Decreased Milk Yield Research Articles

Effects of feeding level, milking frequency, and single injection of cabergoline on feed intake, milk yield, milk leakage, and clinical udder characteristics during dry-off in dairy cows

Abrupt and gradual dry-off strategies by reducing feeding level (normal vs. reduced energy density), reducing milking frequency (twice vs. once daily), and administration of a dopamine agonist after last milking (i.m. saline vs. cabergoline injection) were investigated (2 × 2 × 2 factorial arrangement) for their effects on feed intake, milk yield, energy balance, milk leakage, and clinical udder characteristics in 119 Holstein cows. In the last week before dry-off, cows were assigned to 1 of 4 combinations of feeding level and milking frequency. Within 3 h after last milking, cows were injected with either saline or a dopamine agonist (cabergoline; Velactis, Ceva Santé Animale; labeled for use only with abrupt dry-off, i.e., no preceding reduction in feeding level or milking frequency before last milking). After dry-off, all cows were fed the same diet for dry cows, and data collection continued for a week. Dry matter intake (DMI) was recorded in automated feed bins and milk yield in an automatic milking system where additional concentrate was fed. Clinical udder characteristics and milk leakage were scored 10 times during the week before and the week after dry-off. Before dry-off, total DMI decreased with reduced feeding level compared with normal feeding level, but did not differ between milking frequencies. The combined effect of reduced DMI and diet energy concentration resulted in a 47% lower net energy intake with reduced feeding level compared with normal feeding level during the week before dry-off. Milk yield was approximately 30% lower during the week before dry-off when either feeding level or milking frequency was reduced compared with no change in feeding level or milking frequency, whereas milk yield was 45% lower when both feeding level and milking frequency were reduced. The net energy balance during the week before dry-off was negative with reduced feeding level and more negative when combined with twice-daily milking. After dry-off, udder engorgement was reduced in the 3 gradual dry-off treatments compared with abrupt dry-off. Cabergoline injection after last milking resulted in least udder engorgement and signs of milk leakage for 48 h, but also resulted in abrupt reduction of DMI lasting approximately 24 h irrespective of treatment before dry-off. In conclusion, gradual cessation of lactation by reducing milking frequency to once daily without reducing the feeding level decreased milk yield before dry-off in high-yielding dairy cows and reduced udder engorgement after dry-off without inducing negative energy balance during the period of dry-off. In contrast, reduced feeding level induced negative energy balance, which may compromise welfare due to metabolic stress and hunger. No clear differences in risk of milk leakage after dry-off were observed between abrupt and gradual dry-off management strategies. Use of cabergoline led to fewer signs of milk leakage and reduced udder engorgement during the first days after dry-off, which may positively affect welfare at dry-off. However, the mechanism behind and the welfare consequences of the concomitant abrupt decrease in DMI lasting approximately 24 h needs further investigation to complete our understanding of dopamine agonist use for dry-off.

Modern approach to the treatment of sheep with mastitis

Agriculture in the modern world is closely connected with sheep breeding, which is more often aimed at dairy productivity. Inflammation of the udder lobes, the so-called mastitis, is the most common problem. The culling of sheep due to mastitis, unfortunately, occurs for justified reasons, since it is almost impossible to completely get rid of this disease, due to possible complica-tions of the disease (atrophy, induration, fibrosis of the udder lobes), as well as the treatment of animals in most cases leads to a deterioration in productivity. Mainly young animals with a high genetic potential of milk productivity suffer from this pathology. In most cases, according to our research, subclinical mastitis passes into the clinical phase, with pronounced symptoms of udder lobe dam-age, which can later lead to atrophy and other irreversible complications. Mastitis in productive animals, if we consider the economic damage in farms, leads to a decrease in the productivity of the dairy herd, which is associated with the loss of milk in production, and to a decrease in milk yield due to the presence of impurities and inhibitory substances throughout the treatment and for some time after it. In sheep that have undergone subclinical mastitis, there is a deterioration in the quality characteristics of the products. Milk yield for lactation, as a percentage, milk production becomes 15-20% less. Prevention of subclinical mastitis, timely diagnosis and highquality treatment is an urgent task. The main purpose of this article is to consider the need to improve the effectiveness in the treatment of mastitis, thanks to the use of complex etiotropic therapy, which will ensure the absence of inhibitory substances and allow further sales of products without restrictions, which will increase the economic well-being of the economy, including at cost.

Infectious and Non-infectious Factors Affecting Somatic Cell Count and New Diagnostic Approaches of Intramammary Infections in Dairy Goats: A Review

Background: Intramammary infections constitute major animal health and economic problem in commercial dairy goat farms, being responsible for decreases in milk yield, alter milk composition, and lower milk quality. Objectives: This paper reviews the published literature during the last three decades, highlighting the multiplicity of non-infectious and infectious factors that influence somatic cell count (SCC). Besides that, it intends to contribute to understanding the conventional diagnostic methods and their limitations, and supports the implementation of new technologies for efficient mastitis control, including the use of infrared thermography and ultrasonography. Methods: A search on Medline, ScienceDirect, and University Institutional Repositories databases was performed using “goats, AND mastitis OR intramammary infections OR somatic cells count” for publications from 1990 to present (2020). Results: A total of 144 publications were selected. The SCC is the most important criteria to evaluate the inflammatory status of the mammary glands in goats, but several non-infectious factors (e.g., phenotypic, reproductive, lactational factors) should be taken into consideration for its interpretation. Bacteria and fungi as well as lentivirus are commonly responsive for intramammary infections. Intermittent secretion or environmental contamination of milk pathogens, costs, and time delay poses challenges using conventional diagnostic methods. Ultrasonographic and thermographic techniques applied to the udder seem to be of diagnostic value in acute and chronic mastitis. Conclusions: Unlike other ruminants species, non-infectious factors have a major impact on SCC which should be taken in account for mastitis diagnosis, and according to milk pathogens detection. Further research in imagological techniques is needed to accurately contribute to implant new mastitis control strategies.

Gastrointestinal nematode and Eimeria spp. infections in dairy cattle along a rural-urban gradient.

Endoparasite infections can lead to considerable economic losses in dairy cattle due to decreases in milk yield and quality. Environmental and host-related factors contribute to endoparasite infection intensity and probability. Moreover, advancing urbanization influences parasite infection dynamics in livestock due to close human-animal cohabitation and changes in animal housing conditions. The aim of the present study was to investigate social-ecological effects on gastrointestinal nematode (GIN) and Eimeria spp. infections in dairy cattle along a rural-urban gradient in the emerging Indian megacity Bangalore. In this regard, 726 faecal samples from 441 dairy cattle of different ages and physiological stages were collected from 101 farms and examined at three visits between June 2017 and April 2018. Based on a survey stratification index (SSI) comprising built-up density and distance to the city center, we assigned the farms to urban, mixed and rural areas. GIN eggs were identified in the faeces of 243 cattle (33.5%; 95% confidence interval [CI]: 30.1-36.9%), and Eimeria spp. oocysts in the faeces of 151 cattle (20.8%; 95% CI: 17.9-23.7%). Co-infection rates of GIN and Eimeria spp. were 8.5 to 12.2% higher in rural compared to urban and mixed areas. The SSI effect significantly influenced Eimeria spp. infection probability and oocyst per gram of faeces (OpG; P<0.001) with an infection probability and OpG higher than 26% and 40% for cattle kept in rural areas compared to cattle from urban areas. However, the SSI effect was not significant for the infection probability of GIN and for GIN eggs per gram of faeces (EpG). Infection probabilities and EpG/OpG were significantly higher in calves and heifers compared to lactating and dry cows. Moreover, we estimated significantly lower OpG values in summer compared to the other seasons. No differences were estimated for GIN and Eimeria spp. infection probabilities and EpG/OpG with regard to pasture access and breed. The variations in endoparasite infection intensity and probability observed along the rural-urban gradient of Bangalore reflect the variability in dairy husbandry systems governed by the social-ecological context.

Impact of Claw Disorders in Dairy Cattle on Health, Production and Economics and Practicable Preventive Methods

Problems with claw disorders in dairy cattle herds are very typical and are among the most significant endemic cattle diseases. It is good to realize in what condition we keep the cattle - unsuitable floors and bed boxes, greasy microclimate, frequent movement between groups of animals, significant changes in the feed ration - all this affects the health of claws. Lameness and claw lesions have a great impact on production, welfare and health of dairy cows. They decreases milk yield, have a negative impact on reproductive traits and fertility performance and therefore lameness increases costs including medicine, detection of lameness, control and prevention, and creates losses including reduced milk production, non-sellable milk, reduced reproductive performance, increased culling and animal death. To reduce the effect of claw disorders on dairy cattle, it is necessary to apply the most efficient combination of available methods of prevention. The most effective is the combination of early detection and diagnosis, regular claw trimming, proper diet and clean and suitable enviroment. The aim of this review was to cumulate the existing informations of aspects of claw lessions and known preventive methods for breeders of dairy herds.

Food Security Under The Era Of Climate Change Threat

Food Security Under The Era Of Climate Change Threat

Short Time-Series Expression Transcriptome Data Reveal the Gene Expression Patterns of Dairy Cow Mammary Gland as Milk Yield Decreased Process.

The existing research on dairy cow mammary gland genes is extensive, but there have been few reports about dynamic changes in dairy cow mammary gland genes as milk yield decrease. For the first time, transcriptome analysis based on short time-series expression miner (STEM) and histological observations were performed using the Holstein dairy cow mammary gland to explore gene expression patterns in this process of decrease (at peak, mid-, and late lactation). Histological observations suggested that the number of mammary acinous cells at peak/mid-lactation was significantly higher than that at mid-/late lactation, and the lipid droplets area secreted by dairy cows was almost unaltered across the three stages of lactation (p > 0.05). Totals of 882 and 1439 genes were differentially expressed at mid- and late lactation, respectively, compared to peak lactation. Function analysis showed that differentially expressed genes (DEGs) were mainly related to apoptosis and energy metabolism (fold change ≥ 2 or fold change ≤ 0.5, p-value ≤ 0.05). Transcriptome analysis based on STEM identified 16 profiles of differential gene expression patterns, including 5 significant profiles (false discovery rate, FDR ≤ 0.05). Function analysis revealed DEGs involved in milk fat synthesis were downregulated in Profile 0 and DEGs in Profile 12 associated with protein synthesis. These findings provide a foundation for future studies on the molecular mechanisms underlying mammary gland development in dairy cows.

Invited Review: Ketosis Diagnosis and Monitoring in High-Producing Dairy Cows

This work reviews the current impact and manifestation of ketosis (hyperketonemia) in dairy cattle, emphasizing the practical use of laboratory methods, field tests, and milk data to monitoring this disease. Ketosis is a major issue in high-producing cows, easily reaching a prevalence of 20% during early postpartum when the negative energy balance is well established. Its economic losses, mainly related to decreasing milk yield, fertility, and treatment costs, have been estimated up to €250 per case of ketosis/year, which can double if associated diseases are considered. A deep relationship between subclinical or clinical ketosis and negative energy balance and related production diseases can be observed mainly in the first two months postpartum. Fourier transform infrared spectrometry methods gradually take place in laboratory routine to evaluates body ketones (e.g., beta-hydroxybutyrate) and probably will accurately substitute cowside blood and milk tests at a farm in avenir. Fat to protein ratio and urea in milk are largely evaluated each month in dairy farms indicating animals at risk of hyperketonemia. At preventive levels, other than periodical evaluation of body condition score and controlling modifiable or identifying non-modifiable risk factors, the ruminatory activity assessment during the peripartum seems to be a valuable tool at farms. We conclude that a technological advance progressively takes place to mitigate the effects of these metabolic diseases, which challenge the high-yielding cows.

Promising areas of insurance for farm animals

The article considers proposals for improving the insurance of farm animals with state support. The aim of the study is to develop new programs for insurance of farm animals with state support, based on a decrease in productivity. The main goal in calculating insurance rates is related to the determination and coverage of the likely amount of damage attributable to each policyholder. The insurance scheme of climatic risks in dairy cattle breeding is proposed, taking into account the animals productivity. Based on scientific data on a decrease in milk yield at an air temperature of more than 30°C, it is proposed to compensate for the decrease in productivity during the high temperatures period. In the Samara region, the insurance premium will amount to 1707.8 rubles per head. The total amount of the insurance premium will be 75126.0 thousand rubles, and the amount of state support for this program - 37563.0 thousand rubles in year. Thus, animal insurance and its state support is a reliable tool for reimbursement of losses for agricultural producers in the risky events in the livestock industry.

Heat stress in dairy cows

This review includes an analysis of the literature on various influencing factors influencing heat stress in lactating dairy cows and the way it affects milk production. Signs and symptoms of heat stress in cows are reduced feed consumption and decreased milk yield, elevated breathing rate, increased body temperature and reduced reproductive overall performance. There are other problems for example, a seasonal growth in bulk tank somatic cell counts. The birth weight is decreased in cows which have been exposed to heat stress throughout the dry length. It is established that the most critical is the heat accumulated via direct radiation from the solar. It was found out that high feed consumption results in raised metabolic heat increment. High metabolic warmness increment requires powerful thermoregulatory mechanisms to maintain body temperature in a thermoneutral area and in physiological homeostasis. It is confirmed that heat stress is complicated because the responses to heat stress have an effect on not best the energy stability, but also water, sodium, potassium and chlorine metabolism. Plasma progesterone degrees may be elevated or reduced depending on whether or not the heat pressure is acute or chronic. Water, sodium, potassium and chlorine are vital constituents of sweat, and sweating is a chief, if not the most important, thermoregulatory mechanism used to burn up extra body heat. Strategies to reduce heat stress must be evolved to enable cows to express their full genetic ability. Key words: dairy cows, heat stress, thermoregulatory mechanism, water, feed consumption, mineral elements.

67 Current Status and Future Prospective of the Use of Plant Bioactive Compounds in Dairy and Beef Cattle

Abstract In the last 20 years there has been extensive in vitro research on the effects of plant extracts and essential oils on rumen microbial fermentation. The main objectives have been to improve energy metabolism through a reduction in methane emissions and an increase in propionate production; and to improve protein metabolism by reducing proteolysis and deamination. While the positive results from in vitro studies has stimulated the release of commercial products based on blends of essential oils, there is limited in vivo evidence on the rumen fermentation and production performance effects. A literature search was conducted to select in vivo studies where information on rumen fermentation and animal performance was reported. For dairy cattle, we identified 37 studies of which 21 were adequate to test production performance. Ten studies reported increases and 3 decreases in milk yield. For beef cattle, we identified 20 studies with rumen fermentation profile and 22 with performance data. Average daily gain improved in 7 and decreased in 1 study. Only 1 out of 16 studies reported an improvement in feed efficiency. Data indicate that out of more than 500 products tested in vitro, only around 20 have been tested in vivo in different mixtures and doses. The use of statistical approaches will allow to describe the conditions, doses and responses in dairy and beef cattle performance. The search for postruminal effects offers another alternative use. Evidence for effects on the intestinal and systemic effects on the immune system and antioxidant status (i.e., capsicum, garlic, eugenol, cinnamaldehyde curcuma, catechins, anethol or pinene), and in the modulation of metabolic regulation (capsicum, cinnamaldehyde, curcuma or garlic) may open the opportunity for future applications. However, stability of the product in the GI tract, description of the mechanisms of action and the impact of these changes on performance needs to be further demonstrated.

Modelling THI effects on milk production and lactation curve parameters of Holstein dairy cows.

The main objective of this study was to determine the potential impact of heat stress (HS) on milk production and lactation curve parameters of Holstein dairy cows. Milk, fat, protein, and somatic cell count test-day records collected between 2013 and 2019 from 947 cows in 23 herds were combined with THI calculated from meteorological data recorded between 2013 and 2019. The temperature-humidity index (THI) was used to investigate the effect of heat stress. The severity of heat stress was measured using the temperature-humidity index (THI) and the impacts of different THIs-low (≤68), moderate (68-72), and high (≥72) on production performance and lactation curve parameters were measured. The nonlinear model of Wood was applied for modeling the lactation curve. Analysis of variance was applied to test the effects of three levels of THI on milk production, its composition, and lactation curve parameters. Results showed losses due to heat stress. A decrease in milk yield and fat and protein content was reported. Fat and protein contents tended to decrease steadily with increasing values of THI. Milk yield ranged from 17.882±0.064 (68<THI<72) to 16.503±0.035kg/j (THI>72), fat and protein contents ranged from 3.551±0.041 to 3.449±0.026 and from 3.246±0.031%, to 3.113 (0.029) for 68<THI<72 and THI>72, respectively. Somatic cell score was marked by an increase (from 4.143 to 4.358) at the highest ranges of THI>72 and decreased values (from 4.143 to 3.857) at the lowest ranges of THI. Heat stress showed a significant effect on the parameters of the lactation curve. The increased value of THI showed a significant effect on milk yield THI was in a significant negative correlation with the yield, and quality of milk. The effect of THI was highly significant (P<0.05) for all parameters of the lactation curve and milk yield. Cows exposed to THI between 68 and 72 achieved the highest peak milk yields and the highest total yield of 305 days of lactation (Y305).

Comparative assessment of cows by daughters from different breeding bulls in terms of milk production

The increase in the productivity of cows is inseparably linked with the intensification of selection work with dairy cattle. All over the world, dairy cattle are used to obtain milk, including such related ones as black-and-white, Holstein, Dutch, which differ in economically useful qualities depending on the climatic and ecological-forage conditions of the breeding zone, and the gene pool of breed resources. Animal perfection is achieved by selecting the best males and females for reproduction and individual selection. The transmission of genes from generation to generation is carried out from father to son, from mother to son, from father to daughter, from mother to daughter. The rate of genetic improvement in dairy cattle populations depends on the efficiency of the assessment, selection and use of these groups of animals. Currently, the farm uses the daughters of sire bulls belonging to 3 Holstein lines. Several breeding bulls are used in each line. So, at present, the farm uses 17 bulls-sires of the Vis Back Aydial 1013415 line, 10 bulls of the Reflection Sovering 198998 line and 3 bulls of the Montvik Chief 95679 line, but the daughters of not all breeding bulls are already used in the herd. The belonging of cows to a certain line reliably at a high level of reliability influences the indicators of milk productivity. The decrease in milk yield in cows of the Montvik Chieftain 95679 line is accompanied by an improvement in the quality indicators of milk, namely, MJ in milk. Daughters of bulls-producers of a certain line differ in their productive qualities. The best indicators were found in the groups of daughters of sire bulls: Emen 105018721 and Pilot 63811814 (Reflection Sovering line 198998); Reverse 2708 (Montvik Chieftain line 95679); Tek 69052876 and Fennek 4241542328 (Vis Back Aydial line 1013415).

Influence of the age of cows on the dynamics of dairy efficiency depending on a breeding line

The article suggests that one of the most widespread dairy breeds in the world is the Holstein breed; and the black-mottled breed in the Russian Federation. This breed has been improving during the past four decades by interbreeding it with the best one, the Holstein breed. A large set of the Holsteinized black-mottled livestock of the high thoroughbred cows of the Holstein breed has been produced. The aim of the work is to study the effect of age on the dynamics of dairy efficiency of the Holsteinized cows depending on the breeding line. At present, the dairy herd of the farm actually consists of cows of three breeding lines, Reflection Sovering 198998, Vis Back Ideal 1013415, Montvik Chieftain 95679. The rest breeds are not developing due to the absence of breeding valuable breeding bulls. It was found that the Reflection Sovering breeding line 198998 has that the highest milk yield during the sixth lactation, and then there is a decrease in milk yield. The article considers that the milk yield changes with age, starting from the first lactation, increasing during the second lactation and then it is gradually decreasing in productivity to the fifth one. The regularity of the increase in milk yield of mature cows during the third and fourth lactation is not confirmed of the dairy cows of this breeding line. It can be explained by the intensity of herb replacement, when it accumulates a significant amount of nutrients in the body. That is why, they can be used during the first and the second lactations without restoring nutrients in further. Dairy cows of the Vis Back Ideal 1013415 breeding line have a gradual increase in milk yield, starting from the first to the fourth lactation, by 52, 292, 300 kg or by 0.5; 2.8% and 2.8%, respectively. Further, there is a decrease in dairy efficiency. At reaching physiological maturity they have a natural increase in dairy efficiency. The same tendency is observed with cows of the Montvik Chieftein 95679 breeding line.

Evaluation of the relationship between milk yield and the service period duration of cows

In the Sverdlovsk Region, the breeding stock of the black-and-white Ural breed was covered with the seed of servicing bulls of Canadian, Danish and German selection. They are able to show good average daily milk yields throughout lactation, to produce for a long time without a sharp decrease in milk yield, but at the same time, the problem of a decrease in the reproductive ability of cows and, as a consequence, a decrease in the productive longevity of the breeding stock was identified. The purpose of the work is to assess the relationship between the indicators of milk yield of Holsteinized black-and-white cattle of the Ural breed and the service period duration. It has been established that milk yield in first-calf cows increases with an increase in live weight to 600-624 kg, and then slightly decreases (P≥0.05). Calculation of the correlation coefficient between the characteristics of milk yield per lactation and live weight of first-calf heifers showed that it is different and varies depending on the live weight of cows from -0.36 for cows with a live weight of less than 550 kg to 0.28 for animals with a live weight of over 625 kg. There was a low positive relationship of these characteristics in cows with live weight of 575-599 kg. On average for the herd, it is positive and is 0.15. The service period for first-calf heifers ranged from 99 days (live weight 550-574 kg) to 162 days (live weight over 625 kg). Large milk yields were observed in animals with live weight of 575-599 kg and a service period of 138-140 days. A positive high and medium correlation between milk yield and the service period duration was established in groups of cows with live weight up to 550 and 575-624 kg and on average for the herd. It is impossible to draw an unambiguous conclusion about the influence of the service period duration on the quality indicators of milk, with the exception of the indicator service period – mass fraction of protein (MFP), where it was negative regardless of the live weight of cows.

THE EFFECTIVENESS OF THE USE OF SPLITS AND STRESS - FREE ANIMAL HANDLING METHODS IN THE MTF OF KARAGANDA REGION

The article describes research work in the basic farms of the central region of Kazakhstan. All experimental work was carried out in the conditions of «Astra-Agro LTD LLP» and «Salem» farm in the Karaganda region. When using the split and the fixator, no stress-causing factors (judging by the relatively calm behavior of the animals) were observed, and the average daily milk yield in the experimental group of the Salem farm decreased by 0.400 liters. or by 3.1%, when in the control group there is a sharp decrease in the average daily milk yield within 1.6 liters or 12.4% of milk. According to the results of the control milking in the experimental group of Astra-Agro LTD LLP, the average daily milk yield decreased by 1.2 liters or 9.1% of milk, and in the experimental group it decreased by 0.200 liters or 1.6%. As a result of stress in cows of the control groups noticed a redness of the eyes, the pulse in animals too «Astra-agro LTD» increased by 34% and in KKH «Salem» 38% breath exceeded 35% in LLP «Astra-agro LTD» KH «Salem» 46% of the variance in body temperature was observed. In the experimental group, the pulse of animals exceeded by 9% in «Astra-agro LTD» LLP, in «Salem» farm by 14% and the respiration of cows in «Astra-agro LTD» LLP and in «Salem» farm by 14%, the body temperature also fluctuated within the normal range.

Handling and milking frequency affect milk yield and behavior in dairy ewes

The effects of human handling (friendly versus aversive) and milking frequency (once versus twice daily) on productive and behavioral parameters of two Greek dairy sheep breeds (Karagouniko and Chios) were examined. The experiment started a week after lamb weaning (50 ± 5 days after lamb birth) and lasted for ten weeks. Milk yield, milk flow rate and number of kick responses during milking were weekly recorded. Each milking was alternatively performed by a friendly or an aversive milker. At the end of 4th and 9th week, an isolation - flight distance test was also applied. As shown, Karagouniko ewes had lower daily milk yield but higher milk flow rate than Chios ewes. Higher milk yield was also observed in ewes milked twice compared to those milked once per day. Aversive handling increased the number of kick responses during milking and decreased milk yield. At the same time, ewes exhibited a preference for a specific position in the milking parlor. During the isolation - flight distance test, Karagouniko ewes bleated less, but had longer flight distances compared to Chios ones. Multiparous had a shorter flight distance than the primiparous ewes. Finally, ewes milked once per day displayed more jumps and less bleats compared to those milked twice. It is suggested that specific training programs targeted at the handling improvement with the intention to reduce fear responses could improve productivity in dairy ewes.

Apparent prevalence of Mycoplasma wenyonii, Candidatus Mycoplasma haemobos, and bovine leukemia virus in Wisconsin and Michigan dairy cattle herds

Mycoplasma wenyonii (formerly Eperythrozoon wenyonii) is a hemotrophic, epicellular bacterial parasite of cattle that has been associated with clinical disorders, including hemolytic anemia, decreased milk yield, and peripheral edema. Mycoplasma wenyonii and a related organism, Candidatus Mycoplasma haemobos, have been detected in both ill and apparently healthy cattle, but little is known about their prevalence in US dairy cattle. The objective of this prospective, cross-sectional study was to determine herd-level apparent prevalence of M. wenyonii and C. M. haemobos in dairy cattle located in Wisconsin and Michigan compared with seroprevalence of bovine leukemia virus (BLV) in the same herds. In summer 2018, researchers collected blood samples from 30 lactating cows per herd from randomly recruited farms in selected dairy-intensive counties in each state. During the farm visit, a brief survey was used to collect herd management information. Detection of M. wenyonii and C. M. haemobos were based on PCR testing, and ELISA was used to test for antibodies to BLV. Blood samples were collected from lactating cows located in 64 Wisconsin herds (n = 1,930 samples) and 18 Michigan herds (n = 591 samples). Herd-level apparent prevalence was 100% for both M. wenyonii and C. M. haemobos. Herd-level seroprevalence for BLV was 83 and 100% for Wisconsin and Michigan herds, respectively. Estimated within-herd apparent prevalence of M. wenyonii was 71.7% ± 1.0% (ranging from 23.3 to 93.5%) and for C. M. haemobos was 77.3% ± 1.0% (ranging from 16.7 to 100%). Within-herd prevalence of BLV positive samples was 39.8% ± 1.0% and ranged from 0 to 86.7%. About 22% of cows were concurrently positive for all 3 organisms. Parity and stage of lactation were recorded for 2,317 cows. Prevalence of positive cows for parity groups 1, 2, and ≥3 were 72.0, 73.8, and 67.7% for M. wenyonii; 80.9, 76.8, and 74.9% for C. M. haemobos; and 25.3, 39.7, and 55.5% for BLV, respectively. None or only minor differences in apparent prevalence were observed based on stage of lactation. This is the first report of the prevalence of hemotrophic mycoplasmas in Wisconsin and Michigan dairy herds and indicates that infection with these organisms is endemic. The impact of infection on cattle health and productivity remains unknown, and risk factors associated with infection warrant further study.

In vitro reduction of mycotoxin deoxynivalenol by organic adsorbent

The contamination of feeds and foods with mycotoxins is a serious problem worldwide. Deoxynivalenol (DON), an important mycotoxin from the trichothecene family, is abundant in animal feed. Mycotoxin binders such as Lactic acid bacteria (LAB) detoxify mycotoxins by adsorption and inactivate the toxins through the formation of mycotoxin-organic adsorbent complex or act as biomarkers to convert the toxins into less toxic products. In this study, the effect of organic adsorbent containing Lactobacillus strains and the cell wall of the yeast Saccharomyces cerevisiae was investigated on the reduction of DON. Various parameters including toxin concentration, adsorbent type, incubation time, and the synergism effect were also studied. The detoxification ability was demonstrated in all strains but the combination of Lactobacillus brevis TD4 and Lactobacillus paracasei TD3 in PBS solution and L. brevis TD4 and L. brevis TD10 in MRS broth medium showed the highest reduction rate of DON. Novelty Impact Statement Deoxynivalenol causes devastating effects on animal health as well as agricultural products such as decreased milk yield and lower quality of dairy products. In the current study, the detoxification ability of mycotoxin-organic binders including Lactobacillus and yeast cell wall was investigated and the combination of Lactobacillus brevis TD4 and Lactobacillus paracasei TD3 in PBS solution and L. brevis TD4 and L. brevis TD10 in MRS broth medium showed the highest reduction rate of DON.

Adverse effects of LPS on membrane proteins in lactating bovine mammary epithelial cells.

Mastitis causes a decrease in milk yield and abnormalities in milk components from dairy cows. Escherichia coli and the E. coli lipopolysaccharide (LPS) cell wall component directly downregulate milk production in bovine mammary epithelial cells (BMECs). However, the detailed mechanism by which this occurs in BMECs remains unclear. Various membrane proteins, such as immune sensors (Toll-like receptors, TLR), nutrient transporters (glucose transporter and aquaporin), and tight junction proteins (claudin and occludin) are involved in the onset of mastitis or milk production in BMECs. In this study, we investigated the influence of LPS on membrane proteins using an in vitro culture model. This mastitis model demonstrated a loss of glucose transporter-1 and aquaporin-3 at lateral membranes and a decrease in milk production in response to LPS treatment. LPS disrupted the tight junction barrier and caused compositional changes in localization of claudin-3 and claudin-4, although tight junctions were maintained to separate the apical membrane domains and the basolateral membrane domains. LPS did not significantly affect the expression level and subcellular localization of epidermal growth factor receptor in lactating BMECs with no detectable changes in MEK1/2-ERK1/2 signaling. In contrast, NFκB was concurrently activated with temporal translocation of TLR-4 in the apical membranes, whereas TLR-2 was not significantly influenced by LPS treatment. These findings indicate the importance of investigating the subcellular localization of membrane proteins to understand the molecular mechanism of LPS in milk production in mastitis.