Danish organic dairy production is characterized by a low input of antibiotics for udder treatment and a high input of other mastitis control procedures. A study was conducted in 14 organic dairy herds with the objectives of obtaining a comprehensive description of clinical mastitis cases and identifying characteristic patterns in these results. Clinical signs, inflammatory reactions and microbiological identifications were obtained from 367 cases of clinical mastitis occurring over 18 months. Cow characteristics and preincident values such as milk yield and somatic cell count were obtained for each cow. Signs of previous udder inflammation were present in two-thirds of the clinical mastitis cases. Severe local inflammatory reactions were found in 21% of the cases and some indication of generalized signs such as fever and reduced appetite were found in 35% of the cases. Logistic regression analyses were performed based on the results of an initial (exploratory) multiple correspondence analysis. Coliform mastitis (6% of the cases) was rarely preceded by pathogen isolation or inflammatory reactions in the same quarter. Coliform mastitis cases usually occurred in one quarter only. Escherichia coli infections were typically (truly) acute cases. Bacteriologically negative mastitis (20% of the cases) showed strong similarities with clinical coliform mastitis. Staphylococcus aureus cases (18% of the cases) occurred most frequently in late lactation or around drying-off. Prior isolation of Staph. aureus and slight decreases in milk yield were two factors that interacted but both were strongly and positively related to clinical Staph. aureus. Staph. aureus mastitis typically had a subclinical debut, and increasing degrees and duration of inflammation decreased shedding of this pathogen. Streptococcus dysgalactiae (9% of the cases) mastitis was typically persistent, virulent and manifest in periods of lower cow resistance. More patterns of subclinical and clinical Str. uberis mastitis (23% of the cases) seemed to be present.

As mastitis is associated with leakage of small molecular weight plasma proteins, such as α1-antitrypsin, into milk, this antitrypsin can be used as an indicator of mastitis. A colorimetric procedure was developed for large scale monitoring of milk antitrypsin activity, using microtitration plates and the Multiskan system. The effect of stage of lactation and age of the cow on the antitrypsin concentration and its interrelationship with other mastitis indicators (bovine serum albumin (BSA), somatic cell count) was analysed by computer programs on 1029 cows. Milk antitrypsin activity was high after parturition owing to colostral inhibitors. After the first month of lactation the assay measures only blood-derived antitrypsin and is a good indicator for detecting an increased permeability between blood and milk due to mastitis. Increasing lactation number only slightly affected the antitrypsin and BSA concentrations whereas somatic cell content was markedly affected.

Cholesterol and phospholipid concentrations in serum lipoproteins, plasma activities of lecithin:cholesterol acyltransferase (LCAT) and phospholipid transfer protein (PLTP) and lipoprotein lipase (LPL) activity in adipose tissue biopsies were measured ante and post partum in dairy cows given either free or restricted access to feed during the dry period. After parturition, all cows were fed ad libitum. The purpose of this study was to try to understand the earlier observed marked drop post partum in plasma triacylglycerol (TAG) in terms of lipoprotein metabolism in cows developing fatty liver post partum. As would be expected, free access to feed during the dry period induced a rise of hepatic TAG concentrations post partum associated with a decrease in plasma TAG levels. Total and free cholesterol concentrations in the VLDL, IDL, LDL and HDL2 fractions fell immediately after parturition. VLDL and IDL cholesterol concentrations remained at a constant, low level during the entire sampling period post partum, whereas the drop in LDL and HDL2 cholesterol post partum was followed by a rebound rise. Plasma LCAT and PLTP activities decreased by on average 19% and 33%, respectively, after parturition and then rose to values seen before parturition, but there was no effect of feeding regimen during the dry period. Activities of LCAT and PLTP were significantly correlated with cholesterol and phospholipid concentrations in LDL and HDL2. Plasma LCAT activity, as measured with exogenous substrate, and PLTP activity were both positively correlated with HDL3 phospholipid levels. LPL activity in adipose tissue dropped after parturition, the drop being smaller after feeding ad libitum during the dry period. It is concluded that the drop in adipose tissue LPL activity post partum is at variance with the simultaneous fall in plasma TAG. Possibly, the decrease in adipose tissue LPL activity helps to channel fatty acids away from adipose tissue into the udder. The post-partum changes in lipid transfer proteins in the blood are in line with the changes observed in the levels of the lipoproteins.

Polymorphism in the goat kappa casein gene was studied using the base excision sequence scanning (BESS) method and sequencing. Seven polymorphic sites, corresponding to single nucleotide transversions were detected. Three of these were silent mutations while the other four produced amino acid substitutions. The association between these polymorphic sites was investigated, which resulted in the identification of three goat kappa casein alleles, designated A, B, and C. Protocols for rapid genotyping of the C variant were developed by polymerase chain reaction–restriction fragment length polymorphism using Alw44I and BseNI restriction endonucleases. The occurrence of this allele was found to be very low in Spanish breeds but more frequent in the French Saanen goat. Further studies among different goat populations are necessary to establish the distribution of these alleles and their effects on the quality and functional properties of milk.

As determined by gas-liquid chromatography, the mean fatty acid composition (weight percentages of total fatty acids) of milk fat from sows fed a diet to meet U.S. N.R.C. nutrient requirements was: oleic, 35·3; palmitic, 30·3; linoleic, 13·0; palmitoleic, 9·9; stearic, 4·0; myristic, 3·3; linolenic, 2·5; unidentified 0·7 and 0·5, presumably n-odd chain and branched fatty acids; lauric, 0·3; and capric, 0·2. The corresponding fatty acid composition of colostrum fat was: oleic, 41·7; palmitic, 22·5; linoleic, 20·9; palmitoleic, 5·0; stearic, 5·7; myristic, 1·4; linolenic, 2·4; and unidentified acids, 0·3 and 0·1. Dietary fat increased fat levels in the milk and influenced fatty acid composition of the milk fat. Backfat resembled colostrum fat more than milk fat.

The yields and composition of milk from nursing mares were studied during the first two months of lactation in 11 mares of heavy breeds (784 kg). Daily yield increased from 21·7 to 24·6 kg between weeks 1 and 8 of lactation. Fat, protein, gross energy and Ca concentrations significantly decreased when lactose content increased during this period. Individual variations were higher for yield than for composition. Casein, whey protein and non-protein N (56, 34 and 10% of crude protein, respectively) and amino acid composition did not vary between weeks 1 and 8 of lactation.

Escherichia coli O157[ratio ]H7 in spiked samples of raw milk and ice-cream was enriched in tryptic soy broth for 4 h, captured by immunomagnetic separation, subjected to amplification by polymerase chain reaction of parts of the verotoxin genes (SLT-I and SLT-II), and detected by agarose gel electrophoresis. Using this method, as few as 1 cfu Esch. coli O157[ratio ]H7/g food could be detected in <10 h.

It has been shown that there is a time-dependent transfer of β-casein and the milk serine proteinase system from micelles to milk serum with change of temperature from 38 to 4 °C. It has been established that the γ-caseins can be formed by proteolytic degradation of β-casein. By a simple extraction technique, the very hydrophobic γ-casein fraction was separated from stored milks (26 and 4 °C) and estimated quantitatively. The results showed that the proteolytic degradation of β-casein is faster at 4 °C than at room temperature and this can be explained by the immobilization of enzyme and substrate at the micelle surface at higher temperatures (26 °C).

The results indicate that irreversible changes during cooling for short periods do not cause problems in milk processing, but the formation of γ-caseins and phosphopeptides may influence the technological properties of raw milk stored for more than 48 h.

The conductivity of raw and homogenized milks was measured using apparatus capable of high precision. The effect of fat content was examined and found to conform to the established behaviour for a polydisperse suspension of nonconductors in a homogeneous conducting medium. Homogenization of the milk over a range of pressures was found to have no measurable effect on the conductivity.

Fenvalerate ear tags reduced fly loads on dry dairy cattle by 95% between July and September. Fly dislodging behaviour, such as ear flicks which correlated with numbers of Musca autumnalis on the face and stamps/kicks which correlated with numbers of Stomoxys calcitrans on the legs, was also significantly reduced. There was no significant difference between the tagged and untagged groups in the total time spent grazing each day. Milk yields were not statistically significantly different, but the tagged group showed a greater increase in milk yield between lactations, of 1·45 kg/cow daily in the first 12 weeks of the lactation.

The action of rennin in milk subjected to the ultra-high-temperature heat sterilization process has been studied. The primary phase of rennin action, as determined by the release of peptides soluble in trichloroacetic acid, was partially inhibited as a result of the heat treatment. This was largely due to a reduction in the release of non-carbohydrate-containing peptides from κ-casein. It is suggested that when whole milk is heated the formation of a complex between β-lactoglobulin and κ-casein proceeds more readily with the species of κ-casein which lacks carbohydrate. Evidence is presented which shows that there may be more than one type of carbohydrate moiety attached to κ-casein.

The effects of the isocaloric replacement of part of the dietary concentrate mixture by either tallow or cottonseed oil on the yield and composition of the milk fat was investigated in 2 feeding experiments with a total of 26 cows in midlactation. The concentrates were given with high- or low-roughage diets that supplied either 9·1–9·5 or 1·8–3·2kg hay/day.

In expt 1, the addition of cottonseed oil to the high-roughage diet increased the yield of milk fat during the first 8 days but decreased it during the last 4 days of a 28-day feeding period. In contrast, the inclusion of tallow in the high-roughage diet resulted in an increased yield of milk fat that was sustained throughout the period of 28 days. In expt 2, the intake of dietary fat was less than it was in expt 1 and the inclusion of tallow or cottonseed oil in either the high- or low-roughage diets had little effect on the yield of milk fat.

The inclusion of either fat in the diet increased the yields and percentages of stearic and oleic acids and, in general, decreased the yields and percentages of the medium-chain fatty acids (10:0, 12:0 and 14:0) in the milk fat. The addition of tallow to the diet did not appear to alter the yields of the short-chain fatty acids (C4–C8, 4:0, 6:0 and 8:0) in the milk fat. When the low-roughage diets resulted in a decreased yield of milk fat, the secretion of all the fatty acids in the milk fat was reduced, but the reduction in the secretion of oleic acid was less than the reductions in the secretions of the other constituent fatty acids.

Confocal laser scanning microscopy was used to examine components of whole milk powder. Powder was dispersed in a glycerol suspension containing a fat-soluble fluorescent dye which was excited by laser light to produce images of the fat at the surface of and inside the whole milk powder particle. Lactose crystals, produced in the milk prior to spray drying, were seen to be in the diamond-like, α-hydrate form. The surface coverage and the stability of a wetting agent sprayed on to the surface of whole milk powder particles were examined. The wetting agent was shown to be located as a thin surface layer that partly migrated into creases and folds on the particle surface during storage at 37°C.

The enhancement of the strength of set acid gels by heating milk was related to rheological parameters (water retention capacity, storage modulus) of corresponding stirred gels. To obtain accurate rheological data from stirred gel it was necessary to maintain a constant granulometry of gel particles and to recognize time after stirring as a contributing factor. Two hours after stirring, the gel exhibited a higher storage modulus when milk was heated above 80 °C. A measurement of viscosity of just-stirred yoghurt was sufficient to predict correctly the quality of a stirred gel analysed by viscoelastic measurements. Increased resstance to syneresis of just-stirred gels was related to higher viscosity. The quantity of β-lactoglobulin (β-lg) bound to casein micelles explains the improvement of these gel qualities. We have considered that the structure of the initial firm gel (mesostructure level) was conserved in fragments within the stirred gel. Consequently, the explanation given by various authors for the effect of heating milk on the properties of set gels can also be applied to stirred gels. The same mechanism, described in literature for structure formation of set gels from acidified milk is purposed to explain the role of heating milk on the recovery of gel structure after stirring. The β-lg association with casein micelles during heating favoured micelle connections during the acidification. It also favoured the association of gel fragments after stirring during the recovery in gel structure.

Nine West African dwarf (Fouta djallon), Red Sokoto (Maradi) and Saanen lactating goats, hand-milked, were used for these studies, which lasted 12 weeks. The Saanen goats' milk was obtained weekly from the Western State Ministry of Agriculture and Natural Resources Urban Dairy Farm at Iwo Road, while similar samples were collected from the herd at the University of Ibadan Teaching and Research Farm. The goats were balanced for stage of lactation, namely early, mid- and late-lactation. They were each maintained on giant star grass (Cynodon nlemfuensis) ad lib. and 1kg dairy concentrate mixture daily.

The mean contents, with standard deviations, of the milks of Saanen, West African dwarf and Red Sokoto goats at mid-lactation respectively were: (in percentages), total solids 12·25±0·078, 18·18±0·392, 15·85±0·077; solids-not-fat (SNF) 8·91±0·142, 10·48±0·471, 10·53±0·140; butterfat 3·34±0·141, 7·78±0·621, 5·32±0·098; protein 3·04±0·139, 5·30±0·292, 4·74±0·021; lactose 4·56±0·167, 5·19±0·176, 4·77±0·053; energy (kJ/g dried milk), 21·08±1·11, 25·51±1·74, 22·17±0·51. Breed differences were significant (P < 0·01). The milk of West African dwarf goats contained more of these milk components than the milk of the Red Sokoto or Saanen goats. The Red Sokoto goats gave milk of higher content than did Saanen goats, even at an early stage of lactation.

Butterfat, protein, lactose and energy values were significantly affected by stages of lactation (P < 0·05) and tended to rise with advancing lactation; this was particularly so with West African dwarf goats.

The effect of several parameters on the decarboxylation of α-acetolactic acid (ALA) to diacetyl and acetoin was studied in model experiments. At temperatures > 50 °C, relatively more diacety1 than acetoin was produced. Regardless of temperature, HC1 increased the production of acetoin (58 mol% conversion at max.) and prevented the production of diacetyl. Steam distillation of ALA caused ~ 55 mol%/h conversion to acetoin and 7 mol%/h to diacetyl. Production of acetoin was proportional to the ALA concentration. Based on these results two methods for the quantitative measurement of ALA were developed. Only one of 17 strains of Streptococcus diacetylactis (Lactococcus lactis subsp. lactis biovar. diacetilactis, new nomenclature) and three of three strains of Leuconostoc spp. produced ALA. The implications of these findings are discussed.

The experiments reported in this Research Paper aimed to study the effects of mustard and cumin seeds inclusion on feed utilisation, milk production, composition, and profile of milk fatty acids in lactating Damascus goats. The study was a completely randomised design with repeated measurements in time using fifteen goats (6 ± 2 d of lactation) divided into 3 treatments (5 goats per treatment). Goats were offered a control diet of berseem clover and concentrates (1 : 1 dry matter (DM) basis) or the control diet supplemented with either 10 g/d of dried mustard seeds (mustard treatment) or 10 g/d of cumin seeds (cumin treatment) for 12 weeks. Treatments had no effect (P > 0·05) on feed intake, but enhanced (P < 0·05) digestibility of DM, organic matter, non-structural carbohydrates, and fibre fractions. Digestibility was greater (P < 0·001) with cumin treatment compared with mustard treatment. Mustard and cumin seeds had greater (P < 0·05) ruminal total short chain fatty acids (SCFA) production, and molar proportion of propionate, with greater (P < 0·001) SCFA production for cumin vs. mustard treatment. Mustard and cumin seeds increased (P < 0·05) concentrations of serum total proteins, globulin, and glucose and lowered (P < 0·05) serum cholesterol concentration. Mustard and cumin seeds inclusion elevated milk production (P = 0·007), while cumin increased milk contents (P < 0·05) of fat and lactose. Cumin treatment lowered (P < 0·05) milk saturated fatty acids (SFA) and had greater total unsaturated fatty acids (UFA) and total conjugated linoleic acid (CLA) contents. Overall, supplementing diets of Damascus goats with mustard or cumin seeds at 10 g/daily enhanced feed digestion, ruminal fermentation, milk yield (actual production by 6·8 and 11·1%, and energy corrected milk yield by 10·1 and 15·4%, respectively) and positively modified milk fatty acid profile with a 3·9% decrease in milk individual and total SFA, and an increase in individual and total UFA by about 9·7%, and total CLA by about 23·1%.

Three sources of sensory data: cow's individual rumination duration, activity and milk yield were evaluated as possible indicators for clinical diagnosis, focusing on post-calving health problems such as ketosis and metritis. Data were collected from a computerised dairy-management system on a commercial dairy farm with Israeli Holstein cows. In the analysis, 300 healthy and 403 sick multiparous cows were studied during the first 3 weeks after calving. A mixed model with repeated measurements was used to compare healthy cows with sick cows. In the period from 5 d before diagnosis and treatment to 2 d after it, rumination duration and activity were lower in the sick cows compared to healthy cows. The milk yield of sick cows was lower than that of the healthy cows during a period lasting from 5 d before until 5 d after the day of diagnosis and treatment. Differences in the milk yield of sick cows compared with healthy cows became greater from 5 to 1 d before diagnosis and treatment. The greatest significant differences occurred 3 d before diagnosis for rumination duration and 1 d before diagnosis for activity and milk yield. These results indicate that a model can be developed to automatically detect post-calving health problems including ketosis and metritis, based on rumination duration, activity and milk yield.