Udder Halves Research Articles

Somatic cell count in dairy goats I: association with infectious and non-infectious factors

BackgroundIntramammary infections negatively affect milk quality, animal welfare and productivity in the dairy industry. Somatic cell count (SCC) is the most used screening tool to detect subclinical mastitis caused by intramammary infections. In dairy goats, SCC is greatly influenced by non-infectious factors, which complicates the interpretation. The aim of this research paper was to determine the association between SCC, intramammary infections and non-infectious factors including parity, season, lactation stage, and milk yield in dairy goats. In this longitudinal study, 451 goats from four Norwegian dairy goat herds were sampled for bacteriology and SCC up to nine times during two lactations. Factors like parity, milk yield, and stage of lactation were retrieved from the Norwegian goat recording system.ResultsThe most prevalent udder pathogen findings were Staphylococcus caprae (6.8%), Staphylococcus warneri (6.3%), and Staphylococcus epidermidis (3.8%), all of which had a mild but significant impact on SCC. Staphylococcus aureus was detected in 3.6% of the udder halves and had a major effect on SCC. Parity, stage of lactation, season, and milk yield significantly influenced SCC.ConclusionsThis study highlights that intramammary infections caused by Staphylococcus aureus, along with factors such as increasing parity and the seasonal effects of pasturing, significantly influence the SCC. Understanding these key contributors is essential for improving udder health management and improving milk quality in goat milk production.

An Investigation of Virulence Genes of Staphylococcus aureus in Autologous Vaccines Against Sheep Mastitis

Staphylococcus aureus is well known to be the primary causal agent of clinical or subclinical mastitis in dairy sheep. The production of virulence factors allows S. aureus strains to cause mastitis. In the present study, 96 strains isolated from dairy sheep farms used for the production of autologous vaccines were tested for enterotoxin and hemolysin genes by PCR. In addition, 14 strains isolated from half udders of ewes with subclinical mastitis belonging to a single farm were also tested for the same genes. The phylogenetic trees were constructed, and spatial analysis was performed. Overall, 20 gene patterns were identified, but 43.64% of the tested strains showed the same profile (sec+, sel+, hla+, hld+, hlgAC+). Considering only the enterotoxin genes, four profiles were identified while the evaluation of the hemolysin genes revealed the presence of 12 gene patterns. In the farm with subclinical mastitis, six gene profiles were found. Spatial analysis of the isolated strains and their virulence genes did not show a specific pattern. The present study highlights the importance of identifying and analyzing virulence genes of S. aureus strains involved in dairy sheep mastitis, and the presence of different strains in the same farm.

Therapeutic Efficacy of Eucalyptus Oil as Teat Dip in Subclinical Mastitis in Goats

Mastitis, an inflammation of the parenchyma of mammary gland, results in alterations to the chemical and physical composition of milk due to a variety of infectious and non-infectious causes. The present work was conducted in the Department of Veterinary Medicine, College of Veterinary Science and Animal Husbandry, Nanaji Deshmukh Veterinary Science University, Jabalpur, Madhya Pradesh (M.P.). A total of 256 lactating goats irrespective of age, breed, parity and stage of lactation belonging to both organized and unorganized sectors at Jabalpur were screened from “February 2024 to July 2024”. On the basis of modified California mastitis test (MCMT) score, out of 256 lactating goats, 98 goats were found positive for subclinical mastitis with overall occurrence as 38.28% on animal basis and 33.33% on udder halves basis. Therapeutic study on 24 milk samples positive for subclinical mastitis by MCMT was conducted and categorized into four treatment groups (G1, G2, G3 and G4), each group comprised of 6 goats. Six apparently healthy goats were selected as healthy control group (G5). Two different teat dips viz. Eucalyptus oil 98% + DMSO 2% BID for 14 days in groups G1 and G3 and 5% Povidone iodine BID for 14 days in groups G2 and G4 were used as teat dips, respectively. Moreover, goats of groups G3 and G4 were commonly treated with parenteral antibiotic amoxicillin sulbactam @10 mg/kg b.wt. I/M OD for 3 days. Significantly higher values of somatic cell count, standard plate count, pH, freezing point and significantly lower value of lactose were observed in subclinical mastitis affected goats. The mean density and mean water percentage values varied within normal physiological range. On the basis of restoration of milk parameters and standard plate count, the most effective therapy was elicited by Eucalyptus oil 98%+ DMSO 2% as teat dip in combination with antibiotic amoxicillin sulbactam (G3).

Beta-Glucans Improve the Mammary Innate Immune Response to Endotoxin Challenge in Dairy Ewes.

This study evaluated short-term immune responses of dairy ewes supplemented with barley β-glucan (BG) following an intramammary Escherichia coli lipopolysaccharide (LPS) challenge. In the adaptation period, 36 ewes were fed an alfalfa hay diet ad libitum and barley grain cv. Hispanic (3.8% BG). Then, ewes were assigned into three experimental groups: (1) Control (CON), the same previous diet (13.3 g BG/d); (2) high β-glucans barley (HBG), new barley (cv. Annapurna) containing 10% BG (35 g BG/d); (3) intraperitoneally injected (INP) with a 1.4% BG solution dose (2 g BG/ewe). At d 9, all ewes were infused with an E. coli LPS or saline solution in each udder half. After the challenge, rectal temperature (RT), milk yield and composition, somatic cell count (SCC), and plasma interleukins (IL-1α and IL-1β) were monitored daily. The INP treatment revealed a transitory increase in RT and decreased milk yield by 38%. Milk fat, protein, and SCC increased in LPS-treated udders but not by BG treatment. The IL-1α plasma concentration was similar among groups but INP ewes showed a lower IL-1β concentration suggesting a lower inflammatory response. The BG administration appears more effective intraperitoneally than orally, which needs additional study.

Intramammary Labeling of Epithelial Cell Division

Thymidine analogs such as ethynyl deoxyuridine (EdU) or bromodeoxyuridine (BrdU) can be used to label mitosis of mammary epithelial cells (MEC) and to quantify their proliferation. However, labeling cells in larger animals requires considerable amounts of chemical that can be costly and hazardous. We developed a strategy to infuse EdU into the mammary glands of ewes to directly label mitotic MEC. First, each udder half of nulliparous ewes (n = 2) received an intramammary infusion of one of four different concentrations of EdU (0, 0.1, 1.0 or 10 mM) which was compared to BrdU IV (5 mg/kg) 24 h later. Tissues were analyzed by immunofluorescent histochemistry to detect EdU, BrdU, and total MEC. Of the EdU doses tested, 10 mM EdU yielded the greatest labeling index, while a proportion of MEC were labeled by both EdU and BrdU. We next sought to establish whether intramammary labeling could detect the induction of mitosis after exposure to exogenous estrogen and progesterone (E + P). We first infused EdU (10 mM) into the right udder half of ewes (n = 6) at t 0, followed by thymidine (100 mM) 24 h later to prevent further labeling. Three ewes were then administered E + P for 5 d, while n = 3 ewes served as controls. On d 5, EdU was infused into the left udder half of all mammary glands alongside BrdU IV (5 mg/kg). By the time of necropsy 24 h later an average MEC labeling index of 2.9% resulted from EdU delivered at t 0. In the left half of the udder on d 5, CON glands had a final EdU labeling index of 3.4% while glands exposed to E + P had a labeling index of 4.6% (p = 0.05). The corresponding degree of labeling with BrdU was 5.6% in CON glands, and 12% following E + P (p < 0.001). Our findings reveal that intramammary labeling is an efficient and cost-effective method for single- and dual-labeling of cell division in the mammary glands.

Regulation of gene expression in milk secretory pathways during secretory activation in Holstein cows

Increased transcription of genes involved in lactose synthesis is a key feature of secretory activation of the mammary gland. We determined which genes are transcriptionally regulated during the transition from colostrum to milk in cows and whether more frequent milking of one udder half would increase milk yields and alter gene expression. We enrolled 12 Holstein cows immediately after calving, harvested colostrum, then randomly assigned one udder half to 12 h (2X) or 6 h (4X) milking intervals for 48 h after first milking. After 48 h, all quarters were milked twice daily until d7, when final quarter milk yields were collected. Yields and composition of colostrum and milk were recorded for each 12 h interval. After each milking, a strip sample of hind milk was collected for isolation of RNA from milk fat and quantification of selected transcripts via qPCR. Milk, milk fat, total protein, and lactose yields increased significantly over the initial 48 h and at d7 after calving. Quarters on 4X treatment produced more milk than the contralateral 2X quarters. Genes upregulated concomitantly with milk yields encoded α-lactalbumin (LALBA), β-1,4-galactosyltransferase (B4GALT1), fatty acid synthase (FASN), β casein (CSN2), and folate receptor α (FOLR1). Downregulated genes encoded monosaccharide transporters (SLC2A3, SLC2A8, SLC35A2) and enzymes involved in galactose synthesis (HK1, PGM1, GALE). Three genes were initially downregulated but later upregulated at d7 (LPIN1, SLC2A1, UGP2). Notably, milking frequency had no effect on gene expression. Sequential upregulation first of genes encoding the former enzymes, then of UGP2, may be necessary for copious milk production. However, the local effects of milking frequency on milk production during lactogenesis do not appear to be controlled by transcription of these genes related to lactose synthesis.

Isolation of Aerobic Bacterial Species Associated with Palpable Udder Defects in Non-Dairy Ewes.

The objectives of these studies were to identify associations between udder half defects (hard or lump) and bacteria isolated from milk or mammary tissue swabs, to compare with samples from normal udder halves at different physiological time points and to compare bacterial species isolated via milk and swabs of mammary tissue from within the same udder halves. A total of 1054 samples were aseptically collected from each udder half of 199 non-dairy breed (Romney) ewes from three different studies (Study A, n = 77; Study B, n = 74; and Study C, n = 48). Conventional bacterial culture and MALDI-ToF mass spectrometry were used for bacterial identification. Of the 225 samples from which bacteria were isolated, Mannheimia haemolytica and Streptococcus uberis were the dominantly identified species from defective udder halves, whereas coagulase-negative staphylococcus (CNS) species, mostly Staphylococcus simulans and Staphylococcus chromogenes, were more frequently isolated from normal udder halves. The ongoing presence of bacterial species over time was variable, although less frequently identified species showed less stability over time. A very high agreement (91.5%) of bacterial species identified was observed between the mammary tissue swab and udder half milk samples during post-weaning. In summary, palpable udder half defects were associated with bacterial positivity, and the ongoing presence of the bacteria over time was dependent on the species involved. Hence, culling ewes with palpable udder half defects that had more stable bacterial species could contribute to reducing the recurrence of palpable defects or mastitis.

Intramammary administration of lipopolysaccharides at parturition does not affect the transfer of passive immunity in goat kids

This study evaluated the effect of feeding colostrum obtained from an intramammary administration (IA) of LPS from Escherichia coli (O55:B5) to dairy goats at parturition, on goat kid performance, biochemical parameters (i.e., calcium, lactate dehydrogenase, glucose, total proteins, albumin, and urea) and immune status (i.e., IgG and IgM) during the first month of life. At birth, goat kids were weighted (d 0) and immediately allocated into either the LPS group (n = 15) or the control (CON) group (n = 21) based on the experimental group of the dam. At parturition, 20 multiparous dairy goats were allocated in 1 of the 2 experimental groups (LPS vs. CON). The LPS group received an IA of saline solution (2 mL) containing 50 µg of LPS in each half udder whereas goats in the CON group received an IA of saline solution (2 mL) without LPS. Goat kids were bottle-fed dam colostrum equivalent to 10% of the birth BW divided in 2 meals (i.e., at 3 and 12 h relative to birth), and then fed twice daily with milk replacer ad libitum. Individual milk intake (MI) and BW were recorded on d 7, 15, 21 and 30 of life. Blood samples were collected on d 0, 1, 2, 4, 7, 15, 21 and 30 after birth. Data were analyzed using the MIXED procedure of SAS (9.4; SAS Institute Inc.). The model included IA, time (T), and their interaction (IA × T) as fixed effects, and sex and litter size as random effects. Both groups showed similar MI, except on d 7 relative to birth as the LPS group showed higher MI than the CON group (910.5 ± 69.77 and 683.9 ± 59.64 mL, respectively; mean ± SEM). No differences in BW or rectal temperature were observed between groups, neither in plasma IgG nor IgM concentrations. Despite the IA did not affect calcium, glucose, LDH, total protein, and albumin concentrations an interaction between the IA and T was observed for urea concentration, showing the LPS group higher urea concentrations than the CON group on d 0 (20.1 ± 1.34 and 20.0 ± 1.25 mg/dL, respectively). In conclusion, feeding colostrum from goats that received an IA of LPS at parturition does not affect goat kid performance, plasma immunoglobulin concentrations and serum metabolites during the first month of life.

Postponing first colostrum collection: impact on immunoglobulin G in goat colostrum

This experiment was motivated by the need to understand the impacts of delaying the first colostrum collection on immunoglobulin G (IgG) concentrations in goat colostrum, addressing a gap in caprine-specific research, despite its significance in dairy farming. Concurrently, we examined the relationship between colostral IgG, total protein (TP) and Brix values. Two colostrum samples were collected from 56 Saanen goats, one from each udder half. The first sample was collected from the right teat immediately postbirth, and the second sample was collected from the left teat at one of the predetermined postpartum intervals: 0, 4–6, 8–10, or 12–14 h postpartum, each time interval comprising 14 goats. Colostral IgG was determined by ELISA, Brix was determined by digital refractometry, and TP was determined by the Bradford protein method. Sperman’s correlations and Lin’s concordance correlation coefficient were used to determine the direction and strength of the association and to assess agreement (prediction accuracy) between methods, respectively. Receiver operator characteristic analysis was used to determine Brix and TP thresholds for predicting good-quality colostrum using several cut-offs (20, 30, 40, and 50 g/L IgG). Mean (± SD) for colostral IgG, Brix, and TP were 54 ± 22.6 g/L, 22 ± 5.0%, and 12 ± 2.8 g/dL, respectively. The statistical analysis did not provide evidence of a significant impact of time of first collection (up to 14 h postpartum), on IgG, Brix, and TP. Brix and IgG values exhibited both a high degree of correlation (r = 0.89–90) and concordance (ρc = 0.89–90), indicating a strong and reliable relationship between the two measurements. The prevalence of samples ≥ 20, 30, 40, and 50 g of IgG/L were 96, 88, 71, and 54%, respectively. Optimal Brix and TP thresholds predicting IgG ≥ 20, 30, 40, and 50 g/L IgG were 13.8, 17.5, 20.1, and 22.5%, and 6.8, 9.3, 10.8, and 11.1 g/dL, respectively. Increasing the IgG threshold resulted in lower sensitivity but higher specificity for estimating colostral IgG using Brix or TP values. The present findings indicate that delaying the first colostrum collection up to 14 h postpartum did not result in conclusive changes in colostral IgG concentration, Brix values, or total protein levels. Our results also confirm the reliability of Brix refractometry as an on-farm tool for estimating IgG concentrations in goat colostrum. These results are particularly relevant to intensive dairy systems, offering insights to enhance colostrum management and task prioritisation, especially during the bustling kidding periods.

204 Detecting subclinical mastitis in meat-breed ewes using infrared thermography

Abstract Mastitis, the inflammation of the mammary gland most commonly due to bacterial infection, is an important welfare concern in meat-breed sheep. The objective of our study was to evaluate udder surface temperature obtained from infrared thermography as a diagnostic tool for subclinical mastitis. We predicted that udder halves with subclinical mastitis would have greater surface temperatures than healthy udder halves. We enrolled 39 meat-breed ewes (10 Hampshire, 24 Polypay, 5 Targhee; 2 to 9 yr of age) at the University of Wisconsin-Madison sheep unit. All procedures were approved by the UW-Madison Institutional Animal Care and Use Committee. Milk samples from each udder half were collected in duplicate weekly beginning 2 to 4 d postpartum until 8 wk postpartum. Immediately before milk sampling, the udder was photographed from the rear using a thermal camera. A sample was considered a true infection if at least 100 CFU/mL of a bacterial species were isolated. From each photo, we obtained values for minimum, maximum, and mean skin surface temperature for the right and left udders. Three linear mixed models were fit using minimum, maximum, and mean temperatures as the response variables. Fixed effects were infection status (infected or not), weeks postpartum (wk 1-8), and ambient temperature, with a random effect of udder half nested within animal ID. Contrary to our predictions, infection status did not predict udder skin surface temperature (P &amp;gt; 0.12). Healthy udder halves had a mean temperature of 35.5 ± 0.1°C (mean ± SE), minimum temperature of 29.9 ± 0.3°C, and maximum temperature of 37.8 ± 0.1°C. Infected udder halves had a mean temperature of 35.4 ± 0.1°C, minimum temperature of 30.5 ± 0.3°C, and maximum temperature of 37.7 ± 0.1°C. Our results contradict findings in dairy cows, and suggest more research is needed to evaluate the relationship between udder surface temperature and subclinical mastitis in sheep.

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.

Infrared Thermography of Teat in French Dairy Alpine Goats: A Promising Tool to Study Animal-Machine Interaction during Milking but Not to Detect Mastitis.

There is a need to develop tools for mastitis management in goats and to measure the effects of milking machines on teats. Infrared thermography (IRT), as shown in cows, was a good candidate for early mastitis detection and focusing on milking equipment and settings implicated in potential problems. The aim of this study was to test IRT to detect udder inflammation and the effects of mechanical milking on teats in relation to inflammation status, udder balance, and teat shape in Alpine goats. IRT spectra were compared before and after milking in 551 goats from three commercial herds compared to their individual SCC (somatic cell count). We found no regression or trend between logSCC and IRT measurement or response to milking, even in highly inflamed goat udders. The effect of milking was significant (p < 0.05) with global temperature reduction after milking, but differences were seen between teat parts and unbalanced half udders. The highest reduction in skin temperature was observed at the teat orifice (-1.06 ± 0.05) and the lowest at the teat barrel (-0.37 ± 0.05). The teats with long barrels showed more IRT reactions, which clearly indicates poor adaptation to the liners used. In conclusion, the IRT was not able to detect mastitis, but it is a good tool to diagnose the effects of the milking machine in order to adapt milking equipment and settings to the goats and improve their welfare.

Differences in colostrum components of Katahdin ewes varies with post-weaning FEC EBV

Variation in post-weaning fecal egg count (PFEC) estimated breeding values (EBV) has revealed effects beyond the reduction of parasitism. Previous work demonstrated lambs with a PFEC of < −50 (Low-PFEC) have higher survivability to weaning than lambs with a PFEC of > +50 (High-PFEC). In response to clostridial vaccination, Low-PFEC lambs also generate a more robust and rapid antibody response. These findings prompted curiosity of the maternal influence underpinning differences observed in lamb survivability based upon PFEC genotype. Thus, this study aimed to assess the impact of dam PFEC EBV on IgG concentration, Brix values, and color within colostrum. For Year 1 (YR1), Katahdin ewes from the Virginia Tech SWAREC were selected based on the following criteria: age (3–6 years), have a Katahdin Hair Index EBV (>104, pre-genomic EBV), and be twin bearing. Ewes fitting those criteria were sorted by their PFEC EBV into two groups: Low-PFEC (PFEC < −50; n=20) and High-PFEC (PFEC > +50; n=18) and sampled at three distinct time points, early (within 24-hr post-partition), mid (30-d post-parturition) and late (60-d post-parturition) lactation. For Year 2 (YR2), all lactating ewes at the SWAREC were analyzed and were sorted into three groups: Low-PFEC (PFEC < −50; n=39), Mid-PFEC ( −49 < PFEC < +49; n=38), and High-PFEC (PFEC > +50; n=23) and colostrum samples were taken within 6-hrs post-partition. All colostrum and milk samples were collected by milking 10 mL from each half of the ewes' udder. Total IgG within colostrum and milk was measured using an ovine-specific enzyme-linked immunosorbent assay (ELISA). In YR1, main effects of ewe genotype revealed that Low-PFEC ewes had a greater concentration of IgG across all lactation time points (631 ng/mL vs 222 ng/mL; P < 0.0001). This was primarily driven by IgG differences within colostrum, where a 2.5 fold difference in IgG were observed between Low-PFEC and High-PFEC groups (937 ng/mL vs. 319 ng/mL, P < 0.0001). In YR2, a stepwise decrease in average colostrum IgG concentration from Low-PFEC to High-PFEC groups was observed (825 ng/mL, 513 ng/mL, and 258 ng/mL, respectively; P < 0.0429). Likewise, a stepwise decrease in yellow to blue hue or b* value occurs from Low-PFEC to High-PFEC groups (18.97, 16.91, and 15.22, respectively; P < 0.0459). No correlations were found between IgG and Brix values within the Low-PFEC and High-PFEC grouping; remarkably, Mid-PFEC ewes have a slightly positive correlation between IgG and Brix (r= 0.34, P = 0.0334). These data indicate that Low-PFEC Katahdin ewes generate colostrum with greater antibody concentration and more yellow color. Lambs born to these ewes would have a significant advantage in passive immunity from their dams, which may explain some component of the enhanced lamb survivability observed pre-weaning.

64 The effect of postweaning fecal egg count EBV on colostrum IgG concentration and color in Katahdin dams

Abstract Selection for postweaning fecal egg count (PFEC) EBV has revealed that low-PFEC sheep have greater resistance to gastrointestinal nematode infection, greater survivability to weaning, and greater anamnestic response to booster clostridial vaccination. Therefore, it can be hypothesized that selection for PFEC may result in improved generalized immunity. It has also been reported that good-quality colostrum has a thick consistency and yellowish color. Thus, the aim of this study was to compare IgG concentration and color of colostrum in Katahdin ewes divergent in their PFEC EBV. All lactating ewes at the SWAREC were analyzed and were sorted into three groups: low-PFEC (PFEC &amp;lt; -50, n = 39), mid-PFEC (-49 &amp;lt; PFEC &amp;lt; +49, n = 38), and high-PFEC (PFEC &amp;gt; +50, n = 23) and sampled within 6-h post-partition. Upon parturition, a 20 mL colostrum sample was sterile collected by milking 10 mL from each udder half of the ewes; all samples were placed into pre-labeled 50 mL tubes and frozen on-site. Colostrum samples were thawed and diluted in 36% ammonium sulfate and centrifuged at 3,000 x g for 20 min at 4ºC. The removed whey portion was dialyzed using a 3,000 MW membrane cassette in 1 L of PBS (pH 7.4) at 4ºC for 12 h. Total IgG from colostrum was measured using an ovine-specific enzyme-linked immunosorbent assay (ELISA), and color parameters were measured using a Minolta chromameter. To evaluate IgG and color differences, data were analyzed using the General Linear Model (GLM) procedure of SAS with Tukey’s HSD test to compare the effects of ewe PFEC genotype on colostrum IgG, Yellowness Index (YI), Whiteness Index (WI), L*, b* and a* values. Main effects of ewe PFEC genotype displayed a stepwise decrease in average colostrum IgG from low-PFEC to high-PFEC groupings (825 ng/mL, 513 ng/mL, and 258 ng/mL, respectively; P &amp;lt; 0.0429). Likewise, a stepwise decrease in b* value, indicating relative yellowness, occurs from low-PFEC to high-PFEC groups (18.97, 16.91, and 15.22, respectively; P &amp;lt; 0.0459). These data suggest low-PFEC Katahdin ewes generate greater antibody concentration and yellowness within colostrum. Therefore, lambs born to these ewes would have a significant advantage in passive immunity from their dams, potentially contributing to lamb survivability.

Multi-omics analysis elucidates the host-microbiome interplay in severe udder cleft dermatitis lesions in dairy cows

Udder cleft dermatitis is a skin disease in dairy cattle that is characterized by painful, large open wounds between the udder halves or at the front udder attachment. Its impact on animal welfare and production warrants an in-depth investigation of its pathogenesis. The present study delves into the pathophysiology of severe udder cleft dermatitis, employing a multi-omics approach by integrating transcriptomic and metagenomic data obtained from samples of severe udder cleft dermatitis lesions and healthy udder skin of dairy cattle. All dominant features selected from the virulence factor, taxonomic and transcriptomic data sets, except for the facultative pathogen Streptococcus pyogenes, form a network which could be associated with the healthy udder skin. The severe udder cleft dermatitis-associated Streptococcus pyogenes exhibited a negative correlation with these virulence factors and genes, but was not correlated to the other commensal bacteria in the analysis. Examining the different components interacting with each other could advance our understanding of the pathogenesis of severe udder cleft dermatitis.

Intramammary administration of lipopolysaccharides at parturition enhances immunoglobulin concentration in goat colostrum

In newborn ruminants, transfer of passive immunity is essential to obtain protection against pathogens. This study aimed to increase the permeability of the blood-milk barrier using intramammary lipopolysaccharides (LPS) in goats at parturition to modulate colostrum composition. Twenty multiparous Majorera dairy goats were randomly allocated in one of the two experimental groups. The LPS group (n = 10) received an intramammary administration (IA) of saline (2 mL) containing 50 µg of LPS from Escherichia coli (O55:B5) in each half udder at parturition. The control group (n = 10) received an IA of saline (2 mL). Rectal temperature (RT) was recorded, and a blood sample was collected at parturition (before IA). In addition, RT was measured, and blood and colostrum/milk samples were collected on day (d) 0.125 (3 hours), 0.5 (12 hours), 1, 2, 4, 7, 15 and 30 relative to the IA. Goat plasma immunoglobulin G (IgG) and M (IgM) and serum β-hydroxybutyrate, glucose, calcium, free fatty acids, lactate dehydrogenase and total protein concentrations were determined. Colostrum and milk yields as well as chemical composition, somatic cell count (SCC), IgG and IgM concentrations were measured. The MIXED procedure (SAS 9.4) was used, and the model included the IA, time, and the interaction between both fixed effects. Statistical significance was set as P < 0.05. Goats from the LPS group showed higher RT on d 0.125, 0.5 and 4 relative to the IA compared to the control group (PIA×Time = 0.007). Goat serum biochemical variables and plasma IgG and IgM concentrations were not affected by the IA. Colostrum and milk yield as well as chemical composition were not affected by the IA, except for milk lactose percentage that was lower in the LPS group compared to the control group (4.3 ± 0.08 and 4.6 ± 0.08%, respectively PIA = 0.026). Colostrum SCC was higher in the LPS group than in the control group (3.5 ± 0.09 and 3.1 ± 0.09 cells × 106/mL, respectively; PIA = 0.011). Similarly, milk SCC increased in the LPS group compared to the control group (PIA = 0.004). The LPS group showed higher IgG (PIA = 0.044) and IgM (PIA = 0.037) concentrations on colostrum than the control group (31.9 ± 4.8 and 19.0 ± 4.8 mg/mL, 0.8 ± 0.08 and 0.5 ± 0.08 mg/mL, respectively). No differences in milk IgG and IgM concentrations between groups were observed. In conclusion, the IA of LPS at parturition increases RT, SCC and IgG and IgM concentrations in colostrum without affecting either yield or chemical composition.

Effect of different inflammation states on the antimicrobial components in milk of goat udders after milking cessation.

The aim of this study was to examine the effects of milking cessation under different inflammatory conditions on the changes in antimicrobial components in milk and the process of mammary gland involution. Twenty udder halves were divided into two groups: those with (LPS) and without (control) lipopolysaccharide infusion, followed by cessation of milking for 8weeks. Milk samples were collected weekly. Udder tissue was collected 4weeks after milking cessation to measure the area of the lobule and connective tissue. After milking cessation, the somatic cell count (SCC) in the control group increased, whereas that in the LPS group did not. Lactoferrin (LF) and cathelicidin (Cath)-2 concentrations increased in both groups, whereas only LF was significantly lower in the LPS group than in the control group at week 4. The Cath-7 and S100A8 concentrations were significantly lower in the LPS group than in the control group. The lobule area was higher, and the connective tissue area was lower in the LPS group than in the control group. These results indicate that inflammation at milking cessation decreased the concentrations of some antimicrobial components and interfered with mammary gland involution. Therefore, animals with mastitis should recover prior to the onset of the dry period.

The effects of an inactivated vaccine against Staphylococcus spp. on udder health in primiparous dairy goats: A randomized controlled trial

Staphylococci are the primary pathogens causing clinical and subclinical mastitis in dairy goats. This randomized controlled trial (RCT) evaluates the impact of vaccination with VIMCO® (Hipra, Girona, Spain) on clinical mastitis (CM), gangrenous mastitis (GM), the occurrence of udder asymmetry, somatic cell count (SCC), total bacterial count (TBC) and 10-day average milk yield (10dMY) in primiparous goats. The RCT was performed on a commercial dairy goat farm with 3000 mainly Saanen goats from February to April 2022. A group of 350 pregnant primiparous goats (12 – 16 months of age) was randomly divided into a control group and a vaccinated group. The goats were followed from kidding until on average 72 days in milk (DIM). At on average 20 DIM, all primiparous goats were mixed into a group with 1600 non-vaccinated adult goats. At the first milking after kidding (T = 0), all primiparous goats were scored for clinical mastitis and udder asymmetry. After that, udder asymmetry was scored on T1 (on average 12 DIM) and T2 (on average 62 DIM). Gangrenous mastitis cases were recorded from the start of complete vaccination and during the entire trial period. In addition, individual daily milk yield was recorded automatically by the milking system, and somatic cell count (SCC) was determined once at T2. The prevalence of CM was significantly higher in the control group (5.6%) than in the vaccinated group (0.6%). There was a significantly higher prevalence of udder asymmetry in the control group (7.8%) compared to the vaccinated group (1.2%) at T0 and during the entire study period (16% in control group versus 7.6% in the vaccinated group). Dried-up udder halves and GM were rare and did not differ significantly between both groups. Also, the SCC measurement and the milk yield did not differ between the vaccinated and the control group. Altogether, we show that the VIMCO® vaccine prevents clinical signs of mastitis at the first milking after kidding and udder asymmetry during the first three months after kidding in primiparous goats. Therefore, the vaccine may contribute to udder health control. Effects on SCC, milk yield, the prevalence of dried-up udder glands and GM remain to be demonstrated.

Effects of oyster glycogen intramammary challenge on primiparous cow milk somatic cell counts, milk yields, and milk composition

Mastitis is a common and costly disease in the dairy industry that reduces milk production in affected mammary glands. The local mechanisms that result in reduced milk production of affected mammary glands are incompletely understood; elucidation of these mechanisms is dependent on the use of hypothesis testing studies, but few experimental models exist. The objective of this study was to develop a mastitis challenge model, using a split udder design, to reduce milk yields by approximately 15% in udder halves challenged with oyster glycogen, a known inducer of leukocyte recruitment, relative to udder halves treated with saline. Four primiparous Holstein cows in mid lactation were used. One udder half of each cow was randomly selected and challenged with oyster glycogen (OYGLN), and the opposite udder half was treated with saline (SAL). Milk yields and components were measured at each milking (3×/d) for 3 d postchallenge. No signs of clinical mastitis were observed. Milk somatic cell scores, yields, and components were similar between OYGLN and SAL udder halves at time of challenge. Milk somatic cell scores markedly increased in OYGLN halves postchallenge and were greater than SAL halves for the duration of the trial. Lactose concentrations of OYGLN udder halves were transiently lower than in SAL udder halves, but protein concentrations were greater at 2 milkings postchallenge in OYGLN halves. Milk yields and energy-corrected milk yields did not differ between OYGLN and SAL udder halves overall, nor at any postchallenge milking. A single intramammary challenge of oyster glycogen was unsuccessful in eliciting a disparity in milk yields between challenged and saline control udder halves despite the marked leukocyte infiltration observed in the former. These results indicate an incomplete understanding of how milk yields are reduced in mammary glands affected by subclinical mastitis and that transient somatic cell recruitment and infiltration alone do not directly reduce milk yields during subclinical mastitis.

Milk volatilome as affected by somatic cell count in Holstein cows

The aim of the current trial was to study the impact of a high somatic cell count (SCC) on milk volatilome of fresh raw milk, and its evolution during storage of processed fluid milk. Six Holstein cows were selected from our research dairy herd based on test-day SCC records. Three cows were used to produce low-SCC milk (20 × 103 cells/mL). The three other cows had one-quarter infected by Staphylococcus aureus. Infected and healthy udder halves were milked separately, and high-SCC milk was standardized to 400 × 103 cells/mL by mixing these two milks. The profile of milk volatile organic compounds (VOCs) was determined on raw milk and during the storage of processed milk. The processing included a standardization to 3.25% fat, followed by homogenization, and thermization (65 °C/30 min). This procedure was repeated four times over a period of 7 days. A total of 40 VOC were identified using the solid-phase microextraction technique followed by gas chromatography separation, mass spectrometry analysis, and database search. These VOC were grouped into seven different families, including alcohols (n = 4), free fatty acids (n = 5), sulfur compounds (n = 3), esters (n = 7), ketones (n = 7), aldehydes (n = 12), and aromatic hydrocarbons (n = 2). In raw milk, high SCC was associated with a tendency for lower concentrations of ethyl-hexanoate (P = 0.07), acetone (P = 0.06), and benzaldehyde (P = 0.07) and lower concentrations of trans-2 hexenal (P = 0.04). On the contrary, high SCC was associated with a tendency for greater concentrations of acetic acid (P = 0.09) and hexanoic acid (P = 0.07) and greater concentrations of 2-nonanone (P = 0.02) and pentanal (P = 0.01). Concentrations of most VOC increased during the storage of processed milk. Lower concentrations of butanoic acid (P = 0.09; tendency) and ethyl hexanoate (P = 0.04), and greater concentration of 1-ocen-3-ol (P < 0.01) were observed in high-SCC milk at all times of storage evaluated. Increases in concentrations over time were less pronounced for ethanol (P < 0.01), ethyl butanoate (P = 0.05), and propanal (P = 0.10) in high SCC as compared with low SCC milk. In conclusion, an increase in SCC has a limited effect on milk volatilome, when a SCC standard of 400 × 103 cells/mL for bulk milk is respected.