Reduced Milk Yield Research Articles

A scoping review on associations between paratuberculosis and productivity in cattle.

Paratuberculosis (PTB), or Johne's disease, is a disease with worldwide distribution caused by Mycobacterium avium subsp. paratuberculosis (MAP) that leads to chronic enteritis, primarily in ruminants. Even subclinical infection significantly reduces the animals' performance, and consequences of the disease lead to high economic losses for the cattle industry. To estimate the economic burden of bovine PTB and to evaluate the benefits of a potential control program, accurate estimates of the production effects associated with the disease are required. Therefore, the aim of this scoping review was to provide a comprehensive overview of associations between MAP infection and production parameters in cattle. The studies were collected from three electronic databases. Of the total 1,605 identified studies, 1,432 did not meet the set criteria in the title and abstract screening and a further 106 were excluded during full-text review. Finally, data on 34 different production parameters were extracted from 67 publications. Results show that the magnitude of reported performance losses varies depending on several factors, such as the type of diagnostic test applied, disease status or number of lactations. Studies reported a reduction in milk yield, changes in milk quality (e.g., higher somatic cell count, lower amount of produced milk fat and protein), reduced fertility (e.g., prolonged calving interval and service period, higher abortion rate and calving difficulties), reduced weaning weight, slaughter weight and slaughter value, or a higher risk for mastitis. Results from the studies included in our review show a median decrease of milk yield per infected cow of -452 kg/lactation for raw and -405 kg/lactation for modeled data. Similarly, the amount of produced milk protein fell by a median of -14.41 kg/lactation for modeled data and the amount of produced milk fat by a median of -13.13 kg/lactation. The reviewed studies revealed a prolonged calving interval by around 30 days and a 1.5 to 3 times higher likeliness of culling per lactation in PTB positive animals. Results from this scoping review provide evidence-based inputs for the development of economic models aiming at the estimation of the costs and benefits associated with different disease control scenarios for PTB.

Association between production and reproduction parameters based on parity and breed of dairy cows in the Czech Republic

Abstract. Milk production and the efficiency of dairy cow breeding are significantly influenced by reproductive factors. The purpose of our research was to examine the relationships between selected milk production and reproductive parameters. We evaluated 659 dairy cows, including 444 purebreds from the Czech Fleckvieh and Holstein breeds and 215 crossbreds. Our primary objective was to assess the impacts of breed and parity on specific milk production and reproductive parameters. The study revealed significant results regarding the interaction between certain breed groups and parity. In particular, there was a noticeable increase in milk yield with parity. Furthermore, it was also evident that the highest milk yield values were related to the milk content. Breed group H, which represents cows with a more than 50 % Holstein bloodline, had the highest values of the monitored milk content. Our findings show that first-lactation crossbred Czech Fleckvieh cows had a reduced milk yield, decreased fat, and lactose content in milk. However, they had a more favourable calving interval when compared to purebred Czech Fleckvieh and higher-parity Holstein crossbreds. Crossbred H, in comparison to C100 and C50, whether purebred or crossbred with Czech Fleckvieh, showed a relatively higher content of some milk components. The results for service periods and calving intervals were not statistically significant. The findings of this study highlight the promising potential of higher-parity Holstein crossbred cows in terms of milk yield and the advantages of lower-parity ones concerning milk contents.

Substitution of human edible feeds with integrated use of reduced fat wheat distillers and high-quality forages in a diet for high production lactating dairy cows

This study has investigated the effect of the integration of wheat distillers, without solubles, after lipid extraction (RF-DDG) in a diet based on high-quality forages in partial substitution of human-edible feeds, i.e. corn and soybean meal (SBM), on milk production and quality, feed conversion efficiency and on the human-edible feed conversion efficiency of high producing dairy cows. The experiment was conducted on a commercial dairy farm for an 8-wk period, split into 2 periods, lasting 28 d each (2-wk adaptation and 2-wk experimental period with data collection) on 180 Holstein cows (averaging 130 DIM and 42.0 kg of milk/d at the start of the trial), randomly assigned to 4 pens (45 cows each). The cows, stratified by DIM, were split in two groups assigned two diets that differed according to the human edible feed inclusion: (1) a control diet (CON), based on alfalfa silage, grass silage, high moisture ear corn silage, and soybean meal (SBM) as a protein supplement, 2) a treatment diet (TREAT), in which the control diet was modified using RF-DDG at 13.0 % (dry matter basis) to totally replace soybean meal (SBM).The dry matter intake was similar across treatments, whereas the milk yield was 2.06 kg/d lower for the TREAT diet. The inclusion of wheat RF-DDG increased the milk fat concentrations (3.74 vs 3.54 %) and decreased the milk protein concentration (3.02 vs 3.18 %), milk protein yield (1.19 vs 1.31 kg/d), and milk urea nitrogen (3.63 vs 7.61 mg/dL). Cows fed the TREAT diet showed an increased aNDFom, ADF ADL, NDIN and ADIN intake compared with those fed the CON diet. The TREAT diet resulted in a reduced milk yield as well as a reduced milk protein concentration and yield, which were likely caused by a reduction in the apparent digestibility of the protein and by different essential AA and RDP contents in the TREAT diet compared to the control DIET. The TREAT diet also decreased serum glucose, albumin, as well as the urea nitrogen and total protein in the blood, compared with the CON diet. Furthermore, the TREAT diet led to a reduction in the milk production feed conversion efficiency (in terms of milk yield/DMI and FPCM/DMI) and in the nitrogen utilization of the milk production (28.3 vs 31.0 %). The inclusion of RF-DDG led to a substantial increase in the human-edible feed conversion index for the protein (1.19 vs. 0.74) and for energy (1.66 vs 1.39), thereby improving the net protein and energy food balance. It has been concluded that further research is needed to find an economical process to extract oil from DDG without causing any further thermal stress that could compromise the protein components and amino acid supply of RF-DDG.

PARTIAL MASTECTOMY IN A DAIRY BEETAL GOAT AFFECTED WITH A MAMMARY TUMOR – A CASE REPORT

Mammary tumors are relatively common in dairy goats, negatively impacting production and farmers' economies. Irreversible loss of respective udder reduces milk yield or culling of the animals. In a current case report, A Beetal goat was presented at the UVAS surgery clinic with a udder tumor. After confirmation, a partial mastectomy was performed under general anesthesia and aseptic surgery. The neoplastic growth was resected, and surgery was completed. The overall health status of the animals was improved with an increase in milk yield during post-operative care and a follow-up period of 30 days. The surgical removal of udder tumor could be useful in small ruminants to restore udder health and milk production.

Localized mammary gland changes in milk composition and venous blood metabolite concentrations result from sterile subclinical mastitis

Subclinical mastitis reduces milk yield and elicits undesirable changes in milk composition, but the mechanisms resulting in reduced milk production in affected mammary glands are incompletely understood. This study investigated the effects of sterile inflammation on mammary gland metabolism by assessing changes in milk and venous blood composition. Mid-lactation primiparous Holstein cows (n = 4) had udder halves randomly allocated to treatments; quarters of 1 udder half were infused with 2 billion cfu of formalin fixed Staphylococcus aureus (FX-STAPH) and quarters of the opposite udder half infused with saline (SAL). Blood samples were collected from the right and left subcutaneous abdominal veins in 2.6 h intervals until 40 h post challenge and analyzed for blood gas and metabolite concentrations. Milk from FX-STAPH udder halves had significantly increased SCS by first milking at 8 h post-challenge. By 16 h post-challenge, FX-STAPH udder halves had increased concentrations of protein and lactate and lower lactose concentrations than SAL udder halves. Milk fat concentrations, milk yields, energy corrected milk yields, and the ferric reducing antioxidant power of milk were not significantly different between SAL and FX-STAPH udder halves. Venous blood of FX-STAPH halves had marginally greater concentrations of saturated O2, partial pressures of O2, and glucose concentrations than SAL halves. Conversely, total and partial pressures of CO2 did not differ between udder half treatments suggesting a shift in local metabolite utilization in FX-STAPH udder halves. These results indicate that changes in milk composition resulting from mastitis are accompanied by changes in some key blood metabolite concentrations. The shift in venous blood metabolite concentrations, along with the marked increase in milk lactate, suggests that local mammary tissue and/or recruited and immune cells alters metabolite usage in mammary tissues. Future studies are needed to quantify the uptake of key milk precursors during mastitis.

Feed restriction of lactating cows triggers acute downregulation of mammary mammalian target of rapamycin signaling and chronic reduction of mammary epithelial mass

While there is generally no consensus about how nutrients determine milk synthesis in the mammary gland, it is likely that the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) plays a role as a key integrator of nutritional and mitogenic signals that can influence a multitude of catabolic and anabolic pathways. The objectives of this study were to evaluate acute changes (<24 h) in translational signaling, in addition to chronic changes (14 d) in mammary gland structure and composition, in response to a severe feed restriction. Fourteen lactating Holstein dairy cows were assigned to either ad libitum feeding (n = 7) or a restricted feeding program (n = 7). Feed-restricted cows had feed removed after the evening milking on d 0. Mammary biopsies and blood samples were collected 16 h after feed removal, after which cows in the restricted group were fed 60% of their previously observed ad libitum intake for the remainder of the study. On d 14, animals were slaughtered and their mammary glands dissected. In response to feed removal, an acute increase in plasma nonesterified fatty acid concentration was observed, concurrent to a decrease in milk yield. In mammary tissue, we observed downregulation of the mTORC1-S6K1 signaling cascade, in addition to reductions in mRNA expression of markers of protein synthesis, endoplasmic reticulum biogenesis, and cell turnover (i.e., transcripts associated with apoptosis or cell proliferation). During the 14 d of restricted feeding, animals underwent homeorhetic adaptation to 40% lower nutrient intake, achieving a new setpoint of 14% reduced milk yield with 18% and 29% smaller mammary secretory tissue DM and CP masses, respectively. On d 14, no treatment differences were observed in markers of protein synthesis or mammary cell turnover evaluated using gene transcripts and immunohistochemical staining. These findings implicate mTORC1-S6K1 in the early phase of the adaptation of the mammary gland's capacity for milk synthesis in response to changes in nutrient supply. Additionally, changes in rates of mammary cell turnover may be transient in nature, returning to basal levels following brief alterations that have sustained effects.

Molecular Mechanisms Associated with the Development of the Metritis Complex in Dairy Cattle.

The metritis complex (MC), a group of post-partum uterine diseases, is associated with increased treatment costs and reduced milk yield and fertility. The goal of this study was to identify genetic variants, genes, or genomic regions that modulate MC disease. A genome-wide association study was performed using a single-locus mixed linear model of 1967 genotypes (624,460 SNPs) and metritis complex records. Then, in-silico functional analyses were performed to detect biological mechanisms and pathways associated with the development of MC. The ATP8A2, COX16, AMN, and TRAF3 genes, located on chromosomes 12, 10, and 21, were associated with MC at p ≤ 0.0001. These genes are involved in the regulation of cholesterol metabolism in the stromal tissue of the uterus, which can be directly associated with the mode of transmission for pathogens causing the metritis complex. The modulation of cholesterol abundance alters the efficiency of virulence factors and may affect the susceptibility of the host to infection. The SIPA1L1, DEPDC5, and RNF122 genes were also significantly associated with MC at p ≤ 0.0001 and are involved in the PI3k-Akt pathway, responsible for activating the autophagic processes. Thus, the dysregulation of these genes allows for unhindered bacterial invasion, replication, and survival within the endometrium.

Intramammary lipopolysaccharide challenge in early- versus mid-lactation dairy cattle: Immune, production, and metabolic responses

Study objectives were to compare the immune response, metabolism and production following intramammary lipopolysaccharide (IMM LPS) administration in early and mid-lactation cows. Early (E-LPS; n = 11; 20 ± 4 d in milk [DIM]) and mid- (M-LPS; n = 10; 155 ± 40 DIM) lactation cows were enrolled in an experiment consisting of 2 periods (P). During P1 (5 d) cows were fed ad libitum and baseline data were collected, including liver and muscle biopsies. At the beginning of P2 (3 d) cows received 10 mL sterile saline containing 10 µg of LPS from Escherichia coli O111:B4/mL into the left rear quarter of the mammary gland, and liver and muscle biopsies were collected at 12 h post-LPS. Tissues were analyzed for metabolic flexibility, which measures substrate switching capacity from pyruvic acid to palmitic acid oxidation. Data were analyzed with the MIXED procedure in SAS 9.4. Rectal temperature was assessed hourly for the first 12 h post-LPS and every 6 h thereafter for the remainder of P2. All cows developed a febrile response following LPS, but E-LPS had a more intense fever than M-LPS cows (0.7°C at 5 h after LPS). Blood samples were collected at 0, 3, 6, 9, 12, 24, 36, 48, and 72 h post-LPS for analysis of systemic inflammation and metabolism parameters. Total serum Ca decreased after LPS (26% at 6 h nadir) but did not differ by lactation stage (LS). Circulating neutrophils decreased, then increased post-LPS in both LS, but E-LPS had exaggerated neutrophilia (56% from 12 to 48 h) compared with M-LPS. Haptoglobin increased after LPS (15-fold) but did not differ by LS. Many circulating cytokines were increased post-LPS, and IL-6, IL-10, TNF-α, MCP-1, and IP-10 were further augmented in E-LPS compared with M-LPS cows. Relative to P1, all cows had reduced milk yield (26%) and dry matter intake (DMI; 14%) on d 1 that did not differ by lactation stage (LS). Somatic cell score increased rapidly in response to LPS regardless of LS and gradually decreased from 18 h onwards. Milk component yields decreased after LPS. However, E-LPS had increased fat (11%) and tended to have increased lactose (8%) yield compared with M-LPS cows throughout P2. Circulating glucose was not affected by LPS. Nonesterified fatty acids (NEFA) decreased in E-LPS (29%) but not M-LPS cows. β-hydroxybutyrate (BHB) slightly increased (14%) over time post-LPS regardless of LS. Insulin increased after LPS in all cows, but E-LPS had blunted hyperinsulinemia (52%) compared with M-LPS cows. Blood urea nitrogen (BUN) increased after LPS and the relative change in BUN was elevated in E-LPS cows compared with M-LPS cows (36 and 13%, respectively, from 9 to 24 h). During P1, metabolic flexibility was increased in liver and muscle in early lactating cows compared with mid-lactation cows, but 12 h post-LPS, metabolic flexibility was reduced and did not differ by LS. In conclusion, IMM LPS caused severe immune activation and E-LPS cows had a more intense inflammatory response compared with M-LPS cows, but the effects on milk synthesis was similar between LS. Some parameters of the E-LPS metabolic profile suggest continuation of metabolic adjustments associated with early lactation to support both a robust immune system and milk synthesis.

Relationships between gastrointestinal permeability, heat stress, and milk production in lactating dairy cows

Heat stress (HS) is a global issue that decreases farm profits and compromises animal welfare. To distinguish between the direct and indirect effects of HS, 16 multiparous Holstein cows approximately 100 d in milk were assigned to one of 2 treatments: pair fed to match HS cow intake, housed in thermoneutral conditions (PFTN, n = 8) or cyclical HS (n = 8). All cows were subjected to 2 experimental periods. P1 consisted of a 4 d thermoneutral period with ad libitum intake. During P2, the HS cows were housed in cyclical HS conditions with a temperature humidity index (THI) ranging from 76 to 80 and the PFTN cows were exposed to a constant THI of 64 for 4 d. DMI of the PFTN cow was intake matched to the HS cows. Milk yield, milk composition, rectal temperature, and respiration rate were recorded twice daily, blood was collected daily via a jugular catheter, and cows were fed twice daily. On d 3 of each period, Cr-EDTA and sucralose were orally administered and recovered via 24 h total urine collection to assess gastrointestinal permeability (GIP). All data were analyzed using the GLIMMIX procedure in SAS. The daily data collected in P1 was averaged and used as a covariate if deemed significant in the model. HS decreased voluntary intake by 35% and increased rectal temperature and respiration rate (38.4 vs 39.4°C and 40 vs 71 respirations/min, respectively). HS reduced dry matter intake (DMI) by 35% which accounted for 66% of the decrease in milk yield. The yield, and not concentration, of milk protein, fat, and other solids were lower in the HS cows on d 4 of P2. Milk urea nitrogen (MUN) was higher and plasma urea nitrogen (PUN) tended to be higher on d 3 and d 4 of HS. Glucose was 7% lower in the HS cows and insulin was 71% higher in the HS cows than the PFTN cows on d 4 of P2. No difference in lipopolysaccharide binding protein (LBP) was observed. HS cows produced 7 L/d more urine than PFTN cows. No differences were detected in the urine concentration or percentage of the oral dose recovered for Cr-EDTA or sucralose. In conclusion, HS was responsible for 34% of the reduction of milk yield. The elevated MUN and the tendency for elevated PUN indicate a whole-body shift in nitrogen metabolism. No differences in GIP or LBP were observed. These results indicate that, under conditions of this experiment, activation of the immune system by gut derived lipopolysaccharide was not responsible for the decreased milk yield observed during HS.

Effects of Elevating Zinc Supplementation on the Health and Production Parameters of High-Producing Dairy Cows

This study’s objective was to determine the effects of increasing the dietary added zinc (Zn) on the milk production, milk somatic cell count (SCC), and immunoglobulin and antioxidant marker concentrations in the blood of dairy cows. Twelve Holstein cows (67 ± 2.5 days in milk) were assigned randomly to (1) a diet containing Zn–methionine at 76 mg/kg of DM (CTL) or (2) CTL top-dressed with about 21 mg/kg of DM extra Zn–methionine (+Zn) for 70 d. The concentrations of reduced (GSH) and oxidized (GSSG) glutathione, malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and immunoglobulins in the blood were measured on d 0, 35, and 70. Compared to CTL, +Zn decreased the dry matter intake (DMI) throughout the trial and the milk yield (MY) during the first phase of feeding (0–35 d). It, however, increased the milk yield during the last phase (36–70 d). The +Zn tended to have lower and greater milk protein yields than CTL during the first and last feeding phases, respectively. The +Zn tended to decrease the SCC and was associated with lower plasma GSH: GSSG and lower serum SOD concentrations relative to CTL. The +Zn did not affect the immunoglobulins, MDA, or CAT. Despite the early DMI and MY reduction, the prolonged Zn–methionine supplementation at about 100 mg/kg of DM improved the milk yield, possibly as a result of the improved udder health of dairy cows.

Characterisation of Putative Outer Membrane Proteins from Leptospira borgpetersenii Serovar Hardjo-Bovis Identifies Novel Adhesins and Diversity in Adhesion across Genomospecies Orthologs.

Leptospirosis is a zoonotic bacterial disease affecting mammalian species worldwide. Cattle are a major susceptible host; infection with pathogenic Leptospira spp. represents a public health risk and results in reproductive failure and reduced milk yield, causing economic losses. The characterisation of outer membrane proteins (OMPs) from disease-causing bacteria dissects pathogenesis and underpins vaccine development. As most leptospire pathogenesis research has focused on Leptospira interrogans, this study aimed to characterise novel OMPs from another important genomospecies, Leptospira borgpetersenii, which has global distribution and is relevant to bovine and human diseases. Several putative L. borgpetersenii OMPs were recombinantly expressed, refolded and purified, and evaluated for function and immunogenicity. Two of these unique, putative OMPs (rLBL0972 and rLBL2618) bound to immobilised fibronectin, laminin and fibrinogen, which, together with structural and functional data, supports their classification as leptospiral adhesins. A third putative OMP (rLBL0375), did not exhibit saturable adhesion ability but, together with rLBL0972 and the included control, OmpL1, demonstrated significant cattle milk IgG antibody reactivity from infected cows. To dissect leptospire host-pathogen interactions further, we expressed alleles of OmpL1 and a novel multi-specific adhesin, rLBL2618, from a variety of genomospecies and surveyed their adhesion ability, with both proteins exhibiting divergences in extracellular matrix component binding specificity across synthesised orthologs. We also observed functional redundancy across different L. borgspetersenii OMPs which, together with diversity in function across genomospecies orthologs, delineates multiple levels of plasticity in adhesion that is potentially driven by immune selection and host adaptation. These data identify novel leptospiral proteins which should be further evaluated as vaccine and/or diagnostic candidates. Moreover, functional redundancy across leptospire surface proteins together with identified adhesion divergence across genomospecies further dissect the complex host-pathogen interactions of a genus responsible for substantial global disease burden.

Meta analysis of the prevalence of subclinical mastitis in dairy cattle

Mastitis, which is defined as the inflammation of mammary tissue caused by infectious agents such as bacteria, yeast, fungi and viruses, is considered to be one of the most important problems of dairy enterprises due to reduced milk yield and milk quality. Therefore, studies on mastitis have been continuous from past to present. The presence of too many studies conducted in all around the world in order to estimate the prevalence of mastitis and to determine the factors affecting the disease has necessitated systematic review or meta-analysis studies on this subject. In this study, it was aimed to perform the meta-analysis for the prevalence of cow and udder quarter-based subclinical mastitis in 193 studies conducted around the world, and to determine the effects of some factors on the prevalence of subclinical mastitis using subgroup and meta-regression methods. Because high heterogeneity was detected between studies in the analysis, the random effects model (Der Simonian-Laird method) (Q=15149.869, df=188, p&lt;0.001, I2=98.759; Q=72142.706; df=174, p&lt;0.001; I2=99.774) was used in this study. The publication biases in the study samples were determined by the use of Egger's linear regression test, the Begg and Mazumdar rank correlation test and funnel plots. As a result of the study, the common prevalence of subclinical mastitis in cow and udder quarter-based studies were calculated as 0.46 (95% CI: 0.43-0.48) and 0.32 (95% CI: 0.30-0.34) respectively. The meta-analysis conducted in this study has enabled the elimination of inconsistencies in the prevalence of subclinical mastitis in individual studies conducted around the world, and has provided a stronger and more precise estimate.

Identifying Risk Factors for Stephanofilaria-Caused Ulcerative Dermal Lesions, in Black and White Rhinoceros’ Meta-Population in Kenya

Ulcerative skin lesions caused by Stephanofilaria dinniki are common in populations of the critically endangered eastern black rhinoceros (Diceros bicornis michaeli). Although considered benign, they have been associated with loss of body condition and mortality in rhinoceros. Stephanofilarial lesions in rhinoceros may also lead to delayed puberty, reduced milk yields, and prolonged intercalving periods as observed with a similar disease in cattle. In this study the prevalence and predilection sites of stephanofilarial wounds were examined and the influence of age, sex, normalized difference vegetation index (NDVI), rainfall, temperature, rhinoceros’ species, and population density on the prevalence of stephanofilarial skin lesions was evaluated in 10 rhinoceros’ populations in Kenya. The results revealed that the prevalence of stephanofilarial skin lesions was 0% in the lowland sanctuaries such as Ngulia Rhino Sanctuary, Tsavo West Intensive Protection Zone, and Tsavo East National Park to ≥90% in the highland rhinoceros’ sanctuaries including Solio Wildlife Sanctuary, Ol Pejeta Wildlife Conservancy, Lewa-Borana Wildlife Conservancies, and Nairobi National Park. Generalized linear models revealed that monthly minimum temperature and NDVI negatively influenced the probability of stephanofilarial skin lesions. However, spatial heterogeneity in NDVI, and rhino density were positively related to the probability of rhinoceros’ infection with Stephanofilaria. Black rhinoceros had a higher average prevalence of stephanofilarial wounds (50.9%, n = 228) than white rhinoceros’ (3.6%, n = 110). Temperature and heterogeneity in NDVI can directly influence the presence of the filaria vector Rhinomusca dutoiti as corroborated by the previous studies on their distribution. Moreover, the inverse relationship between NDVI and the prevalence of stephanofilarial skin lesions suggests that nutrition negatively impacts rhinoceros’ immunity. Comprehensive studies on the vectors of Stephanofilaria and their bionomics may illuminate the epidemiological patterns of stephanofilariosis in rhinoceros.

PREVALENCE OF CONTAGIOUS BOVINE MASTITIS PATHOGENS IN SAMPLES OF COLLECTED MILK

Dairy producers suffer significant economic losses due to various diseases of contagious and non-contagious etiology, among which inflammation of the mammary gland is one of the main ones. Mastitis is one of the most common diseases on dairy farms and causes significant economic losses associated with the cost of treating sick cows, reduced milk yield and quality of dairy products, and the risk of premature culling. The causative agents of mastitis are divided into two groups, among which the most important are contagious pathogens, including the five most important infectious agents: Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis, Streptococcus uberis, Streptococcus dysgalactiae, their habitat is sick animals and they are usually transmitted mainly from a healthy cow to a sick cow, especially through milking equipment, hands of machine milking operators, which in turn can lead to infection of the entire dairy herd. Therefore, establishing the prevalence of contagious mastitis pathogens is quite relevant today, it provides information on the possibility of creating rational and effective mastitis control programs on dairy farms, and also fills an important gap in veterinary medicine and farm management practice. The aim of this study was to identify and establish the prevalence of contagious mastitis pathogens in tank milk samples using bacteriological and molecular genetic (PCR-RFLP) studies. Molecular genetic studies were performed by real-time polymerase chain reaction (RT-PCR). Nucleic acids were isolated using the KingFisher Purification System automatic isolation system using the MagMAX™ CORE Nucleic Acid Purification Kit (Thermo Fisher Scientific, USA). For the amplification reaction of the isolated nucleic acids, commercial VetMAX MastiType Micro4 Kit (Applied Biosystems™ by Thermo Fisher Scientific, USA) was used. The reaction was performed on a real-time PCR product detection system using a QuantStudio5 Real Time PCR System (Thermo Fisher Scientific, USA). Bacteriological studies of tank samples of cow milk were carried out according to generally accepted methods, the identification of bacterial cultures obtained on blood agar was carried out by MALDI-TOF using a VITEK®MS device (BioMérieux, France). The VITEK MS KB V3.2.0 US Version database was used to analyze the mass spectra. The results of the study of contagious mastitis pathogens in tank milk samples by PCR-RF revealed that the most common are Streptococcus agalactiae 36% and Streptococcus uberis 35 %, Staphylococcus aureus occupies an intermediate position, accounting for 24 % of all isolates, Mycoplasma bovis, in turn, accounts for only 5% of isolates. When analyzing the data of the results of molecular genetic studies, it was found that the following associations of pathogens of contagious mastitis in tank milk samples were found Streptococcus uberis, Staphylococcus aureus, Streptococcus agalactiae – 29,8 %, Streptococcus agalactiae, Streptococcus uberis – 21,3 %, Streptococcus agalactiae, Staphylococcus aureus – 19,1 %, Streptococcus uberis, Staphylococcus aureus – 14,9 %, Streptococcus uberis, Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis and Streptococcus uberis, Mycoplasma bovis – 4,3 %, respectively. The associations of infectious agents Streptococcus uberis, Mycoplasma bovis, Streptococcus agalactiae; Mycoplasma bovis, Streptococcus agalactiae and Streptococcus uberis, Mycoplasma bovis, Staphylococcus aureus were found once each, which is 2,1 %. The bacteriological examination of tank milk samples showed that the most commonly detected contagious pathogens were Streptococcus agalactiae – 55 % and Streptococcus uberis – 28 %, Staphylococcus aureus accounted for 11 % of isolates, and Streptococcus dysgalactiae was identified in only 6 % of tank milk samples. The following associations of pathogens of contagious mastitis were most often found in tank milk samples: Streptococcus agalactiae and Staphylococcus aureus – 35,7 %, Streptococcus uberis and Staphylococcus aureus – 28,6 %, Streptococcus uberis and Streptococcus agalactiae – 21,4 %. The associations of pathogens Streptococcus uberis, Staphylococcus aureus, Streptococcus agalactiae and Streptococcus uberis, Streptococcus dysgalactiae were found in tank samples only once, which is 7,1 % each.

A retrospective study on the effects of dry period length on milk yield and postpartum health in Holstein dairy cows.

We retrospectively analyzed the effects of dry period length (DPL) on milk yield and postpartum health using 152 commercial dairy farm data, including 46,228 dairy cows in Hokkaido, Japan, and examined the optimal DPL. The DPL was divided into eight categories: ≤25, 26-35, 36-45, 46-55, 56-65 (reference), 66-75, 76-85, and ≥86 d. The total milk yields (the sum of milk yield during the 55 d before and the 305 d milk yield after calving) of cows with DPL of ≤55 d did not differ from the reference group. Cows with DPL of ≤55 d had lower odds ratios (OR) of a displaced abomasum (DA), ketosis, milk fever (MF), and abnormal milk fat-to-protein ratio but had higher puerperal fever (PF) and stillbirth ORs than the reference group. Cows with a DPL of 46-55 d had the lowest PF and stillbirth ORs among the short DPL categories. The extremely short (≤25 d) and long (≥86 d) DPL increased the ORs of mastitis and abnormal liner score of somatic cell counts (SCCs) compared with the reference group. We conclude that shortening DPL can reduce postpartum health problems without reducing milk yield and that the optimal DPL is 46-55 d.

The role of endoplasmic reticulum stress in metabolic diseases and mammary epithelial cell homeostasis in dairy cows.

High-yielding dairy cows undergo various physiological stresses during the transitional phase of the calving cycle. In this period, they experience negative energy balance, subjecting the liver to significant metabolic stress from an influx of nonesterified fatty acids. This metabolic stress not only impairs liver function but also diminishes milk production. Early lactation dairy cows may develop endoplasmic reticulum (ER) stress in the liver, potentially leading to liver-related diseases and contributing to ER stress in mammary epithelial cells, resulting in decreased milk production. Natural products that alleviate ER stress have been identified, and if further in vivo studies confirm their efficacy, they have potential as feed additives to prevent disease and reduce milk yield. Conversely, physiological levels of ER stress play a role in mammary gland development and positively influence protein synthesis in milk. Understanding the threshold level of ER stress in mammary tissue and its detailed mechanisms will be crucial in dairy farming.

Evaluation of Farmers Knowledge, Vulnerability and Adapting Capacity to Climate Change: A Scenario in Bundelkhand Region

Agriculture production in the Bundelkhand region is highly vulnerable to the climate change. To examine the perception, awareness, extent of knowledge on climate change and its impact on agriculture production with coping strategies, a research study was conducted with randomly selected, 70 sample farmers household from two villages of Datia district. More than 80 per cent farmer feels that climate change is serious issue, and it affects water availability and crop production. 77 percent respondents from watershed area expressed their view, that climate change reduced crop yield followed by the reduction in milk yield, disease and pest incidence, rainfall reduction and environment effect. Results shows that respondents of Jigna village (under watershed area) are reported to be more aware about impact of climate change (temp., rainfall, wind velocity) as compared to Dalipura village. Farmers from both villages were reported deforestation, intensified industrialize and air pollution as reason for consequence of climate change. Intensify research efforts and Enlightenment campaign as efforts to overcome climate change are reported by majority of respondents. Changes in existing cropping pattern and soil-water conservation measures suggested as coping-strategies for climate change.

Proteomic profiling of membrane vesicles from Mycobacterium avium subsp. paratuberculosis: Navigating towards an insilico design of a multi-epitope vaccine targeting membrane vesicle proteins

Bacteria typically produce membrane vesicles (MVs) at varying levels depending on the surrounding environments. Gram-negative bacterial outer membrane vesicles (OMVs) have been extensively studied for over 30 years, but MVs from Gram-positive bacteria only recently have been a focus of research. In the present study, we isolated MVs from Mycobacterium avium subsp. paratuberculosis (MAP) and analyzed their protein composition using LC-MS/MS. A total of 316 overlapping proteins from two independent preparations were identified in our study, and topology prediction showed these cargo proteins have different subcellular localization patterns. When MVs were administered to bovine-derived macrophages, significant up-regulation of pro-inflammatory cytokines was observed via qRT-PCR. Proteome functional annotation revealed that many of these proteins are involved in the cellular protein metabolic process, tRNA aminoacylation, and ATP synthesis. Secretory proteins with high antigenicity and adhesion capability were mapped for B-cell and T-cell epitopes. Antigenic, Immunogenic and IFN-γ inducing B-cell, MHC-I, and MHC-II epitopes were stitched together through linkers to form multi-epitope vaccine (MEV) construct against MAP. Strong binding energy was observed during the docking of the 3D structure of the MEV with the bovine TLR2, suggesting that the putative MEV may be a promising vaccine candidate against MAP. However, in vitro and in vivo analysis is required to prove the immunogenic concept of the MEV which we will follow in our future studies. SignificanceJohne's disease is a chronic infection caused by Mycobacterium avium subsp. paratuberculosis that has a potential link to Crohn's disease in humans. The disease is characterized by persistent diarrhea and enteritis, resulting in significant economic losses due to reduced milk yield and premature culling of infected animals. The dairy industry in the United States alone experiences losses of approximately USD 250 million due to Johne's disease. The current vaccine against Johne's disease is limited by several factors, including variable efficacy, limited duration of protection, interference with diagnostic tests, inability to prevent infection, and logistical and cost-related challenges. Nevertheless, a multiepitope vaccine design approach targeting M. avium subsp. paratuberculosis has the potential to overcome these challenges and offer improved protection against Johne's disease.

Characteristics of bacterial contamination of the mammary gland secretion of lactating cows with subclinical mastitis

Subclinical mastitis (SCM) in lactating cows is a common disease characterized by a change in the composition of mammary gland secretion, especially due to an increase in number of somatic cells in it over a long period of time. Etiologically, this disease arises as a result of the pathogenic effect of mixed infections caused mainly by bacteria of Staphylococcus and Streptococcus genera. It should be noted that due to high prevalence, reduction of milk yield and changes in the physical and chemical properties of milk of cows, SCM is a more important problem than clinical forms of mastitis. Thus, the aim of the work was to determine the main causative agents of SCM in lactating cows and their resistance to antibiotics in order to justify the feasibility of using alternative means in the schemes of therapy and prevention of this disease. During the bacteriological examination of mammary gland secretion, streptococci were differentiated by morphological and cultural-biochemical properties, and the pathogenicity of staphylococci was determined by the ability to coagulate rabbit blood plasma in the conditions of the testing laboratory of Smartbiolab LLC (Kharkov) in 2019–2021. Subclinical mastitis in lactating cows was determined using a sample with 5 % dimastine and a thermographic study. Before taking milk samples, the udders were wiped with 70 % alcohol, and the milk was expressed in sterile tubes. The samples were transported in plastic boxes with cooling elements (at a temperature of 8–10 °С) and were examined no later than 4 hours after the moment of selection. The results of research in selected samples Streptococcus spp., which has β-hemolytic properties, was found in 42.9 % of samples, E. coli with hemolytic properties in 28.6 %, and Staphylococcus haemolyticus and Staphylococcus aureus in 14.2 % each. The detected pathogens were characterized by the following indicators of antibiotic resistance: E. coli isolates were insensitive to 8 antibiotics (ampicillin, penicillin, streptomycin, neomycin, spectinomycin, spiramycin, lincomycin, chloramphenicol), and Streptococcus spp. (penicillin, amoxicillin, amoxicillin + clavulonic acid, streptomycin, norfloxacin, gatifloxacin, lincomycin) and Staphylococcus aureus (ampicillin, penicillin, amoxicillin, streptomycin, oxytetracycline, ceftiofur and lincomycin) up to 7, respectively.

Associations of production characteristics with the on-farm presence of Fasciola hepatica in dairy cows vary across production levels and indicate differences between breeds

Fasciola hepatica is one of the economically most important endoparasites in cattle production. The aim of the present work was to evaluate the relevance of production level on the associations of on-farm presence of F. hepatica with farm-level milk yield, milk fat, and milk protein in Holstein cows, a specialised dairy breed, and in Simmental cows, a dual purpose breed. Furthermore, we investigated whether differential associations were present depending on breed. Data from 560 dairy farms across Germany housing 93,672 cows were analysed. The presence of F. hepatica antibodies was determined via ELISA on bulk tank milk samples. Quantile regression was applied to model the median difference in milk yield, milk fat, and milk protein depending on the interaction of breed and fluke occurrence. Whereas a reduction in milk yield (-1,206 kg, p &lt; 0.001), milk fat (-22.9 kg, p = 0.001), and milk protein (-41.6 kg, p &lt;0.001) was evident on F. hepatica positive German Holstein farms, only milk fat (-33.8 kg, p = 0.01) and milk protein (-22.6 kg, p = 0.03) were affected on F. hepatica positive German Simmental farms. Subsequently, production traits were modelled within each of the two breeds for low, medium, and high producing farms in the presence of F. hepatica antibodies and of confounders. On Holstein farms, the presence of F. hepatica seropositivity was associated with lower production, while on German Simmental farms such an association was less evident. This work demonstrates that production level is relevant when assessing the associations between the exposure to F. hepatica with production characteristics. Moreover, both models indicate a breed dependence. This could point towards a differential F. hepatica resilience of specialised dairy breeds in comparison with dual purpose breeds.