumulation of mitochondrial adenine nucleotide translocator (ANT), which provides a possible site for respiratory control. We postulated that thyroid hormone regulates these maturational processes.

METHODS AND RESULTS

We used (31)P MR spectroscopy to determine the relationship between myocardial high-energy phosphates, phosphocreatine, and ADP and oxygen consumption (MVO(2)) during epinephrine stimulation in 32- to 40-day-old lambs thyroidectomized after birth (THY) and age-matched controls. Steady-state protein and mRNA levels for ANT isoforms and beta-F(1)-ATPase were assessed from left ventricular tissues by Western and Northern blotting. With greater doses of epinephrine, THY attained lower peak MVO(2) than controls (P:<0.05). Controls maintained high-energy phosphate levels, unlike THY, which demonstrated significantly decreased phosphocreatine/ATP and increased cytosolic ADP despite lower peak MVO(2). No significant differences in beta-F(1)-ATPase protein or mRNA occurred between groups. However, ANT isoform mRNA levels were 2-fold greater and protein levels 4-fold greater in control hearts.

CONCLUSIONS

These data imply that the maturational shift away from ADP-mediated respiratory control is regulated by thyroid hormone in vivo. Specific thyroid-modulated increases in ANT mRNA and protein imply that this regulation occurs in part at a pretranslational level.

Preclinical diagnosis of scrapie by immunohistochemistry of third eyelid lymphoid tissue

Ovine scrapie is a member of the transmissible spongiform encephalopathies (TSEs), a heterogeneous family of fatal neurologic disorders characterized by deposition of an abnormal isoform (prion protein [PrP] PrP-Sc) of a cellular sialoglycoprotein in neural tissue. PrP-Sc is detectable in some lymphoid tissues of infected sheep months or years before development of clinical disease. Detection of PrP-Sc in these tissues is the basis for live-animal testing. In this study, we characterize the performance of a preclinical diagnostic test for ovine scrapie based on a monoclonal antibody (MAb)-based immunohistochemistry assay of nictitating membrane ("third eyelid")-associated lymphoid tissue. The results of third eyelid immunohistochemistry assay agreed with the scrapie status of the sheep for 41 of 42 clinical suspects with confirmed scrapie and 174 of 175 sheep without scrapie. Third eyelid sampling agreed with the scrapie status for 36 of 41 clinically normal sheep positive for PrP-Sc immunostaining of brain tissue, including 27 sheep with positive biopsy specimens that progressed to clinical disease with confirmed scrapie 3 to 20 months after biopsy. The assay used MAb F89/160.1.5, which binds to residues 142 to 145 of ovine PrP. This antibody can be used in combination with MAb F99/97. 6.1, which binds to residues 220 to 225. One or both MAbs in this cocktail recognize PrP sequences conserved in most mammalian species in which natural TSEs have been reported. Immunohistochemistry assay of routinely formalin-fixed lymphoid tissues with a cocktail of pan-specific MAbs is a practical, readily standardized live-animal and preclinical test for ovine scrapie.

Flow cytometric analysis of an immunodeficiency disorder affecting juvenile llamas

The present study was undertaken to characterize the immune system of llamas and alpacas and establish the basis for an immunodeficiency disorder affecting juvenile llamas. Flow cytometric (FC) analysis of the immune system with a panel of monoclonal antibodies (mAbs) revealed the immune system of llamas and alpacas is similar in leukocyte subset composition to that in ruminants. Peripheral blood mononuclear cells in adults are comprised of surface immunoglobulin (sIg(+)) B-cells (31%+/-8 S.D.), alphabeta T-cells (27%+/-12 S.D.), WC1(+) gammadelta T-cells (16%+/-11 S.D.), and 5-16% monocytes. In contrast to cattle, goats, and sheep, however, the frequency of WC1(+) gammadelta T-cells is not high in juveniles but similar to the frequency in adults. Also, sIg(+) B-cells are present in high concentration in juveniles (43%+/-11 S.D. ). Expression of major histocompatibility class II molecules on resting T-cells was low or absent. Comparative analysis of peripheral blood lymphocyte composition in normal juvenile llamas and llamas presenting with the signs of the juvenile llama immunodeficiency syndrome (JLIDS) revealed the concentration of B-cells is extremely low (1-5%) in affected animals. The findings suggest JLIDS is attributable to an autosomal recessive genetic defect in the development of B-cells.

Prediction of serum IgG1 concentration in beef calves based on age and serum gamma-glutamyl-transferase activity

This study examined the relationship between serum gamma-glutamyl-transferase (GGT) activity and passive transfer status in beef calves less than 18 days of age. Immunoglobulin G1 (IgG1) concentrations were measured in 69 commercial beef calves between the ages of 24 and 72 hours. GGT activities were then measured in these same calves at various ages between 3 and 18 days of age. Models were developed predicting serum IgG1 concentration as a function of calf age and serum GGT activity. Minimal association was present between initial serum IgG1 concentration and serum GGT activity when all calves less than 18 days of age were considered (r2 = 0.065). When the study population was restricted to calves less than 8 days of age, the fit of the developed model was greatly improved (r2 = 0.438). Serum GGT activity has no apparent advantage relative to other assay procedures for predicting passive transfer status in beef calves. If serum GGT activity is to be used to assess passive transfer status in beef calves, application of this procedure should be restricted to calves less than 8 days of age.

Detection of low serum immunoglobulin concentrations in clinically ill calves

The sensitivity, specificity, and accuracy of classification of 4 tests for failure of passive transfer (FPT) were examined in clinically ill neonatal calves. Comparisons were made with serum IgG1 concentrations determined by radial immunodiffusion. Serum samples were obtained from 27 clinically ill calves < or = 21 days of age. The results of 4 commonly used assays, the sodium sulfite turbidity test, the zinc sulfate turbidity test, refractometry, and the serum gamma-glutamyl transferase (GGT) activity test, were compared with radial immunodiffusion determinations of serum IgG1 concentration. Serum GGT activity using a 50 IU/L threshold resulted in correct classification of the highest percentage of calves (93%) with regard to their passive transfer status. The sodium sulfite test with a 1+ end point and refractometry using a 5.5 g/dL end point resulted in correct classification of 85% of the calves studied. When using the sodium sulfite test, the 2+ and 3+ test end points had lower specificity, 0.58 and 0.00, respectively, than the 1+ end point. This loss in specificity resulted in misclassification of calves with adequate serum immunoglobulin concentrations as having FPT. The zinc sulfate turbidity test was inadequately specific (0.33) and resulted in misclassification of 33% of calves.

Conservative management of a ruptured gastrocnemius muscle in a male llama

Rupture of the gastrocnemius muscle was diagnosed in an obese llama using physical examination and ultrasound imaging. Conservative therapy consisting of the use of a cast to immobilize the affected limb permitted the muscle to heal. Only mild, residual gait abnormalities were observed on follow-up examination.

Facial fibrosarcoma in two cows

Fibrosarcoma is a common tumor affecting bone, but is uncommon in cows. Reported here are two bovine cases of facial fibrosarcoma that were very invasive.

Use of age and serum gamma-glutamyltransferase activity to assess passive transfer status in lambs

OBJECTIVE

To develop an algorithm for predicting passive transfer status of lambs of various ages, using the lamb's age and serum gamma-glutamyltransferase (GGT) activity.

DESIGN

Prospective study.

ANIMALS

51 Suffolk, Columbia, and crossbred lambs from 1 to 16 days old.

PROCEDURE

Serum was obtained from all lambs. Serum GGT activity was measured, using a commercially available kit. Serum IgG concentration was determined by use of radial immunodiffusion. Day-1 serum IgG concentration was estimated from sample IgG concentration, lamb age, and the published 14-day half-life of IgG in lambs. Stepwise multivariate regression models were developed to estimate day-1 serum IgG concentration as a function of the natural logarithm of serum GGT activity (In[GGT]) and natural logarithm of lamb age (In[age]) at the time of sampling. These regression models were then used to calculate serum GGT activities that were equivalent to various day-1 IgG concentrations in lambs of various ages.

RESULTS

In(GGT) and In(age) were significantly associated with estimated day-1 IgG concentration. Day-1 serum IgG concentration could be predicted using the formula: IgG = -7,686 + 1,366(In[GGT]) + 1,199(In[age]). The model was moderately accurate in predicting serum IgG concentration (R2 = 0.52).

CLINICAL IMPLICATIONS

Serum GGT activity can be used to assess passive transfer status of lambs.

Evaluation of serum gamma-glutamyltransferase activity as a predictor of passive transfer status in crias

OBJECTIVE

To determine the relationship between serum gamma-glutamyltransferase (GGT) activity and serum IgG concentration in neonatal crias.

DESIGN

Prospective observational study.

ANIMALS

21 llama and 4 alpaca crias from 0 to 5 days old.

PROCEDURE

Serum GGT activity was measured, using a commercially available kit. Serum IgG concentration was determined by use of radial immunodiffusion. With a serum IgG concentration of 1,000 mg/dl (considered adequate passive transfer), specificity and sensitivity of serum GGT activity in the detection of failure of passive transfer were determined. Regression models were developed to determine the relationship between serum GGT activity and serum IgG concentration.

RESULTS

Sensitivity ranged from 0.56 to 0.89, and specificity ranged from 0.88 to 0.31, depending on the value of serum GGT activity chosen as a threshold. Proportion of crias correctly classified ranged from 0.76 to 0.52. Regression models failed to demonstrate a significant relationship between serum GGT activity and serum IgG concentration.

CLINICAL IMPLICATIONS

Passive transfer status in crias cannot be accurately predicted on the basis of serum GGT activity.

Effect of feed availability on post-milking standing time in dairy cows

Control programmes for contagious mastitis pathogens, primarily Streptococcus agalactiae and Staphylococcus aureus, consisting of milking hygiene, treatment or isolation of infected cows and post-milking teat disinfection are relatively effective (McDonald, 1970; Natzke, 1977; Fox & Gay, 1993). Similar control programmes are often ineffective in the prevention of intramammary infections caused by environmental bacteria (Eberhart, 1977; Smith et al. 1985; Erskine et al. 1991; Smith & Hogan, 1993). This disparity of success relates to the fact that the principal source of environmental mastitis pathogens is the cow's environment, rather than another cow with an intramammary infection (Eberhart, 1977; Smith et al. 1985). Infections of environmental origin are particularly noteworthy because they may remain common in well managed herds, and these infections often cause severe clinical signs and high case fatality rates (Eberhart, 1977; Smith et al. 1985; Erskine et al. 1991; Smith & Hogan, 1993).

Control programmes for environmental mastitis usually include premilking teat disinfection, decreased use of water in udder preparation, increased concentrations of dietary vitamin E and selenium, improved sanitation of the environment and modification of cow behaviour in the post-milking period (Eberhart, 1977; Smith et al. 1984, 1985; Weiss et al. 1990; Erskine et al. 1991; Smith & Hogan, 1993). Environmental infections are thought to result when bacteria lacking specific virulence factors penetrate the teat sphincter (Eberhart et al. 1979; Smith et al. 1985). The bulk of these exposures are thought to occur between milkings. Control of these infections is problematic because the cow's teat sphincter remains open after mechanical milking (McDonald, 1975a). Presumably, cows are predisposed to intramammary infections when the open teat sphincter is exposed when cows lie down. Hence, dairy managers are advised to offer fresh feed to cows immediately after milking to increase the likelihood that the teat sphincter will close at least partly before cows become recumbent.

The purpose of this study was to determine the effect of feed availability on post-milking behaviour in dairy cows. Specifically, the measured dependent variable was the length of time that cows remained standing after leaving the milking parlour.

Prediction of serum IgG1 concentration in Holstein calves using serum gamma glutamyltransferase activity

We examined the relationship between serum gamma glutamyltransferase (GGT) activity and serum gamma immunoglobulin G (IgG1) concentration in Holstein calves. Blood samples were collected from calves aged 1 to 3 days. A follow-up sample was obtained from each calf 2, 7, or 15 days after the initial sampling. Serum GGT activity and IgG1 concentration were measured. Regression models were used to predict IgG1 concentration as a function of age and serum GGT activity measured 2, 7, or 15 days later. Serum GGT activity and calf age at the time of the second sample were directly related to serum IgG1 concentration in the initial sample in calves aged 3 to 17 days (r = .54) and in calves aged 3 to 10 days (r = .63). Models were used to estimate the serum GGT activity equivalent to a serum IgG1 concentration of 1,000 mg/dL. One-day-old calves should have serum GGT activities > 200 IU/L. Four-day-old calves should have serum GGT activities > 100 IU/L. One-week-old calves should have serum GGT activities > 75 IU/L. Calves with serum GGT activities < 50 IU/L should be classified as having failure of passive transfer.

Squamous cell carcinoma originating from a cutaneous scar in a llama

A nonhealing wound associated with a laceration in a 12-year-old llama was evaluated. Initial attempts at closure were unsuccessful and biopsy revealed scar tissue. Subsequent biopsies, 18 mo later, revealed squamous cell carcinoma with regional metastasis. This report describes squamous cell carcinoma, secondary to a traumatic wound in a llama.

Ruminal undegradability of blood meal and effects of blood meal on ruminal and postruminal digestion in steers consuming vegetative orchardgrass hay

Four crossbred steers (360 +/- 3 kg) cannulated at the rumen and duodenum were used in a 4 x 4 Latin square design to examine the effects of supplemental blood meal (BM) on voluntary intake, digesta kinetics, ruminal fermentation, site and extent of digestion, and bacterial protein synthesis in steers fed vegetative orchardgrass hay (Dactylis glomerata L.). The levels of BM supplementation were 0, .07, .13, and .20 kg/d. Voluntary intake of OM (8.35 kg/d) was not significantly affected by BM supplementation. No significant effects of BM supplementation were detected for OM flow to the duodenum or digestion in the rumen or lower tract. However, total tract OM digestibility decreased 2.2 percentage units at .20 kg/d of BM intake (lower with vs without BM; P < .10). Total N intake and flow to the duodenum linearly increased (P < .10) with increasing BM level from 251 to 277 g/d and from 158 to 199 g/d, respectively. Ammonia N and bacterial N flows to the duodenum were not affected (P > .10) by BM supplementation. As a result, nonammonia N flow to the duodenum increased linearly (P < .10) with increasing BM supplementation. Ruminal escape N from BM was 83.5, 85.3, and 87.2% for .07, .13, and .20 kg/d of BM, respectively. Apparent bacterial efficiency and true bacterial efficiency were not affected (P > .10) by BM supplementation. Total amino acid and total essential amino acid flows to the duodenum were increased (P < .10) by dietary inclusion of BM. Duodenal flows of all essential amino acids except lysine and valine and of all nonessential amino acids except alanine and proline were increased (P < .10) by BM inclusion in the diet. In summary, supplementation with BM increased ruminal escape N and duodenal flows of total and most essential amino acids.

Stability of gamma-glutamyltransferase activity in calf sera after refrigerated or frozen storage

OBJECTIVES

To examine stability of -glutamyltransferase (GGT) activity in stored serum from neonatal calves.

ANIMALS

10 commercial beef calves between 36 and 60 hours old.

PROCEDURE

Serum samples were obtained from the calves, and each sample was divided into 8 aliquots. Serum GGT activity was measured on day 0 (fresh) and days 1, 2, 3, and 4 of refrigerated storage (4 C) and weeks 1, 2, and 3 of frozen storage (-20 C).

RESULTS

Serum GGT activities for each of the refrigerated aliquots did not significantly differ from day zero, with serum GGT activity (expressed as a percentage of initial activity) > 99% on all 4 days. Serum GGT activity in frozen aliquots decreased significantly after 1 and 2 weeks of frozen storage, 97 and 98%, respectively; however, this decrease in GGT activity was not biologically significant. The observed GGT activity did not decrease significantly in the samples stored frozen for 3 weeks; these samples retained 99% of initial activity.

CONCLUSION

The observed stability of serum GGT activity indicates that serum may be obtained, stored, and batch processed at a later time. This stability during storage is important to the success of a bovine passive transfer monitoring program based on GGT activity.

Evaluation of 3 assays for failure of passive transfer in calves

This study examined the sensitivity, specificity, predictive values, and classification accuracy of 3 commonly used screening tests for failure of passive transfer: the sodium sulfite turbidity test, the zinc sulfate turbidity test, and refractometry relative to serum immunoglobulin G1 (IgG1) concentrations determined by radial immunodiffusion. Serum samples were obtained from 242 calves ranging from 1 to 8 days of age. Using a serum concentration of 1,000 mg/dL IgG1, to define adequate passive transfer, the zinc sulfate test had a sensitivity of 1.00 and a specificity of 0.52 in the detection of inadequate passive transfer. The endpoint of the test appeared to be higher than desired; calves testing negative had mean serum IgG1 concentration of 955 mg/dL and a large proportion of calves with adequate passive transfer were misclassified as positive for failure of passive transfer. Using the qualitative zinc sulfate test, the percentage of calves correctly classified with regard to passive transfer status was less than that observed with either the sodium sulfite test or refractometry. The sensitivity of the sodium sulfite assay was 0.85 at a 1+ endpoint and 1.00 at a 2 or 3+ endpoint. The specificity of the sodium sulfite assay varied from 0.87 at a 1+ endpoint and 0.56 at a 2+ endpoint. The sensitivity and specificity of refractometry varied from 0.01 to 1.00 depending on the choice of endpoint. Refractometry correctly classified the largest proportion of calves with regard to their passive transfer status at test endpoints of 5.0 and 5.5 g/dL, 83% and 82% respectively. The highest percentages of calves correctly classified occurred with the sodium sulfite test using a 1+ endpoint (86.30%) and refractometry using a 5.0 g/dL endpoint (83.00%). A regression equation was developed that permitted calculation of an optimal endpoint for refractometric determinations of total serum protein concentration. A serum protein concentration of 5.2 g/dL was equivalent to 1,000 mg/dL serum IgG1. Optimal selection of tests for passive transfer status in calves will be governed by the prevalence of failure of passive transfer, test performance, and the anticipated costs of classification errors.

Effect of barley variety and dietary barley content on digestive function in beef steers fed grass hay-based diets

Five ruminally and duodenally cannulated steers were used in a 5 x 5 Latin square design with a 2 x 2 + 1 arrangement of treatments to study the effects of barley variety and dietary barley content on digestive function in steers fed grass hay-based diets. Barley varities evaluated were Russell and Steptoe, which had bulk densities of 67.7 and 64.5 kg/hL, respectively. Supplemental treatments were as follows: corn, low Russell (Ru-lo), low Steptoe (St-lo), high Russell (Ru-hi), and high Steptoe (St-hi). Corn, Ru-lo, and St-lo were provided at 30% (DM basis) of grass hay-based diets, whereas Ru-hi and St-hi were provided at 35.5% of diet DM (equal starch content as the corn treatment). No treatment differences (P > .10) were observed for DMI, ruminal particulate passage rate, and NDF total tract digestibility. Ruminal DM and starch digestibility were greater (P < .01) for barley-containing diets than for the corn diet. Similarly, total tract DM (P < .10) and starch (P < .01) digestibility was greater for barley than for corn diets. Microbial protein and non-NH3 N flow to the small intestine were greater (P < .01) for the barley diets than for the corn diet. Starch intake (P < .01) and DM digestibility (P < .10) were greater for high- than for low-barley diets; however, differences due to barley variety were not observed (P > .10). In situ disappearance of grass hay NDF at 8 and 96 h of incubation was greater (P < .05) for barley than for corn diets. Rate of in situ disappearance of grain DM was greater (P < .01) for barley than for corn and for Russell than for Steptoe barley. Responses suggest that ruminal and total tract digestibility and protein flow to the small intestine can be increased with barley compared with corn as an energy supplement to grass hay-based diets.

Left oblique celiotomy approach for cesarean section in standing cows

A left oblique celiotomy approach was used for cesarean section in 18 standing cows (15 beef cows and 3 dairy cows). Indications for cesarean section included oversized or emphysematous fetus and uterine inertia. Poor body condition was identified as a contributing factor for dystocia in 4 cows. Abdominal wall hernias did not develop in any of the cows. Because the incision in this approach extends further cranial and ventral than in the standard left celiotomy approach, the left oblique celiotomy readily permitted manipulation and exteriorization of the gravid uterine horn. Additionally, apposition of the transversus abdominis and internal abdominal oblique muscles was facilitated by use of this technique. Closure of the incision was readily accomplished in all cows.

Survey of dairy managers in the Pacific Northwest identifying factors associated with teat chapping

Telephone interviews were conducted to evaluate the association of teat chapping with combinations of premilking and postmilking teat disinfectants (predip and postdip), other management practices, and climatic conditions. Holstein dairies (n = 100) in the DHIA SCC program were randomly selected from three northwest regions. During nonwinter seasons, herd managers using an iodophor dip without skin conditioner both premilking and postmilking were 9.7 times more likely to report chapping than were those using iodophor with conditioner. The herd managers least likely to report chapping problems were those using conditioner in both the predip and postdip. Use of conditioner in postdip only was associated with intermediate frequency of reported chapping. No conditioner in either predip or postdip was associated with the greatest frequency of reported chapping. Herd managers using a different germicide in the predip and postdip reported more chapping than herd managers using the same germicide. The frequency of chapping was highest during winter in all regions, and the percentage of herd managers reporting chapping within a region was associated with the temperature extremes of the region. For seasons other than winter, characteristics of predip and postdip combinations and parlor exit or barn design were the management factors that best described an association with reported chapping.