Effect of cooking temperature on alkaline phosphatase in the production of raw-milk Pecorino cheese.

Alkaline phosphatase (ALP) is a native raw-milk enzyme used in many countries as the standard assay for rapidly validating the milk pasteurization process. Due to the increased restrictions on the production or import of cheeses produced from unpasteurized milk, ALP activity (<10 mU/g) in cheese was measured as a simple and reliable method to check proper milk pasteurization in cheese for both safety inspection and trading controls. In Sicily, the artisanal cheesemaking of the Protected Denomination of Origin (PDO) semi-hard cheeses made with raw sheep milk, includes the cooking of the curd, after whey separation, in a wooden vat under hot Scotta whey (≥80°C), for 3 to 4 h, and finally is left to cool at ambient temperature. Thus, the temperatures adopted during cheesemaking may inactivate the ALP enzyme. To this purpose, the aim of this study was to demonstrate how different temperatures of Scotta whey (35°C [T35], 60°C [T60], 70°C [T70], 80°C [T80], 90°C [T90], and 100°C [T100]) used during the second cooking of Pecorino cheeses after molding for 3 h, influence the ALP activity in fresh and 3-mo aged cheese, both at core and outside. The results highlight that the rate of reduction of ALP was greater with increasing temperature of the second cooking, in particular for T 80°C curd, indicating that the use of Scotta whey >80°C could be a breakpoint able to reduce the ALP activity to values <10 mU/g. Different effects between the core and the outside portions of the experimental cheeses were found, with a decrease in ALP activity more on the outside than in the core portions, in both fresh and 3-mo aged cheeses, for T80, T90, and T100 treatments. Care must be taken in using ALP to control the use of pasteurized milk in the production of PDO cheeses without considering the cheesemaking processes, such as the second cooking, which could be equal to pasteurization, and an adequate interaction of time and temperature can reduce the ALP activity to values comparable with cheeses produced with pasteurized milk.

Graduate Student Literature Review: History, technologies of production, and characteristics of ricotta cheese.

This review focused on the historical, technological, and analytical characteristics of ricotta cheese available in the literature. Ricotta cheese is a typical dairy product that originated from Italy, used in the preparation of several traditional dishes, both sweet and salted. The available studies pertaining to ricotta cheese revealed a considerable biodiversity in the production with a large number of varieties produced, whose production varies according to the local uses and customs. The review shows the main chemical and microbial characteristics of the product and also the several parameters that affect the mechanism of the production process and the final characteristics of the product, including the raw materials, the processing methods, the season, the animals' diet, the animals' species, and breeds. Ricotta production can be artisanal or industrial, with differences in the making process. New trends in ricotta cheese production have been developed, with particular attention to the functional effect on human health and the novel technologies applied to extend the shelf-life of the products. Currently, it is not easy to find these new developments in the market, probably related to the cost of production, which is not always bearable by the farms. However, despite the large classification reported and the great interest by the cheese industry, just a few numbers of studies were found for artisanal ricotta productions, which still need to be characterized and studied.

Comparison of methods to homogenize ricotta cheese samples for total solids determination.

Ricotta cheese is an Italian dairy product obtained by heat-coagulation of the proteins in whey, resulting from cheese production. The homogenization method applied to collect ricotta cheese samples could affect the total solids (TS) contents of the products. The aim of this study was to determine the effects of 5 different homogenization methods of the samples collection applied for the accuracy in TS determination in ricotta cheese, including un-homogenized method (UNH), un-homogenized combined with the Ultra-Turrax (IKA-Werke GmbH & Co. KG) method (UNH-UTX), spoon-homogenized method (SPN), spoon-homogenized combined with Ultra-Turrax method (SPN-UTX), and Ultra-Turrax homogenized method (UTX). The repeatability and the standard deviation of repeatability are indicators of agreement between repeated measures for TS contents. Results reported that UNH ricotta cheese samples showed large variation in TS content with values ranging from 18.31% to 25.85% and a standard deviation of repeatability higher than 1%; SPN samples showed repeatability values higher than 0.35% and standard deviation of repeatability ranged until 1.36%, suggesting large variability even in this case; the Ultra-Turrax homogenization reported repeatability values lower than 0.1% and standard deviation of repeatability lower than 0.05%, indicating that this method provides repeatable measurements that may reduce the sources of uncertainty in TS determination.

Early-warning signals for disease activity in patients diagnosed with multiple sclerosis based on keystroke dynamics.

Within data gathered through passive monitoring of patients with Multiple Sclerosis (MS), there is a clear necessity for improved methodological approaches to match the emergence of continuous, objective, measuring technologies. As most gold standards measure infrequently and require clinician presence, fluctuations in the daily progression are not accounted for. Due to the underlying conditions of homogeneity and stationarity (the main tenets of ergodicity) not being met for the majority of the statistical methods employed in the clinical setting, alternative approaches should be investigated. A solution is to use a non-linear time series analysis approach. Here, Early-Warning Signals (EWS) in the form of critical fluctuations in Keystroke Dynamics (KD), collected using participant's smartphones, are investigated as indicators for a clinical change in three groups. These are patients with MS and changes in Magnetic Resonance Imaging (MRI), patients with MS but without changes in MRI, and healthy controls (HCs). Here, we report examples of EWS and changes in KD coinciding with clinically relevant changes in outcome measures in both patients with and without differences in the amount of MRI enhancing lesions. We also report no clinically relevant changes in EWS in the HC population. This study is a first promising step toward using EWS to identify periods of instability as measured by a continuous objective measure as a proxy for outcome measures in the field of MS.

Stage of lactation and corresponding diets affect in situ protein degradation by dairy cows.

The influence of stage of lactation and corresponding diets on rates of protein degradation (kd) is largely unstudied. Study objectives were to measure and compare in situ ruminal kd of crude protein (CP) and estimate rumen CP escape (rumen-undegradable protein; RUP) of selected feeds by cows at 3 stages of lactation fed corresponding diets, and to determine the incubation times needed in an enzymatic in vitro procedure, using 0.2 units of Streptomyces griseus protease per percent of true CP, that predicted in situ RUP. Residue CP was measured after in situ fermentation for 4, 8, 12, 24, 36, 48, and 72 h of 5 protein sources and 3 total mixed rations, which were fed to the in situ cows. Two nonlactating (dry) cows and 2 cows each at 190 (mid) and 90 (peak) days of lactation were used. Each pair of cows was offered free-choice diets that differed in composition to meet their corresponding nutrient requirements. Diets had decreasing proportions of forages and contained (dry matter basis) 11.9, 15.1 and 16.4% CP and 54.3, 40.3 and 35.3% neutral detergent fiber, for dry, mid, and peak TMR (TMR1, TMR2, and TMR3), respectively. Intakes were 10.3, 21.4, and 23.8kg of dry matter/d, respectively. Kinetic CP fractions (extractable, potentially degradable, undegradable, or slowly degradable) were unaffected by treatment. Lag time and kd varied among feeds. The kd was faster for all feeds (0.136/h) when incubated in dry-TMR1 cows compared with mid-TMR2 (0.097/h) or peak-TMR3 (0.098/h) cows, and no differences in lag time were detected. Calculated RUP, using estimated passage rates for each cow based on intake, differed between dry-TMR1 (0.382) and mid-TMR2 (0.559) or peak-TMR3 (0.626) cows, with a tendency for mid-TMR2 to be different from peak-TMR3. Using the average kd and lag time obtained from dry-TMR1 to calculate RUP for mid-TMR2 and peak-TMR3 cows using their passage rates reduced RUP values by 6.3 and 9.5 percentage units, respectively. Except for that of herring meal, in vitro residue CP at 6, 12, and 48h of enzymatic hydrolysis was correlated (r=0.90) with in situ RUP of peak-TMR3, mid-TMR2, and dry-TMR1, respectively. Although confounded within treatments, stage of lactation, diet, and intake appeared to affect CP degradation parameters and RUP. Using kd from nonlactating cows, or the RUP calculated from them, may bias diet evaluation or ration formulation for lactating cows. In addition, enzymatic in vitro predictions of RUP should be measured using incubation times that are appropriate for lactating cows.

Association of total mixed ration particle fractions retained on the Penn State Particle Separator with milk, fat, and protein yield lactation curves at the cow level.

As part of a larger project aiming to develop management evaluation tools based on results from test-day (TD) models, the objective of this study was to examine the effect of physical composition of total mixed rations (TMR) tested quarterly from March 2006 through December 2008 on milk, fat, and protein yield curves for 25 herds in Ragusa, Sicily. A random regression sire-maternal grandsire model was used to estimate variance components for milk, fat, and protein yields fitted on a full data set, including 241,153 TD records from 9,809 animals in 42 herds recorded from 1995 through 2008. The model included parity, age at calving, year at calving, and stage of pregnancy as fixed effects. Random effects were herd × test date, sire and maternal grandsire additive genetic effect, and permanent environmental effect modeled using third-order Legendre polynomials. Model fitting was carried out using ASREML. Afterward, for the 25 herds involved in the study, 9 particle size classes were defined based on the proportions of TMR particles on the top (19-mm) and middle (8-mm) screen of the Penn State Particle Separator. Subsequently, the model with estimated variance components was used to examine the influence of TMR particle size class on milk, fat, and protein yield curves. An interaction was included with the particle size class and days in milk. The effect of the TMR particle size class was modeled using a ninth-order Legendre polynomial. Lactation curves were predicted from the model while controlling for TMR chemical composition (crude protein content of 15.5%, neutral detergent fiber of 40.7%, and starch of 19.7% for all classes), to have pure estimates of particle distribution not confounded by nutrient content of TMR. We found little effect of class of particle proportions on milk yield and fat yield curves. Protein yield was greater for sieve classes with 10.4 to 17.4% of TMR particles retained on the top (19-mm) sieve. Optimal distributions different from those recommended may reflect regional differences based on climate and types and quality of forages fed.

Effect of Sicilian pasture feeding management on content of α-tocopherol and ß-carotene in cow milk.

This study was performed to evaluate α-tocopherol and ß-carotene contents of pasture milk under ordinary Sicilian farming conditions. Fourteen dairy farms were allocated into 2 balanced groups on the basis of cultivated (CULT) or spontaneous (SPO) pasture type feeding. Bulk milk per farm was collected 4 times from February through April at 3-wk intervals. Pasture botanical and diet composition, diet nutritional quality, milk yield and composition were estimated each time. Pasture intake levels were calculated based on feed analyses, hay and concentrate amounts fed, and milk yield and chemical composition. According to pasture intake, the farms were split into low pasture intake (LPI; <29.5% of dry matter) and high pasture intake (HPI; >29.5% of dry matter) groups. Milk samples per farm were analyzed for α-tocopherol and ß-carotene contents by HPLC. The SPO group had higher levels of α-tocopherol and ß-carotene in milk (0.7 and 0.3 mg/L, respectively) and milk fat (19.0 and 7.5 mg/kg fat, respectively) compared with the CULT group in milk (0.5 and 0.2 mg/L, respectively) and milk fat (14.6 and 4.9 mg/kg, respectively). High pasture intake compared with LPI increased α-tocopherol in milk fat (18.0 and 16.0 mg/kg of fat, respectively). However, only in the SPO (not in CULT), HPI compared with LPI increased milk α-tocopherol (0.8 vs. 0.6 mg/L, respectively), milk ß-carotene (0.3 vs. 0.2 mg/L, respectively), and milk fat ß-carotene (8.4 vs. 6.6 mg/kg, respectively). Results may be related to the different botanical composition of the respective pasture types and pasture intake. Spontaneous pasture compared with CULT contained a higher mass proportion of Asteraceae, Fabaceae, Cruciferae, Euphorbiaceae, and Malvaceae plants. Milk and milk fat α-tocopherol levels were higher on test-days (TD)-1, TD-2, and TD-4 compared with TD-3. For HPI farms, milk fat ß-carotene content was higher on the first 2 TD compared with the last 2 TD. These differences could be related to plant biological stage. On Sicilian dairy farms, the highest milk α-tocopherol and ß-carotene contents may be obtained feeding high levels of SPO pasture in the spring.

Association of total-mixed-ration chemical composition with milk, fat, and protein yield lactation curves at the individual level.

The objective of this study was to examine the effect of the chemical composition of a total mixed ration (TMR) tested quarterly from March 2006 through December 2008 for milk, fat, and protein yield curves for 27 herds in Ragusa, Sicily. Before this study, standard yield curves were generated on data from 241,153 test-day records of 9,809 animals from 42 herds in Ragusa province collected from 1995 to 2008. A random regression sire-maternal grandsire model was used to develop variance components for yields. The model included parity, age at calving, year at calving, and stage of pregnancy as fixed effects. Random effects were herd × test date, sire and maternal grandsire additive genetic effect, and permanent environmental effect modeled using third-order Legendre polynomials. Model fitting was carried out using ASReml. Subsequently, the model with estimated variance components was used to examine the influence of TMR crude protein, soluble N, acid detergent lignin, neutral detergent fiber, acid detergent fiber, starch, and ash on milk, fat, and protein yield curves. The data set contained 46,531 test-day milk yield records from 3,554 cows in the 27 herds recorded during the study period. Initially, an analysis was performed using one dietary component (one-component analysis) within each model as a fixed effect associated with the test-day record closest to the months the TMR was sampled within each herd. An interaction was included with the nutrient component and days in milk. The effect of the TMR chemical component(s) was modeled using a ninth-order Legendre polynomial. The conditional Wald F-statistic for the fixed effects revealed significant effects for acid detergent fiber, neutral detergent fiber, crude protein, starch, and their interactions with days in milk on milk, fat, and protein yield. On the basis of these results, a multicomponent analysis was performed in which crude protein, neutral detergent fiber, and starch were simultaneously included in the model with days in milk interactions. Although both analyses revealed that diet composition influenced production responses depending on lactation stage, the multiple-component analysis showed more pronounced effects of starch and neutral detergent fiber relative to crude protein for all traits throughout lactation.

How do dairy cows chew?--particle size analysis of selected feeds with different particle length distributions and of respective ingested bolus particles.

Not only feed but also respective bolus particle size could alter diet efficiency and cow performance. The objective of this project was to characterize particle size of selected feeds and respective swallowed boli. Feed samples included 6 different particle length rye grass hay samples, 1 grass silage, 1 corn silage, and 1 total mixed ration (TMR). Rye grass hay samples consisted of long hay and chopped hay particles retained on the 19- (19_PSPS hay), 8- (8_PSPS hay), and 1.18-mm (1.18_PSPS hay) Penn State Particle Separator (PSPS) screens and those collected on the pan (PSPS_pan hay). A sixth hay treatment was rye grass forage cut at 50-mm lengths and dried to hay (50-mm hay). Treatments were offered to 4 nonlactating and 4 lactating cows following rumen evacuation. Swallowed boli were collected and the number of chews per gram of ingested feed dry matter was determined. Feed and bolus particles of lengths ≥5mm were collected on a 1.6-mm screen using a horizontal wet sieving technique. This cut point was chosen, as the literature suggests that most fecal particles are shorter than 5mm. Dry matter proportions on this screen (PROP_1.6) were determined and particle lengths of retained particles were measured by image analysis. Mean particle lengths (ML) were calculated considering particles ≥5mm in length. Boli of long hay, of 19_PSPS hay, of 8_PSPS hay, and of 50-mm hay had similar ML of 10 to 11mm. Bolus PROP_1.6 were also similar between these treatments, ranging from 0.54 to 0.69. Bolus particle lengths and distributions of these treatments were not related to respective hay particles. Bolus of 1.18_PSPS hay had PROP_1.6 of 0.51 and a smaller ML of 8mm. The PSPS_pan hay had PROP_1.6 of only 0.33, but was still chewed intensely. Apparently, little particle size reduction occurred when cows ate the TMR or the silages. Feed and respective bolus PROP_1.6 were as follows: 0.66 and 0.59 in grass silage, 0.52 and 0.55 in corn silage, and 0.44 and 0.38 in the TMR. Feed and respective bolus ML were as follows: 13.8 and 11.6mm in grass silage, 12.0 and 11.2mm in corn silage, and 13.1 and 12.5mm in the TMR. Rye grass hay particles retained on PSPS screens ≥8mm, with ML of at least 25mm were longer compared with TMR particles, but respective bolus particles were shorter. Bolus particle size is not associated with the size of large feed particles chewed to a constant size that is appropriate for deglutition. This size may be related to feed chemical composition.

Effect of brine composition and brining temperature on cheese physical properties in Ragusano cheese.

Composition and physical properties of cheeses are influenced by temperature, salt, and calcium concentration of brine. This work aimed to examine conditions of brine under which the cheese matrix contracts or expands in absence of restrictions imposed by surface rind development during overnight block formation. Three experimental 4-kg blocks of Ragusano cheese were produced at 3 different stretching temperatures (70, 80, and 90°C) and cut into pieces weighing approximately 40 to 50 g. One piece from each was chemically analyzed at time 0. All other pieces were measured for weight and volume and placed in plastic bags containing 300 mL of different brine solutions (2% NaCl with 0.1% Ca; 10% NaCl with 0, 0.1, 0.2, or 0.4% Ca; 18% NaCl with 0.1% Ca; and 26% NaCl with 0.1% Ca) at 3 different temperatures (4, 12, and 20°C). After 24h of brining, the cheeses were analyzed for weight, volume, chemical, and microstructural changes. Salt concentration in brine significantly influenced composition, weight, and volume of the cheeses after brining. Salt concentration was inversely related to cheese volume and weight. Changes in weight caused by altering the brining temperature were sufficient to reach statistical significance, and statistically significant volume changes were induced by brining temperature and its interaction with salt content. The highest volume increase (30%) occurred in the cheese stored in the 2% NaCl brine at the coldest temperature, whereas the greatest volume decrease was recorded in cheeses brined in the 26% NaCl brine. Composition was not affected by brining temperature. Calcium concentration did influence weight, volume, and composition, except on a fat-on-dry-basis. When cheeses were brined without added calcium, cheese volume and weight increased at all temperatures. At high calcium levels (0.4%), syneresis occurred and volume decreased, especially at 20°C (-16.5%). Microstructural investigation with porosity measurement confirmed weight and volume changes.

Objective estimation of body condition score by modeling cow body shape from digital images.

Body condition score (BCS) is considered an important tool for management of dairy cattle. The feasibility of estimating the BCS from digital images has been demonstrated in recent work. Regression machines have been successfully employed for automatic BCS estimation, taking into account information of the overall shape or information extracted on anatomical points of the shape. Despite the progress in this research area, such studies have not addressed the problem of modeling the shape of cows to build a robust descriptor for automatic BCS estimation. Moreover, a benchmark data set of images meant as a point of reference for quantitative evaluation and comparison of different automatic estimation methods for BCS is lacking. The main objective of this study was to develop a technique that was able to describe the body shape of cows in a reconstructive way. Images, used to build a benchmark data set for developing an automatic system for BCS, were taken using a camera placed above an exit gate from the milking robot. The camera was positioned at 3 m from the ground and in such a position to capture images of the rear, dorsal pelvic, and loin area of cows. The BCS of each cow was estimated on site by 2 technicians and associated to the cow images. The benchmark data set contained 286 images with associated BCS, anatomical points, and shapes. It was used for quantitative evaluation. A set of example cow body shapes was created. Linear and polynomial kernel principal component analysis was used to reconstruct shapes of cows using a linear combination of basic shapes constructed from the example database. In this manner, a cow's body shape was described by considering her variability from the average shape. The method produced a compact description of the shape to be used for automatic estimation of BCS. Model validation showed that the polynomial model proposed in this study performs better (error=0.31) than other state-of-the-art methods in estimating BCS even at the extreme values of BCS scale.

Electric and magnetic fields do not modify the biochemical properties of FRTL-5 cells.

BACKGROUND: Electric and magnetic fields (EMF) might be involved in human disease and numerous research and scientific reviews have been conducted to address this question. In particular thyroid structural and functional alterations caused by various forms of non-ionizing radiation have been described. AIM: The aim of this study was to analyze the possible effects of EMF on thyroid, in particular we analyzed the effects caused by a GSM (Global System for Mobile Communications) signal (900 MHz) on cultured thyroid cells (FRTL- 5). MATERIAL AND METHODS: The experimental setup was designed in order to expose samples to a radiofrequency wave in well-controlled conditions. We used the FRTL-5 cell line, an epithelial monoclonal continuous cell line derived from Fisher rat thyroid tissue growing as monolayer, expressing the TSH receptor and the sodium-iodide symporter (NIS). FRTL-5 were subsequently irradiate for 24, 48, and 96 h with EMF (800-900 MHz, power-frequency of mobile communication systems) and iodide uptake and cAMP production were measured. RESULTS: The irradiation of cells with EMF at 900 Mhz for 24, 48, and 96 h did not influence the level of cAMP production and was not able to modify iodide accumulation in FRTL- 5 cells with respect to basal conditions. CONCLUSIONS: In conclusion, EMF do not seem to be able to interfere with the biochemical properties of FRTL-5 cells in vitro.

Associations of breed and feeding management with milk production curves at herd level using a random regression test-day model.

Earlier studies identified large between-herd variation in estimated lactation curve parameters from test-day milk yield and milk composition records collected in Ragusa province, Italy. The objective of this study was to identify sources of variation able to explain these between-herd differences in milk production curves, by estimating associations of animal breed (Holstein Friesian vs. Brown Swiss), feeding system [separate feeding (SF) vs. total mixed ration (TMR)], and TMR chemical composition on milk and milk components herd curves. Data recorded from 1992 through 2007 for test-day (TD) milk, fat, and protein yields from 1,287,019 records of 148,951 lactations of 51,489 cows in 427 herds were processed using a random regression TD model. Random herd curves (HCUR) for milk, fat, and protein yields were estimated from the model per herd, year, and parity (1, 2, and 3+) using 4-order Legendre polynomials. From March 2006 through December 2007, samples of TMR were collected every 3 mo from 37 farms in Ragusa province. Samples were analyzed for dry matter, ash, crude protein, soluble nitrogen, acid detergent lignin, neutral detergent fiber, acid detergent fiber, and starch. Traits used to describe milk production curves were peak, days in milk at peak, persistency, and mean. Association of feeding system and animal breed with HCUR traits was investigated using a general mixed model procedure. Association of TMR chemical composition with HCUR traits was investigated using multivariate analysis with regression and stepwise model selection. Results were consistent for all traits and parities. Feeding system was significantly associated with HCUR peak and mean, with higher values for TMR. Animal breed was significantly associated with HCUR persistency, with higher values for Brown Swiss herds. Furthermore, animal breed influenced HCUR peak and mean, with higher values for Holstein Friesian herds. Crude protein had the largest effect on HCUR peak and mean, whereas the interaction between crude protein and dry matter mainly affected persistency. When provided by a national evaluation system, HCUR can be used as an indicator of herd feeding management.

A state indicator on regional scale for high-voltage power lines: defining a priority for in situ inspections.

An integrated system to evaluate the magnetic field generated by power lines exposure has been developed using a specific simulation model (PLEIA-EMF). This is part of a software toolset, subjected to internal suitability verifications and in-field validations. A state indicator related to each span has been determined using the data extracted from digital cartography, the magnetic field calculated by PLEIA and the number of people living in the nearest buildings. In this way, it is possible to determine eventual criticalities in the considered area, focusing attention on those cases with more considerable exposure levels and involving a higher number of people. A campaign of inspections has been planned using PLEIA simulations. The reliability of stored technical data and the real population exposure levels have been evaluated in critical cases, individuated through the following described methodology. The procedures leading to the indicator determination and the modalities of in situ inspections are here presented.

Measurement of electromagnetic fields generated by air traffic control radar systems with spectrum analysers.

Air traffic control (ATC) primary radars are 'classical' radars that use echoes of radiofrequency (RF) pulses from aircraft to determine their position. High-power RF pulses radiated from radar antennas may produce high electromagnetic field levels in the surrounding area. Measurement of electromagnetic fields produced by RF-pulsed radar by means of a swept-tuned spectrum analyser are investigated here. Measurements have been carried out both in the laboratory and in situ on signals generated by an ATC primary radar.

Characterisation and measurement of signals generated by DVB-H 'GAP-filler' repeaters.

DVB-H (Digital Video Broadcasting Handheld) is the standard developed by DVB Project and approved by ETSI with the aim of providing the reception of DVB signals even in mobility but also data transfers and multimedia services. The introduction and development of the DVB-H system is still ongoing. In this context, this work focuses on the temporal trend of electromagnetic impact of an urban DVB-H repeater (called 'gap-filler') for exposure assessment purposes; it also describes a method for its measurement by means of narrow band instrumental chains.

Variance components for test-day milk, fat, and protein yield, and somatic cell score for analyzing management information.

Test-day (TD) models are used in most countries to perform national genetic evaluations for dairy cattle. The TD models estimate lactation curves and their changes as well as variation in populations. Although potentially useful, little attention has been given to the application of TD models for management purposes. The potential of the TD model for management use depends on its ability to describe within- or between-herd variation that can be linked to specific management practices. The aim of this study was to estimate variance components for milk yield, milk component yields, and somatic cell score (SCS) of dairy cows in the Ragusa and Vicenza areas of Italy, such that the most relevant sources of variation can be identified for the development of management parameters. The available data set contained 1,080,637 TD records of 42,817 cows in 471 herds. Variance components were estimated with a multilactation, random-regression, TD animal model by using the software adopted by NRS for the Dutch national genetic evaluation. The model comprised 5 fixed effects [region x parity x days in milk (DIM), parity x year of calving x season of calving x DIM, parity x age at calving x year of calving, parity x calving interval x stage of pregnancy, and year of test x calendar week of test] and random herd x test date, regressions for herd lactation curve (HCUR), the animal additive genetic effect, and the permanent environmental effect by using fourth-order Legendre polynomials. The HCUR variances for milk and protein yields were highest around the time of peak yield (DIM 50 to 150), whereas for fat yield the HCUR variance was relatively constant throughout first lactation and decreased following the peak around 40 to 90 DIM for lactations 2 and 3. For SCS, the HCUR variances were relatively small compared with the genetic, permanent environmental, and residual variances. For all the traits except SCS, the variance explained by random herd x test date was much smaller than the HCUR variance, which indicates that the development of management parameters should focus on between-herd parameters during peak lactation for milk and milk components. For SCS, the within-herd variance was greater than the between-herd variance, suggesting that the focus should be on management parameters explaining variances at the cow level. The present study showed clear evidence for the benefits of using a random regression TD model for management decisions.

Prevalence of mastitis pathogens in Ragusa, Sicily, from 2000 to 2006.

The objective of this study was to report the prevalence of intramammary infections (IMI) in Ragusa, Sicily, from milk samples (n = 18,711) collected between October 2000 and June 2006 from 101 dairy herds. Milk samples were collected at 9,747 cow sampling events from 5,285 individual cows. Samples were individual quarter (92.8%) or composite samples (7.2%) from an individual cow. Logistic regression was used to examine the prevalence of IMI at the level of milk sample and at the level of cow, controlling for year and season of collection, type of sample (individual quarter or composite), and type of housing and bedding of the cow at the time of collection. Bedding and housing types were as follows, respectively (number of herd groups): bedding: none (61), organic [51 (straw, 50; sawdust, 1)], and sand (3); housing: bedded pack (37), free stalls (57), tie stalls (4), and paddock (17). Raw prevalence of cow IMI for a sample event was as follows (percentage of cow samples): no growth, 47.4%; coagulase-negative staphylococci, 22.6%; Staphylococcus aureus, 20.6%; other Streptococcus spp., 11.1%; Streptococcus agalactiae, 2.3%; coliform bacteria, 2.9%; and other organisms, 5.8%. Prevalence of IMI differed by bedding type for Staph. aureus (none, 24.5%; organic, 12.7%; sand, 12.3%) and coagulase-negative staphylococci (none, 13.1%; organic, 27.4%; sand, 26.9%) but not for Streptococcus spp. or coliform bacteria. Prevalence of Streptococcus spp. IMI differed by housing type (tie stalls, 22.2%; bedded pack, 12.8%; free stalls, 8.4%; paddock, 7.1%). Housing was not associated with the prevalence of IMI for other bacteria. Herd monthly prevalence of Staph. aureus and Streptococcus spp. IMI was associated with decreased mean milk production (Staph. aureus, -1.42 kg/d per cow, SEM 0.51; Streptococcus spp., -1.31 kg/d per cow, SEM 0.64) and increased mean linear score (Staph. aureus, 1.01 units/d per cow, SEM 0.16; Streptococcus spp., 0.59 units/d per cow, SEM 0.22). Herds (n = 11) with a mean linear score (MLS) less than 3.3 units had the lowest prevalence of Staph. aureus IMI and monthly MLS and the greatest monthly mean milk production compared with other herds grouped by MLS [MLS 3.31 to 3.99 (n = 20), MLS 4.00 to 4.46 (n = 20), MLS >4.46 (n = 17), and MLS not available (n = 33)]. Implementation of a milk quality program to control gram-positive organisms is important for Ragusa.

Variability of bacterial biofilms of the "tina" wood vats used in the ragusano cheese-making process.

Ragusano cheese is a "protected denomination of origin" cheese made in the Hyblean region of Sicily from raw milk using traditional wooden tools, without starter. To explore the Ragusano bacterial ecosystem, molecular fingerprinting was conducted at different times during the ripening and biofilms from the wooden vats called "tinas" were investigated. Raw milks collected at two farm sites, one on the mountain and one at sea level, were processed to produce Ragusano cheese. Raw milk, curd before and after cooking, curd at stretching time (cheese 0 time), and cheese samples (4 and 7 months) were analyzed by PCR-temporal temperature gel electrophoresis (PCR-TTGE) and by classical enumeration microbiology. With the use of universal primers, PCR-TTGE revealed many differences between the raw milk profiles, but also notable common bands identified as Streptococcus thermophilus, Lactobacillus lactis, Lactobacillus delbrueckii, and Enterococcus faecium. After the stretching, TTGE profiles revealed three to five dominant species only through the entire process of ripening. In the biofilms of the two tinas used, one to five species were detected, S. thermophilus being predominant in both. Biofilms from five other tinas were also analyzed by PCR-TTGE, PCR-denaturating gradient gel electrophoresis, specific PCR tests, and sequencing, confirming the predominance of lactic acid bacteria (S. thermophilus, L. lactis, and L. delbrueckii subsp. lactis) and the presence of a few high-GC-content species, like coryneform bacteria. The spontaneous acidification of raw milks before and after contact with the five tinas was followed in two independent experiments. The lag period before acidification can be up to 5 h, depending on the raw milk and the specific tina, highlighting the complexity of this natural inoculation system.

Body condition assessment using digital images.

This project assessed the ability to assign a body condition score (BCS) to a dairy cow from digital photographs or videos. Images were taken from the rear of the cow at a 0 to 20 degrees angle relative to the tail head. Four observers assigned a BCS to each of 57 cows at a farm visit (live, farm 1) and later from a photograph (photo). Means +/- standard deviations of BCS by method and observer were as follows: live = 3.25 +/- 0.51, 3.42 +/- 0.49, 3.32 +/- 0.58, 3.13 +/- 0.62; photo = 3.36 +/- 0.52, 3.32 +/- 0.43, 3.44 +/- 0.62, 3.14 +/- 0.6 for observers 1 to 4, respectively. Body condition score means differed across observers for live (observer 2 higher and observer 4 lower, compared with observers 1 and 3) and photo methods (observer 3 lower, compared with observers 1, 2, and 3); however, within observer, the mean live BCS did not differ from the mean photo BCS. Correlation coefficients between BCS assigned live and from photos were 0.84, 0.82, 0.82, and 0.90 for observers 1 to 4, respectively. Subsequently, observer 1 visited 2 farms, assigned a live BCS, and digitally photographed 187 cows (56 and 131 cows from farms 2 and 3, respectively). Observers 2, 3, and 4 assigned a BCS from the photographs. Means +/- standard deviations of BCS by observer (method) were 1 (live) 3.35 +/- 0.55; 2 (photo) 3.33 +/- 0.49; 3 (photo) 3.60 +/- 0.54; and 4 (photo) 3.26 +/- 0.62. The mean BCS for observer 3 was higher and that for observer 4 was lower than for observers 1 and 2. Correlation coefficients between observer 1 and observers 2 through 4 were 0.78, 0.76, and 0.79, respectively. Observer 1 assigned a BCS to 41 cows at a farm visit and 3 wk later assessed the BCS of cows from a video taken at a farm visit by a different individual. Cows were restrained in headlocks at a feed bunk when assessing BCS and for video production. No difference was detected for the mean BCS, for the standard deviation of the mean BCS, or in the distribution of BCS between the live and video assessments. Mean and SD for 17 groups of Holstein cows from 20 farms were used to generate 10,000 random samples of BCS. Groups of 25, 50, 100, and 150 cows were created from the random samples, and estimates of mean BCS were determined by sampling 3 to 80% of the group. Estimates of mean BCS with a sample size of 30% or more from a group of cows fell within the 95% confidence limit of the true mean more than 98% of the time. Digital photographs provide adequate imaging for assessment of BCS. Sampling 30% of a group should be adequate to assess the mean BCS. Video imaging allowed a rapid assessment of BCS but did not permit identification of individual cows.