Subclinical ketosis is a metabolic disorder which often goes undiagnosed and leads to constricted performance and an impairment of general condition. In the current study subclinical ketosis was characterised by a β-hydroxybutyrate (BHB) concentration of >1·2 mmol/l in blood serum. To generate this metabolic situation, an animal model was created. The model, based on group-specific interaction of dietary energy supply and body condition, is appropriate for testing the medical effectiveness of treating this kind of ketosis and its concomitants. During the trial, 18 dairy cows (primiparous and pluriparous) were assigned, according to their body condition score (BCS) 6 weeks before expected parturition, to a normal [6·78 MJ net energy for lactation (NEL)/kg dry matter; 20% concentrate] or to a high-energy feeding group (7·71 MJ NEL/kg dry matter; 60% concentrate). Therefore cows with the highest BCS were allocated to the high-energy group to enhance the contrast with the control group. Statistical analysis was done using the MIXED procedure of SAS. Effects were declared significant when P-values were ⩽0·05. Owing to the higher energy concentration and dry matter intake, the energy intake and balance was significantly higher in the high-energy feeding group, with strong effects on lipid metabolism and health in blood and liver post partum. Within the first 2 weeks after calving, 8 out of 9 cows (89%) of the high-energy group had BHB values indicative of subclinical ketosis. These cows also had significantly higher values of non-esterified fatty acids (NEFA), aspartate transaminase (AST) and glutamate dehydrogenase (GLDH) post partum, as well as a raised total lipid content of the liver. RQUICKI, a calculated parameter which is based on serum concentrations of glucose, insulin and NEFA to assess the insulin sensitivity, was not affected by treatment. Therefore, RQUICKI does not seem to be the right parameter for diagnosing decreased insulin sensitivity in cows affected by subclinical ketosis. The milk fat and the fat:protein ratio of the high-energy group was also higher, even though there was no decrease in milk yield for cows with subclinical BHB values.

The double use of cheese whey (culture medium and thermoprotectant for spray drying of lactobacilli) was explored in this study for adding value to this wastewater. In-house formulated broth (similar to MRS) and dairy media (cheese and ricotta whey and whey permeate) were assessed for their capacity to produce biomass of Lactobacillus paracasei JP1, Lb. rhamnosus 64 and Lb. gasseri 37. Simultaneously, spray drying of cheese whey-starch solution (without lactobacilli cells) was optimised using surface response methodology. Cell suspensions of the lactobacilli, produced in in house-formulated broth, were spray-dried in cheese whey-starch solution and viability monitored throughout the storage of powders for 2 months. Lb. rhamnosus 64 was able to grow satisfactorily in at least two of the in-house formulated culture media and in the dairy media assessed. It also performed well in spray drying. The performance of the other strains was less satisfactory. The growth capacity, the resistance to spray drying in cheese whey-starch solution and the negligible lost in viability during the storage (2 months), makes Lb. rhamnosus 64 a promising candidate for further technological studies for developing a probiotic dehydrated culture for foods, utilising wastewaters of the dairy industry (as growth substrate and protectant) and spray drying (a low-cost widely-available technology).

Goats in Canary Islands are milked once a day by tradition, but in most countries with high technology on farms, goats are milked twice a day, which is known to improve milk yield. Therefore it is important to know whether the increase of milking frequency can improve the production without impairing milk quality. The objective of this study was to investigate the short term effects of three milking frequencies on milk yield, milk composition, somatic cell count (SCC) and milk protein profile in dairy goats traditionally milked once a day. Twelve Majorera goats in early lactation (48±4 d in milk) were used. During a 5-week period, goats were milked once a day (X1) in weeks 1 and 5, twice a day (X2) in weeks 2 and 4, and three times a day (X3) in week 3. Milk recording and sampling were done on the last day of each experimental week. Milk yield increased by 26% from X1 to X2. No differences were obtained when goats were switched from X2 to X3, and from X3 to X2. The goats recovered the production level when they returned to X1. Different patterns of changes in the milk constituents due to the milking frequency effect were observed. Fat percentage increased when switched from X1 to X2, then decreased from X2 to X3, and from X3 to X2, whereas it did not show significant differences from X2 to X1. Milking frequency did not affect the protein and lactose percentages. SCC values were unaffected when goats were milked X1, X2 and X3, but then they increased slightly when milking frequency was returned to X2 and X1. Finally, quantitative analysis showed an increase in intensities of milk protein bands from X1 to X2, but the intensities of casein bands (αS1-CN, αS2-CN, β-CN, κ-CN) and major whey proteins (α-La, β-Lg) decreased from X2 to X3.

The aim of this work was to evaluate the capacity of Lactobacillus kefir strains to remove cadmium cations and protect eukaryotic cells from cadmium toxicity. Lb. kefir CIDCA 8348 and JCM 5818 were grown in a 1/2 dilution of MRS broth supplemented with Cd(NO3)2 ranging 0 to 1 mM. Growth kinetics were followed during 76 h at 30 °C by registering optical density at 600 nm every 4–10 h. The accumulated concentration of cadmium was determined on cultures in the stationary phase by atomic absorption. The viability of a human hepatoma cell line (HepG2) upon exposure to (a) free cadmium and (b) cadmium previously incubated with Lb. kefir strains was evaluated by determining the mitochondrial dehydrogenase activity. Lb. kefir strains were able to grow and tolerate concentrations of cadmium cations up to 1 mM. The addition of cadmium to the culture medium increased the lag time in all the concentrations used. However, a decrease of the total biomass (maximum Absorbance) was observed only at concentrations above 0·0012 and 0·0011 mM for strains CIDCA 8348 and JCM 5818, respectively. Shorter and rounder lactobacilli were observed in both strains upon microscopic observations. Moreover, dark precipitates compatible with intracellular precipitation of cadmium were observed in the cytoplasm of both strains. The ability of Lb. kefir to protect eukaryotic cells cultures from cadmium toxicity was analysed using HepG2 cells lines. Concentrations of cadmium greater than 3×10−3 mM strongly decreased the viability of HepG2 cells. However, when the eukaryotic cells were exposed to cadmium pre-incubated 1 h with Lb. kefir the toxicity of cadmium was considerably lower, Lb. kefir JCM 5818 being more efficient. The high tolerance and binding capacity of Lb. kefir strains to cadmium concentrations largely exceeding the tolerated weekly intake (TWI) of cadmium for food (2.5 μg per kg of body weight) and water (3 μg/l) addressed to human consumption, is an important added value when thinking in health-related applications.

The objective of the study was to record, by means of ultrasonographic examination, changes occurring in the udder of ewes during involution and to compare differences between progressive or abrupt udder drying-off. In group A ewes, udder drying-off took place progressively during a period of 22 d; ewes were milked twice daily for the last time on day(D) 0; then, they were hand-milked once daily for a week (D1–D7), which was followed by another week during which ewes were hand-milked once every 2 d (D9, D11, D13), followed by a third week during which ewes were hand-milked once every 3 d (D16, D19, D22). In group B ewes, the procedure took place abruptly; ewes were milked twice daily for the last time on D0 and no milking was carried out after that. B-mode and Doppler ultrasonographic examination of the udder of all ewes was performed throughout the drying-off procedure. Appropriate data management and analysis were performed. Progressive changes of the various parameters evaluated throughout the study period were significant in both groups (P<0·005). Gray-scale results of mammary parenchyma progressively decreased during the study and differed significantly between group A and group B (P=0·049). A temporary increase in cistern volume was evident after cessation of lactation, but differences were not significant between the two groups (P>0·3). Diameter of the external pudendal artery progressively decreased during the study and differed significantly between the two groups (P=0·037). Both resistance index and pulsatility index progressively increased throughout the study period in both groups; for both parameters, differences between the two groups were significant (P<0·0005). B-mode ultrasonographic examination indicated differences in remodelling of the extracellular matrix in relation to the procedure for udder drying-off. Volume of the gland cistern did not appear to be affected by the procedure for udder drying-off. Doppler ultrasonographic examination confirmed that blood flow during initiated involution was lower than during a progressive procedure for drying-off.

Male dairy calves may be transported from their farm of origin at a young age. This process may involve an extended period off feed and indirect consignment through an intermediate facility, prompting potential welfare concerns. To assess the impact of transport, 59 male Holstein-Friesian dairy calves (5–9 d old) were either (1) held in situ on farm (control); (2) transported for 6 h; (3) transported for 12 h; or (4) transported for 1 h to a holding facility where they were kept for 6 h and then transported for 5 h. All treatments included a 30-h period of feed (milk) withdrawal, and calf responses were measured over time from before their last feed until the completion of the study after the transport and feed withdrawal periods. Apart from increases in serum creatine kinase in calves transported for 12 h, transported calves generally did not differ in blood concentrations of glucose, beta-hydroxybutyrate, lactate, total protein or in packed cell volume, compared with controls (P>0·05). Calf responses to the indirect consignment treatment did not differ from those of other transported calves. Withdrawal of feed for 30 h caused calves to lose 6% of body weight; blood glucose varied from 3·96 mmol/l immediately before daily feeding to 5·46 mmol/l at 3 h post feeding, and then declined to 3·43 mmol/l at 30 h. Calves lay down for 22–32% of the time during transport, and did not show a rebound effect in lying behaviour post arrival in comparison with controls. Best practice transport of 6–12 h duration, including indirect consignment via a holding facility, did not significantly affect calf blood biochemistry and metabolism in comparison with untransported animals. However, extending the time off feed beyond the daily feeding interval resulted in reduced blood glucose concentrations, suggesting that time off feed needs to be carefully managed in young transported dairy calves.

The importance of small ruminants to the dairy industry has increased in recent years, especially in developing countries, where it has a high economic and social impact. Interestingly and despite the fact that the mammary gland is the specialised milk production organ, very few authors studied the modifications occurring in the mammary gland through the lactation period in production animals, particularly in the small ruminants, sheep (Ovis aries) and goat (Capra hircus). Nevertheless, understanding the different mammary gland patterns throughout lactation is essential to improve dairy production. In addition, associating these patterns with different milking frequencies, lactation number or different diets is also of high importance, directly affecting the dairy industry. The mammary gland is commonly composed of parenchyma and stroma, which includes the ductal system, with individual proportions of each changing during the different periods and yields in a lactation cycle. Indeed, during late gestation, as well as during early to mid-lactation, mammary gland expansion occurs, with an increase in the number of epithelial cells and lumen area, which leads to increment of the parenchyma tissue, as well as a reduction of stroma, corresponding macroscopically to the increase in mammary gland volume. Throughout late lactation, the mammary gland volume decreases owing to the regression of the secretory structure. In general, common mammary gland patterns have been shown for both goats and sheep throughout the several lactation stages, although the number of studies is limited. The main objective of this manuscript is to review the colostrogenesis and lactogenesis processes as well as to highlight the mammary gland morphological patterns underlying milk production during the lactation cycle for small ruminants, and to describe potential differences between goats and sheep, hence contributing to a better description of mammary gland development during lactation for these two poorly studied species.

Probiotic Lactobacillus and Bifidobacterium species are generally fastidious bacteria and require rich media for propagation. In milk-based media, they grow poorly, and nitrogen supplementation is required to produce high bacterial biomass levels. It has been reported that caseinomacropeptide (CMP), a 7-kDa peptide released from κ-casein during renneting or gastric digestion, exhibits some growth-promoting activity for lactobacilli and bifidobacteria. During the digestive process, peptides derived from CMP are detected in the intestinal lumen The aim of this study was to evaluate the effects of peptic and tryptic digests of CMP on probiotic lactic acid bacteria growth in de Man, Rogosa and Sharpe broth (MRS) and in milk during fermentation at 37 °C under anaerobic conditions. The study showed that pepsin-treated CMP used as supplements at 0·5 g/l can promote the growth of probiotics even in peptone-rich environments such as MRS. The effect was strain-dependent and evident for the strains that grow poorly in MRS, with an improvement of >1·5 times (P<0·05) by addition of pepsin-treated CMP. Trypsin-treated CMP was much less efficient as growth promoter. Moreover, pepsin-treated CMP was effective in promoting the growth in milk of all probiotic lactic acid bacteria tested, with biomass levels being improved significantly, by 1·7 to 2·6 times (P<0·05), depending on the strain. Thus, supplementation of MRS and of milk with pepsin-treated CMP would be advantageous for the production of high biomass levels for Bifidobacteria and Lactobacilli.

Recently it has been demonstrated that there are differences between sheep and goats in respect to adaptation to a calcium-restricted diet. It was the aim of the present study to evaluate whether species-specific peculiarities also occur when calcium homoeostasis is challenged by lactation. Therefore, we investigated the time courses of plasma parameters related to calcium homoeostasis (calcium, phosphate, calcitriol, the bone resorption marker CrossLaps® and the bone formation marker osteocalcin) during the transition period in multiparous animals of both species and compared the results to data from a former study carried out with dairy cows. As in cows, plasma calcium and the ratio of bone formation to bone resorption decreased at parturition in goats while plasma calcitriol increased. On day 10 post partum the bone parameters of goats reached prepartum values again, which was not the case in cows. Sheep were found to experience a challenge of calcium homoeostasis already 10 d before parturition, reflected by a very low ratio of bone formation to bone resorption, which was not accompanied by an increase in plasma calcitriol. Additionally, sheep and goats which had been in milk for 3 months were sampled, dried-off and sampled again 6 weeks later. In dried-off animals there were no detectable differences in parameters of bone metabolism. In conclusion we could show that the contribution of bone mobilisation to the compensation for the enhanced calcium demand due to lactation differs between the three ruminant species.

Stearoyl-CoA desaturase 1 (SCD1) greatly contributes to the unsaturated fatty acids present in milk and meat of cattle. The SCD1 enzyme introduces a double bond into certain saturated fatty acyl-CoAs producing monounsaturated fatty acids (MUFA). The SCD1 enzyme also has been shown to be active in the bovine mammary gland converting t11 18 : 1 (vaccenic acid) to c9 t11 conjugated linoleic acid (CLA). The objective of this study was to determine any association between the gene expression of SCD1 and occurrence of its products (c9 14 : 1, c9 16 : 1, c9 18 : 1, and c9 t11 18 : 2) in various bovine tissues. Tissue samples were obtained from lactating Holstein cows (n=28) at slaughter, frozen in liquid nitrogen and stored at −80 °C. Total RNA was extracted and converted to complementary DNA for quantitative real time polymerase chain reaction (PCR) analysis of the SCD1 gene. Extracted lipid was converted to fatty acid methyl esters and analysed by GC. Tissues varied in expression of SCD1 gene with mammary, cardiac, intestinal adipose, and skeletal muscle expressing greater copy number as compared with lung, large intestine, small intestine and liver (371, 369, 328, 286, 257, 145, 73, and 21 copies/ng RNA, respectively). Tissues with high mRNA expression of SCD1 contained greater SCD1 protein whereas detection of SCD1 protein in tissues with low SCD1 mRNA expression was very faint or absent. Across tissues, the desaturase indices for c9 18 : 1 (r=0·24) and sum of SCD products (r=0·20) were positively correlated with SCD1 gene expression (P<0·01 for both). Within each tissue, the relationship between SCD1 gene expression and the desaturase indices varied. No correlation was detected between SCD1 expression and desaturase indices in the liver, large and small intestines, lung, cardiac or skeletal muscles. Positive correlations, however, were detected between SCD1 expression and the desaturase indices in intestinal adipose tissue (P<0·02 for all) except 14 : 1, whereas only c9 18 : 1, c9 t11 18 : 2 and sum of all desaturase indices were positively correlated with SCD1 expression in mammary tissue (P⩽0·03). Overall, the relationship between SCD1 gene expression and occurrence of its products seems to be tissue specific.

The objective of this study was to estimate heritability and crossbreeding parameters (breed and heterosis effects) of various fatty acid (FA) concentrations in milk fat of New Zealand dairy cattle. For this purpose, calibration equations to predict concentration of each of the most common FAs were derived with partial least squares (PLS) using mid-infrared (MIR) spectral data from milk samples (n=850) collected in the 2003–04 season from 348 second-parity crossbred cows during peak, mid and late lactation. The milk samples produced both, MIR spectral data and concentration of the most common FAs determined using gas chromatography (GC). The concordance correlation coefficients (CCC) between the concentration of a FA determined by GC and the PLS equation ranged from 0·63 to 0·94, suggesting that some prediction equations can be considered to have substantial predictive ability. The PLS calibration equations were then used to predict the concentration of each of the fatty acids in 26 769 milk samples from 7385 cows that were herd-tested during the 2007–08 season. Data were analysed using a single-trait repeatability animal model. Shorter chain FA (16 : 0 and below) were significantly higher (P<0·05) in Jersey cows, while longer chain, including unsaturated longer chain FA were higher in Holstein-Friesian cows. The estimates of heritabilities ranged from 0·17 to 0·41 suggesting that selective breeding could be used to ensure milk fat composition stays aligned to consumer, market and manufacturing needs.

The aim of this work was to study how machine milking (MM) carried out in suitable conditions affects teat wall thickness and teat canal length and their return after milking to pre-milking conditions, in comparison with other milk extraction methods considered biological referents: lamb suckling (LS), milk removal by catheter (RC) and hand milking (HM). Three Latin square experiments were designed, using 11 ewes in the first experiment (LS), 13 in the second (RC) and 12 in the third (HM). Each of the Latin squares was divided into two periods: in the first, the left gland of each animal was machine milked and the corresponding treatment (LS, RC and HM) was applied to the right gland. Subsequently, in the second period the extraction methods were interchanged. During the experimental period, 4 sampling days were carried out (2 in each experimental period), where ultrasound scans were taken before (B) and immediately after milking (A) and at 1 (1 h), 2 (2 h), 3 (3 h), 4 (4 h), 6 (6 h), 8 (8 h) and 10 (10 h) hours after milking finished. Teat wall thickness (TWT), teat wall area (TWA), teat end area (TEWA) and teat canal length (TCL) were measured in all the ultrasound images. MM increased TWT after milking compared with RC. TWT, TWA, TEWA and TCL were lower (P<0·05) in HM than in MM. No significant differences (P>0·05) were found between LS and MM for any variable. The extraction method affected the recovery time of the variables, with total teat recovery at 6 h after RC and 4 h after HM. In the case of LS, the TEWA and TCL values were recovered sooner, as of 3 h. Teat recovery time after MM was similar to the extraction method with which it was compared in each experiment. Thus, considering the similar increase in wall thickness and their recovery time compared with the reference methods, it was concluded that machine milking, carried out in optimum conditions and respecting the time interval between milkings usually applied on sheep farms (8–12 h), would not affect teat integrity. Moreover, given the variability observed in teat thickness recovery time between the different experiments, further research should be carried out to study which factors intrinsic and extrinsic to the animal may affect the teat wall thickness and recovery time after machine milking.

The assumption, that metabolites derived from the activity of the mammary gland epithelial cells reflect changes in milk secretion and its coagulation properties, was tested in dairy cows. The experiment included cows with uninfected udders and cows with one of the glands infected by different bacteria specie. Analysis were carried at the cow level (including all four glands), or at the gland level. High and significant correlations among the concentrations of lactose, glucose, glucose-6-posphate, milk related respiratory index (the ratio between the concentrations of citrate/lactate+malate in milk) and milk-derived glycolytic index (the ratio between glucose-6-phosphate and glucose in milk) and milk clotting parameters were found. The physiological basis for these relations and their ability to predict the deterioration in milk quality in subclinically infected glands and in glands previously clinically infected with Escherichia coli are discussed.

Caseinophosphopeptides (CPPs) are multifunctional bioactive peptides containing phosphorylated seryl residues in their sequence. In the present study, method for the production of CPPs from buffalo milk casein was optimised and characterised for their sequence, calcium solubilising and calcium binding activities. Response surface methodology was used to optimise the conditions for hydrolysis of buffalo casein by trypsin to obtain maximum yield of CPPs. The optimum hydrolysis conditions were as follows: hydrolysis pH 7·5, temperature 37 °C, hydrolysis time 7·0 h. Under these conditions, the experimental yield obtained was 10·04±0·24%, which is slightly lower than value predicted by the model. These CPPs were able to solubilise 1·03±0·08 mg la/mg CPPs in presence of excess phosphate and bind 0·935 mg of Ca/mg of CPPs. Eight phosphopeptides i.e. αs1-CN f (37-58) 2P; αs1-CN f (37-58) 3P; αs1-CN f (35-58) 2P; αs1-CN f (35-58) 3P; αs2-CN f (2-21) 4P; αs2-CN f (138-149) 1P; β-CN f (2-28) 4P and β-CN f (33-48) 1P were identified by LC-MS/MS which contained motif for binding of divalent minerals. The sequences of these CPPs differed from that of derived from bovine casein.

The aim of the study was to evaluate the interference of acid and alkaline detergents employed in the cleaning of milking equipment of caprine dairy farms on the performance of microbial tests used in antibiotic control (BRT MRL, Delvotest MCS, and Eclipse 100). Eight concentrations of commercial detergents, five acid (0–0·25%) and five alkaline (0–1%) were add to antimicrobial-free goat's milk to evaluate the detergent effect on the response of microbial inhibitor tests. To evaluate the effect of detergents on the detection capability of microbial tests two detergents at 0·5 ml/l (one acid and one basic) and eight concentrations of four β-lactam antibiotics (ampicillin, amoxicillin, cloxacillin and benzylpenicillin) were used. Milk without detergents was used as control. The spiked samples were analysed twelve times by three microbial tests. The results showed that the presence of acid detergents did not affect the response of microbial tests for any of the concentrations tested. However, at concentrations equal to or greater than 2 ml/l alkaline detergents positive results were found in microbial tests (16·7–100%). The detection limits of the screening tests for penicillins were not modified substantially by the presence of detergents. In general, the presence of acid and alkaline detergents in goat's milk did not produce a great interference in the microbial tests, only high concentrations of detergents could cause non-compliant results, but these concentrations are difficult to find in practice if proper cleaning procedures are applied in goat dairy farms.

Soy proteins as the health-promoting ingredients and candidate fat substitutes in dairy products are good substrates for the cross-linking action of the enzyme transglutaminase. Non-fat set yogurt samples were prepared from the milks enriched with soy protein isolate (SPI) and/or treated with the enzyme transglutaminase. The highest titrable acidity was recorded for the yogurt enriched with SPI and treated with the enzyme throughout the cold storage for 21 d. SPI-enrichment of yogurt milk increased the water holding capacity. Although enrichment with SPI did not influence the count of Streptococcus themophilus, increased that of Lactobacillus bulgaricus ∼3 log cycles. The enzymatic treatment of SPI-enriched milk however, suppressed the bacteria growth-promoting influence of SPI due probably to making the soy proteins inaccessible for Lactobacillus. SPI-enrichment and enzymatic treatment of milk decreased the various organic acids content in yoghurt samples; influence of the former was more significant. The cross-linking of milk proteins to soy proteins was confirmed with the gel electrophoresis results.