The use of the immunomodulator OmniGen-AF (OMN) feed supplement, where the response in milk yield, health, and reproduction is uncertain, allows for an application of type I (use the product when it is not profitable) and type II (do not use the product when it is profitable) analysis to aid decision-making regarding its profitability. This study applies a type I and II error analysis to quantify the economic risk of investing in OMN feed supplementation using data from a controlled study and a field dataset collected on dairy farms. Four prediction models were applied considering the expected value and SD of the response in milk yield; milk and health; milk and reproduction; and milk, health, and reproduction. Uncertainty in the milk response was modeled following a normal distribution with mean 0.15 kg/cow per day and SD 0.81 kg/cow per day. This distribution was left-truncated at 0 kg, which resulted in a mean (expected) response of 0.7 kg/cow per day. Based on the field dataset, the reduction in health costs and reproduction were estimated at $0.086 and $0.33/cow per day. All 3 responses were assumed to be present or not in the first 90 DIM. The increase in milk yields necessary to pay for the OMN supplementation considering a response in milk yield only; milk and health; milk and reproduction; and milk, health, and reproduction were 0.45, 0.19, -0.56, and -0.82 kg/cow per day, respectively. The break-even OMN cost per cow per day when considering the increases in milk yield; milk and health; milk and reproduction; and milk, health, and reproduction were $0.23, $0.31, $0.56, and $0.65, respectively. Production responses resulted in costs exceeding revenue with a type I error cost of $2.62 for milk and $0.47 for milk and health response for the broke even. There was no type I error cost associated when considering the responses in milk and reproduction, and the combination of milk, health, and reproduction, which implies that there is no risk of using OMN when it is not profitable (= the product is profitable for certain). Type II costs were associated with returns that are unrealized because of failing to use OMN when it is profitable with an opportunity cost of $9.92, $15.53, $37.23, and $45.08 per cow per day for the responses in milk yield; milk and health; milk and reproduction; and milk, health, and reproduction, respectively. We concluded that a type I and II error analysis applied to the use of the OMN feed additive provided additional insights beyond a break-even analysis to support economic decision-making when the response on dairy farms is uncertain. The type I and II error analysis can aid in decision-making process to evaluate the adoption of a new technology.

Objective: Is use of dry cow therapy, teat sealant, or dry cow therapy + teat sealant more effective in controlling heifer mastitis and decreasing SCC than no treatment? Materials and Methods: At 2 mo prepartum, 304 mammary quarters of 76 pregnant Holstein heifers were randomly assigned to (1) dry cow therapy, (2) teat sealant, (3) dry cow therapy + teat sealant, or (4) untreated control. Before treatment, mammary secretion samples were collected and stored for bacteriological analysis. After calving, infection data were compared with data collected prepartum, and treatment means were separated using SAS 9.3. Results and Discussion: Compared with cure rate in untreated controls (55.2%), treatment with dry cow therapy (100%), teat sealant (85.7%), or dry cow therapy + teat sealant (96.1%) resulted in greater cure rates and lower SCC in quarters infected prepartum with Staphylococcus aureus or coagulase-negative staphylococci. Prevention rates against all new intramammary infections (IMI) were similar for control quarters (95.9%), dry cow therapy (92.2%), teat sealant (97.9%), and dry cow therapy + teat sealant (95.9%). Implications and Applications: Although the IMI prevention rates were similar across treatments, the majority of heifers did have at least one quarter infected with Staph. aureus or coagulase-negative staphylococci, which dry cow therapy has been shown to be very effective in curing as well as decreasing future SCC. In problem herds, an udder health program should incorporate treating all quarters with dry cow therapy to cure existing IMI plus teat sealant to prevent new IMI, under supervision of the herd veterinarian.

Enhancing immunological responses to vaccination is an important goal in many herd health management systems. OmniGen-AF®(OG) is an immunomodulatory feed additive that has been shown to enhance innate immune function in ruminants and its effects on adaptive immunity require additional study. The objective of this study was to evaluate post-vaccine antibody titers and circulating cellular memory development in heifers fed OG and administered a commercially available modified-live bovine respiratory disease (BRD) vaccine. Twenty-four Holstein heifers were assigned to one of two diets for 170 days: Control TMR (CON; n = 11), or TMR plus OG (TRT; 9 g/100 kg BW/day; n = 13). Samples for hematology, serology, and cellular assays were collected on D-110, 0, 21, 42, and 60 of the trial. Heifers were administered two priming doses of a modified-live BRD vaccine, with a third dose given on D0. There were no significant differences in total WBC and absolute number or the percentage of circulating lymphocytes, monocytes, neutrophils, RBC, or platelets on D-110 through D21. On D42 and D60, CON had significantly higher numbers of lymphocytes. On D0, mean serum neutralizing (SN) titer to BHV-1 was significantly higher for CON compared to TRT. SN titers were not significantly different between CON and TRT at any other time point for BHV-1, BVDV type 1, or BVDV type 2. TRT mounted a significantly stronger recall proliferative response to 0.5 multiplicity of infection (MOI) of BHV-1, BVDV type 1 and BVDV type 2 on D42 and D60; 0.25 MOI of BVDV type 1 on D21 and D42; and 0.25 MOI BVDV type 2 on D42 compared to CON. IL-4 production induced by 0.5 and 1.0 MOI BHV-1 (D42 and D60); 0.25 MOI of BVDV type 1 (D21); and 0.25 and 0.5 MOI of BVDV type 2 (D60) were significantly higher for TRT than CON. IL-17 production induced by 0.25 MOI of BVDV type 1 was significantly higher on D60 for TRT compared to CON. IFN-gamma and IL-10 were not significantly different between treatments. These data indicate feeding OG has a beneficial effect on responses to vaccine antigens in Holstein dairy heifers.

Teat disinfection, both before and after milking, is the most important mastitis management tool for reducing the incidence of new intramammary infections in dairy cows. Between milkings, cows are exposed to pathogenic mastitis-causing microorganisms in the environment in which they are managed that are present in soil, manure, bedding materials, water, and mud. These pathogens contaminate the teat skin of the udder, and include environmental bacteria such as Streptococcus uberis and Escherichia coli. The practice of pre-dipping reduces the bacterial load with these environmental pathogens, which subsequently reduces the new infection rate. During the milking process, teats are exposed to the contagious organisms such as Streptococcus agalactiae, Staphylococcus, aureus, and Mycoplasma species. Post-dipping by immersion of teats in a disinfectant immediately after milking cluster removal kills the majority of contagious bacteria, thereby preventing the establishment of new infections during the post-milking period. Whether preand/or post-dipping are used, dairy producers must ensure that they are using products that have been proven effective against mastitis-causing bacteria through valid scientific testing. In this study, the germicidal efficacies of Forticept Udder Wash (pre-dip) and Forticept Udder Forte (post-dip) (Lidan, Inc., NY, NY) in reducing the new intramammary infection rate under natural exposure to mastitis pathogens were evaluated and compared with a proven iodine preand post-dip product as a positive control. Results of the 6-month trial demonstrated a new infection rate of 10.5% among mammary quarters pre-dipped and post-dipped in Forticept products, and a rate of 5.8% among quarters pre-dipped and post-dipped in the positive control iodine product; the difference was not significant (P < 0.06). In addition, average somatic cell count (SCC) was 304,000/ml among mammary quarters pre-dipped and post-dipped in Forticept products, and 239,000/ml among quarters pre-dipped and post-dipped in the positive control product; the difference was not significant (P < 0.06). Average teat condition scores were very similar (P < 0.96) among quarters pre-dipped and post-dipped in Forticept products (Score = 1.40), and quarters pre-dipped and post-dipped in the positive control (Score = 1.46). Findings suggest that under the conditions of this study, the new mammary quarter infection rate, SCC, and teat condition scores were similar among quarters dipped in Forticept products and quarters dipped in the positive control product.

A trial was conducted to determine if feeding OmniGen-AF® (OG) to 22 late lactation cows 60 days prior to and during the early dry period, a time of increased susceptibility to mastitis, could reduce disease incidence in a dairy herd experiencing major health issues. Treated cows (n = 11) consumed a ration containing OG [9 g/100 kg of body weight/day] beginning 60 days before dry-off, during the dry period, and through 30 days in milk (DIM). Control cows received the same ration during the dry period through 30 DIM only. Body weights, body condition scores (BCS), intramammary infection (IMI) prevalence, new IMI rates, somatic cell counts (SCC), milk yield, and adverse health events were measured. No differences were found between treatments for body weight or BCS. Adverse health event data at calving showed no differences between treatments except for percentage of cows with hyperketonemia, which was lower among treated cows (63.6% vs 100%). Prevalence of IMI from calving through 30 DIM for treated cows (6.1%) was lower than controls (11.05%); likewise, new IMI rate during this time for treated cows (0.61%) was lower than controls (5.81%). The SCC from calving through 30 DIM for treated cows (215,000/ml) was lower than controls (493,000/ml). Average production/day at the first DHIA test (~33 DIM) showed that treated cows produced more milk (39.9 kg) than controls (35.34 kg). In conclusion, feeding OG 60 days prior to dry-off reduced hyperketonemia and mastitis, lowered SCC, and numerically increased milk yield in a dairy herd experiencing major health issues.

The presence of mastitis in bred dairy heifers can adversely affect the development of milkproducing tissues, leading to less than maximal milk production and increased somatic cell counts (SCC) during the first lactation. Use of nonlactating cow therapy has been beneficial in curing existing intramammary infections (IMI), and teat sealants have been beneficial in preventing new IMI from developing. When used together, the combination of the two products may be more effective than either alone in controlling mastitis in these young dairy animals. Recent studies to examine this combination demonstrated that cure rates after the infusion of nonlactating cow therapy + teat seal, although 96.1% effective, were similar to nonlactating cow therapy alone (100% cure) and teat seal alone (85.7% cure), all of which were significantly (P < 0.001) elevated over untreated controls (55.2% cure); prevention rates ranged between 92.2 and 97.9% for all 4 treatments. Thus, although all 3 infusion treatments were effective in curing existing IMI and preventing new ones, the combination of nonlactating cow therapy + teat seal was no more effective than either treatment alone in controlling mastitis as initially hypothesized. What was unexpected was the 85.7% cure rate (P < 0.001) in quarters infused with teat seal alone. The purpose of the proposed research was to determine why teat seal was effective in curing existing IMI, the results of which may be instrumental in supporting claims that teat seal is a product that not only prevents new IMI as the product label states, but in addition, cures existing IMI. To accomplish this, mammary secretions were collected 24, 48, and 72 h after treatment from quarters of heifers randomly assigned to: 1) untreated control, 2) nonlactating cow therapy, 3) teat seal, or 4) the combination of the two products. The SCC, differential leukocyte count, and cytokine activity of secretions were compared among treatments to determine if quarters infused with a treatment that included teat seal, e.g., teat seal alone or teat seal + antibiotic, elicited an SCC, differential leukocyte, or cytokine response that could be the basis for the elevated cure rate in teat seal-infused quarters that was previously observed. Results demonstrated that SCC were not different among treatments; however, significant changes in differential leukocyte counts and cytokine activity were observed. The percentage of neutrophils increased significantly after all 3 infused treatments and were elevated over controls. Concomitantly, percentages of lymphocytes and macrophages decreased after all 3 infused treatments, and were lower than controls. Eosinophil counts were significantly elevated after infusion with nonlactating cow therapy and teat seal treatments. Concentrations of tumor necrosis factor alpha (TNF-α) and the ratio of TNF-α to interleukin (IL)-8 were elevated in quarters treated with teat seal compared with other treatments. Results suggest that recruitment of neutrophils into quarters infused with teat seal, as well as the high level of TNF-α in mammary secretions may have provided antibacterial activity that resulted in the high cure rate after treatment with this infusion product. As observed in previous trials, infusion with nonlactating cow therapy (100% cure), teat seal (87.5% cure), or the combination of the two products (100% cure) were effective in curing existing IMI, and prevention rates ranged between 95 and 100%.

to Enhance the Antibody Response to Vaccination Abstract A novel adjuvant (Immunoboost ®) to enhance antibody titer response to a commercial vaccine (Lysigin ® ) against Staphylococcus aureus mastitis in dairy heifers was evaluated. In Phase 1, hyper-immunization with Lysigin ® to enhance serum titers did not result in titers that exceeded conventional immunization. In Phase 2,anti- S. aureus titers in heifers immunized with Lysigin ® + Immunoboost ® tended to be elevated (P = 0.10) over heifers immunized with Lysigin ® alone by day (D) 7 continuing through D14. By D21, titers in the Immunoboost ® group were elevated (P = 0.05) over conventional vaccinates through D35, returning to baseline by D42.After booster injections on D42, the Immunoboost ® group exhibited increased (P = 0.05) titers over conventional vaccinates on D49through D63, remaining elevated through D84. Findings suggest that Immunoboost ® enhancedanti- S. aureus titer responses to commercial vaccination, and supportthe use of immunization to control S. aureus mastitis in dairy heifers.

Mastitis is an inflammation of the mammary gland caused by bacteria that affects one in every three cows, and costs the producer an average of $180/cow/year. Penetration of bacteria into the teat canal causing mastitic infections may be enhanced by hyperkeratosis, a thickening of the teat canal keratin, which provides a breeding ground for bacteria. The objective of this project was to determine if a correlation exists between elevated teat end scores (degree of hyperkeratosis) and presence of mastitis as indicated by elevated somatic cell counts (SCC). Purebred Holstein cows (n = 30) were assessed and sampled between 30 and 100 d in milk. Each animal was given a teat end score (TES) at sampling on a scale of 1 (smooth) to 4 (rough ring) according to level of severity, and teat canal swabs as well as milk samples were collected aseptically from each quarter for microbiological examination to determine infection status and, if infected, the pathogen(s) present. All milk samples were further evaluated for SCC using a DeLaval Cell Counter. The association of TES, infection status, and SCC was analyzed using the CORR procedure of SAS. A strong positive correlation was seen between level of infection and SCC for each quarter (P = 0.001) and for TES and age of the cow (P = 0.001). The average TES for uninfected quarters was 2.00, while the average TES for infected quarters was 2.42. However, there was no correlation between presence of infection and TES (P = 0.444) or SCC and TES (P = 0.439). When infected quarters were compared for pathogen and average TES, the following observations were made: CNS (TES = 1.9), Streptococcus (TES = 2.), Prototheca (TES = 2.0), S. aureus (TES = 2.6), mold (TES = 3.0) and E. coli (TES = 3.0). While no correlation was found for the presence of infection and teat end scores, the observation regarding the presence of specific mastitis causing bacteria and elevated teat end scores is an area for future investigation. This observation also suggests that teat end hyperkeratosis is associated with presence of mastitis caused by certain pathogens and that management practices should be in place to promote healthy teat ends for decreased mastitis incidence rates.

Vaccination of cows in late gestation is sometimes used to improve maternal antibody titers in their calves. However, scant published research has reported the relationship between serum antibody titers to specific infectious agents in vaccinated cows, the colostrum of these cows, and the serum of calves consuming their colostrum. As part of a larger study, the relationship between cow serum and colostrum antibody titers and calf titers was evaluated. Fifty-four multiparous Jersey and Jersey-cross cows were vaccinated between dry-off and calving with commercially available vaccines containing bovine herpesvirus-1 (BHV-1), bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), rotavirus, coronavirus, E. coli J-5, and Salmonella siderophore receptor and porin (SRP); blood was collected at dry off, mid-dry, and at calving. Calves born to enrolled cows were fed colostrum from only their dams; calf serum was collected at 7 and 30 d of life. Antibody titers against agents in the vaccine were measured in serum and colostrum of cows by standard neutralizing techniques or ELISA, and correlations between cow serum antibodies at 30 d before calving, cow colostrum, and calf serum antibodies at 7 d of life were evaluated. Correlations between cow serum antibodies and colostrum antibodies for different agents were significant (P < 0.05) but only moderately strong (Pearson correlation coefficient [PCC] range: 0.32–0.7), and varied for different agents. Similarly, correlations between cow colostrum antibodies and calf serum antibodies were usually significant, but only moderate (PCC range: 0.36–0.77). The R2 value for the correlation between colostrum antibodies and calf antibodies ranged from 0.11–0.59, indicating that for most agents, the colostrum antibody titer to a given agent did not explain a majority of variation in the calf serum antibody titer to that agent. Antibody titers to specific agents in cows are significantly, but not strongly, correlated with their colostrum antibody titers, and colostrum antibody titers are significantly but not strongly, related to antibody titers in calves. These data suggest that, in addition to maternal antibody concentration, other factors have an important impact on serum antibody titers to specific infectious agents in young dairy calves.

Presence of mastitis in pregnant as well as unbred dairy heifers can adversely affect the development of milk-producing tissues, leading to less than maximal milk production and increased SCC during their first lactation. Use of nonlactating cow therapy or teat sealants have been beneficial in curing existing IMI and preventing new IMI from developing. When used together, the combination of the two products may be more effective than either alone in controlling mastitis in these young dairy animals. To examine this, 4 quarters of each of 76 pregnant heifers were treated randomly 30 to 60 days prepartum as follows: 1) untreated control, 2) dry cow therapy, 3) teat sealant, or 4) dry cow therapy + teat sealant. Results demonstrated that compared to the spontaneous cure rate in untreated controls (55.2%), treatment with dry cow therapy (100%), teat sealant (85.7%), or dry cow therapy + teat sealant (96.1%) resulted in greater (P < 0.001) cure rates in quarters infected prepartum with Staphylococcus aureus or CNS. The reason for the 85.7% cure rate in teat sealant-treated quarters remains unclear. Additionally, SCC 3 d after calving were lower (P < 0.05) in quarters previously infected and cured, that were treated with dry cow therapy (914 x 10 3 /mL), teat sealant (587 x 10 3 /mL), and dry cow therapy + teat seal (534 x 10 3 /mL), compared with untreated controls (1638 x 10 3 /mL). Although the prevention rate against new IMI was similar for control quarters (95.9%) and those receiving dry cow therapy (92.2%), teat sealant (97.9%), and the combination of dry cow therapy + teat sealant (95.9%), it is recommended to implement an udder health program that incorporates treating all quarters with dry cow therapy to cure existing IMI plus a teat sealant to prevent new IMI.

Health, milk yield and milk quality records representing 473,711 cows from 787 dairy herds from the U.S. and Canada were collected to evaluate herd effects of feeding OmniGen-AF® (Phibro Animal Health Corp., Quincy, IL) to the entire herd. OmniGen-AF (OG) was fed at 56 g/hd/d to all dry and lactating cows for a minimum of 90 d (Post-OG). Health and production metrics were compared to the previous 90 d period (Pre-OG). Herds were enrolled in all months of the year (Jan-Mar, n = 239; Apr-June, n = 224; Jul-Sep, n = 176; Oct-Dec, n = 149) and herd size ranged from 31 to 9,046 cows. Health and production records were collected from DC305, DRMS and PCDART systems and the data were analyzed using paired t test (SAS, Statistical Analysis System) comparing the Pre-OG to Post-OG health events and production. The data were analyzed for all herds (n = 787) by herd size ( ≤ 100 hd, n = 188; 101 to 500 hd, n = 340; 501 to 1,000 hd, n = 120; ≥ 1,001 hd, n = 141). Monthly cases of mastitis, late term abortions, dead cows, and number of hospital cows/d, expressed as a % of total herd cows, differed (P < 0.001) between the Pre- and Post-OG 90 d periods (−24.6%, −28.6%, −23% and −17.4%, respectively). Health event responses to feeding OG were observed to vary by herd size and Pre-OG SCC; however significant reductions in cases/mo. of mastitis, abortions, deaths and metritis were common in all herds regardless of size and SCC during the Pre-OG period. Herds were also stratified by Pre-OG SCC cells/ml ( < 200,000, n = 309; 200,001 to 300,000, n = 237; 300,001 to 400,000, n = 146; ≥ 400,001, n = 95).The average Pre-OG SCC across all herds was 275,753 cells/ml with 73% of herds reporting a reduction in SCC during the Post-OG period. Changes in SCC were proportional to the Pre-OG SCC level. Significant reductions (P < 0.001) in SCC were observed in herds with Pre-OG SCC of 200,001 to 300,000 (−23,087), 300,001 to 400,000 (−57,850) and > 400,001 (−128,465) cells/ml. Milk production was reported by 532 herds with an average milk yield change from Pre-OG to Post-OG of +0.35 kg/hd/d (P < 0.001). Maintaining good health is a key component to cow productivity and these data suggest that feeding OmniGen-AF along with sound nutrition and management practices for dry and lactating cows can influence health, milk yield and milk quality in commercial dairies.

Because of the importance of bred heifers to the future milk production of any dairy operation, it is critical that udder health be maximized to ensure that animals freshen free of intramammary infection (IMI). During the heifer’s first gestation, the presence of mastitis can compromise the development of milk-producing tissues, and in the case of Staphylococcus aureus, milk yield may be reduced up to 10% over the first lactation (Nickerson, 2009; Owens, 1991). Milk quality is also reduced due to an increase in the somatic cell count (SCC) for the duration of the lactation (Paradis et al., 2010). In some of the worst cases, mammary tissue is replaced with scar tissue, causing the heifer to calve with a blind or nonfunctional quarter.

The purpose of this study was to evaluate the effect of a feed additive (OmniGen-AF(®), reported to have immune modulating activity) on innate immunity and health events during the periparturient period in dairy heifers when immunity is suppressed. From 60 days prepartum through calving, supplemented heifers (n=20) received OmniGen-AF(®) daily and were compared with unsupplemented controls (n=20). Blood leukocyte innate immune activity (phenotype markers, phagocytic activity, and reactive oxygen species--ROS production) was measured prior to feeding (60 days prepartum), 30 days later, and on days 1, 7, 14, and 30 postpartum. Adverse health events (udder edema, ketosis, displaced abomasum, and death) and milk production were measured at calving and into early lactation. The fraction of leukocytes with measurable CD62L (L-selectin) on their surface from supplemented heifers tended to be greater during the periparturient period in treated heifers than controls (p=0.100). Likewise, leukocyte phagocytosis of Escherichia coli and Staphylococcus aureus during this time period tended to be greater in heifers supplemented with OmniGen-AF(®) (p=0.100). Conversely, ROS production in response to phorbol myristate acetate or when leukocytes were stimulated with killed S. aureus lysate tended to be greater among control heifers compared with supplemented animals (p=0.100). Supplemented heifers exhibited fewer incidents of udder edema than controls (p=0.030) and tended to exhibit a lower rate of new cases of mastitis (p=0.098); however, no differences were observed in milk somatic cell counts or level of milk production. Results demonstrate a positive role of OmniGen-AF(®) in amplifying leukocyte function consistent with antibacterial activity during the periparturient period, and support the continued study of dietary supplementation to enhance mammary gland health in dairy cows.

The purpose of this investigation was to evaluate the efficacy of a staphylococcal bacterin (Lysigin ® ) in reducing the prevalence of staphylococcal mastitis and somatic cell counts (SCC) in a commercial dairy goat herd. Does were vaccinated (n = 15) or left as controls (n = 15) and the levels of mastitis and SCC were monitored at approximately 6-wk intervals over an 18-mo period. Prior to and after vaccination, Staphylococcus caprae (42.5%), S. xylosus (15.1%), and S. simulans (10.0%) were the predominant causes of intramammary infections (IMI) in the herd. The new infection rate was 1.64 IMI/doe among vaccinates, which was lower than but not different (P < 0.12) from controls (2.67 IMI/doe). The majority of new IMI across treatments were caused by S. caprae (31.7%) and S. xylosus (23.9%). The spontaneous cure rate of existing IMI after immunization was 1.28 cures/doe in vaccinates, which was higher than that observed in controls (0.6 cures/doe; P < 0.043); the majority of spontaneous cures occurred with S. caprae (44.4%) and S. xylosus (22.3%). Average SCC from milk samples of vaccinated does over the trial showed a tendency to be lower than that of nonvaccinated controls (1274 x 103/ml vs. 1529 x 103/ml, respectively) (P < 0.10). In addition, bulk tank SCC averaged for the 5 pre-vaccination sampling dates was 1293 x 103/ml, and for the 14 post-vaccination dates, SCC averaged 1052 x 103/ml. The freezing of milk samples had no deleterious effect on determining SCC. Results support the continued study of mastitis vaccines for use in managing staphylococcal mastitis and SCC in dairy goats.

This investigation evaluated the efficacy of a bacterin in reducing the prevalence of staphylococcal mastitis and somatic cell counts (SCC) in a dairy goat herd. Does were vaccinated or left as controls, and the levels of mastitis and SCC monitored over 18 months. Staphylococcus caprae (42.5%), S. xylosus (15.1%), and S. simulans (10.0%) were the predominant causes of intramammary infections (IMI). The infection rate was 1.64 IMI/doe among vaccinates, which tended to be lower (P < 0.12) than controls (2.67 IMI/doe). The spontaneous cure rate of IMI after immunization was 1.28 cures/doe in vaccinates, which was higher than controls (0.6 cures/doe; P < 0.043). Average SCC of milk samples from vaccinates tended to be lower than that of controls (1274 × 10(3)/ml vs. 1529 × 10(3)/ml, respectively) (P < 0.10). Results support the continued study of mastitis vaccines for use in managing staphylococcal mastitis and SCC in dairy goats.

The purpose of this investigation was to evaluate the effect of an immunostimulating feed supplement (OmniGen-AF®) on the antimicrobial properties of blood leukocytes in dairy heifers in an attempt to prevent mastitis. Blood leukocytes from supplemented and unsupplemented controls were used. Phagocytic activity and reactive oxygen species (ROS) production were studied on d 0 (prior to feed supplementation) and on days 30 and 60 after supplementation. L-selectin and IL-8R mRNA expressions on blood leukocytes were evaluated on d 0 (prior to feed supplementation) and monthly thereafter for 15mo. On d 30 after supplementation, neutrophils from treated heifers exhibited greater binding and internalization of Escherichia coli and greater ROS production compared with unsupplemented controls. L-selectin mRNA expression was increased in supplemented heifers vs. controls; however, IL-8R mRNA expression was not different. Results support the continued study of dietary supplementation as an additional management tool to enhance udder health in dairy heifers.