Horizontal Transmission of Shiga Toxin-Producing Escherichia coli within Groups of Dairy Calves

To examine the dissemination of Shiga-toxigenic Escherichia coli (STEC) within cattle groups, dairy calves on two farms utilizing different calf-rearing practices were exposed to a traceable STEC strain. Test strain dissemination differed significantly between farms, with a higher prevalence being associated with group penning. Pen floors and calf hides may be the main environmental mechanisms of transmission. Dairy calf husbandry represents a control point for reducing on-farm STEC prevalence.     

Horizontal transmission of Shiga toxin-producing Escherichia coli within groups of dairy calves

To examine the dissemination of Shiga-toxigenic Escherichia coli (STEC) within cattle groups, dairy calves on two farms utilizing different calf-rearing practices were exposed to a traceable STEC strain. Test strain dissemination differed significantly between farms, with a higher prevalence being associated with group penning. Pen floors and calf hides may be the main environmental mechanisms of transmission. Dairy calf husbandry represents a control point for reducing on-farm STEC prevalence.     

Effect of bicozamycin on the eradication of Shiga toxin-producing Escherichia coli in calves

Fifty-nine calves, aged 11 days to 9 months, from three farms breeding Japanese Black beef cattle in Miyazaki Prefecture, Japan, were examined for the presence of Shiga toxin-producing Escherichia coli (STEC). A high prevalence of STEC was detected among calves, with 45 (76.3%) animals carrying STEC including different serogroups (O26, O74, O111, O114, O119, O127, O153, O157, and ONT) and toxin types. The number of STEC in the feces was estimated by a combined method involving enumeration of colony-forming units by a plate-most-probable-number (plate-MPN) technique and polymerase chain reaction for the detection of Shiga toxin genes. Fecal shedding ranged from 10(1) to 10(10) MPN/g feces. To evaluate the safety and efficacy of bicozamycin (BCM: previously named as bicyclomycin) in eradicating STEC, 30 calves carrying STEC with or without diarrhea were examined. Fifteen calves were treated orally with BCM (10 mg/kg/day) once daily for 5 days, and the other 15 were untreated. Twenty-four hours after the last dose, fecal specimens were collected from both groups to compare the number of coliforms and STEC with those before treatment. BCM-treated animals had a significantly lower number of coliforms and STEC compared to the untreated calves. The STEC eradication rate was 86.6% (13/15) in the BCM-treated group, compared to 0% (0/15) in the control group. The corresponding cure rates for diarrhea were 87.5 (7/8) and 0% (0/3), respectively. No adverse reactions were observed in the calves during treatment. It is concluded that BCM is an effective agent for the eradication of STEC in calves with or without diarrhea.     

Molecular Characterization of Shiga Toxin-Producing Escherichia coli Isolated from the Environment of a Dairy Farm

Environmental samples were taken from ground, cattle water troughs, and feeders from a dairy farm with different STEC prevalence between animal categories (weaning calves, rearing calves, and dairy cows). Overall, 23 % of samples were positive for stx genes, stx(2) being the most prevalent type. Isolates were analyzed by PCR monoplex to confirm generic E. coli and by two multiplex PCR to investigate the presence of stx(1), stx(2), eae, saa, ehxA, and other putative virulence genes encoded in STEC plasmids: katP, espP, subA, and stcE. The toxin genes were subtyped and the strains were serotyped. The ground and the environment of the rearing calves were the sites with the highest number of STEC-positive samples; however, cattle water troughs and the environment of cows were the places with the greater chance of finding stx(2EDL933) which is a subtype associated with serious disease in humans. Several non-O157 STEC serotypes were detected. The serotypes O8:H19; O26:H11; O26:H-; O118:H2; O141:H-; and O145:H- have been asociated with human illness. Furthermore, the emergent pathogen STEC O157:H- (stx(1)-ehxA-eae) was detected in the environment of the weaning calves. These results emphasize the risk that represents the environment as source of STEC, a potential pathogen for human and suggest the importance of developing control methods designed to prevent contaminations of food products and transmission from animal to person.     

Estimation of genetic parameters for young stock survival in beef x dairy crossbred calves

Young stock survival is a trait of crucial importance in cattle breeding as calf mortality leads to economic losses and represents an animal welfare issue. The aim of this study was to estimate genetic parameters and sire breeding values for young stock survival in beef x dairy crossbred calves. Two traits were analysed with a univariate animal model: young stock survival between 1 to 30 days and 31 to 200 days after birth. Breed combinations with Belgian Blue sires outperformed all other sire breeds. The lowest survival rates were found for breed combinations with Jersey dams or Blonde d’Aquitaine sires. The results showed low but significant heritabilities (0.045 to 0.075) for both survival traits. Differences in breeding values between sires ranged from −2.5% to 3.5% and from −5.4% to 4.7% survival from 1 to 30 days and 31 to 200 days, respectively. Based on these findings, we concluded that it is feasible to breed for improved young stock survival in beef x dairy crossbred calves. This will hopefully contribute to increasing the survival rate of the calves and reduce economic losses for the farmers.     

Effects of calf breed on milk production and other economic traits of Holstein dams

Production of purebred or crossbred feeder calves for beef, especially HolsteinxJapanese-Black (HxJB) and Japanese-Black (JB), from dairy cattle using artificial insemination or embryo transfer have been used widely in Japan. However, dairy farmers feel uneasy about the effects of calf breed on the economic traits of dams. In this study, those effects were investigated in 798 Holstein heifers bearing Holstein, HxJB, JB or other breed calves. The results of the least-squares ANOVA indicated the effects of calf breed to be significant for gestation length (P<0.01) and calf birth weight (P<0.01) but not for milk yield, fat yield, protein yield, peak yield, day of peak, number of artificial inseminations per pregnancy or days open. Frequency of dystocia was lower in dams bearing HxJB calves than in those bearing Holstein calves (P<0.05). There were no significant differences for frequencies of still birth, retained placenta and subsequent pregnancy. The present data suggest that the effects of calf breed do not place a serious problem on the economic traits of Holstein dams. In conclusion, it is indicated that the production of JB and HxJB feeder calves from Holstein dams does not result in a decrease in dam productivity.     

Review: passive immunity in beef-suckler calves

Colostrum-derived passive immunity is central to the health, performance and welfare of neonatal beef-suckler calves, and economics of beef-farming enterprises. Compared to dairy calves, mainly Holstein-Friesian, there is much less research carried out on passive immunity and associated factors in beef calves. Thus, this review aimed to summarise and interpret published information and highlight areas requiring further research. The transfer of immunoglobulin G1 (IgG1) from blood to mammary secretions is greater for beef × dairy cows compared to most beef breed types. Considerable between-animal variance is evident in first-milking colostrum yield and immunoglobulin concentration of beef-suckler cow breed types. First-milking colostrum immunoglobulin concentrations are similar for within-quarter fractions and for the front and rear quarters of the udder. First-milking colostrum yield is higher for beef × dairy cows than beef × beef and purebred beef breeds, and higher for multiparous than primiparous cows, but generally colostrum immunoglobulin concentration is relatively similar for each of the respective categories. Consequently, colostrum immunoglobulin mass (volume × concentration) production in beef cows seems to be primarily limited by colostrum volume. The effect of maternal nutrition during late gestation on colostrum yield is not well documented; however, most studies provide evidence that colostrum immunoglobulin concentration is not adversely affected by under-nutrition. Factors that impinge upon the duration between birth and first suckling, including dam parity, udder and teat anatomy and especially dystocia, negatively impact on calf passive immunity. Colostrum immunoglobulin mass ingested relative to birth weight post-parturition is the most important variable determining calf passive immunity. Research indicates that feeding the beef calf a colostrum volume equivalent to 5% of birth weight shortly after parturition, with subsequent suckling of the dam (or a second feed) 6 to 8 h later, ensures adequate passive immunity, equivalent to a well-managed suckling situation. Within beef-suckler cow genotypes, calf passive immunity is similar for many common beef breeds, but is generally higher for calves from beef × dairy cows. Compared to older cows, calves from younger cows, especially primiparous animals, have lower serum immunoglobulin concentrations. Most studies have shown no adverse impact of maternal dietary restriction on calf passive immunity. The prevalence of failure of passive transfer (FPT) in beef calves varies considerably across studies depending on the test used, and what cut-off value is assumed or how it is classified. The accuracy and precision of methodologies used to determine immunoglobulin concentrations is concerning; caution is required in interpreting laboratory results regarding defining colostrum ‘quality’ and calf passive immune ‘status’. Further research is warranted on colostrum-related factors limiting passive immunity of beef calves, and on the validation of laboratory test cut-off points for determining FPT, based on their relationships with key health and performance measures.     

Interactive response of the horn fly (Diptera: Muscidae) and selected breeds of beef cattle

Statistically significant differences were observed in the population density of the horn fly, Haematobia irritans irritans (L.), on different breeds of beef cattle. The European breed Chianina had a population density of horn flies generally less than or equal to 50% than that of the British cattle breeds (Angus, Hereford, Polled Hereford, and Red Poll) and another European breed (Charolais). Generally, no significant difference existed among numbers of horn flies on Hereford, Polled Hereford, and Red Poll cows in 1988 or among Angus, Hereford, Polled Hereford, and Red Poll cows in 1989. Factors other than color appeared to be involved in the selective process between the horn fly and its host. Population densities on two white European breeds (Charolais and Chianina) were significantly different on all weekly intervals except for 4 wk in both 1988 and 1989. No significant difference existed among Charolais and British breeds except during 4 wk in 1988 and 3 wk in 1989. When weaning weights of all calves were adjusted for the effects of age to 205 d, sex of calf, and age of dam, the indirect effect of the horn fly on weaning weight showed a significant linear regression. Each 100 flies per cow caused a reduction of 8.1 kg in calf weaning weight. Cows within each breed with low numbers of horn flies weaned significantly heavier calves than cows with higher numbers of horn flies.     

Isolation and characterization of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) from calves and lambs with diarrhoea in India

AIMS: To determine the prevalence and molecular characteristics of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) in calves and lambs with diarrhoea in India. METHODS AND RESULTS: Faecal samples originating from 391 calves and 101 lambs which had diarrhoea were screened for presence of E. coli. A total number of 309 (249 bovine and 60 ovine) E. coli strains were isolated. A total of 113 bovine and 15 ovine strains were subjected to multiplex polymerase chain reaction (m-PCR) for detection of stx1, stx2, eaeA and EHEC hlyA genes. STEC and EPEC belonging to different serogpoups were detected in 9.73% of calves studied. Six per cent and 26.66% of lambs studied were carrying STEC and EPEC, respectively. Majority of the STEC serogroups isolated in this study did not belong to those which have been identified earlier to be associated mainly with diarrhoea and enteritis in cattle and sheep outside India. The most frequent serogroup among bovine and ovine EPEC was O26 (40%). One of the most important STEC serogroup O157, known for certain life-threatening infections in humans, was isolated from both bovine and ovine faecal samples. CONCLUSIONS: A high percentage of STEC and EPEC belonging to different serogroups are prevalent in calves and lambs with diarrhoea in India and could be the cause of disease in them. SIGNIFICANCE AND IMPACT OF THE STUDY: The study reports, for the first time, the isolation and characterization of STEC and EPEC serogroups associated with diarrhoea in calves and lambs in India. Many STEC and EPEC strains belonged to serogoups known for certain life-threatening diseases in humans.     

BPEX Pig Health Scheme: a useful monitoring system for respiratory disease control in pig farms?

Background

Both O157 and non-O157 Shiga toxin - producing Escherichia coli (STECs) cause serious human disease outbreaks through the consumption of contaminated foods. Cattle are considered the main reservoir but it is unclear how STECs affect mature animals. Neonatal calves are the susceptible age class for STEC infections causing severe enteritis. In an earlier study, we determined that mycotoxins and STECs were part of the disease complex for dairy cattle with Jejunal Hemorrhage Syndrome (JHS). For STECs to play a role in the development of JHS, we hypothesized that STEC colonization should also be evident in beef cattle with JHS. Aggressive medical and surgical therapies are effective for JHS, but rely on early recognition of clinical signs for optimal outcomes suggesting that novel approaches must be developed for managing this disease. The main objective of this study was to confirm that mouldy feeds, mycotoxins and STEC colonization were associated with the development of JHS in beef cattle.

Results

Beef cattle developed JHS after consuming feed containing several types of mycotoxigenic fungi including Fusarium poae, F. verticillioides, F. sporotrichioides, Penicillium roqueforti and Aspergillus fumigatus. Mixtures of STECs colonized the mucosa in the hemorrhaged tissues of the cattle and no other pathogen was identified. The STECs expressed Stx1 and Stx2, but more significantly, Stxs were also present in the blood collected from the lumen of the hemorrhaged jejunum. Feed extracts containing mycotoxins were toxic to enterocytes and 0.1% of a prebiotic, Celmanax Trademark, removed the cytotoxicity in vitro. The inclusion of a prebiotic in the care program for symptomatic beef calves was associated with 69% recovery.

Conclusions

The current study confirmed that STECs and mycotoxins are part of the disease complex for JHS in beef cattle. Mycotoxigenic fungi are only relevant in that they produce the mycotoxins deposited in the feed. A prebiotic, Celmanax Trademark, acted as a mycotoxin binder in vitro and interfered with the progression of disease.     

Isolation of shiga toxin-producing Escherichia coli strains from healthy cattle of the region of Lower Silesia

The aim of the study was to determine if cattle from the region of Lower Silesia is the reservoir of shiga toxin-producing E. coli strains (STEC) and the analysis of virulence factors of isolated STEC strains. The ability of tested animal strains to shiga toxin synthesis was analysed in cytotoxicity assay in vitro on Vero cell line and then confirmed by detection of shiga toxin-encoding genes by PCR. STEC strains were isolated from 12 (15,2%) of animals examined, 21,4% of these strains were obtained from 9 of 42 calves, and 8,1% from 3 of 37 cows. Most of STEC isolated (75%) was enterohemolysin-producing. The cattle from the region of Lower Silesia is the reservoir of pathogenic for humans sorbitol-fermenting non-O157 STEC strains.     

Virulence markers and serotypes of Shiga toxin-producing Escherichia coli, isolated from cattle in Rio Grande do Sul, Brazil

AIMS: To determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) and serotypes and virulence markers of the STEC isolates from beef and dairy cattle in Rio Grande do Sul, Brazil. METHODS AND RESULTS: Faecal samples from beef cattle were collected at slaughterhouses. The isolates were submitted to colony hybridization assay with specific DNA probes for stx1, stx2 and eae genes, and serotyped for the identification of O and H antigens. Thirty-nine per cent of beef cattle surveyed harboured at least one STEC strain. Among the distinct serotypes identified, 10 were shared by both beef and dairy cattle. Most of the strains isolated harboured stx2. Genotypic and phenotypic profiles allowed the identification of 34 and 31 STEC strains, isolated from beef and dairy cattle, respectively. Serotypes O10:H14, O15:H21, O96:H21, O119:H4, O124:H11, O128:H21, O137:H-, O141:H19, O159:H42, O160:H2 and O177:H11, identified in this study, have not been previously reported as STEC isolated from cattle. CONCLUSIONS: Cattle are an important reservoir of STEC strains associated with human diseases in South America. SIGNIFICANCE AND IMPACT OF THE STUDY: Determining the prevalence, genotypic profile and serotypes of STEC strains isolated from cattle enables the prediction of possible risk for public health.     

Reasons and risk factors for beef calf and youngstock on-farm mortality in extensive cow-calf herds

Raising calves and youngstock is an essential part of beef production. High on-farm mortality (unassisted death and euthanasia) is a consequence of poor animal health and welfare, and is economically unfavourable. The present study aimed to identify the reasons and risk factors for beef calf and youngstock on-farm mortality, using registry data for the years 2013 to 2015. Cox regression models were applied for the data of four age groups: calves up to 30 days (n=21 075), calves 1 to 5 months (n=21 116), youngstock 6 to 19 months (n=22 637) and youngstock ⩾20 months of age (n=9582). We found that dystocia, small birth weight and older parity of the mother increased the mortality hazard in calves up to 30 days of age. A summer birth was a common protective factor against mortality for calves up to 30 days and calves 1 to 5 months of age, compared with birth in other seasons. Among calves 1 to 5 months old, being the offspring of a first-parity cow was associated with significantly higher risk of death compared with calves who were the offspring of third- or higher-parity cows. A high herd-level stillbirth rate was associated with higher mortality hazard. The most commonly reported reasons for calf mortality were digestive disorders and respiratory disease. According to the models of youngstock from 6 months of age, male sex was a risk factor for mortality. Cattle having more than 10% dairy breed experienced a higher mortality risk in the ⩾20 months age group. No significant differences were found across regions, herd size or different breeds in any of the calf or youngstock groups. Metabolic and digestive disorders, as well as traumas and accidents, were the most common causes of mortality in beef youngstock older than 6 months. We can conclude that in young calves, animal-level factors associated with calving had a high impact on mortality. Further, timing calving for the warmer spring months would benefit calf survivability. Further studies including complementary information about farm factors adapted across the whole youngstock period is highly needed to provide sound recommendations in reducing on-farm mortality.     

Sources of sire-specific genetic variance for birth and weaning weight in Bruna dels Pirineus beef calves

This research investigated two sources of sire-specific genetic effects on the birth weight (BWT) and weaning weight (WWT) of Bruna dels Pirineus beef calves. More specifically, we focused on the influence of genes located in the non-autosomal region of the Y chromosome and the contribution of paternal imprinting. Our analyses were performed on 8130 BWT and 1245 WWT records from 12 and 2 purebred herds, respectively, they being collected between years 1986 and 2010. All animals included in the study were registered in the Yield Recording Scheme of the Bruna dels Pirineus breed. Both BWT and WWT were analyzed using a univariate linear animal model, and the relevance of paternal imprinting and Y chromosome-linked effects were checked by the deviance information criterion (DIC). In addition to sire-specific and direct genetic effects, our model accounted for random permanent effects (dam and herd-year-season) and three systematic sources of variation, that is, sex of the calf (male or female), age of the dam at calving (six levels) and birth type (single or twin). Both weight traits evidenced remarkable effects from the Y chromosome, whereas paternal imprinting was only revealed in WWT. Note that differences in DIC between the preferred model and the remaining ones exceed 39 000 and 2 800 000 DIC units for BWT and WWT, respectively. It is important to highlight that Y chromosome accounted for ∼2% and ∼6% of the total phenotypic variance for BWT and WWT, respectively, and paternal imprinting accounted for ∼13% of the phenotypic variance for WWT. These results revealed two relevant sources of sire-specific genetic variability with potential contributions to the current breeding scheme of the Bruna dels Pirineus beef cattle breed; moreover, these sire-specific effects could be included in other beef cattle breeding programs or, at least, they must be considered and appropriately analyzed.     

The use of embryo transfer in the field for increased calf crops in beef and dairy cattle

Non-surgical transfer of one embryo to 63 previously synchronized inseminated recipients was performed on farms to induce twinning in beef and dairy cattle. All the transfers were done by technicians of A.I. centers. After calving, a twinning rate of 44.4% was achieved with no differences between beef Charolais heifers (45.4%), lactating Normande cows (42.8%) and dairy Friesian cows (45.4%). Compared with controls, the calving crop after a three-breeding-cycle period was significantly higher with recipients: 1.16 calf per treated recipient vs. 0.83 calf per control animal. It would seem that the possibility of obtaining about one-third more calves with embryo transfer could be of economical interest to increase meat production from cattle herds.     

Prevalence of Carriage of Shiga Toxin-Producing Escherichia coli Serotypes O157:H7, O26:H11, O103:H2, O111:H8, and O145:H28 among Slaughtered Adult Cattle in France

The main pathogenic enterohemorrhagic Escherichia coli (EHEC) strains are defined as Shiga toxin (Stx)-producing E. coli (STEC) belonging to one of the following serotypes: O157:H7, O26:H11, O103:H2, O111:H8, and O145:H28. Each of these five serotypes is known to be associated with a specific subtype of the intimin-encoding gene (eae). The objective of this study was to evaluate the prevalence of bovine carriers of these “top five” STEC in the four adult cattle categories slaughtered in France. Fecal samples were collected from 1,318 cattle, including 291 young dairy bulls, 296 young beef bulls, 337 dairy cows, and 394 beef cows. A total of 96 E. coli isolates, including 33 top five STEC and 63 atypical enteropathogenic E. coli (aEPEC) isolates, with the same genetic characteristics as the top five STEC strains except that they lacked an stx gene, were recovered from these samples. O157:H7 was the most frequently isolated STEC serotype. The prevalence of top five STEC (all serotypes included) was 4.5% in young dairy bulls, 2.4% in young beef bulls, 1.8% in dairy cows, and 1.0% in beef cows. It was significantly higher in young dairy bulls (P < 0.05) than in the other 3 categories. The basis for these differences between categories remains to be elucidated. Moreover, simultaneous carriage of STEC O26:H11 and STEC O103:H2 was detected in one young dairy bull. Lastly, the prevalence of bovine carriers of the top five STEC, evaluated through a weighted arithmetic mean of the prevalence by categories, was estimated to 1.8% in slaughtered adult cattle in France.     

Immune responses after oral inoculation of weanling bison or beef calves with a bison or cattle isolate of Mycobacterium avium subsp. paratuberculosis

Paratuberculosis is endemic in domestic and wild ruminants worldwide. We designed the following study to compare host immune responses and pathologic changes in beef calves and bison calves after challenge with either a cattle or bison (Bison bison) strain of Mycobacterium avium subsp. paratuberculosis. In the first part of the study, six bison and six beef calves were orally inoculated with a cattle isolate of M. avium subsp. paratuberculosis over a 2 wk period. In the second part, an additional six bison and six beef calves were similarly inoculated with a bison strain of M. avium subsp. paratuberculosis. Throughout each of the studies, blood and fecal samples were taken monthly for a 6 mo infection period. Tissue samples were obtained at necropsy for culture and histopathologic analyses. Results from this study demonstrated that bison calves were more susceptible to tissue colonization than beef calves after challenge with the cattle isolate and, conversely, that beef calves were more susceptible to the bison strain of M. avium subsp. paratuberculosis. Although lesions were minimal they were most apparent in the jejunum and distal ileum. Interferon-gamma (IFN-gamma) responses were noted in some calves by 1 mo postinoculation and were sustained longer in beef calves after challenge with the bison isolate. Antibody was not detected in either beef or bison calves during the 6 mo infection period. These results indicate that the host response to strains of M. avium subsp. paratuberculosis may differ between ruminant species.     

The impact of a leptin gene SNP on beef calf weaning weights

Prior research indicates that a SNP at position 305 of exon 2 in the leptin gene affects milk production in dairy cows. Dairy cows with at least one copy of the T allele have been shown to have higher milk production than CC cows. If that effect carries over to beef breeds, it is reasonable to expect that CT and TT beef cows will wean heavier calves than CC beef cows. We tested this hypothesis for a herd of mixed breed cows using anova. Results indicated that both crossbred CT and TT beef cows wean significantly heavier beef calves than CC crossbred beef cows. A lack of observations generally hinders detection of significance in other breeds. However, two other comparisons were found to be significant. The results suggest further investigation into the link between leptin genotype and calf weaning weights. Aside from interest to animal scientists, these results have the potential to alter mating and replacement selection decisions by cow-calf producers, given the importance of weaning weights on profitability.     

Pre-slaughter handling of cattle and Shiga toxin-producing Escherichia coli (STEC)

AIMS: The aim of the study was to monitor the shedding and transmission of generic and Shiga toxin-producing Escherichia coli (STEC) in a consignment of cattle during lot feeding. METHODS AND RESULTS: Faecal and environmental samples were tested for total E. coli and screened with PCR specific for Shiga toxin and O157 rfb. STEC were isolated using colony hybridization and characterized by serology and genotyping. STEC prevalence initially decreased after the diet shift from pasture to grain, although there were intermittent peaks in numbers of cattle shedding STEC and E. coli O157. Water troughs and soil were intermittently contaminated. Common genotypes and serotypes were isolated from animals, water and soil in the feedlot, with additional types introduced at slaughter. CONCLUSION: STEC and E. coli O157 are endemic in cattle and intermittent peaks in shedding occur. Prevention of these peaks and/or reduction in transmission is required to reduce the risk of carcass contamination during slaughter. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings contribute to the understanding of the ecology of STEC and suggest control points for reducing STEC contamination in feedlot cattle production.     

Regucalcin Expression in Bovine Tissues and Its Regulation by Sex Steroid Hormones in Accessory Sex Glands

Regucalcin (RGN) is a mammalian Ca²⁺-binding protein that plays an important role in intracellular Ca²⁺ homeostasis. Recently, RGN has been identified as a target gene for sex steroid hormones in the prostate glands and testis of rats and humans, but no studies have focused on RGN expression in bovine tissues. Thus, in the present study, we examined RGN mRNA and protein expression in the different tissues and organs of veal calves and beef cattle. Moreover, we investigated whether RGN expression is controlled through sex steroid hormones in bovine target tissues, namely the bulbo-urethral and prostate glands and the testis. Sex steroid hormones are still illegally used in bovine husbandry to increase muscle mass. The screening of the regulation and function of anabolic sex steroids via modified gene expression levels in various tissues represents a new approach for the detection of illicit drug treatments. Herein, we used quantitative PCR, western blot and immunohistochemistry analyses to demonstrate RGN mRNA and protein expression in bovine tissues. In addition, estrogen administration down-regulated RGN gene expression in the accessory sex glands of veal calves and beef cattle, while androgen treatment reduced RGN gene expression only in the testis. The confirmation of the regulation of RGN gene expression through sex steroid hormones might facilitate the potential detection of hormone abuse in bovine husbandry. Particularly, the specific response in the testis suggests that this tissue is ideal for the detection of illicit androgen administration in veal calves and beef cattle.