The keeping quality of various mixtures, made up of raw milk and skim milk-powder in varying proportions, has been studied. It has been found that the keeping quality of unpasteurized samples containing milk powder was slightly better than that of raw milk. The keeping quality of the pasteurized mixtures was satisfactory during the time of storage for 40 hr. at 23 and 18° C. and for 60 hr. at 10° C.

This research communications addresses the hypothesis that a part of iso 17:0 and anteiso 17:0 in milk fat could come from endogenous extraruminal tissue synthesis. In order to confirm this a linear regression model was applied to calculate the proportions of iso 17:0 and anteiso 17:0 in milk fat that could come from elongation of their putative precursors iso 15:0 and anteiso 15:0, respectively. Sixteen dairy goats were allocated to two simultaneous experiments, in a crossover design with four animals per treatment and two experimental periods of 25 d. In both experiments, alfalfa hay was the sole forage and the forage to concentrate ratio (33 : 67) remained constant. Experimental diets differed on the concentrate composition, either rich in starch or neutral detergent fibre, and they were administered alone or in combination with 30 g/d of linseed oil. Iso 15:0, anteiso 15:0, iso 17:0 and anteiso 17:0, the most abundant branched-chain fatty acids in milk fat, were determined by gas chromatography using two different capillary columns. The regression model resolved that 49% of iso 17:0 and 60% of anteiso 17:0 in milk fat was formed extraruminally from iso 15:0 and anteiso 15:0 elongation.

Various types of proteolytic cocci, including several acid-proteolytic strains, have been isolated from foremilk and rennet extract (l) and subsequently from ripened Cheddar cheese. A study of the proteolytic activities of these cultures in milk forms the subject of this investigation.

The main objective of this research communication was to explore the extent of milkability changes caused by the incidence of clinical mastitis. Our second objective was to investigate if the milkability of cows shortly before mastitis incidence significantly differed in comparison with healthy cows. Milk yield, milking time, average milk flow, partial milk flows and the occurrence of bimodal milk flows were monitored during the first 120 d in milk for all cows that calved on the farm during the experimental period (n = 127). A veterinarian diagnosed 27 cows with clinical mastitis, while the remaining healthy cows served as a control group. The period surrounding the mastitis was monitored in a timeline from 2 weeks before to 4 weeks after the diagnosis. We did not observe any significant differences in milkability between the healthy cows and the cows in the pre-mastitis period, which suggests that monitoring these might not be useful for early mastitis detection. Milk yield and milk flow were significantly decreased in the week of mastitis diagnosis compared to the pre-mastitis period. Milking time was not affected in the week of diagnosis, but was significantly increased in the following week, because milk yield returned to pre-mastitis values, but average milk flow was still significantly decreased. Milk yield was normalized to pre-mastitis values as the first of monitored parameters. Milk flow returned to pre-mastitis values in the fourth week after mastitis diagnosis. Milking time was the only parameter that was significantly affected up to a month after diagnosis. Our results showed that milkability changes caused by mastitis are significant and should not be ignored. The ability to adjust milking settings for cows diagnosed with mastitis could become a useful tool for improving mastitis treatment.

Sicilo-Sarde dairy flock test-day data were analysed (1) to check predicting ability of ten milk recording procedures, based on information from a single monthly or bimonthly milking and (2) to look for the best pair of factors for predicting daily milk yield from either morning or afternoon milkings for the alternate testing method (AT). Prior to analyses, data were adjusted for variation factors with known significant effect. Number of test-day observations was 4755 from 458 lactations of 288 ewes. Losses of precision associated with simplified methods were evaluated by comparing estimated lactation yields with those observed both in a reference plan, where the two daily milkings were recorded at 2-weekly intervals and in the official A4 milk recording (monthly recording of the two daily milkings). Ranking of simplified plans based on their accuracy was still the same under either monthly or twice-monthly frequency. Estimates of lactation yields showed more lack of precision when the usual monthly designs were compared with twice-monthly sampling of both a.m. and p.m. milkings. Losses of precision ranged from 5·1%, for the A4 plan, to 14·6%. Thus, milk production should be estimated from both mikings when their measurement is economically feasible. When only one milking is weighed, designs based on—or beginning with—the a.m. milking were more accurate. There was no evidence of improvement in sampling accuracy by adjustment for milking interval or production level. For practical and economic reasons, the design alternating a.m. and p.m. milkings, without adjustment, is suggested for ovine milk recording. In such a case, new factors for estimating daily production from the measured milking (1·7, 2·3) should be used rather than the factors currently in use (2, 2) because they improved the loss of precision by more than 13% in a monthly recording system.

This Research Communication addresses the hypothesis that exogenously administered phospholipase A2 (PLA2) affects the inflammatory responses of bovine mammary epithelial cells (bMEC) in vitro with the aim of providing preliminary justification of investigation into the uses of exogenously administered PLA2 to manage or treat bovine mastitis. Primary bMEC lines from 11 lactating Holstein dairy cows were established and the expression of 14 pro-inflammatory genes compared under unchallenged and lipopolysaccharide (LPS)-challenged conditions, with and without concurrent treatment with bovine pancreatic PLA2G1B, a secreted form of PLA2. No differences in the expression of these genes were noted between PLA2-treated and untreated bMEC under unchallenged conditions. Following LPS challenge, untreated bMEC exhibited significant downregulation of CXCL8, IL1B, CCL20, and CXCL1. In contrast, PLA2-treated bMEC exhibited significant downregulation of IL1B and CCL20 only. These findings indicate that exogenous PLA2 affects the expression of some pro-inflammatory factors in immune-stimulated bMEC, but does not influence the constitutive expression of these factors. Further investigation of the influence of exogenous PLA2 in the bovine mammary gland is justified.

Teat dipping is widely used in dairy cattle, especially to protect against contagious mastitis. Here we determine the effect of the device called ‘Electrical Teat Dipping’ (ETD), which was developed by combining teat dipping application and electrical field stimulation technique on teats. For this purpose, the front teats of 100 Holstein breed milking cows were evaluated in two groups, with ETD being applied once to the left front teat of these cows, and conventional teat dipping (CTD) being applied once to the right front teat, both after milking. Ultrasonographic measurements of the teats were made before milking and after teat dipping. We found that the width of the teat canal (1.88 ± 0.07 mm) in the teat using ETD was narrower after the application compared to those with CTD (2.28 ± 0.05 mm). Based on our findings, we conclude that the effects of ETD on the teat are very positive and can potentially be used as a new approach in the preventative control of mastitis in cows.

The study reported in this Research Communication was conducted to investigate the molecular characterisation of buffalo SCAP gene, expression analysis, and the association between single nucleotide polymorphisms and milk production traits in 384 buffaloes. Sequence analysis revealed the SCAP gene had an open reading frame of 3837 bp encoding 1279 amino acids. A ubiquitous expression profile of SCAP gene was detected in various tissues with extreme predominance in the mammary gland during early lactation. Moreover, eleven SNPs in buffalo SCAP gene were identified, six of them (g.1717600A>G, g.1757922C>T, g.1758953G>A, g.1759142C>T, g.1760740G>A, and g.1766036T>C) were found to be significantly associated with 305-day milk yield. Thus, buffalo SCAP could sever as a candidate gene affecting milk production traits in buffalo and the identified SNPs might potentially be genetic markers.

Whole casein, β-casein, β-lactoglobulin and euglobulin were labelled with 131I. The conditions under which iodination was carried out were chosen so as to avoid any modification of the original characteristics of the proteins. This was checked by starch-gel electrophoresis and determination of sedimentation constants, apparent molecular weights and, for euglobulin, the clustering effect on fat globules.

As was shown by autoradiograms of the starch-gel plates, the radioactivity was incorporated in all zones of the electrophoresis pattern.

Individual quarter milk samples were taken from 719 cows in 7 dairy herds and examined for mastitis-causing pathogens. Analyses were made to ascertain the prevalence of mastitis infection when the results from a single quarter were compared with those from all 4 quarters. There was a very close similarity between the 2 methods of assessment. When the number of samples is limited, sampling of a single quarter instead of all 4 quarters permits more cows to be examined.

The keeping quality of properly refrigerated pasteurized milk and cream is primarily determined by post-pasteurization contamination by Gram-negative psychrotrophic bacteria (Phillips et al. 1981; Schröder et al. 1982). Reliable and rapid methods of assessing the levels of contamination by these organisms are therefore of commercial interest.

The following average fractionation of serum calcium in the dairy cow has been reported:

Zabadi was manufactured using reconstituted skim milk powder prepared with different ratios of water and sweet whey and the organoleptic properties and chemical composition of the milks were measured. Sweet whey could be used successfully to replace up to 50% of the water added for reconstitution, whilst with 75 or 100% whey a sweet off flavour appeared. However, these higher levels could be used for fruit flavoured zabadi, and about 40–60% less sucrose could be used because of the additional glucose + galactose contributed by the whey.

1. In commercial practice dairy liquids of fat contents ranging from 3 to 90% are subjected to deodorization by steam distillation treatment.

2. Increase in fat test of cream causes a rise in the vapour/liquid equilibrium coefficient for tainting substances of low butterfat/skim-milk distribution ratio, and a fall for substances of high-distribution ratio, in cream.

3. Increase in fat content of cream reduces the amount of tainting substance in the cream per unit weight of butterfat in the cream, for substances of all butterfat/skim-milk distribution ratios.

4. Separation of milk to cream of a high fat content greatly facilitates the elimination of substances of low butterfat/skim-milk distribution ratio from the cream and butter.

5. Variation in temperature of separation, by its effect on the distribution ratio for tainting substances, could affect the content of these substances in the final cream, and could possibly cause a change in the character of the cream.

6. In the partition of tainting substance between butter and buttermilk in the churning process, fat content of cream affects the proportion of residual taint passing from the treated cream into the butter.

7. It is pointed out that, because of the effect of salt in increasing the vapour/liquid equilibrium coefficient of some steam volatile substances, the threshold concentration for a tainting substance in butter can be expected to vary with variation in the rate of salting of the butter.

CXCL8 (also known as IL-8) is a member of the CXC subfamily of chemokines that binds two of the seven transmembrane G-protein-coupled receptors (GPCRs), CXCR1 and CXCR2, to mediate and regulate leucocyte accumulation and activation at sites of inflammation. They are known to play a critical role in both disease susceptibility and infection outcome. The aim of this study was to investigate the entire sequences of CXCL8 and CXCR2 genes in thirty-one Simmental sires to evaluate the effects of genomic variants on the indexes of the bulls for milk, fat and protein yields, and for somatic cell score (SCS). Five new single nucleotide polymorphisms (SNPs) were found in CXCR2 gene. The analysis of association indicated that one SNP in CXCL8 and two in CXCR2 influenced the considered traits. To evaluate the existence of functional haplotypic effects, combinations among the three genomic variants (SNP 1 in CXCL8, SNP 6 and SNP 7 in CXCR2) were investigated. Four different haplotypic alleles were identified in the experimental population, one of which at a high frequency (61%). Bulls with Hap 4 (G-C-G at SNP 1, SNP 6, and SNP 7 respectively) had more favourable indexes for SCS (P < 0.05). These results suggest that the SNPs in CXCL8 and CXCR2 may be potential genetic markers to improve udder health in the Simmental breed.