This study examined the hypothesis that xanthosine (XS) treatment would promote mammary-specific gene expression and stem cell transcripts and have a positive influence on milk yield of dairy goats. Seven primiparous Beetal goats were assigned to the study. Five days after kidding, one gland (either left or right) was infused with XS (TRT) twice daily for 3 d and the other gland with no XS infusion served as a control (CON). Mammary biopsies were collected at 10 d and RNA was isolated. Gene expression analysis of milk synthesis genes, mammary stem/progenitor cell markers, cell proliferation and differentiation markers were performed using real time quantitative PCR (RT-qPCR). Results showed that the transcripts of milk synthesis genes (BLG4, CSN2, LALBA, FABP3, CD36) and mammary stem/progenitor cell markers (ALDH1 and NR5A2) were increased in as a result of XS treatment. Average milk yield in TRT glands was increased marginally (approximately ~2% P = 0·05, paired t-test) per gland relative to CON gland until 7 wk. After 7 wk, milk yield of TRT and CON glands did not differ. Analysis of milk composition revealed that protein, lactose, fat and solids-not-fat percentages remained the same in TRT and CON glands. These results suggest that XS increases expression of milk synthesis genes, mammary stem/progenitor cells and has a small effect on milk yield.

Samples of butter were reworked at various times after removal from the churn, either in a laboratory mixer or by pressing between a microscope slide and cover glass. Moisture distribution was studied by microscopic examination and by indicator papers.

Reworking within 30 min of completion of the original working caused no change in moisture distribution but delayed reworking caused aggregation of water droplets. The further the setting of the butter had proceeded before reworking, the greater was the extent of aggregation.

Cream-cooling treatments which resulted in a softer butter delayed or decreased the aggregation of droplets caused by reworking.

A theory is suggested relating changes on reworking with the formation of a crystal structure on setting.

The experiments reported in this research communication aimed to plot the expression pattern of Sirt3, a master regulator of energy metabolism and antioxidation defence, in the liver of dairy goats during perinatal period. Ten healthy dairy goats in late pregnancy were chosen, and needle biopsy was applied to collect liver samples at 1-week intervals. Protein levels of hepatic Sirt3 were analysed by western-blotting. Serum enzyme activities of manganese superoxide dismutase (Mn-SOD) and non-esterified fatty acids (NEFA) levels were measured, and their correlation with Sirt3 mRNA levels was also estimated. Compared with >3-week before parturition (BP), Sirt3 proteins were significantly reduced at 1-week after parturition (AP) and 2-week AP (P < 0·05), but increased on the day of parturition (P < 0·01). Correlation analysis revealed a positive association between hepatic Sirt3 mRNA levels and serum enzyme activity of Mn-SOD (r = 0·46), but a negative association between that and serum NEFA levels (r = −0·41). These data indicate that the decreased hepatic expression of Sirt3 might be one of the reasons that dairy goats undergo oxidative stress after parturition.

The possibility that some of the factors governing the inheritance of milk might be inherited in a sex-linked manner has been suggested by one of the writers. The need was felt for further investigation. There are two main avenues by which this question may be explored: by planned experiment with cattle or by a study of the existing milk records. The former method is slow and very costly, but would probably give conclusive results. The latter does not require experiment to provide the necessary facts, but the data may be somewhat vitiated by lack of control over conditions of nutrition and husbandry which undoubtedly affect, to a great extent, the amount of milk which a cow may yield in a lactation.

The bulked milk from a flock of Awassi sheep was analysed in two successive seasons. In the second season a wider range of analyses of samples taken from the time the first few ewes came into milk until almost the end of the production season (minimum and maximum numbers in milk 8 and 199) gave the following average values: specific gravity, 1·0366; titratable acidity, 0·217%; pH, 6·65; fat, 6·88%; protein, 6·18%; lactose, 5·75%; solids-not-fat, 12·99%; ash, 0·928%; CaO, 0·29%; p2O5, 0·32%; CaO in ash, 31·5%; P2O5 in ash, 34·3%.

The results are compared with the published compositional figures for sheep's and cow's milks.

An experiment has been performed with 2 Jersey cows to determine the effect of a reduction in udder temperature on milk production. One half of the udder was covered while the other half was cooled by an increase in air movement at an air temperature of 6−10°C; for closely clipped udders it was estimated that the cooling conditions might be equivalent to an air temperature of −10°C with low air movement. Yields of milk, fat, protein and lactose were reduced significantly at the morning milking after 22 h cooling; the decreases which occurred at the afternoon milking after 9 h cooling, in all components except fat, were not significant. Wisconsin Mastitis Tests on the milk indicated that changes in udder health did not contribute to these effects.

Carbonyl sulphide (COS) was detected in the headspace of Cheddar cheeses in concentrations ranging from 0·01 ng ml-1 to 0.3 ng ml-1. It was also found in the headspace above certain packaging materials and sealing materials used in the analytical procedures. Evidence that COS was produced within the cheese was given by the findings that experimental cheese containing added cysteine had consistently higher COS levels (up to 1·0 ng ml-1) and that COS could be produced chemically from mixtures of cysteine or methionine with riboflavin and ascorbic acid in laboratory trials.

We have reported previously on the kinetics of thermal inactivation at 80–120°C of the extracellular proteinase from Pseudomonas fluorescens 22F (Schokker & van Boekel, 1997, 1999b). During these studies, we noted some inactivation during the heating up and cooling periods, but allowed for this by calculating the residual activity as a fraction of the activity after the heating up period of 2 min followed by cooling to 0°C. However, it may be of interest to evaluate the extent of inactivation during these heating up and cooling periods. If the temperature dependence of the reaction rate behaves according to Eyring's theory, inactivation would, of course, be slower than at the final heating temperature. However, during the heating and cooling of the enzyme solution, the temperature also passes the region in which autoproteolysis occurs (Schokker & van Boekel, 1998a). Prolonged residence time in the critical zone for autoproteolysis may cause increased inactivation, as has been demonstrated in electrophoresis experiments for proteinases from other Ps. fluorescens strains (Barach & Adams, 1977; Richardson, 1981; Diermayr et al. 1987). Consequently, the inactivation during the first few minutes would be dependent on factors influencing both autoproteolytic and thermal inactivation.

In most of our heating experiments (Schokker & van Boekel, 1997, 1999b), inactivation during heating up was relatively rapid compared with inactivation at the final heating temperature, leading to a biphasic inactivation curve. This was also found for proteinases from many other Ps. fluorescens strains. In some studies the inactivation during heating up was not taken into account when analysing the kinetics of thermal inactivation (Patel et al. 1983; Yan et al. 1985; Fairbairn & Law, 1986), which led to misinterpretation of the mechanism or the kinetic values. Others explained the biphasic inactivation curve by autoproteolysis (Barach & Adams, 1977; Richardson, 1981; Stepaniak & Fox, 1983; Kroll & Klostermeyer, 1984; Diermayr et al. 1987), or stabilization by Ca2+ of a small portion of the proteinase to heat inactivation (Stepaniak & Fox, 1983; Azcona et al. 1988).

In this paper we discuss the influence of protein, enzyme purification and Ca2+ activity on inactivation during the heating up and cooling periods. The aim of this study was to determine, using kinetic modelling, whether the inactivation during heating up and cooling periods could be explained by autoproteolysis and thermal inactivation, or whether other mechanisms are involved in the strong initial inactivation.

The lactose-fermenting coliform organisms in milk and dung have been investigated.

A large proportion of those recovered from raw milk by direct plating proved to be of the Bact. aerogenes type and a number of “intermediates” was also present.

In dung faecal Bact. coli largely predominated, the proportion of Bact. aerogenes being very small.

If the implication of these experiments be accepted it is possible that many of the coliform types found in milk are derived, not from faeces, in which the proportion of aerogenes is small, but from external sources, such as contaminated utensils, and from food-stuffs.

The pH ranges of growth of streptococci and lactobacilli in dextrose yeast casein digest broth have been studied. Nearly all the group I and II streptococci grew at pH 8·8, but only the enterococci grew at pH 4·8; all group III types (heterofermentative) grew at pH 4·4. Only a few lactobacilli grew at pH. 8·8 but most were able to grow at pH 4 if other conditions were favourable. The enterococci, Str. lactis and Str. cremoris could be differentiated by the alkaline limits of growth.

We examined the latent structure of 26 cheese related phenotypes in dairy cattle. Traits related to milk yield and quality (8 traits), milk protein fractions (8 traits), coagulation and curd firmness indicators (CF, 5 traits) and cheese-making phenotypes (cheese yields (%CY) and nutrient recoveries in the curd (REC), 5 traits) were analysed through multivariate factor analysis (MFA) using a varimax rotation. All phenotypes were measured in 1264 Brown Swiss cows. Ten mutual orthogonal, latent variables (factors; Fs) were obtained explaining 74% of the original variability. These Fs captured basic concepts of the cheese-making process. More precisely, the first 4 Fs, sorted by variance explained, were able to capture the underlying structure of the CY percentage (F1: %CY), the CF process with time (F2: CFt), the milk and solids yield (F3: Yield) and the presence of nitrogen (N) in the cheese (F4: Cheese N). Moreover, 4 Fs (F5: as1-β-CN, F7: κ-β-CN, F8: as2-CN and F9: as1-CN-Ph) were related to the basic milk caseins and 1 factor was associated with the α-LA whey protein (F10: α-LA). A factor describing udder health status (F6: Udder health), mainly loaded on lactose, other nitrogen compounds in the milk and SCS, was also obtained. Further, we inferred the effects of some potential sources of variation (e.g. stage of lactation and parity) including feeding and management systems. Stage of lactation had a significant effect for 7 of the 10 Fs, followed by parity of the cow (3 Fs), dairy system and feeding (3 Fs). Our work demonstrates the usefulness of MFA in reducing a large number of variables to a few latent factors with biological meaning and representing groups of traits that describe a complex process like cheese-making. Such an approach would be a valuable tool for studying the influence of different production environments and individual animal factors on protein composition and cheese-making related traits.

Milk and dairy products have great importance in human nutrition related to the presence of different nutrients, including protein, fatty acid profile and bioactive compounds. Dietary supplementation with foods containing these types of compounds may influence the chemical composition of milk and dairy products and hence, potentially, the consumer. Our objective was to summarize the evidence of the effect of supplementation with antioxidants and phenolic compounds in the diets of dairy animals and their effects on milk and dairy products. We conducted a systematic search in the MEDLINE/PubMed database for studies published up until July 2022 that reported on supplementation with antioxidants and phenolic compounds in diets that included plants, herbs, seeds, grains and isolated bioactive compounds of dairy animals such as cows, sheep and goats and their effects on milk and dairy products. Of the 94 studies identified in the search, only 15 met the inclusion criteria and were analyzed. The review revealed that supplementation with false flax cake, sweet grass, Acacia farnesiana, mushroom myceliated grains and sweet grass promoted an effect on the milk lipid profile, whereas supplementation with dried grape pomace and tannin extract promoted an effect on the milk and cheese lipid profiles. In six studies, the addition of Acacia farnesiana, hesperidin or naringin, durum wheat bran, mushroom myceliated grains, dried grape pomace and olive leaves increased the antioxidant activity of milk. In conclusion, supplementation with bioactive compounds had a positive impact which ranged from an increase in antioxidant capacity to a decrease in oxidative biomarkers such as malondialdehyde.

This research communication explores the value of routinely collected bulk tank milk quality data for estimating dairy cattle welfare at herd level. Selected bulk tank milk quality parameters (somatic cell count, total bacterial count, urea, protein and fat contents) recorded during the years 2014–2016 in 287 Italian dairy farms were compared with the animal welfare data of each farm. The welfare assessment data were extracted from the database of the Italian Reference Centre for Animal Welfare (CReNBA), which includes the outputs of the application of the CReNBA welfare assessment protocol for dairy cows, used at national level for on-farm controls. The statistical analysis was carried out using the correlation coefficient for Kendall's Tau ranks, in order to investigate the presence of a categoric relationship between the selected bulk tank milk quality parameters and the overall animal welfare score or the scores of the single areas A (farm management and staff training), B (housing) and C (animal-based measures). Somatic cell count, total bacterial count, urea and proteins demonstrated only a few statistically significant and very weak correlations with farm animal welfare data, while no significant correlations were obtained for milk fat content. Given the weak correlations found, the selected bulk tank milk parameters seems to be able to provide only limited information about the welfare level of the herd, thus it could be difficult to use them for drawing up a pre-screening model for identifying herds at risk of poor welfare.

We carried out a thorough genetic evaluation of Streptococcus dysgalactiae isolated from clinical bovine mastitis cases and performed a phylogenetic analysis to represent the evolutionary relationship between S. dysgalactiae sequences. A total of 35 S. dysgalactiae strains were isolated from cases of clinical mastitis identified at a large commercial dairy farm located near Ithaca, New York. Whole-genome sequencing identified twenty-six antibiotic resistance genes, four of which were acquired genes, in addition to fifty virulence genes. Multi-locus sequence typing detected three new sequence types (STs). We conclude that a high proportion of this microorganism carries multiple virulence determinants and resistance genes, and that this indicates its potential to cause mastitis. Eight different STs were identified, of which ST453 (n = 17) was the most prevalent and ST714, ST715, ST716 were novel STs.

We hypothesised that a relationship would exist between hair fatty acids, especially C12:0, C14:0 and C16:0, and parameters of energy metabolism such as energy intake, energy mobilisation, and energy requirement for maintenance and milk performance. For this study, 11 primiparous German Holstein cows were available from which hair samples at weeks 6 and 8 of lactation were analysed. The average body weight of these animals was 558 ± 27 kg at calving and milk yield at 100-days in milk was 3,537 ± 529 kg. Feed intake and milk yield were measured daily. Body weight and back fat thickness were measured at calving and in weeks 2, 4, and 8 of lactation. Energy balance and energy utilisation were calculated until week 6 of lactation. Spearman's correlation coefficients were found to be significantly positive for the relationship between the percentage of C12:0 and C14:0 fatty acids in the hair in lactation week 8 and energy intake in weeks 5 and 6 (0.62 < r < 0.65, P < 0.05). If the animals are grouped according to their energy utilisation between weeks 1 and 6 into two groups higher (n = 6) or lower (n = 5) than the median, animals of the high energy utilising group had a higher energy intake. These animals had also higher percentages of the C12:0 fatty acid in their hair fat (week 6: 4.9% vs. 3.1%, P < 0.05; week 8: 4.3% vs. 2.9%, P = 0.05). Our hypothesis is supported, and this study justifies further investigation of the content of medium-chain fatty acids in hair samples as biomarkers for the metabolic status of a cow during early lactation.

In this Research Communication we evaluate the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify 380 bacteria isolated from cases of bovine mastitis in Brazil. MALDI-TOF MS identifications were compared to previous identifications by biochemical tests and 16S rRNA sequencing. MALDI-TOF MS achieved a typeability of 95.5%. The accuracy of MALDI-TOF MS for the identification of Staphylococcus isolates was 93.2%. The agreement between MALDI-TOF MS and biochemical identification of Streptococcus agalactiae was 96%, however, the agreement between these techniques for identifying other catalase-negative, Gram-positive cocci was lower. Agreement in identifying Gram-negative bacteria at the genus level was 90.5%. Our findings corroborate that MALDI-TOF MS is an accurate, rapid and simple technique for identifying bovine mastitis pathogens. The availability of this methodology in some research institutions would represent a significant step toward increasing the diagnosis and epidemiological studies of bovine mastitis and other animal infectious diseases in Brazil.

A peptic hydrolysate of proteinaceous material of whey from Mozzarella cheese manufacture was incubated with α-chymotrypsin under conditions leading to the formation of plastein products. The influence of incubation time, concentration and molecular size of substrate was studied. The most favourable conditions for the plastein synthesis were 12 h incubation time and 35% (w/v) concentration of peptides having mol. wt in the range 451–1450.

The recovery of milk constituents from cheese whey is affected by various processing conditions followed during production of Ricotta cheese. The objective of the present investigation was to optimize the temperature (60–90 °C), pH (3–7) and CaCl2 concentration (2·0–6·0 mm) for maximum yield/recovery of milk constituents. The research work was carried out in two phases. In 1st phase, the influence of these processing conditions was evaluated through 20 experiments formulated by central composite design (CCD) keeping the yield as response factor. The results obtained from these experiments were used to optimize processing conditions for maximum yield using response surface methodology (RSM). The three best combinations of processing conditions (90 °C, pH 7, CaCl2 6 mm), (100 °C, pH 5, CaCl2 4 mm) and (75 °C, pH 8·4, CaCl2 4 mm) were exploited in the next phase for Ricotta cheese production from a mixture of Buffalo cheese whey and skim milk (9 : 1) to determine the influence of optimized conditions on the cheese composition. Ricotta cheeses were analyzed for various physicochemical (moisture, fat, protein, lactose, total solids, pH and acidity indicated) parameters during storage of 60 d at 4 ± 2 °C after every 15 d interval. Ricotta cheese prepared at 90 °C, pH 7 and CaCl2 6 mm exhibited the highest cheese yield, proteins and total solids, while high fat content was recorded for cheese processed at 100 °C, pH 5 and 4 mm CaCl2 concentration. A significant storage-related increase in acidity and NPN was recorded for all cheese samples.

The work carried out by us on the nutritive value of commercially sterilized milk shows definitely that certain factors are injured in the course of the heat treatment. The biological value of the proteins is slightly but unmistakably decreased, most probably because of the partial destruction of one or more essential amino-acids. Of the vitamins, vitamin C is the most markedly affected. It is decreased by half and, in view of the severity of the heat treatment, it is remarkable that the loss is not greater. The anaerobic conditions which exist during the application of the highest sterilizing temperatures may account for the survival of a part of this labile factor. Vitamin B1 also suffers serious loss, the destruction amounting to 30 % of the original value. Neither vitamin A and carotene nor vitamin B2 (flavin) are affected by the heat treatment. The fate of other components of milk was not studied by us, but experiments on rats on the effect of sterilization on the total nutritive value of milk indicates that vitamin B1 was the first limiting factor of sterilized milk.

The study aimed at clarifying the problem of the hitherto contradictory results regarding usefulness of BoLA-DRB3 locus as a marker in selection against mastitis and for milk yield. Treating the BoLA-DRB3 locus effect as random was proposed in place of considering it fixed. Somatic cell counts and milk yields recorded monthly on a test day (22 424) of 619 Polish Holstein cows genotyped for BoLA-DRB3 were analysed with an animal model including a random effect for genotype at this locus. The BoLA-DRB3 alleles were defined as restriction patterns obtained with three endonucleases. Two alternative BoLA-DRB3 additive genotype (co)variance structures were constructed for 161 genotypes recorded. One was based on the allelic similarity of the genotypes resulting in element values of 0 (no common allele), 0·5 (one allele in common), and 1 (diagonal). The other considered restriction site similarity (up to 3 in 1 allele) giving element values of 0 (no common restriction sites) and then increasingly in steps of 1/6 up to 6/6 (diagonal), where the numerator represents the number of common sites between genotypes. The DRB3 variance component for the natural logarithm of somatic cell count did not exceed 0·006 of the polygenic additive component or 0·003 for milk yield. Hence, unless we fail to detect the causative site or to properly define traits being the projection of a site, the effect of the genotype at the BoLA-DRB3 locus does not explain variation in somatic cell count and milk yield at a degree expected of a genetic marker.