Effect of protein supplementation on reproductive and productive performance in <Emphasis Type="Italic">Bos indicus</Emphasis> × <Emphasis Type="Italic">Bos taurus</Emphasis> heifers raised in the humid tropics of Costa Rica

In order to evaluate the effect of protein supplementation on the productive and reproductive performance of heifers, 45 Bos indicus × Bos taurus heifers, 673 ± 146 days of age and weighing about 340 kg, were divided into two groups. The control group (n = 23) continued without supplementation, but the supplemented group (SG; n = 22) received concentrate at a rate of 1% BW kg per day. Animals were adapted to the concentrate over a 15-day period and then supplemented for 30 days, after which estrus was synchronized using a progesterone implant. Back fat thickness (BFT) was assessed by ultrasound. The SG had better average daily weight gain than the nonsupplemented group (0.63 ± 0.16 vs. 0.51 ± 0.13 kg/day, P < 0.05) and tended to show a better percentage ovulation (P < 0.10, 77% vs. 57%, respectively). However, this tendency was not reflected in the final pregnancy rates. No differences were observed between groups in dry matter intake and body condition scores. SG with a high BFT (>0.70 cm) showed a better ovulation percentage than those with low BFT (<0.69 cm; P < 0.01). Additionally, the pregnancy rate of supplemented heifers with high BFT tended to be better than heifers with low BFT in this same group (67% vs. 30%, respectively, P < 0.10). It is concluded that protein supplementation improved reproductive performance and that ultrasonography to measure BFT may be used to estimate reproductive performance.     

The effect of the control of endo- and ectoparasites on weight gains in crossbred cattle (<Emphasis Type="Italic">Bos taurus taurus</Emphasis> × <Emphasis Type="Italic">Bos taurus indicus</Emphasis>) in the central region of Brazil

Endo- and ectoparasite infections are among the most important causes of disease and production losses in beef cattle in tropical and subtropical regions. Nevertheless, most treatments are given without epidemiological information and without evaluating their effect on the development of the animals. In this work we present the results of a study of the effect of treatments against endo- and ectoparasites in crossbred steers, during three cycles of field trials in the Brazilian Cerrado region. Three anthelmintic treatments during the winter and three acaricidal treatments during the spring/summer provided significant additional weight gain in three and two experimental trials, respectively. In the trials, steers treated for gastrointestinal nematodes gained a mean of 33 kg more and those treated for ectoparasites had additional mean weight gains of 13 kg compared with non-treated steers.     

Doxycycline treatment for <Emphasis Type="Italic">Dirofilaria immitis</Emphasis> in dogs: impact on <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> and <Emphasis Type="Italic">Enterococcus</Emphasis> antimicrobial resistance

Doxycycline is an antibiotic that, in addition to the classic antibacterial use, is also prescribed to fight parasitic diseases, like heartworm disease in dogs. Despite the concern that the overuse of this antibiotic may decrease susceptibility of clinically important bacteria, the consequences of the prolonged doxycycline therapy in heartworm-infected dogs have never been studied before. We have analyzed the impact of this therapy on Staphylococcus aureus and Enterococcus antimicrobial resistance. In this study, 17 heartworm-infected dogs (10 that had completed the doxycycline treatment and 7 dogs that had not yet begun) were included. Twenty-four isolates of Staphylococcus aureus were obtained from two locations of each dog. After treatment, 73.3% of isolates were resistant to at least one antibiotic but only 22.2% of isolates before treatment. Most of doxycycline resistant isolates were obtained from dogs that have received treatment. Erythromycin resistance or intermediate susceptibility was detected in 45.6% of isolates, most of them from dogs after treatment. For Enterococci, 48 isolates were obtained from fecal samples (25 before treatment and 23 after treatment). Before treatment, 32% of isolates were resistant at least to one antibiotic while after, this data increase up to 65%. Comparing isolates before and after treatment, a clear increase in resistance to doxycycline (12% against 21.74%) and erythromycin (20% against 39.13%) was observed. Although the present work is a preliminary research, the results encourages the development of further studies to determinate the effect of prolonged doxycycline therapy on antimicrobial resistance.     

Seroprevalence of antibodies to <Emphasis Type="Italic">Neospora caninum</Emphasis> in <Emphasis Type="Italic">Bos javanicus</Emphasis> (‘Bali cattle’) from Indonesia

A cross-sectional survey was performed to obtain first information on the presence of Neospora caninum infection in Bos javanicus (‘Bali cattle’), the predominant beef cattle in the Eastern Islands of Indonesia. Serum samples were collected from 438 Bali cattle of two age classes (<2 years, >2 years) and both genders at three slaughterhouses in the Bali island, and examined for N. caninum-specific antibodies using native NcSRS2 (p38 antigen) as an ELISA antigen. The estimated overall seroprevalence of antibodies was 5.5% (95% CI: 3.5–8.0%). The seroprevalence was not significantly associated with age class or gender of the animals. The results give first serological evidence for the presence of natural N. caninum infection in Bos javanicus and indicate its occurrence in Indonesia.     

Molecular detection of <Emphasis Type="Italic">Chlamydophila abortus</Emphasis>, <Emphasis Type="Italic">Coxiella burnetii</Emphasis>, and <Emphasis Type="Italic">Mycoplasma agalactiae</Emphasis> in small ruminants’ aborted fetuses in southern Iran

Abortion in sheep and goats has become increasingly important worldwide because of the significant economic losses and potential zoonotic implication of commonly involved pathogens. Therefore, this cross-sectional study was conducted in southern Iran to detect the Chlamydophila abortus and Coxiella burnetii, as zoonotic pathogens, and Mycoplasma agalactiae, as a neglected abortifacient agent in small ruminants’ aborted fetuses, by using polymerase chain reaction (PCR). From a total of 300 aborted fetuses (183 sheep and 117 goats), 46 samples (15.5%) were positive by PCR, 11% for C. abortus, 2% for C. burnetii, and 3% for M. agalactiae. Also, the association of suggested risk factors with abortion due to these bacterial agents was investigated using univariable and multivariable logistic regression. Results of the statistical analysis showed significant association of C. abortus with flock size (OR?=?2.82, P?=?0.014), season (P?<?0.05), and the number of pregnancy in the aborted dam (OR?=?2.5, P?=?0.05). Our results indicated that C. abortus has a relatively substantial role in small ruminant abortions, and C. burnetii and M. agalactiae are likely important abortifacient agents in our region, too. Regarding veterinary and/or public health importance of these bacterial agents, more attention from veterinary and/or human health services and, maybe, a surveillance system for control and prevention of them are recommended.     

Human–animal interaction,stress, and embryo production in <Emphasis Type="Italic">Bos indicus</Emphasis> embryo donors under tropical conditions

This study investigated the effect of human–animal interaction (HAI) and the stress response on the quality of embryo production in superovulated Nelore (Bos indicus) cattle, under tropical conditions. Thirty-two females underwent a superovulation protocol for 5 days. Cortisol concentrations were determined in blood plasma collected on days 0, 4, and 5. Artificial insemination was performed on days 4 and 5, and nonsurgical embryo flushing on day 11. Embryo production and viability were determined. Human stimulation, animal behaviors, accidents, and handling time were recorded to assess HAI. Cattle age was negatively correlated with accidents, frequency of aversive behaviors, and negative stimuli by stockperson during transit through corral compartments to receive superovulation treatments. The factor analysis revealed two distinct groups. The first group was called stressed and had higher cortisol concentration than the nonstressed group, 16.0 ± 2.1 and 12.5 ± 1.0 ng/mL, respectively. Comparisons between these groups showed that the frequency of voice emissions by the stockperson and the number of accidents were higher in the stressed group, and also, the mean handling time was longer in the stressed group than for the nonstressed. As a result, viability rate of the embryos was 19% lower in the stressed group (P < 0.05). This indicates that intensive negative HAI is likely related to stress, which affects embryo production in a superovulation program.     

‘Nano-immuno test’ for the detection of live <Emphasis Type="Italic">Mycobacterium avium</Emphasis> subspecies <Emphasis Type="Italic">paratuberculosis</Emphasis> bacilli in the milk samples using magnetic nano-particles and chromogen

Early rapid detection of Mycobacterium avium subspecies paratuberculosis (MAP) bacilli in milk samples is the major challenge since traditional culture method is time consuming and laboratory dependent. We report a simple, sensitive and specific nano-technology based ‘Nano-immuno test’ capable of detecting viable MAP bacilli in the milk samples within 10 h. Viable MAP bacilli were captured by MAP specific antibody-conjugated magnetic nano-particles using resazurin dye as chromogen. Test was optimized using true culture positive (10-bovine and 12-goats) and true culture negative (16-bovine and 25-goats) raw milk samples. Domestic livestock species in India are endemically infected with MAP. After successful optimization, sensitivity and specificity of the ‘nano-immuno test’ in goats with respect to milk culture was 91.7% and 96.0%, respectively. Whereas, it was 90.0% (sensitivity) and 92.6% (specificity) with respect to IS900 PCR. In bovine milk samples, sensitivity and specificity of ‘nano-immuno test’ with respect to milk culture was 90.0% and 93.7%, respectively. However, with respect to IS900 PCR, the sensitivity and specificity was 88.9% and 94.1%, respectively. Test was validated with field raw milk samples (goats-258 and bovine-138) collected from domestic livestock species to detect live/viable MAP bacilli. Of 138 bovine raw milk samples screened by six diagnostic tests, 81 (58.7%) milk samples were positive for MAP infection in one or more than one diagnostic tests. Of 81 (58.7%) positive bovine raw milk samples, only 24 (17.4%) samples were detected positive for the presence of viable MAP bacilli. Of 258 goats raw milk samples screened by six diagnostic tests, 141 (54.6%) were positive for MAP infection in one or more than one test. Of 141 (54.6%) positive raw milk samples from goats, only 48 (34.0%) were detected positive for live MAP bacilli. Simplicity and efficiency of this novel ‘nano-immuno test’ makes it suitable for wide-scale screening of milk samples in the field. Standardization, validation and re-usability of functionalized nano-particles and the test was successfully achieved in field samples. Test was highly specific, simple to perform and easy to read by naked eyes and does not require laboratory support in the performance of test. Test has potential to be used as screening test to estimate bio-load of MAP in milk samples at National level.     

Sapogenin Levels in <Emphasis Type="Italic">Narthecium ossifragum</Emphasis> Plants and <Emphasis Type="Italic">Ovis aries</Emphasis> Lamb Faeces during Two Alveld Outbreaks in Møre og Romsdal,Norway, 2001

The proposal that saponins produced by the lily bog asphodel (Narthecium ossifragum) may be the direct cause of the hepatogenous photosensitization disease alveld seen in Norwegian lambs was investigated by comparing sapogenin levels in two control and two toxic pastures, and in faeces from lambs grazing the four pastures in the Halsa and Surnadal municipalities, Møre og Romsdal county, Norway. Generally similar levels of sapogenins, determined after hydrolysis of parent plant saponins, were found in Narthecium leaves collected in June/July 2001 from the two alveld outbreak areas and two nearby control areas. Differences in the median sapogenin levels determined for leaf samples in outbreak and control areas were not statistically significant. The total level of free and conjugated sapogenins in faeces recovered from the rectums of lambs grazing the outbreak and control pastures areas varied greatly. The results obtained do not support the hypothesis that a dose–response relationship exists between Narthecium saponin levels and the occurrence of alveld outbreaks.     

Feeding <Emphasis Type="Italic">Moringa oleifera</Emphasis> fresh or ensiled to dairy cows—effects on milk yield and milk flavor

Moringa oleifera, either fresh or ensiled, was compared with Elephant grass as a main feedstuff for dairy cows. To test the effects feed had on milk yield, milk composition, ration digestibility, and the organoleptic characteristics of milk, six lactating dairy cows were used in a Changeover 3 × 3 Latin Square experiment, replicated twice. With equal intake of metabolizable energy the intake of protein and fiber differed (p < 0.001) between all diets where fresh Moringa had the highest and the Elephant grass diet had the lowest intake. Compared with the control diet, ensiled Moringa had higher digestibility (P < 0.05) of both protein and fiber. With the exception of DM digestibility, no digestibility differences were found between fresh Moringa and Moringa silage treatments. Milk yield did not differ between any of the treatments and averaged 13.7 kg cow day⁻¹. Milk composition was similar among all treatments. Milk from the fresh Moringa treatment, however, had a grassy flavor and aroma, significantly different from the other two treatments, even though it was normal in color and appearance. No organoleptic differences were found between milk from the control treatment and the Moringa silage treatment. The conclusion is that Moringa silage can be fed to dairy cows in large quantities to produce the same quantity and quality of milk as traditional diets.     

Do camels (<Emphasis Type="Italic">Camelus dromedarius</Emphasis>) play an epidemiological role in the spread of Shiga Toxin producing <Emphasis Type="Italic">Escherichia coli</Emphasis> (STEC) infection?

In the present work, faecal and serum samples from 400 camels were investigated for the presence of Shiga Toxin producing E.coli (STEC) and Anti-Shiga Toxin (Anti-Stx) antibodies, respectively. The used samples were obtained from adult male camels of five east African countries (Egypt, Somalia, Djibouti, Kenya and Sudan) between the years 2002-2004. One E.coli isolate per camel was randomly selected to be cultured on Gassner, Chromocult and sorbit agar for the detection of O157:H7 strains. In the same time, a Stx-specific PCR screening was performed for the isolates using the shiga toxin specific primers Mk1-Mk2. Vero cells were also used for shiga toxin neutralization assay. None of the investigated isolates reacted positively with the Stx-specific primers. Also, none of the studied sera could neutralize the Stx on tissue culture. The obtained results indicate that camels do not play any significant epidemiological role in STEC infection and transmission. The possible reasons for the absence of STEC in the investigated samples are discussed in brief.     

Experimental Infection of Pigs with ‘<Emphasis Type="Italic">Candidatus</Emphasis> Helicobacter suis’

‘Candidatus Helicobacter suis’ is a spiral-shaped bacterium that colonizes the stomach of more than 60% of slaughter pigs. The role of ‘Candidatus Helicobacter suis’ in gastric disease of pigs is still unclear. Experimental studies in pigs are lacking because this bacterium is unculturable until now. An inoculation protocol using ‘Candidatus Helicobacter suis’ infected mouse stomach homogenate was used to reproduce the infection in pigs. Control animals were inoculated using negative mouse stomach homogenate. Pigs were inoculated three times with one-week intervals and euthanized 6 weeks post inoculation. Tissue samples were taken from different mucosal stomach regions to detect ‘Candidatus Helicobacter suis’ by PCR and urease test. Mucosal inflammation was evaluated on formalin-fixed tissue samples. Lesions in the pars oesophagea were scored macroscopically. Infection was succesful in all challenged animals, with the antrum and the fundus being predominantly positive. Infection was associated with infiltration of lymphocytes and plasma cells in the antral mucosa, evolving to follicular gastritis. No apparent inflammation of the fundic stomach region was detected in the infected animals. A clear link between ‘Candidatus Helicobacter suis’ and pars oesophageal lesions could not be found.     

Comparative study on responses of cattle and water buffalo (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) to experimental inoculation of <Emphasis Type="Italic">Brucella abortus</Emphasis> biovar 1 by the intraconjunctival route—a preliminary report

The preliminary study was conducted to assess the virulence of a strain of Brucella abortus (1969D) and to compare the susceptibility of water buffalo and cattle calves to infection by the intraconjunctival route. Seven of each cattle and water buffalo (Bubalus bubalis) calves aged 3–6 months were inoculated intraconjunctivally with counts ranging from 1.5 × 10⁷ to 1.7 × 10¹⁰ colony forming units of B. abortus. Animals were monitored over an 8-week period for clinical manifestations and serological and hematological evidence of infection. At slaughter, eight lymph nodes from each animal were sampled for bacteriological and histopathological assessments. Lymph nodes from three water buffalo (43%) and five cattle (71%) yielded B. abortus (P = 0.048). Parotid/prescapular lymph nodes were most sensitive in detecting B. abortus. Our data suggest that B. abortus strain 1969D may be used as challenge strain, and water buffalo appeared to have a lower susceptibility to B. abortus infection than cattle.     

Animal production and genetic resources in Guinea Bissau: I – Northern <Emphasis Type="Italic">Cacheu</Emphasis> Province

A survey of the animal production systems and genetic resources was conducted in Northern Cacheu Province, Guinea Bissau. Animal owners and their families, village chiefs, shepherds and local officials were interviewed. The vast majority of the population is dedicated to very small-scale subsistence farming where animal ownership has an important role in both food supply, ceremonial events and as form of cash reserve. Cattle (N'Dama and West African Shorthorn breeds) are owned by the two larger ethnic groups in the area, the Felupes and the Balantas that have however different management practices. Sheep are relatively scarce whereas goats (West African Dwarf) are the most important small ruminant species for both ethnic groups. Pigs (crioulo breed) and dwarf chickens play a very important role as they are the only species regularly used in trade at the village level.     

Epidemiological investigation of <Emphasis Type="Italic">Borrelia burgdorferi</Emphasis> in horses in the municipality of Sinop—MT,Brazil

Borrelia burgdorferi sensu stricto is the main etiological agent of Lyme disease (LD) in the USA. In Brazil, it is believed that a similar spirochete is the causal agent of the Baggio–Yoshinari syndrome (BYS), a zoonosis also transmitted by ticks, whose clinical manifestations are similar to those of LD. Despite the epidemiological importance, there are no studies reporting the presence and the prevalence of B. burgdorferi among horses in Mato Grosso State. The aim of this study was to detect and measure the frequency of IgG antibodies anti-B. burgdorferi American strain G39/40 in horses in the municipality of Sinop, MT—Brazil, using the indirect enzyme-linked immunosorbent assay (ELISA) for serological diagnosis. Blood samples from 367 horses were collected in 81 farms. An epidemiological questionnaire was applied during the visits to obtain information related to the animals and the farms. From the 367 horses, 214 were positive for B. burgdorferi sensu stricto according to the results of the ELISA test, representing an apparent prevalence of 54.04% [CI?=?0.4548051–0.6237234]. Concomitantly, 89 blood samples were taken for molecular analysis by nested polymerase chain reaction (PCR). According to the PCR test results, none of the samples were reactive, although 53 of these samples were reactive according to ELISA. Seventy five farms (92.59%) had at least one reactive horse for B. burgdorferi. Our results support the hypothesis of the presence of anti-Borrelia spp. antibodies in horses in Mato Grosso, reaching a high animal prevalence. Besides that, leisure/sport purposes proved to be a risk factor, with an odds ratio of 3.16. These findings clearly indicate the need of borreliosis control in Sinop and make a significant contribution to the knowledge of the disease in Mato Grosso.     

Panton–Valentine leukocidin and some exotoxins of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> and antimicrobial susceptibility profiles of staphylococci isolated from milks of small ruminants

The aims of this study were to determine the existence of pvl gene, some toxin genes, and mecA gene in Staphylococcus aureus strains isolated from sheep milk and to examine antimicrobial resistance profiles in staphylococci from sheep and goats' milk. The milk samples were collected from 13 different small ruminant farms in Kirikkale province from February to August 2009. A total of 1,604 half-udder milk samples from 857 ewes and 66 half-udder milk samples from 33 goats were collected. Staphylococcus spp. were isolated and identified from the samples. Toxin genes and mecA gene among S. aureus strains were determined by PCR. Antimicrobial susceptibility of staphylococci was examined by the disk diffusion method on Mueller-Hinton agar, and interpreted according to the Clinical Laboratory Standards Institute (CLSI) guidelines. The prevalence of subclinical intramammary infection in both ewes and goats was 5.2%. The most prevalent subclinical mastitis agents were coagulase-negative staphylococci and S. aureus with prevalences 2.8% (n:46) and 1.3% (n = 21), respectively. The prevalence of resistances in isolated Staphylococcus spp. to penicilin G, tetracycline, erythromycin, gentamicin, and enrofloxacin were found as 26.9% (18), 7.5% (5), 6.0% (4), 3.0% (2), and 1.5% (1), respectively. Only 3 of the 21 S. aureus ewe isolates (13.4%) were shown to harbor enterotoxin genes being either seh, sej or sec. However, fourteen (66.6%) of the 21 S. aureus isolates had pvl gene while none of the isolates harbored mecA gene. In conclusion, Staphylococci were shown to be the most prevalent bacteria isolated from subclinical mastitis of ewes and goats and these isolates were susceptible to most of the antibiotics. In addition, S. aureus strains isolated from ewes were harboring few staphylococcal enterotoxin genes. However, Panton–Valentine leukocidin produced by S. aureus could be an important virulence factor and contribute to subclinical mastitis pathogenicity.     

Cross-sectional survey of brucellosis and associated risk factors in the livestock–wildlife interface area of <Emphasis Type="Italic">Nechisar</Emphasis> National Park,Ethiopia

A cross-sectional survey was carried out to investigate the seroprevalence of ovine and bovine brucellosis in the livestock–wildlife interface area of Nechisar National Park, Ethiopia. Furthermore, producer’s knowledge about brucellosis and its zoonotic potential was assessed using a structured questionnaire. A total of 268 cattle and 246 goat sera were collected from 50 herds and 46 flocks and subjected to Rose Bengal test (RBT) and enzyme-linked immunosorbent assay (ELISA) in parallel to detect anti-Brucella species antibodies. Positive reactions were further confirmed with compliment fixation test (CFT). Flock and herd level seroprevalence rate was 12.8% (95% CI 4.8–25.7) and 32.0% (95% CI 19.5–46.7) in goats and cattle, respectively. An overall animal-level seroprevalence of 4.5% (95% CI 2.25–7.86) and 9.7% (95% CI 6.44–13.89) was recorded for goats and cattle, respectively. Seroprevalence showed an increasing trend with age, where adult cattle >?2 years. Goats (>?1 year) recorded relatively higher seroprevalence, but the differences were not statistically significant. Similarly, female cattle and goats recorded a relatively higher seroprevalence, 11 and 5.6%, respectively, compared to males but the difference was not significant. However, a significant (P <?0.01) variation of seroprevalence was noted for parity (bovine), higher in animals in second parity, and abortion history, in both species, higher in animals that experienced abortion. Interviews revealed lack of awareness about brucellosis and food safety related to the zoonotic potential from consuming raw animal products (milk and meat). Ninety-eight percent of respondents did not consider handling abortion material is risky, and only a very low proportion (8%, n?=?50) was able to mention limited zoonotic diseases (anthrax and Taenia cysticercosis) could be transmissible to people. The study indicated that brucellosis is endemic in domestic animals in the interface area and calls for further broad epidemiological investigation of the disease in livestock, human and wildlife following ‘one health’ unified research approaches beside enhancing public awareness.     

Endemic status of <Emphasis Type="Italic">Trypanosoma evansi</Emphasis> infection in a horse stable of eastern region of India – a field investigation

Diagnosis of Trypanosoma evansi infection in a horse stable of Eastern Region of India on the basis of examination of Giemsa stained blood smears have been done. A high percentage (12.74%) of horses of this stable was found suffering from T. evansi infection. This high prevalence of T. evansi in horses, in this area could be considered as an alarming situation which has never been explored previously in horses of Eastern Region of India. After a period of 2 months and 18 days of treatment with quinapyramine sulphate and quinapyramine chloride, reinfection with T. evansi in treated horses of this stable were noticed. Clinical signs of affected horses and possible causes of reinfection have been discussed.     

The effect of a <Emphasis Type="Italic">β</Emphasis>-mannanase-based enzyme on growth performance and humoral immune response of broiler chickens fed diets containing graded levels of whole dates

The use of low-quality whole dates in broilers’ diets was evaluated. The apparent metabolizable energy (AMEn) of whole dates and date pits was determined with or without a β-mannanase-based enzyme (Hemicell – a registered trademark of ChemGen Corp., Gaithersburg, MD. Dried Bacillus lentus fermentation solubles with 158 million units/kg minimum enzyme activity. Recommended usage rate is 0.4 g kg⁻¹ of feed. ChemGen Corp., Gaithersburg, MD, USA). A 3 × 2 factorial arrangement consisting of whole dates (0, 175, and 350 g kg⁻¹) and enzyme (0 or 0.4 g kg⁻¹) was performed to assess the effect of the enzyme on the nutritive value of whole dates (experiment 2) in broilers’ diet. Enzyme improved AMEn contents of the whole dates and date pits. The diets containing 175 or 350 g kg⁻¹ whole dates produced body weight gain (BWG) similar to those obtained without dates. Enzyme improved BWG and feed conversion ratio throughout the experimental period. In conclusion, whole dates can be included in broiler diets at levels up to 350 g kg⁻¹. In addition, β-mannanase supplementation would have beneficial effects on performance and immunity in birds fed on corn–soy or corn–soy–whole dates diets.     

Interleukin-1β infusion in bovine mammary glands prior to challenge with <Emphasis Type="Italic">Streptococcus uberis</Emphasis> reduces bacterial growth but causes sterile mastitis

Dairy cows are especially vulnerable to intramammary infection by the bacterial pathogen Streptococcus uberis in the dry period. Use of immunotherapeutic agents at drying off could increase cellular defences in the gland and prevent establishment of new S. uberis infections. This study investigated the potential of infusing recombinant bovine interleukin-1 beta (rbIL-1beta) in the mammary glands as a prophylactic agent against subsequent intramammary challenge with S. uberis in the early dry period. Immediately after the last milking at commencement of the dry period, one cow from each of 10 monozygous twinsets was infused with 10 microg of rbIL-1beta in two quarters and the other twin was infused with the carrier agent, sterile phosphate buffered saline. Twenty-four hours later, the quarters were infused with 10(3) colony-forming units (CFU) of S. uberis. Bacteriology, somatic cell count (SCC), concentrations of specific cytokines and antibody responses were monitored in mammary gland secretions and sera for the next 21 days. Infusion of rbIL-1beta into mammary glands at commencement of the dry period was associated with less new S. uberis intramammary infections, as determined by the number of quarters with bacterial growth. However, high SCC in quarters following infusion of rbIL-1beta masked the full beneficial effect of this procedure.