Use Of Milk Samples Research Articles

Use of milk samples in epizootic surveillance of cattle diseases

Relevance. The analysis of the possibility of using milk as a non-invasive type of samples in the epizootological control of diseases of cattle is given. During pathogenesis, many etiologic agents cause breast lesions or are excreted together with milk, which makes milk an ideal sample for laboratory diagnostics of infectious diseases of cattle, since it is available in any quantity and its samples are easy to collect.Methods. Conventional methods of document analysis were used.Results. It is shown that milk samples can be used both at the individual and at the population level for early identification of infected herds, screening of infected herds and use to obtain evidence of the well-being of herds. The availability of commercial diagnostic test systems for detecting antibodies in milk to the causative agents of leukemia of cattle, viral diarrhea of cattle, Brucella abortus, Mycobacterium avium subspecies paratuberculosis, Fasciola hepatica, Q fever (Coxiella burnetii) makes available programs for the control and eradication of diseases in dairy herds and at the level of countries. The use of combined non-invasive milk samples makes it possible to combat slowly progressive and chronic cattle infections of dairy cattle (bovine leucosis, paratuberculosis, brucellosis), and exclude carrier animals from the production chain in real time, which indicates the feasibility of introducing this type of samples into veterinary practice in the Russian Federation.

Diagnostic Role of Circulating Immune Complexes During Cow Leukemia

In chronic infections caused by retroviruses, antigen antibody immune complexes (AAC) appear in body fluids. In the course of the studies to clarify the structure of the AAC we proved that immune complexes in cattle leukemia could contain the virus's viral DNA. The role of circulating immune complexes in the pathogenesis of the bovine leukemia virus (BLV) infection is not sufficiently studied. AAC containing the viral DNA may be formed during the death of infected B-lymphocytes by linking non-invasive viral DNA to surface IgMs with high DNA affinity. Determining the appearance of AAC with the viral DNA in biological fluids depending on the stages of the infectious process is an important criterion in antileukemia measures. The article describes the results of research to determine circulating immune complexes containing the provirus DNA in the milk of cows infected with BLV as compared with hematological changes at different stages of the infection process. It is reported that the viral DNA in the AAC of the milk of cows infected with BLV is detected much earlier than hematological changes that allow to consider them leukemia patients. Of the 12 cows studied, by the end of the experiment, six cows had AAC containing the viral DNA in their milk samples. And only one cow with the detection of the viral DNA in the AAC of milk showed parallel hematological changes typical for leukemia. The use of milk samples for molecular genetic analysis to identify BLV in AAC is quite a promising area for assessing the epizootic situation on farms and is very informative in determining the animal status.

ПРОВИРУСНАЯ ДНК ВЛКРС В ПАТОГЕНЕЗЕ ЛЕЙКОЗА КОРОВ

The article describes the results of studies of the dynamics of changes in the titers of circulat-ing immune complexes (CIC) in milk, the detection of proviral DNA in them, as well as hematologi-cal changes at different stages of the infectious process in cows infected with BLV. Information is given that proviral DNA in the CEC of milk of cows infected with VLBV is detected much earlier than hematological changes, which make it possible to consider them as patients with leukemia. The use of milk samples for molecular genetic analyzes to identify VLBV at the CEC is a fairly promis-ing direction for assessing the epizootic situation in farms and very informative in determining the status of an animal.

Variation in milk, serum, and blubber fatty acids in young, free‐ranging Steller sea lions

AbstractWe determined the fatty acid signatures in milk, serum, and blubber samples collected from young free‐ranging Steller sea lions (Eumetopias jubatus) and investigated the partitioning of fatty acids among these matrices. We assessed the relationship of fatty acids in each matrix with region, age, season, sex, and body condition to gain information needed to determine the most appropriate type of samples to collect and analyze to address future research questions. The variability of fatty acid composition was almost entirely explained by sample type, highlighting the importance of selecting a matrix consistent with the study objectives. Regional differences in fatty acid composition were found in all sample types and these differences varied among matrices. The proportion of fatty acids in milk and serum were influenced by season of capture whereas blubber samples were more affected by age of the pup. The influence of season on the fatty acid signatures in milk and serum highlights the use of these samples over blubber in studies investigating seasonal changes in diet. Further, our findings suggest that the use of milk samples collected from the stomachs of pups may be a viable alternative to directly collecting milk from adult females.

Implications of Carryover on the Diagnostic Indicators for Intramammary Infections in Dairy Herds

Carryover is the phenomenon that a milk sample from cow B also contains some fraction of milk from cow A that was milked just before cow B in the same milking unit. Many studies reported that carryover of a small amount of milk from one DHI cow sample to the next at the time of collection is possible due to residual milk in the milking unit, milk meter or milk sampler [1-3]. The use of milk samples obtained from milk meters for PCR testing could be carryover of milk components that will contaminate one or more subsequent samples [4]. Carryover has been reported in both conventional and automatic milking systems (AMS) however, milk samples obtained from AMS are more prone to carryover than traditionally obtained samples because of the greater complexity of AMS including valves, pumps, containers and connecting tubes. It was reported that the degree of carryover in AMS was higher (up to 20%) compared to conventional milking parlours [5]. The routinely collected milk samples of DHI are subjected for analysis of some milk parameters such as fat, protein and somatic cell counts (SCC). Based on the milk fat, a statistically nonsignificant estimated carryover was 2% in conventional milking systems [1] while in earlier study, carryover degree was 6-7% based on milk fat in the Milko-Tester device [6]. In a recent study, the estimated degree of carryover in conventional milk system using fluorescent tracers (yellow dye) was 3.5% in an experimental setup [5].

Identification of the Variability of Metabolites in Human Milk using Gas Chromatography‐Mass Spectrometry (GC‐MS) Profiling

A significant amount of research has been conducted into the macronutrient content of human milk. As such, the variation of milk components such as fat, protein and lactose have been well defined, however, little is known about the metabolites in human milk. Our preliminary investigation has detected approximately 200 metabolites in human milk. In this study we investigated the metabolites present in milk using GC‐MS profiling. Mothers (n=10) of healthy infants (1–18 months) provided approximately 5ml of freshly expressed breastmilk for analysis. Samples were mixed with methanol and snap frozen at −80ºC. Metabolites were extracted and GC‐MS was performed to obtain a metabolite profile for each sample. Data analysis was performed using Analyzer Pro® software. Whilst many of the metabolites in these profiles are yet to be identified, we were able to determine which of the metabolites exhibited the greatest variation. The profiling of these metabolites provides a platform for future research into the metabolic pathways that exhibit the greatest variation in the lactating human breast. These techniques will allow further elucidation of the physiology of the lactating human breast and have the potential to assist in the use of milk samples for the diagnosis of lactation difficulties such as mastitis and inadequate milk supply. Funded by an unrestricted research grant from Medela AG, Switzerland.

Formation of whey protein/ κ-casein complexes in heated milk: Preferential reaction of whey protein with κ-casein in the casein micelles

Studies of the formation of soluble κ-casein/whey protein (WP) complexes in heated (90 °C 10 min −1) milk and related mixtures of proteins have been made. The use of milk samples containing different genetic variants, and having different compositions, allowed the effects of changing the natural protein balance on the formation of particles to be investigated. In addition, studies were made of the effects of addition of WP or of purified κ-casein to the milk samples. The addition of WP caused an increase in the amount and the size of the complexes, but addition of κ-casein to the milk had little or no effect on the complex formation, nor did it seem that the added κ-casein could react with the WP in the milk. Conversely, in systems where the casein micelles were absent, the purified κ-casein reacted well with WP, suggesting that in milk heated at its normal pH the WP react preferentially with the κ-casein on the casein micelles.

Use of milk samples from a milk evaluation program for the genotyping of cows

Abstract. Milk can be an attractive DNA-resource for genotyping milking cows, e.g. for paternity control or QTL analysis within a daughter design. The use of milk collected within the established milk evaluation programs enables the collection of large numbers of samples. Nevertheless, there are limitations when using the remedies of tested milk samples, e.g. permutations of samples or partially degraded DNA. A DNA preparation method suitable for samples from routine milk recording has been developed that combines an initial centrifugation step with direct lysis of cells and purification from comparatively high volumes by using silica membrane spin columns. The method yields high quality genomic DNA from fresh samples and PCR grade DNA from remedies of tested samples. In addition the potential use of milk samples within a daughter design was evaluated. We collected reference samples from 119 Simmental dairy cows from 6 half sib families. From 89 of these dairy cows remedies of milk samples were obtained from the routine milk laboratory. Paternity could be established by microsatellite analyses for all 119 reference cases. From the 89 milk laboratory samples 86 were successfully microsatellite typed. In 81 cases the genotypes from milk and reference sample were identical. In summary it could be shown that it is possible to genotype dairy cows from test laboratory milk samples, but results have to be used carefully taking into account inherent limitations. The use of milk as compared with tissue samples as a source for DNA within daughter designs is discussed.

Use of milk samples and monoclonal antibodies directed against BLV-p24 to identify cattle infected with Bovine leukemia virus (BLV)

An indirect double-antibody sandwich (IDAS) enzyme-linked immunosorbent assay (ELISA) using milk samples was developed to identify cows infected with bovine leukemia virus (BLV). Two monoclonal antibodies (McAbs) were used. One, which was directed against BLV core protein p24, was used to coat ELISA plates; the other was used to prepare a horseradish peroxidase (HRP) conjugate directed against bovine immunoglobulin. The IDAS-ELISA detected antibodies directed against BLV-p24 in 97% of the milk samples collected from known seropositive cows identified by the agar gel precipitation test (AGTP). Even when milk samples were diluted 1:50, 93% of the seropositive cows were identified. Only 0.43% of the 4000 milk samples collected in The Netherlands reacted nonspecifically. Nonspecific binding disappeared, however, when these samples were diluted 50 times in BLV-negative milk. In a comparative evaluation of BLV test-kits in various European laboratories, our IDAS-ELISA using McAb directed against p24 was one of the most sensitive.