Proteomic and metabolomic studies on milk during bovine mastitis

The principal objectives of the study presented in this thesis were to study the changes of milk proteomes, peptidomes and metabolomes during the course of bovine mastitis in comparison with normal milk samples and to discover new bovine mastitis biomarkers using various modern and up-to-date methodologies such as proteomics, peptidomics and metabolomics. Bovine mastitis caused by bacterial infection of the mammary gland of dairy cows is often associated with loss of milk production due to a reduction in milk composition and quality which in turns, lead to negative economic impact on dairy industry. Two important acute phase proteins (APPs) which serve as valuable biomarkers in bovine mastitis were investigated in every chapter using developed and validated enzyme linked immunosorbent assay (ELISA) for bovine milk haptoglobin and commercially available ELISA for bovine milk serum amyloid A3 (M-SAA3). These APPs were quantified alongside somatic cell counts (SCC) and California Mastitis Test (CMT) to confirm the disease status of each animal used in this study. Proteomic methodologies were applied including 1D gel electrophoresis, 2D gel electrophoresis, MALDI-TOF analysis and difference gel electrophoresis to investigate the changes of milk proteome in both subclinical and clinical mastitic milk samples in comparison with healthy milk samples. However these investigations did not reveal novel biomarkers for mastitis. Next, peptidomic methodologies were used to study the changes in milk peptidome and to detect the presence of any significant disease biomarkers in the presence of bovine mastitis by using CE-MS and LC-MS/MS. A total of 31 and 14 polypeptides can be used to discriminate control from infected groups and E. coli from S. aureus infected groups respectively. Lastly, metabolomic methodology was applied with an intention to study the changes in milk metabolome and ultimately to detect the presence of novel biomarkers in bovine mastitis. Di- and tri-peptides were found higher in S. aureus than in E. coli infected groups and based on metabolic pathways, arachidonic, arginine and galactose metabolites were seen increased in mastitic milk samples in comparison to healthy milk samples. Overall, the findings detailed in this thesis indicate that the use of advanced proteomic and metabolomic methodologies could deliver on their promise of the discovery of potential significant bovine mastitis biomarkers. Further studies are needed for validation of these proposed biomarkers and it was hoped that better prevention and treatment methods for bovine mastitis can be achieved in the future

Antimicrobial Usage and Resistance in Dairy Cattle Production

Antimicrobial resistance (AMR) has been a public health threat globally, with millions of lives lost due to AMR infections each year. The cases of AMR continue to escalate and cause devastating effect to both humans and animals. AMR contributes to high morbidity and mortality of the livestock, which results in staggering economic losses to the livestock producers. The main factor for AMR to arise in this industry is mainly due to the eagerness of livestock producers to meet high demand by using antimicrobials to promote animal growth and disease prevention. From a public health perspective, AMR in dairy cattle can also jeopardize human population due to the potential dissemination of AMR pathogens to humans via consumption of infected dairy products or direct contact with infected dairy cattle. At the current rate of unrestricted antimicrobial usage, AMR will be expedited and soon we will run out of effective treatment for even the simplest infection. World Health Organization (WHO) has issued a set of guidelines for the use of medically important antimicrobials on animals to mitigate the adverse consequences of AMR on human. Thus, this chapter will explain antimicrobial usage in dairy cattle production and the recent approaches and challenges on AMR

Management of lower urinary tract obstructive disease using bladder tube cystotomy in a Saanen buck

This report describes a procedure of bladder tube cystotomy to relieve progressing bladder distension in a goat diagnosed to have obstructive urolithiasis. This one-year old Saanen buck was presented with a complaint of not passing urine and being in discomfort for almost three days. On physical examination, pulsation of the urethra in the perineal region could be felt and swelling and pain along the prepuce and perineum were indicated on deep palpation. Amputation of the urethral orifice and attempt to catheterise the urethra failed to relieve bladder distension; thus, bladder tube cystotomy procedure was performed. Following this procedure, all vital parameters returned to normal and normograde cystourethrogram was performed to radiographically assess the lower urinary tract of the goat. The outcome of this case supports that the bladder tube cystotomy technique provides an effective method to allow immediate relief of a distended bladder, allowing the urethra to heal as the urine outflow is diverted through the catheter and allows normograde cystourethrography to be performed

Development of recombinant cells encoding surface protein of Corynebacterium pseudotuberculosis against caseous lymphadenitis in goats

Caseous lymhadenitis is an infectious disease caused by an intracellular bacterium, Corynebacterium pseudotuberculosis. Control is via vaccination. This report describes construction of two recombinant cells; one that carried the putative surface-anchored protein, the SpaA (pET32/LIC-SP31) and the other the glyceraldehyde-3-phosphate dehydrogenase protein, the GAPDH (pET32/LIC-SP40). The recombinant cells were introduced into goats before aAntibody response by the goats and protective capacities of the recombinant cells were measured. Fifteen goats were divided into3 groups. Group 1 was injected intramuscularly with PBS, Groups 2 and 3 were injected on days 0 and 14 with 106CFU/ml of recombinant pET32/LIC-SP31 and pET32/LIC-SP40 cells, respectively. Serum samples were collected weekly to determine the antibody levels using ELISA. Two weeks after the last vaccination, all goats were challenged subcutaneously with 109CFU/ml of live C. pseudotuberculosis. The results revealed that goats exposed to the recombinant cells showed significantly (p0.05) higher level in the first 7 weeks than the recombinant pET32/LIC-SP31. Following challenge at week 6, abscesses were observed in the lymph nodes of all groups while C. pseudotuberculosis was successfully isolated. The recombinant cells were able to induce humoral response but failed to protect the goats against challenge by live C. pseudotuberculosis

The Impact of Lameness on Dairy Cattle Welfare: Growing Need for Objective Methods of Detecting Lame Cows and Assessment of Associated Pain

Dairy cows are the major animals reared for milk production worldwide. Lameness is a manifestation of painful condition due to injury or disease in the foot, regarded as a major welfare problem in dairy cows. An effective lameness management requires prompt identification of lame cows. The objectives of this systematic review were to discuss the various techniques of detecting lameness, assessment of the associated pain, and the impact of lameness on dairy cow welfare. Results from the literature search yielded 534 papers, with 102 papers meeting the inclusion criteria. The eligible studies were discussed in two sections which were; (1) lameness detection systems and their application in pain assessment using four methods: gait and behavioral variables, physiological parameters, pressure nociceptive threshold and blood biomarkers; (2) impact of lameness on animal-based welfare measures. Despite the limitations in the use of automated locomotion scoring systems, results showed the technique remains a promising tool for the prompt detection of lame cows compared with manual systems (MLSS). More investigation of such systems could aid the validation of pain in cows with various degree of lameness. Further studies are required for early lameness detection and minimizing the welfare implications in dairy herds

Preventive Hoof Trimming and Animal-Based Welfare Measures Influence the Time to First Lameness Event and Hoof Lesion Prevalence in Dairy Cows

Background: The objectives of this study were to, (1) investigate the impact of the Dutch five-step hoof trimming (HT) technique on time to lameness and hoof lesion prevalence in grazing (GR) and non-grazing (NGR) dairy cows, and (2) determine the association between potential benefits of HT and animal-based welfare measures during lactation. A total of 520 non-lame cows without hoof lesions from 5 dairy farms (GR = 2, NGR = 3) were enrolled at early (within 30 days in milk; DIM) and late lactation (above 200 DIM), and randomly allocated to either trimmed (HGR or HNGR) or control groups (CON-GR and CON-NGR). Locomotion scores, body condition, hock condition, leg hygiene, and hoof health were assessed at monthly intervals until the following 270 days in milk. The data were analyzed using Kaplan-Meier survival analysis, multivariable Cox, and logistic regression models. The overall incidence rate of lameness was 36.2 cases/100 cows/month, with corresponding rates of 27.4, 31.9, 48.4, and 45.8 cases/100 cows/month in HGR, HNGR, CON-GR, and CON-NGR, respectively. Time to first lameness event was significantly higher in HGR (mean ± S.E; 8.12 ± 0.15) compared to CON-GR (7.36 ± 0.26), and in HNGR (8.05 ± 0.16) compared to CON-NGR (7.39 ± 0.23). The prevalence of hoof lesions in the enrolled cows was 36.9%, with a higher occurrence in CON-GR (48.8%) than HGR (23.2%), and in CON-NGR (52.6%) compared to HNGR (32.2%). The majority of hoof lesions were non-infectious in grazing (HGR vs. CON-GR; 21.3 vs. 33.3%) and non-grazing herds (HNGR vs. CON-NGR; 25.0 vs. 40.4%). The risk of lameness was higher in underconditioned cows (Hazard ratio; HR = 3.1, 95% CI 1.2–7.4), presence of hoof lesion (HR = 33.1, 95% CI 17.6–62.5), and there was variation between farms. Aside HT, lower parity (OR = 0.4, 95% CI 0.2–0.8), normal hock condition (OR = 0.06; 95% 0.01–0.29), and absence of overgrown hoof (OR = 0.4; 95% 0.2–0.7) were protective against non-infectious hoof lesions. Functional HT is beneficial as a lameness preventive strategy during lactation; however, ensuring older cows are in good body condition and free from hock injuries are equally important

Antibiotic susceptibility of Staphylococcus aureus and Escherichia coli isolated from dairy goats in selected farms in Selangor, Malaysia

Antimicrobial resistance (AMR) has become a major problem worldwide with significance public health impact in both animal and human populations. Staphylococcus aureus (S. aureus) is a common pathogen in domestic livestock and Escherichia coli (E. coli) is a normal flora in the gut and these organisms are considered as effective indicators for AMR surveillance. Increased in antimicrobial resistance of these bacteria in veterinary medicine leads to difficulties in choosing effective antibiotics to treat diseases they caused. This study aimed to evaluate the susceptibility of S. aureus and E. coli isolated from dairy goats in selected farms located in Selangor, Malaysia against different antibiotics. Milk and faecal samples were collected from 36 dairy goats and samples were prepared for the isolation of S. aureus and E. coli isolates respectively. The isolates were subjected to antibiotic susceptibility test. All 11 (100%) E. coli isolates showed resistance to amoxicillin and penicillin while 3 (27%) of the 11 S. aureus isolates, showed resistance towards the same class of antibiotic. Both S. aureus and E. coli isolates showed high susceptibility to four antibiotics, namely trimethoprim-sulfamethazole, neomycin, tetracycline and enrofloxacin. This study provided information regarding the antibiotic resistance of S. aureus and E. coli in relation to the antimicrobial usage practice in selected dairy goat farms located in Selangor, Malaysia

Dairy farmers perceptions of and actions in relation to lameness management

Lameness continues to be a welfare and economic issue for dairy cows. However, the consequences of lameness seem to be better understood by veterinarians and related personnel in comparison to dairy farmers. Prompt detection and treatment of lame cows is essential in reducing its negative impact on milk processing systems. To that end, understanding farmers’ perceptions regarding the significance of lameness to dairy cows is vital. One fundamental aspect is the underestimation of lameness prevalence by dairy farmers, which is as a result of different understanding of the problem. The same applies to their decision to treat lame cows and to adopt various detection and management practices. All of these shortcomings contribute to poor cattle welfare and economic losses in dairy production. This review summarizes the results of studies that have investigated dairy farmers’ perceptions of lameness and the associated implications on the wellbeing and productivity of dairy cows. Factors associated with farmers’ attitudes toward claw health and lameness management are also presented. Additionally, economic observations relating to lameness prevention, treatment and the adoption of lameness detection systems are also highlighted. To strengthen these points, interventional programmes requiring farmers’ participation are discussed as a promising approach in answering some of these challenges. A review of the literature indicates both the opportunities and barriers inherent in the tackling the lameness issue from the farmers’ perspectives. Such knowledge is crucial in identifying measures on how to motivate dairy farmers towards proper lameness management

Differentiation of Malaysian farmed and commercialised edible bird's nests through nutritional composition analysis

The growing demand of edible bird’s nest (EBN) worldwide as well as competition from neighbouring countries has made the EBN industry one of the rising industries in Malaysia with stringent exportation requirement by China. However, as majority of the EBN products in the market is in commercialised form, studies on the nutritional composition of these commercialised EBN in comparison with farmed, raw EBN are limited. The farmed EBN samples were taken from 4 different regions of Malaysia: Perak (central), Kelantan (eastern), Johor (southern) and Sarawak (west Borneo) while the commercialised sample was obtained from a local drug store. Proximate, amino acid and elemental composition were performed on these EBNs. Farmed EBNs mainly comprised protein followed by carbohydrate while the commercialised EBN had similar protein and carbohydrate composition. The total collection of essential amino acid in commercialised EBN was higher (237.9 mg/g protein) compared to the farmed EBN which was between 156.81 − 236.6 mg amino acid/g protein. Among the essential amino acids, valine was found to be highest in both commercialised and farmed EBN. The differences between the nutritional compositions of EBNs could be due to the process of commercialisation of the EBN as well as seasonal, breeding sites and diet of the swiftlets. Farmed EBN therefore can be considered to be more nutritional due to higher protein levels