Serum metabolome differences associated with subclinical intramammary infection caused by Streptococcus agalactiae and Prototheca spp. in multiparous dairy cows.

Mastitis is one of the most significant diseases in dairy cows and causes several economic losses. Somatic cell count (SCC) is often used as an indirect diagnostic tool for mastitis, especially for subclinical mastitis (SCM) where no symptoms or signs can be detected. Streptococcus agalactiae is one of the main causes of contagious mastitis, and Prototheca spp. is an alga-inducing environmental mastitis that is not always correlated with increased milk SCC. The aim of this study was to evaluate the changes in the metabolomic profile of blood in relation to subclinical intramammary infection (IMI) in dairy cows. In addition, differences resulting from the etiologic agent causing mastitis were also considered. Forty Holstein-Friesian dairy cows in mid and late lactation were enrolled in this cross-sectional design study. Based on the bacteriological examination of milk, the animals were divided into 3 groups: group CTR (control group; n = 16), group A (affected by SCM with IMI caused by Strep. agalactiae; n = 17), and group P (affected by SCM with IMI caused by Prototheca spp.; n = 7). Blood samples from the jugular vein were collected in tubes containing clot activator; the serum aliquot was stored until metabolomic analysis by 1H-nuclear magnetic resonance spectroscopy. Statistical analysis was conducted by fitting a linear model with the group as the fixed effect and SCC as the covariate. Forty-two metabolites were identified, and among them 10 were significantly different among groups. Groups A and P showed greater levels of His and lactose and lower levels of acetate, Asn, and dimethylamine compared with group CTR. Group A showed high levels of Val, and group P showed high levels of Cit and methylguanidine, as well as lower levels of 3-hydroxybutyrate, acetone, allantoin, carnitine, citrate, and ethanol. These metabolites were related to ruminal fermentations, energy metabolism, urea synthesis and metabolism, immune and inflammatory response, and mammary gland permeability. These results suggest systemic involvement with subclinical IMI and that the metabolic profile of animals with SCM undergoes changes related to the etiological agent of mastitis.

Effect of intramammary infection and inflammation on milk protein profile assessed at the quarter level in Holstein cows.

In this study we wanted to investigate the associations between naturally occurring subclinical intramammary infection (IMI) caused by different etiological agents (i.e., Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, and Prototheca spp.), in combination with somatic cell count (SCC), on the detailed milk protein profile measured at the individual mammary gland quarter. An initial bacteriological screening (time 0; T0) conducted on individual composite milk from 450 Holstein cows reared in 3 herds, was performed to identify cows with subclinical IMI. We identified 78 infected animals which were followed up at the quarter level at 2 different sampling times: T1 and T2, 2 and 6 wk after T0, respectively. A total of 529 quarter samples belonging to the previously selected animals were collected at the 2 sampling points and analyzed with a reversed phase HPLC (RP-HPLC) validated method. Specifically, we identified and quantified 4 caseins (CN), namely αS1-CN, αS2-CN, κ-CN, and ß-CN, and 3 whey protein fractions, namely ß-lactoglobulin, α-lactalbumin, and lactoferrin (LF), which were later expressed both quantitatively (g/L) and qualitatively (as a percentage of the total milk nitrogen content, % N). Data were analyzed with a hierarchical linear mixed model with the following fixed effects: days in milk (DIM), parity, herd, SCC, bacteriological status (BACT), and the SCC × BACT interaction. The random effect of individual cow, nested within herd, DIM and parity was used as the error term for the latter effects. Both IMI (i.e., BACT) and SCC significantly reduced the proportion of ß-CN and αS1-CN, ascribed to the increased activity of both milk endogenous and microbial proteases. Less evident alterations were found for whey proteins, except for LF, which being a glycoprotein with direct and undirect antimicrobial activity, increased both with IMI and SCC, suggesting its involvement in the modulation of both the innate and adaptive immune response. Finally, increasing SCC in the positive samples was associated with a more marked reduction of total caseins at T1, and αS1-CN at T2, suggesting a synergic effect of infection and inflammation, more evident at high SCC. In conclusion, our work helps clarify the behavior of protein fractions at quarter level in animals having subclinical IMI. The inflammation status driven by the increase in SCC, rather the infection, was associated with the most significant changes, suggesting that the activity of endogenous proteolytic enzymes related to the onset of inflammation might have a pivotal role in directing the alteration of the milk protein profile.

Associations between subclinical intramammary infection and milk fatty acid profile at the quarter level in Holstein cattle.

Mastitis, especially the subclinical form, is the most common economic and health problem in dairy cows. Little is known about changes in milk fatty acid (FA) composition according to infection/inflammation status of the mammary gland. The aim of this study was to investigate the associations between naturally occurring subclinical intramammary infection (IMI) from different pathogens, i.e. Streptococcus agalactiae, Staphylococcus aureus, Streptococcus uberis and Prototheca spp., and the detailed milk FA profile assessed at quarter level in Holstein cows. After an initial bacteriological screening (T0) on 450 Holstein cows reared in three dairy herds, we identified 78 cows positive at the bacteriological examination. These animals were followed up at the quarter level two weeks (T1) and six weeks (T2) after T0. In total, 600 single-quarter samples were obtained at T1 and T2. Individual FAs were determined using the gas chromatography analytical method. Investigated traits were 70 individual FAs, 12 FA groups, and six desaturation indices. The associations between subclinical IMI combined with somatic cell count (SCC) and milk FA profile were investigated using a hierarchical linear mixed model (i.e., observational unit was quarter within cow) with the following fixed effects: days in milk (DIM), parity, herd, SCC, bacteriological status (BACT, positive and negative), and the SCC × BACT interaction. The random effect of individual cow nested within herd, DIM and parity was used as the error term for the latter effects. The most significant associations were detected at T2. Notably, IMI reduced the proportions of individual short-chain FA, especially 4:0 and 6:0 (-14%), but increased the proportion of the most abundant medium-chain FA (MCFA), 16:0 (+4%). A reduction in the desaturation indices was observed mostly for 14:1 index (-9%), in line with the reduction in 14:1 (-10%). Somatic cell count significantly affected 14 individual FAs. In particular, samples with high SCC (≥200 000) had significantly lower proportions of 8:0, 10:0, 11:0, 12:0, and 13:0 compared with samples with low SCC (<200 000). Increasing SCC in animals positive at the bacteriological examination were associated with a reduction in total MCFA at T2 (while in negative animals, they remained constant across SCC classes), possible evidence that elongation of the FA chain from 11 to 16 carbons is affected by a combination of infection and SCC. This study showed that subclinical IMI and SCC are mainly associated with reductions in the synthesis of FA and the desaturation process in the mammary gland.

Blood biochemical changes upon subclinical intramammary infection and inflammation in Holstein cattle.

The aim of this study was to investigate the associations between subclinical intramammary infection (IMI) from different pathogens combined with inflammation status and a set of blood biochemical traits including energy-related metabolites, indicators of liver function or hepatic damage, oxidative stress, inflammation, innate immunity, and mineral status in 349 lactating Holstein cows. Data were analyzed with a linear model including the following fixed class effects: days in milk, parity, herd, somatic cell count (SCC), bacteriological status (positive and negative), and the SCC × bacteriological status interaction. Several metabolites had significant associations with subclinical IMI or SCC. Increased SCC was associated with a linear decrease in cholesterol concentrations which ranged from -2% for the class ≥50,000 and <200,000 cells/mL to -11% for the SCC class ≥400,000 cells/mL compared with the SCC class <50,000 cells/mL. A positive bacteriological result was associated with an increase in bilirubin (+24%), paraoxonase (+11%), the ratio paraoxonase/cholesterol (+9%), and advanced oxidation protein product concentration (+23%). Increased SCC were associated with a linear decrease in ferric reducing antioxidant power concentrations ranging from -3% for the class ≥50,000 and <200,000 cells/mL to -9% for the SCC class ≥400,000 cells/mL (respect to the SCC class <50,000 cells/mL). A positive bacteriological result was associated with an increase in haptoglobin concentrations (+19%). Increased SCC were also associated with a linear increase in haptoglobin concentrations, which ranged from +24% for the class ≥50,000 and <200,000 cells/mL (0.31 g/L) to +82% for the SCC class ≥400,000 cells/mL (0.45 g/L), with respect to the SCC class <50,000 cells/mL (0.25 g/L). Increased SCC were associated with a linear increase in ceruloplasmin concentrations (+15% for SCC ≥50,000 cells/mL). The observed changes in blood biochemical markers, mainly acute phase proteins and oxidative stress markers, suggest that cows with subclinical IMI may experience a systemic involvement.

Associations between ultrasound hepatic measurements, body measures, and milk production traits in Holstein cows.

Ultrasound (US) imaging has been proposed as a noninvasive tool for monitoring liver dysfunction in dairy cows. This study, carried out on 306 clinically healthy Holstein cows in the first 120 d of lactation kept in 2 herds in northern Italy, aimed at investigating the association between US imaging-derived traits, namely predicted liver triacylglycerol content (pTAG, mg/g), liver depth (LD, mm), portal vein depth (PVD, mm) and area (PVA, mm2), and body size measurements, body condition score (BCS), and milk productivity indicators. Transcutaneous US examination, milk sampling, body size measurements (withers height and heart girth), and BCS were collected once from all cows in 10 sampling batches. The body weights (BW) of a subsample of 73 cows were recorded and used together with an existing data set of BW and measures of Holstein Friesian cows (n = 399) to develop a regression equation to predict BW, which was then used to compute productivity indicators by scaling the milk production traits to predicted BW. Body size measures, BCS, milk traits, and productivity indicators were classified (low, medium, and high) in 0.75 units of standard deviation of the residuals generated from a linear model that included the effects of parity, days in milk, and sampling batch. Liver pTAG, PVA, PVD, and LD were analyzed with a sequence of linear mixed models that included the fixed effects of days in milk and parity and the random effect of sampling batch as common terms, whereas the classes of body and milk traits and the productivity indicators were included one by one. The US-related traits were found to be associated with body size measurements and BCS. Specifically, pTAG was inversely related to BCS, whereas PVD and LD increased with increasing heart girth, BCS, and predicted BW. Generally, no relevant associations were observed between the US parameters and milk production traits, including when expressed in terms of productivity. In conclusion, this study suggests that US measures of liver dimensions of clinically healthy cows are related to their size, whereas pTAG concentrations reflect body condition status, with no particular implications for milk production and productivity. Moreover, healthy cows seemed able to counteract the metabolic stress of the first 120 d of the lactation period without straining liver functionality. Finally, US imaging proved to be a promising technique to assess liver metabolic conditions. However, further studies are needed to confirm its potential as a noninvasive tool for monitoring liver conditions in healthy cows.

Quarter-level analyses of the associations among subclinical intramammary infection and milk quality, udder health, and cheesemaking traits in Holstein cows.

In this study, we investigated associations among subclinical intra-mammary infection (IMI) and quarter-level milk composition, udder health indicators, and cheesemaking traits. The dataset included records from 450 Holstein cows belonging to three dairy herds. After an initial screening (T0) to identify animals infected by Streptococcus agalactiae, Streptococcus uberis, Staphylococcus aureus, and Prototheca spp., 613 quarter milk samples for 2 different sampling times (T1 and T2, 1 mo after T1) were used for analysis. Milk traits were analyzed using a hierarchical linear mixed model including the effects of days in milk, parity and herd, and bacteriological and inflammatory category [culture negative with somatic cell count (SCC) <200,000 cells/mL; culture negative with SCC ≥200,000 cells/mL; or culture positive]. All udder health indicators were associated with increased SCC and IMI at both sampling times. The largest effects were detected at T2 for milk lactose (-7% and -5%) and milk conductivity (+9% and +8%). In contrast, the increase in differential SCC (DSCC) in samples with elevated SCC was larger at T1 (+17%). Culture-negative samples with SCC ≥200,000 cells/mL had the highest SCC and greatest numbers of polymorphonuclear-neutrophils-lymphocytes and macrophages at both T1 and T2. Regarding milk cheesemaking ability, samples with elevated SCC showed the worst pattern of curd firmness at T1 and T2. At T2, increased SCC and IMI induced large decreases in recoveries of nutrients into the curd, in particular recovered protein (-14% and -16%) and recovered fat (-12% and -14%). Different behaviors were observed between Strep. agalactiae and Prototheca spp., especially at T2. In particular, samples that were positive for Strep. agalactiae had higher proportions of DSCC (+19%) compared with negative samples with low SCC, whereas samples that were positive for Prototheca spp. had lower DSCC (-11%). Intramammary infection with Prototheca spp. increased milk pH compared with culture-negative samples (+3%) and negative samples that had increased SCC (+2%). The greatest impairment in curd firmness at 30 min from rennet addition was observed for samples that were positive for Prototheca spp. (-99% compared with negative samples, and -98% compared with negative samples with high SCC). These results suggest that IMI caused by Prototheca spp. have detrimental effects on milk technological traits that deserve further investigation of the mechanisms underlying animals' responses to infection.

Infrared thermography as a rapid and non-invasive diagnostic tool to detect inflammatory foot diseases in dairy cows.

In this study the potential usefulness of infrared thermography (IRT) as a non-invasive tool to rapidly screen the most common non-infectious foot lesions in dairy cows was evaluated. Thirty-eight healthy cows and 38 cows affected by foot diseases were enrolled. Diseased cows showed the following disorders at lateral and medial claw in the hind foot: white line lesion, sole ulcer, sole haemorrhage, horizontal fissure, axial fissure. Thermography images of hind foot were collected for each animal using a digital infrared camera. Foot temperature was measured in four regions: central area of the hind foot (A1), interdigital area of the hind foot (A2), lateral (A3) and medial (A4) claw in the hind foot. Higher temperature values in the regions A1 and A2 compared to A3 and A4 were found in both healthy and diseased cows (p0.001). Cows affected by foot diseases showed higher foot temperature values compared to healthy cows (p0.05) in all considered regions. This study highlights the potential application of IRT as a reliable, practical tool for detection of hoof lesions in dairy cows. Multiple scanning images and comparisons between affected and healthy anatomical structures could be useful in defining the consistency of abnormality.

Short communication: Association between udder health status and blood serum proteins in dairy cows.

The aim of this study was to investigate the association between udder health (UH) status and blood serum proteins (i.e., total protein, albumin, globulin, and albumin-to-globulin ratio) in dairy cows. Blood and milk samples were collected from 1,508 cows of 6 different breeds (Holstein Friesian, Brown Swiss, Jersey, Simmental, Rendena, and Alpine Grey) that were housed in 41 multibreed herds. Bacteriological analysis was performed on milk samples with somatic cell count (SCC) >100,000 cells/mL and bacteria identification was confirmed by multiplex-PCR assays. Milk samples were grouped into 7 clusters of UH status: healthy (cows with milk SCC <100,000 cells/mL and not cultured); culture-negative samples with low, medium, or high SCC; and culture-positive samples with contagious, environmental, and opportunistic intramammary infections. Data of blood serum proteins were analyzed using a linear mixed model that included the fixed effects of stage of lactation, parity, breed, herd productivity (high or low production) and UH status, and the random effect of herd-date within herd productivity. Culture-negative samples with high milk SCC, which were most likely undergoing a strong inflammatory response and whose pathogens could not be isolated because they were engulfed by macrophages or because they had already cleared, and milk samples infected by contagious and environmental bacteria were associated with greater globulin concentrations (and lower albumin-to-globulin ratio) in blood. Variation in blood serum proteins seems to be associated with inflammatory status rather than infection, as serum globulin significantly increased in UH status groups with the highest milk SCC and no differences were observed among intramammary infections pathogens. Blood serum proteins can be a mammary gland inflammation indicator, but cannot be used to differentiate among different UH status groups.

Variation in blood serum proteins and association with somatic cell count in dairy cattle from multi-breed herds.

Blood serum proteins are significant indicators of animal health. Nevertheless, several factors should be considered to appropriately interpret their concentrations in blood. Therefore, the objectives of this study were (1) to assess the effect of herd productivity, breed, age and stage of lactation on serum proteins and (2) to investigate association between serum proteins and somatic cell count (SCC) in dairy cattle. Milk and blood samples were collected from 1508 cows of six different breeds (Holstein Friesian, Brown Swiss, Jersey, Simmental, Rendena and Alpine Grey) that were housed in 41 multi-breed herds. Milk samples were analyzed for composition and SCC, while blood samples were analyzed for serum proteins (i.e. total protein, albumin, globulin and albumin-to-globulin ratio (A : G)). Herds were classified as low or high production, according to the cow's average daily milk energy yield adjusted for breed, days in milk (DIM) and parity. Data were analyzed using a linear mixed model that included the fixed effects of DIM, parity, SCS, breed, herd productivity and the random effect of the Herd-test date within productivity level. Cows in high producing herds (characterized also by greater use of concentrates in the diet) had greater serum albumin concentrations. Breed differences were reported for all traits, highlighting a possible genetic mechanism. The specialized breed Jersey and the two dual-purpose local breeds (Alpine Grey and Rendena) had the lowest globulin concentration and greatest A : G. Changes in serum proteins were observed through lactation. Total protein reached the highest concentration during the 4th month of lactation. Blood albumin increased with DIM following a quadratic pattern, while globulin decreased linearly. As a consequence, A : G increased linearly during lactation. Older cows had greater total protein and globulin concentrations, while albumin concentration seemed to be not particularly affected by age. A linear relationship between serum proteins and SCS was observed. High milk SCS was associated with greater total protein and globulin concentrations in blood. The rise in globulin concentration, together with a decrease in albumin concentrations, resulted in a decline in A : G as SCS of milk increased. In conclusion, such non-genetic factors must be considered to appropriately interpret serum proteins as potential animal welfare indicator and their evaluation represents an important first-step for future analysis based on the integration of metabolomics, genetic and genomic information for improving the robustness of dairy cows.

Associations between pathogen-specific cases of subclinical mastitis and milk yield, quality, protein composition, and cheese-making traits in dairy cows.

The aim of this study was to investigate associations between pathogen-specific cases of subclinical mastitis and milk yield, quality, protein composition, and cheese-making traits. Forty-one multibreed herds were selected for the study, and composite milk samples were collected from 1,508 cows belonging to 3 specialized dairy breeds (Holstein Friesian, Brown Swiss, and Jersey) and 3 dual-purpose breeds of Alpine origin (Simmental, Rendena, and Grey Alpine). Milk composition [i.e., fat, protein, casein, lactose, pH, urea, and somatic cell count (SCC)] was analyzed, and separation of protein fractions was performed by reversed-phase high performance liquid chromatography. Eleven coagulation traits were measured: 5 traditional milk coagulation properties [time from rennet addition to milk gelation (RCT, min), curd-firming rate as the time to a curd firmness (CF) of 20 mm (k20, min), and CF at 30, 45, and 60 min from rennet addition (a30, a45, and a60, mm)], and 6 new curd firming and syneresis traits [potential asymptotical CF at an infinite time (CFP, mm), curd-firming instant rate constant (kCF, % × min-1), curd syneresis instant rate constant (kSR, % × min-1), modeled RCT (RCTeq, min), maximum CF value (CFmax, mm), and time at CFmax (tmax, min)]. We also measured 3 cheese yield traits, expressing the weights of total fresh curd (%CYCURD), dry matter (%CYSOLIDS), and water (%CYWATER) in the curd as percentages of the weight of the processed milk, and 4 nutrient recovery traits (RECPROTEIN, RECFAT, RECSOLIDS, and RECENERGY), representing the percentage ratio between each nutrient in the curd and milk. Milk samples with SCC > 100,000 cells/mL were subjected to bacteriological examination. All samples were divided into 7 clusters of udder health (UH) status: healthy (cows with milk SCC < 100,000 cells/mL and uncultured); culture-negative samples with low, medium, or high SCC; and culture-positive samples divided into contagious, environmental, and opportunistic intramammary infection (IMI). Data were analyzed using a linear mixed model. Significant variations in the casein to protein ratio and lactose content were observed in all culture-positive samples and in culture-negative samples with medium to high SCC compared to normal milk. No differences were observed among contagious, environmental, and opportunistic pathogens, suggesting an effect of inflammation rather than infection. The greatest impairment in milk quantity and composition, clotting ability, and cheese production was observed in the 2 UH status groups with the highest milk SCC (i.e., contagious IMI and culture-negative samples with high SCC), revealing a discrepancy between the bacteriological results and inflammatory status, and thus confirming the importance of SCC as an indicator of udder health and milk quality.

Evaluation of venous blood gas levels, blood chemistry and haemocytometric parameters in milk fed veal calves at different periods of livestock cycle.

An evaluation of blood chemistry profile in relation to specific stages of livestock cycle can help better understand variations in physiological conditions in order to adjust management systems to animal needs. In addition to basal hematological investigation, the acid-base balance and blood gases are essential tools in evaluating metabolism in calves. The relationship between blood gas parameters, diet and growth should be further investigated. The aim of this study was to evaluate changes in acid-base status, blood gases, serum chemistry and hematological parameters in veal calves at different periods of livestock cycle. One hundred twenty-eight healthy cross breeding calves were enrolled in a farm in North-East Italy. Blood samplings were carried out from the jugular vein on day 1 (t1), 60 (t2) and 150 (t3) after arrival. Blood gas analysis was performed and hematological parameters were evaluated. One-way ANOVA and Tukey-Kramer post-hoc test were performed to assess differences between blood parameter values at the different periods. The main differences in blood gas parameter levels during the livestock cycle concerned pH, Base Excess and HCO3 with higher values recorded in t3. Urea, creatinine, gamma-glutamyl transpeptidase and bilirubin mean values were significantly higher in t1 than in t2 and t3. Aspartate aminotransferase increased from t1 to t2 and t3. Alkaline Phosphatase was higher in t2. Fe levels severely dropped in t2 and in t3, and the decrease led to a restrained but significant reduction in haemoglobin values. A correspondent decrease in the other haemocytometric parameters was found.

An appraisal of the Maltese national livestock database with regard to bovines.

The creation of a centralised national livestock database for the islands of Malta and Gozo is of crucial importance for the identification and traceability of bovines. It is also important for compliance with the legal obligations that followed Malta's accession to the European Union in May 2004. This paper describes how the processes of identification, registration and traceability of bovines have changed since Malta's accession. The validation and integration of data originating from different departmental sections (such as the identification and registration section), the slaughterhouse and the National Veterinary Laboratory, ensures that any discrepancies are highlighted and can be investigated. Events recorded in the database enable the compliance and eligibility of bovine producers to be cross-checked when applications for European Union benefits are made. The main drawbacks and weak points of the system include financial costs for the government department, potentially late notification of the births and deaths of newborn calves, and insufficient uptake among bovine producers of the latest technology for notification of events such as births, deaths and movement of bovines.

Evaluation of the udder health status in subclinical mastitis affected dairy cows through bacteriological culture, somatic cell count and thermographic imaging.

Subclinical mastitis in dairy cows is a big economic loss for farmers. The monitoring of subclinical mastitis is usually performed through Somatic Cell Count (SCC) in farm but there is the need of new diagnostic systems able to quickly identify cows affected by subclinical infections of the udder. The aim of this study was to evaluate the potential application of thermographic imaging compared to SCC and bacteriological culture for infection detection in cow affected by subclinical mastitis and possibly to discriminate between different pathogens. In this study we evaluated the udder health status of 98 Holstein Friesian dairy cows with high SCC in 4 farms. From each cow a sample of milk was collected from all the functional quarters and submitted to bacteriological culture, SCC and Mycoplasma spp. culture. A thermographic image was taken from each functional udder quarter and nipple. Pearson's correlations and Analysis of Variance were performed in order to evaluate the different diagnostic techniques. The most frequent pathogen isolated was Staphylococcus aureus followed by Coagulase Negative Staphylococci (CNS), Streptococcus uberis, Streptococcus agalactiae and others. The Somatic Cell Score (SCS) was able to discriminate (p<0.05) cows positive for a pathogen from cows negative at the bacteriological culture except for cows with infection caused by CNS. Infrared thermography was correlated to SCS (p<0.05) but was not able to discriminate between positive and negative cows. Thermographic imaging seems to be promising in evaluating the inflammation status of cows affected by subclinical mastitis but seems to have a poor diagnostic value.

Serum acute phase proteins in cows with SARA (Subacute Ruminal Acidosis) suspect / Proteínas séricas de fase aguda em vacas com suspeita de SARA (Subacute Ruminal Acidosis)

The aim of this study was to evaluate the variations of Acute Phase Proteins (APPs) and other blood constituents during the onset of the sub-acute ruminal acidosis (SARA) pathological status. A total of 108 cows from 12 dairy herds were randomly selected and divided into three Groups of 36 animals each. All animals were subjected to a rumenocentesis. Group A was composed by subjects with a rumen pH>5.8, Group B was composed by subjects with a rumen pH ≤5.5≤5.8 and Group C was composed by subjects with a rumen pH<5.5. Blood samples were collected by jugular venipuncture and Haptoglobin (Hp), Serum Amyloid A (SAA), Total Proteins, Albumin and White Blood Cells (WBC) were determined. One-way ANOVA showed a statistical significance on Rumen pH, Hp, SAA. SARA seems not stimulate the APPs production from liver.

O objetivo deste estudo foi avaliar as variações de Proteínas de Fase Aguda (APPs) e outros constituintes sanguíneos durante o início do status patológico de sub-acute ruminal acidosis (SARA). O total de 108 vacas de 12 rebanhos leiteiros foram aleatoriamente selecionados e divididos em três grupos com 36 animais cada. Todos os animais foram submetidos a ruminocentesis. O Grupo A foi composto por sujeitos com rumen pH>5.8, o Grupo B foi composto por sujeitos com rumen pH ≤5.5≤5.8 e o Grupo C foi composto por sujeitos com rumen pH<5.5. Amostras sanguíneas foram coletas por punção venosa jugular e Haptoglobin (Hp), Serum Amyloid A (SAA), Proteínas totais, Albumin e células brancas do sangue (WBC) foram determinadas. ANOVA em via única mostrou significância estatística em Rumen pH, Hp, SAA. SARA não parece estimular a produção de APPs pelo fígado.

Influence of temperature and humidity on rumen pH and fatty acids in dairy cows.

The aim of this study was to investigate the variations of rumen pH and fatty acids (acetic acid, propionic acid, iso-butyric acid, n-butyric acid, iso-valerianic acid, n-valerianic, caproic acid and total fatty acids) in 245 early lactating dairy cows under different temperature and humidity conditions. The animals were divided into six groups and rumen fluid was collected by rumenocentesis on 22 dairy cows in April (Group A), 33 in May (Group B), 43 in June (Group C), 48 in July (Group D), 36 in September (Group E) and 60 in October (Group F). One-way analysis of variance (ANOVA), followed by the Bonferroni's test, showed a significant effect of environmental variations on all studied parameters (P < 0.0001). Changes in studied parameters can be explained in relation to the microbial population and shift in the optima for rumen conditions associated with variations of environmental conditions. We can affirm that the microbial assemblages that underlie energy and protein supply to wild ruminant are evident especially in relation to temperature and humidity conditions.

Anaplasma Phagocytophilum intragranulocytic morulae in aborting sheep: a herd case in Sicily.

The present report describes the haematological and serological findings observed in a dairy sheep farm during an aborting outbreak. Fifty ewes divided into two groups were included in the study: group A consisted of 35 healthy ewes and group B consisted of 15 ill subjects. From each ewe, blood samples were collected for microscopic examination and serological assay. After 3 months, all ewes were subjected to microscopic examination, serological and biochemical assay. Morula-containing granulocytes characteristic of A. phagocytophilum was observed in all animals of group B. Antibodies against A. phagocytophilum were observed in only one animal of group A. Seroconversion was observed after 3 months in five ewes of group A and all animals of group B. Only one subject with negative serology was positive to PCR. Our results confirm the endemicity of sheep tick-borne fever (TBF) in Sicily and the problem to breeding in an endemic area. We suggest that is necessary to combine the different assays depending on the stage of infection for a correct diagnosis in endemic areas. Periodic evaluation of seroconversion could be helpful to evaluate the progression of TBF in a flock.

A comparison of daily total locomotor activity between the lactation and the dry period in dairy cattle.

The objective of this study was to investigate the influence of farming management on the total locomotor activity (TLA) behaviour in dairy cattle. We recorded 24h/day TLA in five not pregnant Holstein Friesian cows during parts of the lactation and dry periods, by means of an activity monitoring system (Actiwatch mini®) for seven days in each period. During mild lactation (period 1) animals were milked and fed twice a day. During the dry (period 2) they were kept to graze all day. In both periods hay and water were available ad libitum. Differences between the photophase and the scotophase were evaluated with a Student t-test. One-way repeated measure ANOVA was used to determine a statistical significant effect of time. A trigonometric statistical model was used to describe the main rhythmic parameters: mean level, amplitude, acrophase and robustness of rhythm. Our results showed a circadian rhythm of daily TLA in both periods, with different percentages of robustness, and acrophase in the middle of the photophase. The different patterns of activity in the two periods were attributed to the management practise during milking period. These results could be taken in consideration during farming management for the evaluation of such systems used in livestock, with respect to production and welfare.

Effect of desmopressin on immune-mediated haemorrhagic disorders due to canine monocytic ehrlichiosis: a preliminary study.

To evaluate the possible use of desmopressin acetate (DDAVP) in haemorrhagic disorders consequent to canine monocytic ehrlichiosis (CME), three dogs infected by Ehrlichia canis, with a history of thrombocytopenia and recent bleeding, were studied. The dogs were administered desmopressin (1 µg/kg b.w. s.c.) every 24 h on three occasions. Blood samples were collected immediately before, and after 2 and 48 h the first DDAVP administration, to assess haematological, clinical chemistry and clotting time parameters. Spontaneous bleeding stopped within 1 h after the first DDAVP injection. Buccal mucosa bleeding time (BMBT) was shortened from 9.6 to 2.3 min within 2 h after the treatment. A statistically significant increase in platelet PLT count and fibrinogen, and a statistically significant decrease of PT and aPTT were observed after DDAVP administration. The haemorrhagic disorders caused by CME appear to be quickly corrected by DDAVP administration, giving the clinician the time necessary to administer appropriate chemotherapy.

Physiological values and factors affecting the metacarpal bone density of healthy feedlot beef cattle as measured by dual-energy X-ray absorptiometry.

The metacarpal bone mineral density of 136 healthy feedlot beef cattle of four different breeds (Charolaise, Limousine, Irish Crossbreed and Slovakian Crossbreed) raised and fed on standard conditions was measured by means of a dual-energy X-ray absorptiometry technique in an ex vivo study design. The average reference values (mean ± SD) of bone mineral density (BMD) for animals aged between 12 and 22 months and weighing between 236 and 546 kg have been reported and the effects of (i) breed, (ii) gender, (iii) age and (iv) body weight on bone mineral density have been considered. A significant difference (i) among different breeds and (ii) between genders resulted, whereas a high correlation between bone density and (iii) age and (iv) body weight was detected within the same breed and gender, with body weight being the most important factor affecting BMD. A modern new technological insight into the study of bovine bone physio-pathology is proposed.

Subacute rumen acidosis in lactating cows: an investigation in intensive Italian dairy herds.

Subacute rumen acidosis (SARA) represents one of the most important metabolic disorders in intensive dairy farms that affects rumen fermentations, animal welfare, productivity and farm profitability. The aim of the present study was to study the occurrence of SARA in intensive Italian dairy herds and to determine the relationship between diet composition, ruminal pH and short chain fatty acids (SCFA) concentration. Ten commercial dairy herds were investigated; twelve cows in each herd were selected randomly among animal without clinical signs of disease, with good body condition and between 5 and 60 day-in-milk (DIM), to perform rumenocentesis and obtain rumen fluid. Ruminal pH was determined immediately after sampling and concentration of SCFA in ruminal fluid was determined on samples after storage. An other objective of this research was to study in detail the effects of rumenocentesis on animal health: this study could confirm the extreme validity of this technique as ruminal sampling. Results were subject to anova and correlation analysis using SIGMA STAT 2.03. The results indicated the presence of SARA in three herds (more than 33% cows with rumen pH < 5.5), a critical situation (more than 33% cows with rumen pH < 5.8) in five farms and a normal rumen pH condition in two herds. In particular, dairy herds show on average SCFA concentration of 150, 145, 123 mmol/l for low pH, critical pH and normal pH herds respectively. There were not significant differences among diet composition even if herds with SARA showed a light discordance between initially chemistry composition and residual feed. In the affected herds it was not possible to understand the exact causes of SARA. Animal management seems to be one of the most important factors in developing SARA including total mixed ration preparation.