This review summarises current knowledge on camel milk proteins, with focus on significant peculiarities in protein composition and molecular properties. Camel milk is traditionally consumed as a fresh or naturally fermented product. Within the last couple of years, an increasing quantity is being processed in dairy plants, and a number of consumer products have been marketed. A better understanding of the technological and functional properties, as required for product improvement, has been gained in the past years. Absence of the whey protein β-LG and a low proportion of к-casein cause differences in relation to dairy processing. In addition to the technological properties, there are also implications for human nutrition and camel milk proteins are of interest for applications in infant foods, for food preservation and in functional foods. Proposed health benefits include inhibition of the angiotensin converting enzyme, antimicrobial and antioxidant properties as well as an antidiabetogenic effect. Detailed investigations on foaming, gelation and solubility as well as technological consequences of processing should be investigated further for the improvement of camel milk utilisation in the near future.

The composition of grass/clover silage varies depending on time of harvest time. In particular silage from late regrowths is expected to contain lower fibre and higher linolenic acid concentrations compared to spring growth, thereby autumn silage is expected to increase linolenic acid content of milk fat. Rapeseed supplementation is expected to increase milk production and to increase all C18 fatty acids in milk fat. An interaction between rapeseed and silage type is expected, as hydrogenation of unsaturated fatty acids in rapeseed is expected to be less when low fibre silage is fed. Thirty-six Jersey cows were used in a 4 × 4 Latin square design, for 4 periods of 3 weeks and with a 2 × 2 factorial arrangement of treatments: spring grass/clover silage from primary growth or autumn grass/clover silage which was an equal mixture of 3rd regrowth and 4th regrowth, with or without rapeseed supplementation. Dry matter intake and milk production was higher for autumn than for spring silage. Rapeseed supplementation did not affect dry matter intake, but increased milk production. The concentrations of C18 : 1cis9, C18 : 2n6 and β-carotene and C18 : 3n3 in milk were increased whereas the concentrations of C16 : 0, riboflavin and α-tocopherol were decreased with autumn silage. The majority of C18 FAs in milk and α-tocopherol concentration increased with rapeseed whereas C11 : 0 to C16 : 0 FA were reduced. Autumn silage reduced biohydrogenation of C18 : 2n6, whereas rapeseed increased biohydrogenation of C18 : 2n6 and reduced biohydrogenation of C18 : 3n3. Apparent recovery of C18 : 2n6 was reduced with rapeseed. Minor interaction effects of silage type and rapeseed addition were observed for some milk fatty acids. Feeding silage from late regrowth increased linolenic acid concentration in milk fat. Rapeseed inclusion increased milk production, and increased C18 : 0 as well as C18 : 1 fatty acids, but not C18 : 2 and C18 : 3 in milk fat. Interactions between silage type and rapeseed supplementation were minimal.

The aim of the study reported in this Research Communication was to investigate the effect of a combined acetylmethionine, cyanocobalamin and α-lipoic acid treatment, on some metabolic parameters of early lactating high-yielding dairy cows. Thirty cows were randomly divided into two groups: experimental group (EG, n = 20) and control group (CG, n = 10). EG received 20 ml of treatment and CG received 20 ml of placebo. The treatments were administered for seven times every 2 d. Blood samples were collected from all cows at 3 time points: 10 ± 2, 30 ± 2 and 50 ± 2 d postpartum. Glucose, β-hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), triglycerides, total cholesterol (TC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamiltransferase (GGT), total bilirubin (TB), conjugated bilirubin (CB), total proteins (TP), globulins, albumin and urea concentrations were determined. Two-way repeated measure analysis of variance was applied. Significant differences in the values of glucose, BHB, NEFA, triglycerides, TC, AST and urea were found between EG and CG. Moreover, the increased glucose, TC, ALT, GGT, TP and globulins, and the reduced BHB, NEFA, AST, triglycerides, TB, CB and urea concentrations were evident in both groups, but the changes were more pronounced in EG. Our findings indicate that our treatment positively influenced liver metabolism in high-yielding dairy cows.

Dairy cows with fatty liver or ketosis exhibit hyperketonemia, oxidative stress, and a low rate of very low density lipoprotein (VLDL) assembly, and there may be a potential link among these characteristics. Therefore, the objective of this study was to determine the effect of acetoacetic acid (AcAc) on the assembly of VLDL in cow hepatocytes. Cultured cow hepatocytes were treated with different concentrations of AcAc with or without N-acetylcysteine (NAC, an antioxidant). AcAc treatment decreased the mRNA expression and activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), and significantly increased malondialdehyde (MDA) content, indicative of oxidative stress. Furthermore, AcAc treatment significantly down-regulated the mRNA expression of apolipoprotein B100 (ApoB100), apolipoprotein E (ApoE), and low density lipoprotein receptor (LDLR), which thus decreased VLDL assembly and increased triglyceride (TG) accumulation in these bovine hepatocytes. Importantly, NAC relieved AcAc-induced oxidative stress and increased VLDL assembly. In summary, these results suggest that AcAc-induced oxidative stress affects the assembly of VLDL, which increases TG accumulation in bovine hepatocytes.

While laboratory tests for measuring the concentration of NEFA in serum are well established, a point of care test to determine NEFA on farm is not available. Several hand-held measuring devices, however, have been validated for measuring β-hydroxybutyrate (BHBA) in cattle or cholesterol, triglycerides (TAG), and high-density lipoproteins (HDL) in human medicine, respectively. The objective of this study was to evaluate the association between NEFA and different parameters related to lipid metabolism. Specifically, we set out to determine if it is feasible to predict the concentration of NEFA by means of surrogate measures. The concentration of BHBA was determined by a hand-held device evaluated for use in cows, whereas the concentrations of the other parameters were determined by laboratory analysis because hand-held devices for cholesterol, TAG and HDL are only evaluated for human medicine so far. A total of 254 cows were included in the trial. One blood sample was taken from each cow between d 10 and d 1 prepartum. Second and third samples were collected on d 2 and d 10 postpartum, respectively. The coefficients of correlation between parameters were calculated and a receiver-operator characteristic curve analysis has been used. The prediction of NEFA concentrations using only one of the parameters was insufficient. However, a NEFA concentration ≥0·5 mEq/l could be predicted with a high sensitivity (i.e. Se = 0·88) and specificity (i.e. Sp = 0·93) from d 3 to d 1 prepartum and a NEFA concentration ≥0·7 mEq/l could be reliably predicted on d 2 postpartum (i.e. AUC = 0·89, Se = 0·89, Sp = 0·76) when using a combination of BHBA, cholesterol and TAG as surrogates. Overall, our results suggest that a combination of different parameters of lipid metabolism could be used as surrogates for NEFA.

This research communication describes relationships between pre-weaning average daily gain (ADG) and dam parity with future productivity of dairy calves. Higher ADG before weaning has been shown to be related to greater milk production in the first lactation of Holstein calves fed milk replacer. However, data is limited on the relationship between pre-weaning ADG and first lactation performance of Holstein calves fed whole milk. Data of three hundred and thirty-two Holstein calves from 35 primiparous and 297 multiparous cows was investigated to evaluate the relationship between the dam parity and pre-weaning ADG with the first lactation performance. Results indicated that birth (P < 0·01), and weaning body weight (P < 0·001) were greater in calves born from multiparous cows. Neither 305 d milk production nor pre-weaning ADG differed significantly between calves born to primiparous or multiparous cows, although milk yield tended to be higher in the former and ADG higher in the latter. Correlations between 305 d milk yield and pre-weaning ADG, dam parity and birth body weight were low and non-significant, although there was a tendency for a positive correlation between ADG and milk yield.

The objective of this study was to determine the economic value of obtaining timely and more accurate clinical mastitis (CM) test results for optimal treatment of cows. Typically CM is first identified when the farmer observes recognisable outward signs. Further information of whether the pathogen causing CM is Gram-positive, Gram-negative or other (including no growth) can be determined by using on-farm culture methods. The most detailed level of information for mastitis diagnostics is obtainable by sending milk samples for culture to an external laboratory. Knowing the exact pathogen permits the treatment method to be specifically targeted to the causation pathogen, resulting in less discarded milk. The disadvantages are the additional waiting time to receive test results, which delays treating cows, and the cost of the culture test. Net returns per year (NR) for various levels of information were estimated using a dynamic programming model. The Value of Information (VOI) was then calculated as the difference in NR using a specific level of information as compared to more detailed information on the CM causative agent. The highest VOI was observed where the farmer assumed the pathogen causing CM was the one with the highest incidence in the herd and no pathogen specific CM information was obtained. The VOI of pathogen specific information, compared with non-optimal treatment of Staphylococcus aureus where recurrence and spread occurred due to lack of treatment efficacy, was $20.43 when the same incorrect treatment was applied to recurrent cases, and $30.52 when recurrent cases were assumed to be the next highest incidence pathogen and treated accordingly. This indicates that negative consequences associated with choosing the wrong CM treatment can make additional information cost-effective if pathogen identification is assessed at the generic information level and if the pathogen can spread to other cows if not treated appropriately.

This research communication aimed to compare somatic cell count (SCC), the main marker of udder health status, in organic farms not using antibiotics (O, n = 6), organic farms using antibiotics (OA, n = 7) and conventional farms (CA, n = 5) using antibiotic treatments, all of them at pasture. SCC was statistically significantly higher in O (173780) compared to CA (93325) and OA (107152). Milk yield had a significant diluting effect on SCC and differences between groups increased with parities. Stratified analysis of SCC depending on lactation number and % of monthly SCC test with different linear scores (LS) indicated that there is no difference in udder health in the primiparous heifers from the three groups of farms, but it deteriorates in older cows because of chronic infections in O (possibly due to lack of antibiotic use). Our results suggest that the non-use of antibiotics had an effect in udder health leading to higher occurrence of clinical and subclinical mastitis. Therefore, preventive management practices for mastitis control are essential in organic farms.

Restrictions regarding the use of antibiotics make selective antibiotic dry cow therapy (DCT) mandatory on organic farms in Germany. This requires methods for identifying cows with an intramammary infection (IMI) at dry-off. The aim of this field study was to create a decision scheme for the use of DCT based on cow level factors associated with IMI at dry-off and the probability of both cure and new infection (NI) during the dry period. Data from 250 cows from five organic farms were collected including somatic cell counts (SCC) from Dairy Herd Improvement (DHI) records, California mastitis test (CMT) results at dry-off, clinical mastitis (CM) history, parity and dry-off treatment. IMI at dry-off were most accurate identified using a geometric mean SCC of 100 000 cells/ml as a threshold at either one or three DHI records prior to dry-off. Using a combination of SCC with either CM history, CMT at dry off or parity slightly increased the sensitivity of detection (SE). The probability of cure of the infection over the dry period increased with use of both antibiotic DCT and application of an internal teat sealant (ITS) and decreased when the dry period was longer than 56 d. The risk of NI decreased with the use of ITS and infections with minor pathogens at dry-off. Compared with the selection performed by the farmers during the study period identification of IMI based on the selection criterion with a defined SCC threshold achieved a higher SE.

Water buffalo Mozzarella cheese is more appreciated in the summer, but milk production is higher during wintertime, as water buffalo are seasonally polyoestrous animals. The aim of the study reported in this Research Communication was to evaluate the effect of the reversing of the calving period on Mozzarella cheese composition and quality traits. Ten batches of Mozzarella cheeses produced during the summer and winter periods were analysed for pH, colour, chemical composition. Seasonal differences were observed for cheese yield (26·66% in winter and 25·61% in summer), moisture content (66·54% in winter and 61·18% in summer) colour and consumer evaluation.

In cheese, a negative oxidation-reduction (redox) potential is required for the stability of aroma, especially that associated with volatile sulphur compounds. To control the redox potential during ripening, redox agents were added to the salted curd of Cheddar cheese before pressing. The control cheese contained only salt, while different oxidising or reducing agents were added with the NaCl to the experimental cheeses. KIO3 (at 0·05, 0·1 and 1%, w/w) was used as the oxidising agent while cysteine (at 2%, w/w) and Na2S2O4 (at 0·05 and 0·1%, w/w) were used as reducing agents. During ripening the redox potential of the cheeses made with the reducing agents did not differ significantly from the control cheese (E h ≈ −120 mV) while the cheeses made with 0·1 and 0·05% KIO3 had a significantly higher and positive redox potential in the first month of ripening. Cheese made with 1% KIO3 had positive values of redox potential throughout ripening but no starter lactic acid bacteria survived in this cheese; however, numbers of starter organisms in all other cheeses were similar. Principal component analysis (PCA) of the volatile compounds clearly separated the cheeses made with the reducing agents from cheeses made with the oxidising agents at 2 month of ripening. Cheeses with reducing agents were characterized by the presence of sulphur compounds whereas cheeses made with KIO3 were characterized mainly by aldehydes. At 6 month of ripening, separation by PCA was less evident. These findings support the hypothesis that redox potential could be controlled during ripening and that this parameter has an influence on the development of cheese flavour.

Lactobacillus fermentum Lf2 is a strain which is able to produce high levels (approximately 1 g/l) of crude exopolysaccharide (EPS) when it is grown in optimised conditions. The aim of this work was to characterize the functional aspects of this EPS extract, focusing on its application as a dairy food additive. Our findings are consistent with an EPS extract that acts as moderate immunomodulator, modifying s-IgA and IL-6 levels in the small intestine when added to yogurt and milk, respectively. Furthermore, this EPS extract, in a dose feasible to use as a food additive, provides protection against Salmonella infection in a murine model, thus representing a mode of action to elicit positive health benefits. Besides, it contributes to the rheological characteristics of yogurt, and could function as a food additive with both technological and functional roles, making possible the production of a new functional yogurt with improved texture.

The aim of this Research Communication was to investigate the changes in physicochemical, colour, apparent viscosity and texture properties in low-fat goat milk yogurts prepared with cupuassu pulp by the addition of inulin (SI), maltodextrin (SM), whey protein (SW) and skim milk powder (SP). Three batches of each cupuassu goat milk yogurt were prepared and analysed on the 1st day of storage by pH, proximate composition, colour, apparent viscosity, and texture. In comparison to yogurts from whole (W) or skimmed milk (S), all of the fat replacers improved the physicochemical properties (P < 0·05). The addition of the carbohydrates (inulin and maltodextrin) and proteins (whey protein and skim milk powder) also influenced the colour of the low-fat cupuassu goat milk yogurt (P < 0·05). All fat replacer treatments (SI, SM, SW and SP) presented a higher (P < 0·05) apparent viscosity than W and S yogurts. However, only the addition of skim milk powder increased the texture parameters (firmness and consistency) (P < 0·05). These results suggest that skim milk powder can be used to improve the texture properties of low-fat cupuassu goat milk. Furthermore, inulin, maltodextrin, and whey protein can potentially be applied in the goat dairy industry to increase the viscosity of yogurts.

Antibiotics are commonly used in poultry feed as growth promoters. This practice is questioned given the arising importance of antibiotic resistance. Antimicrobial peptides can be used as food additives for a potent alternative to synthetic or semi-synthetic antibiotics. The objective of this study was to develop a peptide production method based on membrane adsorption chromatography in order to produce extracts with antimicrobial activity against avian pathogens (Salmonella enterica var. Enteritidis, Salmonella enterica var. Typhimurium, and two Escherichia coli strains, O78:H80 and TK3 O1:K1) as well as Staphylococcus aureus. To achieve this, buttermilk powder and purified lactoferrin were digested with pepsin. The peptide extracts (<10 kDa) were fractionated depending on their charges through high-capacity cation-exchange and anion-exchange adsorptive membranes. The yields of cationic peptide extracts were 6·3 and 15·4% from buttermilk and lactoferrin total peptide extracts, respectively. Antimicrobial activity was assessed using the microdilution technique on microplates. Our results indicate that the buttermilk cationic peptide extracts were bactericidal at less than 5 mg/ml against the selected avian strains, with losses of 1·7 log CFU/ml (Salm. Typhimurium) to 3 log CFU/ml (E. coli O78:H80); viability decreased by 1·5 log CFU/ml for Staph. aureus, a Gram-positive bacterium. Anionic and non-adsorbed peptide extracts were inactive at 5 mg/ml. These results demonstrate that membrane adsorption chromatography is an effective way to prepare a cationic peptide extract from buttermilk that is active against avian pathogens.