Milliliter Of Milk Research Articles

Early pumping frequency and coming to volume for mother's own milk feeding in hospitalized infants.

To identify daily pumping frequencies associated with coming to volume (CTV: producing > 500 milliliters of milk per day by postnatal day 14) for mothers of infants in the neonatal intensive care unit (NICU). We compared demographics and daily pumping frequencies for mothers who did and did not experience CTV. Of 427 mothers who produced milk, 201 (50.1%) experienced CTV. Race, insurance, delivery type and birthweight were associated with CTV. For mothers who experienced CTV, average pumping episodes increased daily, stabilizing at 5 pumping episodes per day by postnatal day 5 (5 × 5). Women who experienced CTV were also more likely to have pumped between 0100 and 0500 (AM pumping). In multivariable analysis birthweight, 5 × 5 and AM pumping were each independently associated with CTV. Supporting mothers of NICU infants to achieve 5 or more daily pumping sessions by postnatal day 5 could improve likelihood of achieving CTV.

The effects of implementing management practices on somatic cell count levels in bovine milk

Somatic cell count (SCC) can be used as a proxy for the prevalence of mastitis in a herd, reflecting the hygiene conditions and management practices on dairy farms, and thus an indicator of milk quality. In this study, we investigated how the adoption of management practices in milking systems can contribute to the reduction of SCC levels and improve milk quality. We collected data regarding management practices from 91 dairy farms in three municipalities of southeastern Pará: Parauapebas, Curionópolis, and Eldorado dos Carajás. Fifty milliliters of milk from each farm were collected in bottles containing bronopol, to preserve SCC. An exploratory factorial analysis (EFA) was performed to reduce the number of variables (management techniques) on dairy farms to some latent factors. We then used the selected factors to estimate the bovine mastitis management index to classify farms according to their use of technology and management techniques. Our results showed that most of the farmers (65.9%) used management techniques inefficiently in their systems, resulting in a significant loss of product quality, while only 3.3% had adopted the full set of techniques. The EFA results demonstrated that simple management practices including regular cleaning of the milking lines, a strip cup test, the California mastitis test, and washing teats with water before milking could be adopted to improve milk quality. However, in scenarios where the regulations become more rigorous, most farmers are unable to meet the maximum allowable SCC requirements, necessitating management innovations to reduce SCC. Therefore, the dissemination of knowledge, technical assistance, and access to new technologies is essential for improving management practices, and thus milk quality.

EVALUATION OF THE NITROGEN FRACTIONS IN MILK OF BUNAJI (WHITE FULANI) CATTLE IN A HOT AND HUMID ENVIRONMENT

One hundred milliliters of milk produced in the first 150 days of lactation of 24. Bunaji (White Fulani) cattle in Ibadan contained an average of 703, 659, 44, 557, 146, 21, 27 and 54 mg total nitrogen (TN), protein nitrogen (PN), non-protein nitrogen (NPN), casein nitrogen (CN), non-casein nitrogen NCN), proteoses-peptone nitrogen (PPN), lactoglobulin nitrogen (LGN) and lactalbumin nitrogen (LAN) respectively. CN, NCN, PN, NPN, PPN, LGN and LAN accounted for 79.2, 20.8, 93.7, 63, 3.1, 3.9 and 7.6% of TN respectively. CN constituted 833% of PN while one-third of NCN consisted of P PN and LGN. The most abundant component of NCN was LAN which occurred twice as high as LGN. The influence of stage of lactation was significant (P < 0.05) on TN, more remarkable on PN and CN but not significant (P >005) on NCN, NPN, PPN, LGN and LAN, Only TN and CN were significantly (P < 0.05) correlated (r 0.989). The positive or negative relationships between the other nitrogen fractions were trivial.

Combination of procedure for ultra rapid extraction (PURE) and loop-mediated isothermal amplification (LAMP) for rapid detection of <i>Mycoplasma bovis</i> in milk

Polymerase chain reaction (PCR) is typically used for the early detection of mycoplasma in bovine milk; it requires 3 days to obtain results because of the necessary enrichment process. A more rapid, simple, and accurate detection method is required to directly detect the Mycoplasma bovis (M. bovis) gene in milk. In this study, we assess the utility of combining the following two methods to achieve this goal: the loop-mediated isothermal amplification (LAMP), which is more sensitive than PCR, and the procedure for ultra rapid extraction (PURE), which adsorbs and filters components that inhibit DNA amplification/detection. LAMP was examined using DNA extracts obtained by four methods. This showed that PURE had the highest sensitivity and specificity and that the combination of PURE and LAMP was able to detect M. bovis in milk. We then showed that the detection limit of M. bovis was 102 colony-forming units per milliliter of milk using the PURE–LAMP. Finally, the respective sensitivities of the PURE–LAMP and PCR were 57% and 86% for bulk tank milk, 89% and 74% for mature milk, 85% and 92% for colostrum/transitional milk, and 97% and 95% for mastitis milk. The specificity was 100% for all milk samples in both LAMP and PCR. We conclude that PCR was suitable for detecting mycoplasma in bulk tank milk and that the PURE–LAMP could detect mycoplasma within 2 hr and was also effective for mature and mastitis milk.

Fundamental studies of milk exosomes Camelus dromedarius, Camelus bactrianus and hybrids from Kazakhstan

Milk contains extracellular vesicles that are released by udder cells and are recognized as a new mechanism for transmitting information from mother to newborn. In this study, extracellular vesicles were isolated from milk of C. dromedarius, C. bactrianus and hybrids from Kazakhstan using optimized density gradient ultracentrifugation. Vesicles were visualized using transmission electron microscopy and characterized using nanoparticle tracking analysis. The purified extracellular vesicles had a heterogeneous size distribution ranging from 25 to 170 nm in diameter with an average yield of 9.5*108 – 4.2*1010 particles per milliliter of milk. Combining classical and advanced proteomic approaches, a comprehensive proteomic analysis of camel milk vesicles was carried out. One thousand ten (1010) unique proteins have been identified that are involved in various biological processes, including most markers associated with small vesicles. As a result, the extracellular vesicles of camel milk are enriched with exosomal proteins. The most common biological processes have been associated with the synthesis and secretion of exosomes. They are mainly involved in molecular functions such as poly RNA and ATP binding, protein binding and structural constituent of the ribosomes. Key words: camel milk, exosomes, extracellular vesicles, proteome. &nbsp

Фундаментальные исследования экзосом молока Camelus dromedarius, Camelus bactrianus и гибридов Казахстана

Milk contains extracellular vesicles that are released by udder cells and are recognized as a new mechanism for transmitting information from mother to newborn. In this study, extracellular vesicles were isolated from milk of C. dromedarius, C. bactrianus and hybrids from Kazakhstan using optimized density gradient ultracentrifugation. Vesicles were visualized using transmission electron microscopy and characterized using nanoparticle tracking analysis. The purified extracellular vesicles had a heterogeneous size distribution ranging from 25 to 170 nm in diameter with an average yield of 9.5*108 – 4.2*1010 particles per milliliter of milk. Combining classical and advanced proteomic approaches, a comprehensive proteomic analysis of camel milk vesicles was carried out. One thousand ten (1010) unique proteins have been identified that are involved in various biological processes, including most markers associated with small vesicles. As a result, the extracellular vesicles of camel milk are enriched with exosomal proteins. The most common biological processes have been associated with the synthesis and secretion of exosomes. They are mainly involved in molecular functions such as poly RNA and ATP binding, protein binding and structural constituent of the ribosomes.

KARAKTERISTIK BAKTERI ASAM LAKTAT YANG DIISOLASI DARI SUSU KUDA SUMBA

The purpose of this study was to isolate and identify the lactic acid bacteria found in Sumba mares milk. This research will be carried out from September to November 2017 at the Veterinary Laboratory of the Livestock Service Office of East Nusa Tenggara Province. The research stages are isolation of lactic acid bacteria from Sumba mares milk by growing lactic acid bacteria on MRS agar media, and identifying lactic acid bacteria with gram staining, catalase test, motility test, and total plate count testing. Based on the results of the study, the presence of lactic acid bacteria originating from Sumba mares milk was characterized by the presence of colonies of lactic acid bacteria from Sumba mares milk which grew on MRS media agar as a selective medium for lactic acid bacteria. Based on the results of testing the characteristics of lactic acid bacteria Sumba mares milk has Gram positive, the negative results in the catalase test are characterized by not forming gas bubbles when the bacteria are added with H2O2. Based on the motility test obtained negative results or bacteria are non-motile and the number of lactic acid bacteria that can be a total picture of lactic acid bacteria that exist in Sumba mares milk in milliliter of milk. The conclusion are lactic acid bacteria isolated from Sumba mares milk has characteristic as Gram positive, basil or stem shaped, negative catalase and non motile, and has a total lactic acid bacteria of 3.5 x 108 cfu/ml (est).
 
 

An Insight in Key Volatile Compounds in Goat Milk Based on their Odor Active Values

Goat milk is known to possess an off-flavor generally known as ‘goaty flavor’, which is not appreciated by consumers. Mostly the short-chain fatty acids are responsible for this undesirable sensory attribute. The objective of the present work was to identify the volatile compounds present in goat milk and to relate their impact on aroma characteristics. Volatile compounds from the milk were obtained by using a simultaneous distillation and extraction technique utilizing Likens and Nickerson’s apparatus. Two hundred milliliter of milk was used and extraction was carried out at 55°C for 120 min by using a mixture of pentane-ethyl ether (2:1) solvent. The extracts were concentrated and analyzed for the identification of volatile compounds using a system of high resolution gas chromatograph coupled with mass spectrometer. Better separation was achieved in a non-polar capillary column. A total of 91 volatile compounds were positively identified and these represented mostly the classes of compounds belonging to esters, aldehydes, alcohols, fatty acids, ketones and aromatics. The main compounds and their concentrations were hexanol (9481.92 µg/L), pentanoic acid (3040.08 µg/L), 2-pentanone (1651.03 µg/L), methyl 9-octadecenoate (1613.88 µg/L), methyl hexadecanoate (1060.61 µg/L) and 2-pentanol (1683.28 µg/L), while the compounds with their OAVs of 5 and higher that contribute in goat milk aroma were decanal (88), (E)-2-hexenal (72), hexanol (47), octanal (40), ethyl hexanoate (35), pentanal (34), nonanal (30), 2-pentanone (24), heptanal (23), methyl hexanoate (20), γ-dodecalactone (11), 2-heptanone (10), heptanol (9), ethyl octanoate (9), 2-pentadecanone (9), β-ionone (8), α-pinene (5), 2-methylthiophene (5), octadecanal (5).

Decay of Mycobacterium bovis in whole milk submitted to pasteurization parameters

Parameters for milk pasteurization were established a long time ago, considering the thermal resistance of Mycobacterium bovis, and the systematic adoption of this process has drastically reduced the incidence of human tuberculosis caused by this pathogen. However, more recently, molecular methods have allowed the identification of genetic variations in this bacterium that may lead to greater thermal resistance. The aim of this study was to investigate whether genetic variation leads to variation in the death pattern of this bacterium during the milk pasteurization process. Samples of UHT (ultra-high temperature)-treated whole milk were artificially contaminated with four different Mycobacterium bovis spoligotypes and were subjected to pasteurization by low-temperature long-time (LTLT) and high-temperature short-time (HTST) treatments. The M. bovis spoligotypes were quantified (Colony Forming Unit per milliliter of milk) before and during the thermal process. The decay of the pathogen was quantified by calculating the difference between the measurements at the beginning and at the end of the thermal treatment. The data demonstrated that the LTLT and HTST pasteurization processes considerably reduced the M. bovis load in the milk; however, the bacterium was not eliminated. There was no difference in the thermal resistance of the spoligotypes tested or in the efficiency of pasteurization processes (LTLT versus HTST). However, heating phase was more effective in reducing the M. bovis load than the target temperature maintenance phase.

English

In this study, the bacteriological quality and the presence of Staphylococcus aureus, Escherichia coli O157:H7, Bacillus cereus, Salmonella species, and Pseudomonas species were studied in raw milk, cultured milk, milk handlers and packaging containers. A total of 36 samples were collected over 3 months from three different farmers. Samples were analyzed for means of counts per milliliter of milk for total bacterial count (TBC), total coliform count (TCC), total E. coli count (TEC), S. aureus, B. cereus, Salmonella spp. and Pseudomonas spp. Microbial load ranged between 0.81 and 7.6 log10 cfu/ml for various critical sampling locations. Isolates of E. coli, S. aureus and B. cereus were taken for simple polymerase chain reaction (PCR) to investigate the presence of virulent genes, rfB, sei, and cytK with amplicon sizes of 1.0 kb, 500 bp and 320 bp, respectively. The sei gene was detected in 19% of the samples and 2.8% were found to have the cytK gene. The rfB gene could not be picked in E. coli. The results show poor hygienic practices at the processors and potential risk to the consumers. Key words: Fresh milk, fermented milk, packaging container, milk handler, pathogens.

Direct Determination of Glyphosate, Glufosinate, and AMPA in milk by Liquid chromatography/tandem mass spectrometry

A simple high-throughput liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for the determination of glyphosate, aminomethylphosphonic acid (AMPA) and glufosinate in milk using a reversed-phase liquid chromatography column with weak anion/cation exchange stationary phase. One milliliter of milk was shaken with three milliliters of water containing Na2EDTA and acetic acid for 10 minutes, to precipitate the protein content in the sample. After centrifugation, the supernatant was passed through an Oasis HLB SPE to retain suspended particulates and phospholipids. The sample was directly injected and analyzed in 6 min, with no sample concentration or derivatization steps. Two multiple reaction monitoring (MRM) channels were monitored in the method for each target compound to achieve true positive identification. Three internal standards corresponding to each analyte were used to counter matrix suppression effects. The linearity of the detector response was demonstrated in the range of 4 to 1000 ng/mL for each analyte, with a minimum coefficient of determination (R2) value of more than 0.995. Through the use of this internal standard calibration method, the average recovery for all analytes at 0.025, 0.1, 0.5, and 2 µg/g (n = 7) are between 84-111% with a relative standard deviation of less than 8%.https://doi.org/10.21423/jrs-v03n02p020 (DOI assigned 8/7/2019)

Screening method for early detection of mastitis in cows

Mastitis in cows is an inflammation of the mammary gland usually caused by bacterial infection of udder tissues. This disease causes considerable damages to the cattlemen when reducing the quantity and the quality of the produced milk. An early detection and corrective action can lead to early cure. Although the universal method to measure mastitis levels is by determining the somatic cell counts per milliliter of milk, the electrical conductivity of milk could be a rapid test for checking the acceptability of milk to monitor the effects of udder infection. In this paper a low-cost circuit for estimating the quality of raw milk based on AC electrical conductivity measurements is proposed. It consists in the use of a modified Wheatstone bridge to minimize the parasitic effects. A conductivity cell consisting of two electrodes and a coaxial cable was also designed. The temperature of the milk is also measured and compensated its effect. This system can help the farmer to detect quickly and economically the state of health of their cows from a simple measurement of electrical conductivity performed on the dairy farm itself.

The effects of beverages on plaque acidogenicity after a sugary challenge

Caries prevention traditionally has emphasized the restriction of cariogenic foods and beverages, but it has placed less emphasis on how the choice, combination and sequence of consumed foods and beverages may help reduce plaque acidogenicity. The authors conducted a study to examine whether whole milk, 100 percent apple juice or tap water affect dental plaque acidity in people after a sugary challenge. Twenty adults participated in a randomized controlled crossover study. Participants consumed four combinations of foods: 20 grams of dry sugary Froot Loops (FL) (Kellogg's, Battle Creek, Mich.) cereal, 20 g of FL followed by 50 milliliters of milk (FL/milk), 20 g of FL followed by 50 mL of juice (FL/juice) and 20 g of FL followed by 50 mL of water (FL/water). The authors used a touch microelectrode to take plaque pH readings at the interproximal space just below the contact area between the maxillary premolars on both left and right sides at two and five minutes after FL consumption and at two to 30 minutes after milk, juice or water consumption. Consumption of FL plaque pH (standard deviation [SD]) was 5.83 (0.68) at 30 minutes, whereas plaque pH (SD) in the FL/milk group was 6.48 (0.30), which was significantly higher than that for FL/juice (5.83 [0.49]) or FL/water (6.02 [0.41]) (P < .005) at 35 minutes. Drinking milk after a sugary cereal challenge significantly reduced plaque pH drop due to the sugary challenge. When discussing the cariogenicity of foods and beverages with patients, dentists and other health care professionals should emphasize that the order of ingesting sugary and nonsugary foods is important and may affect their oral health.

335 GENETIC ENGINEERING OF GOATS FOR THE PRODUCTION OF A BIOSIMILAR ANTIBODY IN MILK

Dairy animals provide an attractive production platform for biosimilar antibodies due to the high protein production capacity of the mammary gland and easy access to milk. Goats are well suited for this approach as they offer a relatively short gestation time and good milk yield and are fully validated for the production of recombinant therapeutics. To generate transgenic goats capable of producing a biosimilar version of cetuximab, a monoclonal antibody for epidermal growth factor receptor and approved for the treatment of specific cancers, we co-transfected primary female fetal fibroblasts with expression constructs for cetuximab’s heavy (HC) and light (LC) chains under the control of the goat β-casein regulatory sequences. Beta-globin insulators were added to both transgenes to minimize position effects, and an antibiotic selection marker was placed downstream of the HC transgene sequences to allow for the isolation of stable transgenic cell clones. Selected cell clones were screened by PCR for the presence of both transgenes. Positive cell clones were analysed by Southern blot with a β-casein-specific probe. This allowed for the simultaneous detection of both transgenes, and the endogenous β-casein gene served as a standard to determine transgene copy numbers. The cell clones showed a broad range of copy numbers, from single copy insertions to &gt;100 copies for the HC and LC transgenes. Interestingly, most of the cell clones had more LC than HC transgene copies. Ten cell clones were selected to generate transgenic founders using somatic cell nuclear transfer. We were able to produce 43 live kids from 9 cell lines following transfer of between 26 and 153 one- and two-cell embryos per line into recipients (range of 4 to 15 embryos per recipient). The one cell clone that we used unsuccessfully had the lowest number of transferred embryos (11). The efficiency for the production of live kids per transferred embryos was, on average, 5.1% (range of 1.0 to 9.7%). Kids from 5 lines were hormonally induced into lactation at the age of 10 weeks. Two lines with high copy numbers (≥30) produced either no or only a few drops of milk, whereas the lines with ≤25 transgene copies gave up to several milliliters of milk per day. Western analyses confirmed cetuximab production levels of 15 g L–1 in 2 of the lines with ≤25 transgene copies and ~45 g L–1 in a high copy number line; one low copy number line showed good HC but very low LC expression. Our data demonstrate that cetuximab can be produced in significant quantities in transgenic goats. Future work is aimed at determining production levels under natural lactation conditions and characterising glycosylation patterns to fully understand the pharmacodynamic properties of the antibody. Supported by GTC, the NZ Ministry of Science and Innovation and AgResearch.

10.1007/s11171-008-2005-z

A biotechnological system for the production of human β-interferon was developed on the basis of a hybrid gene constructed from the coding sequence of the β interferon gene, inserted into the first exon of the sheep beta-lactoglobulin gene. It is intended for the expression of human β-interferon in mammary glands of transgenic animals. Two lines of transgenic rabbits were obtained using the hybrid gene. The tissue specificity of the expression of the transgene and the frequency of its inheritance in the first and second generations were studied. The activity of interferon was 2.2 × 104 − 7.2 × 104 IU per milliliter of milk of transgenic female rabbits.

Diagnosis of Intramammary Infections at Dry-off Based on Sampling Strategy, Epidemiology of Pathogens, and Agreement Beyond Chance

Isolation of pathogens from duplicate or multiple milk samples is currently considered the gold standard in diagnosis of bovine intramammary infections (IMI). However, in large field studies and especially in normal dairy production conditions, collection of single samples is often the most practical option to determine the causal agents of mastitis in a herd. The objective of the present study was to determine how well results between the first and the second sample in pairs of duplicate and successive quarter milk samples agree, using 5 different IMI definitions, based on the number of colony forming units (CFU) per milliliter of milk and epidemiology of the pathogens isolated. Agreement between microbiologic results from the first and the second sample of a pair was assessed by calculating the percentage of agreement and kappa coefficient. Milk samples collected at dry-off from 561 Holstein cows in 4 Ohio dairy herds were included in the analyses. Results of the study indicate that the agreement between the first and the second sample of a duplicate pair was high when criteria to call a sample positive was adjusted for the number of CFU/ml of milk by considering the epidemiology of different mastitis organisms. This finding suggests that an IMI can be accurately diagnosed with single samples. For contagious pathogens (Staphylococcus aureus) a cutoff of 100 CFU/ml and a cutoff of 1,000 CFU/ml for major environmental and minor pathogens will serve as a sensible approach to diagnose bovine IMI with single milk samples.

Real-time polymerase chain reaction-based identification of bacteria in milk samples from bovine clinical mastitis with no growth in conventional culturing

In more than 30% of milk samples from clinical and subclinical bovine mastitis, bacteria fail to grow even after 48h of conventional culture. The “no-growth” samples are problematic for mastitis laboratories, veterinarians, and dairy producers. This study provides the first investigation of the bacteriological etiology of such samples, using a real-time PCR-based commercial reagent kit. The assay targets the DNA of the 11 most common bacterial species or groups in mastitis and the staphylococcal blaZ gene (responsible for penicillin resistance) and can identify and quantify bacterial cells even if dead or growth-inhibited. A study was made of 79 mastitic milk samples with no-growth bacteria in conventional culture, originating from cows with clinical mastitis. Of the 79 samples, 34 (43%) were positive for 1 (32 samples) or 2 (2 samples) of the target bacteria. The positive findings included 11 Staphylococcus spp. (staphylococci other than Staphylococcus aureus), 10 Streptococcus uberis, 2 Streptococcus dysgalactiae, 6 Corynebacterium bovis, 3 Staph. aureus, 1 Escherichia coli, 1 Enterococcus, and 1 Arcanobacterium pyogenes. The positive samples contained as many as 103 to 107 bacterial genome copies per milliliter of milk. This study demonstrates that in nearly half of the clinical mastitis cases in which conventional culture failed to detect bacteria, mastitis pathogens were still present, often in substantial quantities. The clearly elevated N-acetyl-β-d-glucosaminidase activity values of the milk samples, together with clinical signs of the infected cows and quarters, confirmed the diagnosis of clinical mastitis and indicated that real-time, PCR-based bacterial findings are able to reveal bacteriological etiology. We conclude that all common mastitis bacteria can occur in large quantities in clinical mastitis samples that exhibit no growth in conventional culture, and that the real-time PCR assay is a useful tool for bacteriological diagnosis of such milk samples. Low bacterial concentration is commonly speculated to explain the no-growth milk samples. This hypothesis is not supported by the results of the current study.

Expression of human interferon β in mammary glands of transgenic rabbits

A biotechnological system for the production of human beta interferon was developed on the basis of a hybrid gene constructed from the coding sequence of the beta interferon gene inserted into the first exon of the sheep beta lactoglobulin gene. It is intended for the expression of human beta interferon in mammary glands of transgenic animals. Two lines of transgenic rabbits were obtained using the hybrid gene. The tissue specificity of the expression of the transgene and the frequency of its inheritance in the first and second generations were studied. The activity of interferon was 2.2 x 10(4)-7.2 x 10(4) IU per milliliter of milk of transgenic female rabbits. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http:// www.maik.ru.

Détermination du moment du post-partum où l’axe hypophyse ovaires de la vache zébu (&lt;em&gt;Bos indicus&lt;/em&gt;) allaitante est sensible à la GnRH synthétique

Afin de déterminer le moment du puerpérium où l’axe hypophyse ovaires de la vache zébu (Bos indicus) allaitante est fonctionnel, une dose unique de 100 μg de gonadolibérine (GnRH) synthétique a été injectée par voie intramusculaire à 60 vaches zébus allaitantes réparties en six lots. Les animaux en étaient à leurs 7e, 10e, 15e, 20e, 2e et 30e jours de lactation (10 animaux/lot/stade). Dix millilitres de lait ont été prélevés sur les animaux avant l’injection (A : 1re série d’échantillons), aux 5e, 6e, 7e, 8e jours (B : 2e série d’échantillons) et aux 20e, 21e, 22e, 23e, 24e jours (C : 3e série d’échantillons) après l’injection de GnRH. Dans chaque lot, les échantillons obtenus avant l’injection de GnRH ont été considérés comme témoins. Au total, 600 échantillons de lait ont servi à déterminer les taux de progestérone par radio-immunodosage. Parmi les animaux injectés 15 jours après la mise bas, 60 p. 100 ont été sensibles à la GnRH avec une sécrétion moyenne de progestérone de 2,67 ± 1,89 nmol/L. Cette réponse a augmenté au fur et à mesure que s’est allongé le puerpérium. Trente jours après le vêlage, tous les animaux ont répondu favorablement au traitement (concentration moyenne de progestérone : 4,09 ± 1,90 nmol/L) et ont présenté une réduction significative (p &lt; 0,05) de l’intervalle vêlage gravidité comparé aux animaux traités aux 7e et 10e jours après le vêlage. Ces observations montrent que dès le 15e jour après la mise bas, l’axe hypophyse ovaires de la vache zébu allaitante est sensible à l’application de la GnRH exogène et que ce type de traitement peut améliorer les performances de reproduction de ces animaux.

Modeled detection time for surveillance for foot-and-mouth disease virus in bulk tank milk

To estimate when foot-and-mouth disease virus (FMDV) would first be detected in bulk tank milk of dairies after exposure to FMDV. Hypothetical dairy herds milking 100, 500, or 1,000 cows. For each day after herd exposure to FMDV, infection, milk yield, and virolactia were simulated for individual cows with low and high rates of intraherd transmission to estimate when a PCR assay would detect virus in bulk tank milk. Detection limits were based on assumptions for the number of virus genomes per milliliter of milk and for analytical sensitivity of a PCR assay. A mean of 10% of the cows was predicted to have FMD lesions from 7 to 8 days and from 13.5 to 15 days after herd exposure for herds with high and low intraherd transmission rates, respectively. Herd bulk milk volume decreased by 10% by 8.5 to 9.5 days and by 15 to 16.5 days after herd exposure for herds with high and low transmission rates, respectively. Mean times by which FMDV would be first detected in bulk milk were 2.5 days and 6.5 to 8 days after herd exposure, which were extended for 10 to 11 days and 17 to 18 days for herds with high and low transmission rates, respectively. PCR screening of bulk milk for FMDV would likely detect FMDV in dairy herds several days sooner than might be expected for owner reporting of clinical signs and thus should be worthy of consideration for regional, national, or global FMD surveillance.