Veterinary and Animal Science最新文献

Enzootic Bovine Leukosis (EBL), caused by the bovine leukosis virus (BLV), is a global infectious disease affecting livestock. This study focuses on studying the frequency and genetic traits of BLV in three Creole breeds including Chino Santandereano (Chino), Casanareño (CAS), and Sanmartinero (SM) in Eastern Colombia. We implemented a cross-sectional survey between 2019 and 2020 across four departments (Arauca, Casanare, Santander and Meta) in Eastern Colombia to assess the molecular characteristics of BLV infection in these breeds. A total of 253 cattle were analyzed, of which 42.6 %, 28.8 %, and 28.4 % belonged to the Chino, CAS, and SM breeds, respectively. BLV provirus was detected using nested polymerase chain reaction (n-PCR) targeting the conserved region of the env viral gene. Subsequently, the obtained amplicons were sequenced and subjected to phylogenetic analyses. The overall BLV infection frequency was 26.48 % (95 % CI: 21.01 – 31.98 %), with Chino exhibiting the highest frequency (35.1 %) following by SAM and CAS, respectively (P < 0.05). Other epidemiological variables associated with the infection included age, department, and season (P < 0.05). BLV-positive animals exhibited elevated levels of total serum proteins (P < 0.05), while molecular characterization revealed the exclusive circulation of BLV genotype 1 within these breeds. This study provides an updated assessment of BLV infection in Creole breeds from the eastern of Colombia, underscoring their lower infection frequency compared to introduced breeds and their reduced susceptibility to developing clinical signs. The epidemiological and molecular characteristics observed should be considered in developing control programs aimed at improving genetic resistance to BLV in Colombian cattle.

Horses can become obese and develop related health issues such as laminitis from excessive grazing on high-quality pasture grass; limiting pasture intake can allow weight loss to occur. The objective of this study was to determine the effect of space-restricted rotational grazing on body weight (BW) and time budgets in horses. Eight mature geldings and mares with maintenance-only requirements were randomly assigned to either a space-restricted rotational grazing group (SRG; BW 512 ± 6 kg; n = 4) or a continuous grazing group (CG; BW 517 ± 49 kg; n = 4) for 42 d SRG horses grazed an area with dimensions to provide 80–90 % of mean digestible energy requirement for the 4 horses over a 7-d grazing period; whereas, the CG horses continuously grazed similar non-toxic endophyte-infected tall fescue pasture providing greater than maintenance requirements for the 42 d Horses in the SRG group were moved to a new area every 7 d for 6 weeks. On d 7 at 1600 h of each week, horses were brought inside, and feed was withheld overnight. At 0700 h the next day, BWs were recorded prior to turnout. Observers recorded behaviors simultaneously on SRG and CG horses every six minutes throughout the day three days per week according to an ethogram. This included 30 s scans of all horses. Proportion of grazing and standing had an inverse relationship. Proportion of grazing was affected by the treatment by time interaction, which grazing was displayed more in SRG than CG during weeks 2 and 3, and then reversed weeks 4, 5 and 6.

The objective of this study was to investigate the effects of feeding cow's milk replacer and probiotic supplementation on growth performance, blood metabolites, ruminal fermentation parameters, and nutrient digestibility in male lambs, with ewe's milk serving as the control treatment. Eighteen male lambs with an average initial body weight of 5.0 ± 1.2 kg and age of 15 ± 4 days were randomly assigned to three experimental groups: ewe's milk, cow's milk replacer, and cow's milk replacer with probiotic supplementation. The experiment was conducted using a completely randomized design. Lambs fed ewe's milk showed significantly higher average daily gain (218.4 g/day) compared to those fed cow's milk replacer (183.7 g/day) or cow's milk replacer with probiotic (209.1 g/day). Similarly, dry matter intake was highest in the ewe's milk group (585.6 g/day) compared to the cow's milk replacer (435.9 g/day) and cow's milk replacer with probiotic (510.5 g/day) groups. Blood glucose levels were higher in the ewe's milk group (75.3 mg/dL) compared to the cow's milk replacer (70.3 mg/dL) and cow's milk replacer with probiotic (72.1 mg/dL) groups. Probiotic supplementation resulted in increased blood urea nitrogen (15.6 mg/dL) and total protein (7.3 g/dL) levels compared to the other groups. Furthermore, the ewe's milk group showed higher apparent dry matter (76.1%) and crude protein (68.5%) digestibility compared to the other treatments. The fecal score on day 30 was higher in the cow's milk replacer group (2.34) compared to the ewe's milk (1.24) and cow's milk replacer with probiotic (1.45) groups. There were no significant differences in the carcass traits of the experimental lambs. In conclusion, based on the results of this study, it seems that feeding cow's milk + probiotic as a replacement for ewe's milk did not significantly affect the performance, carcass traits, and blood and fermentation parameters in infant lambs.

The study aimed to assess the digestibility, growth performance, and selected biochemical and hematological parameters of Bandjock Local pigs (BLP) and Duroc X Large White pigs (DLW). We hypothesize that the use of local ingredients in diet formulation associated to improved rearing conditions, enhance the growth performance, digestibility, biochemical and hematological parameters of BLP. The trial involved dividing twenty-four eight-week-old weaner pigs into two groups. Each group was randomly assigned to separate pig units. Animal management and feeding were consistent between both groups. The trial lasted for 120 days during which the growth performance, the digestibility of ingested nutrients, and biochemical and hematological parameters were evaluated. The results indicate that DLW pigs registered a weight gain (46.56±5.19 kg) significantly higher than BLP pigs (34.02), with a statistically similar feed conversion ratio. Except for albumin which was significantly higher in DLW and urea in BLP, there were no significant differences (p > 0.05) in total protein, cholesterol, globulin, triglycerides, creatinine, AST, and ALT as well as hematological parameters between the breeds. However, the exotic DLW had a relatively high mean blood platelets and white blood cell concentration. Although the fecal nitrogen was higher in BLP and the urinary nitrogen was lower in the DLW, there were significant differences (p < 0.05) for urine, fecal, and total excreted nitrogen in both breeds. The lowest scores in nutrient digestibility were recorded with BLP compared to DWL, except for crude fibers. The results of this study demonstrated that using diet formulated with local ingredients and improved rearing conditions, Cameroonian local indigenous pigs have a better productivity compared to exotic breeds. It suggests that efforts should be made by authorities to promote and valorize the rearing of indigenous pigs in complement to exotic pig breeds in view of strengthening the Cameroonian pig industry.

Q fever is a zoonosis whose main reservoirs are domestic ruminants. Surveillance in these species is carried out mainly with serological tests, which, however, have limited diagnostic performance, and their manufacturing requires laboratories equipped with high biosafety requirements for antigen production. Recombinant ELISAs do not depend on these requirements and, being based on a single antigen, can reduce potential false positivity by identifying antibodies specific to a phase of infection. The aim of this study was to apply a new technology (dual antigen test) to a recombinant protein (Ybgf), an antigen produced in recombinant form and already used in previous studies for the design of an indirect ELISA. The successfully produced recombinant antigen was used to coat 96-well plates and, at the same time, another antigen aliquot was conjugated with HRP to obtain an HRP-conjugated Ybgf. After setting the test conditions, the results obtained with the recombinant double antigen test were compared with those obtained with a commercial assay (considered as reference assay) testing a total of 514 ruminant samples (280 goats and 234 cattle). A concordance of 86.2 and a Cohen's Kappa value of 0.72 were obtained, with no significant difference between the two species tested. Notably, the test proved to be highly specific, having correctly identified 250 out of 253 animals. This research represents an additional effort to use recombinant antigens to enhance serological methods in veterinary medicine. In a “one-health scenario”, improving the performance of serological tests used in veterinary practice also means improving the surveillance of this infection.

The emergence of Salmonella enterica serovars that produce extended-spectrum beta-lactamase and exhibit multi-drug resistance (MDR) poses a substantial global threat, contributing to widespread foodborne illnesses and presenting an alarming issue for public health. This study specifically concentrated on the isolation and identification of ESBL-resistant genes (bla_TEM, bla_SHV, bla_CTX-M1, bla_CTX-M2, bla_CTX-M9, MultiCase_ACC, MultiCase_MOX, MultiCase_DHA, bla_OXA) and the antibiogram profiling of Salmonella enterica serovars found in goat meat samples procured from retail outlets in Bangladesh. During the research in the Sylhet district of Bangladesh, researchers gathered a total of 210 samples of goat meat from 13 different Upazilas. Primarily, cultural and biochemical methods were used for isolation of bacteria from the selected samples. Salmonella enterica serovars Typhimurium and Enteritidis, along with three ESBL-resistant genes, were identified through polymerase chain reactions (PCRs). The disk diffusion test was used to determine antimicrobial susceptibilities. Out of 210 samples analysed, Salmonella spp. was detected in 18.10 % (38 out of 210), with S. Enteritidis and S. Typhimurium found in 9.05 % (19 out of 210) and 5.24 % (11 out of 210) of the samples, respectively. A total of 72.73 % (8/11) of S. Enteritidis and 100 % (19/19) of S. Typhimurium isolates were positive by Multidrug-resistant patterns. The positive outcomes were found of S. Typhimurium tested 63.16 % (12 out of 19) for the bla_TEM gene and 21.05 % (4/19) for the bla_SHV, gene. The study proposes that the retail goat meat market channel could be a prominent transmission way of ESBL-producing MDR Salmonella enterica serovars, representing a significant public health hazard.

Heat stress (HS) occurs when animals are enable to effectively dissipate excessive body heat, potentially affecting their welfare and productivity. Several tools can be used to mitigate HS in dairy cows. The aim of this study was to evaluate the effect of thermoregulatory mineral supplementation on dairy cows’ physiological response to HS and reproductive status. Thirty pluriparous Holstein dairy cows (2.8 ± 0.3 lactation), from a semi confinement production system (freestall barn), were enrolled in a 35 days duration experiment, and divided into two groups: 15 cows receiving a thermoregulatory mineral mixture containing calcium, sodium, chlorine, and potassium (200 g/day; TRT); and, 15 cows that did not receive any type of supplement (CON). Data on respiration rates (RR), rectal temperature (RT), milk yield, barn temperature, relative humidity, and temperature and humidity index (THI) were obtained on weekly evaluations (D7, D14, D21, D28, and D35). ANOVA and correlation analysis were used to compare variables between groups, and physiological and climate variables, regardless of group. Related to farm's protocols, on D0 and D35, all cows were submitted to US evaluation and categorized as inseminated, pregnant, and not pregnant, and this data analysed using Fisher's exact test. Cows in the TRT group had lower RT, compared to the CON group (38,8 °C and 39,0 °C, respectively; P = 0.0147), however both averages were within physiological range. As to physiological variables, stronger positive correlations were found between RR and RT with barn temperature and THI. In this study, the thermoregulatory mineral supplement did not significantly affect physiological responses to HS or reproductive status.

The reproductive performance of lactating dairy cows is gradually declining, and one of the causes of this problem is the presence of long-term infertility repeat breeder cows (RBCs). The causes of RBCs are largely thought to be maternal factors, including the uterine environment. This study aimed to accurately investigate the uterine environment of RBCs using uterine tissue and fluid. Next, we investigated the effect of nobiletin in bovine endometrial epithelial cells to explore the possibility of improving the uterine environment of RBCs.

Uterine fluid was collected by flushing the uterus and endometrial tissues were collected by biopsy on day 7 of the estrous cycle from both normal fertile cows and RBCs (n = 5 in each group). A comprehensive analysis of the uterus revealed that gene expression and altered pathways differed between normal fertile cows and RBCs. Especially, pathways of natural killer cell-mediated cytotoxicity, cell cycle, and calcium signaling pathway were picked up in the uterine tissues of RBCs. In the uterine fluid, the levels of lipopolysaccharide were higher in the RBC than in normal group (P = 0.08). In in vitro experiment, treatment with the uterine fluid from RBCs upregulated inflammation-related pathways and molecules such as interleukin-8 (IL-8) in bovine endometrial epithelial cells. The treatment with nobiletin suppressed IL-8 induced by the treatment with uterine fluid.

In conclusion, the uterine environment of RBCs was found to be in inflammatory condition, causing the lower reproductive performance. It is necessary to develop methods to improve to the anti-inflammatory state in the uterine environment of RBCs.

The effects of genetic factors on the lactation traits of the Azawak cattle breed are estimated from 11,998 monthly milk records from 1275 complete lactations from 471 Azawak cows bred at the Toukounous experimental centre (Niger), using a multi-trait animal model based on the REML method. The results show that heritability was moderate for persistency (h² = 0.23), peak lactation (h² = 0.34), milk yield at 305 days (h² = 0.30), daily milk yield (h² = 0.33) and total milk yield (h² = 0.35). In addition, very high repeatability estimates ranging from 0.50 to 0.58 were associated with the last four traits. Significant phenotypic correlations varying from 0.23 to 0.40 existed between the two reproductive traits (age at first calving and calving interval) and the lactation traits. Similarly, the significant genetic correlations between the traits of milk production and reproduction traits were unfavorable, varying according to the lactation traits considered from 0.32 to 0.87 for age at first calving and from 0.48 to 0.97 for calving interval, indicating that selection for milk yield only should result in a longer calving interval and a later age at first calving. Estimates of the heritability of lactation traits are moderate, as are those of many functional reproductive traits, so the genetic gain from selection on milk production traits alone would be rapid, but antagonistic with reproductive performance.

A commercial triple-strain Bacillus-based probiotic was tested to determine its effect on the colonization of the ceca by Salmonella Enteritidis (SE) in commercial layer pullets. Two treatments were tested, each with containing 128 day-of-hatch LSL layer chicks. On top of a standard diet: 1) no supplement (Control, CON), and 2) Probiotic (GalliPro® Fit, 500 g/MT, 1.6 × 10⁶ CFU/g of finished feed, PRO). Environmental swabs were collected from each treatment group and tested to ensure freedom from SE prior to challenge. At 21 days of age, the SE challenge strain was administered orally at a dose of 3.3 × 10⁸ CFU/bird. Pullets from each treatment group (n=32) were euthanized at 6-, 10-, 14-, and 18-days post infection (dpi). Contents from the ceca were aseptically collected and assessed for presence and abundance of SE. No differences in the prevalence of SE positive ceca following oral inoculation (P>0.05) were observed between treatment groups at 6-, 10-, 14-, or 18-dpi. Counts of SE in the ceca of the PRO group were not significantly different (P>0.05) from those of CON at 6- or 10-dpi. However, significantly lower counts of SE in the ceca of the PRO group were observed at 14-dpi (P<0.05) and 18-dpi (P<0.05) compared with CON. SE counts were 1.24 and 1.34 logs lower than CON at 14- and 18-dpi, respectively. In conclusion, supplementation of the triple-strain Bacillus-based probiotic resulted in lower cecal counts of SE compared to those that did not receive an effective probiotic, thereby reducing the risk of foodborne pathogens prior to harvest through sustainable, natural methods.