An evaluation of cumulative risks from offshore produced water discharges in the Bass Strait.

Chemical analyses and toxicity testing using six marine species were used to characterize the hazard of produced waters (PW) to marine life from twelve Australian offshore platforms. Hazard data were used in conjunction with platform-specific plume discharge dilution and species sensitivity distribution modeling to estimate cumulative risks by calculating the multiple substance potentially affected fraction of species in the local marine environment. Results provided two independent lines of evidence demonstrating that cumulative risks to marine life from these discharges meet intended 95% species protection goals at the edge of the mixing zone. A limited number of PW constituents (hydrocarbons, sulphide and ammonia) appeared to dictate risk thereby informing management and providing a rationale for more targeted analyses in future monitoring studies. Based on these findings a tiered framework is proposed to foster consistent screening and potential refinement of cumulative risk evaluations for PW discharges.

Allergic responses induced by goat milk αS1-casein in a murine model of gastrointestinal atopy.

Up to 3% of young children develop milk allergy and this may influence the development of immune-mediated diseases in later life. One protein that has been associated with allergic reactions to ruminant milk is α(S1)-casein (CN). Studies suggest that goat milk with low levels of α(S1)-CN may reduce allergenicity of milk, but the dose response to α(S1)-CN has not been confirmed. In this study, we examined the immune response to varying levels of goat α(S1)-CN in a mouse model of gastrointestinal allergy. BALB/c mice (aged 5 wk) were given intraperitoneal injections with α(S1)-CN and aluminum as adjuvant at 1 and 3 wk to sensitize mice to the antigen. In wk 5, groups of fasting mice (n=8/group) were challenged 4 times on alternate days by intragastric gavage with saline or 2, 10, or 20mg of α(S1)-CN. Serum levels of specific IgE, IgG(1), and IgG(2a) antibodies and mouse mast cell protease-I were determined. Interleukin-4, IL-10, and IFN-γ responses to 48-h activation with antigen were measured in cultured splenocytes. We determined that mice sensitized with α(S1)-CN had higher titers of specific IgG(1) and IgE antibodies compared with controls; however, groups challenged with differing doses of α(S1)-CN did not differ. The group challenged with the highest dose of α(S1)-CN had a 10-fold increase in mouse mast cell protease-I compared with the group challenged with saline. Both IL-4 and IL-10 were produced in a dose-dependent manner by cultured splenocytes incubated with α(S1)-CN. Overall, α(S1)-CN stimulated the production of cytokines associated with allergic disease in a dose-dependent manner. Thus, milk with lower levels of α(S1)-CN should contribute to a lesser antigenic burden.

Relationship between estimated breeding value for somatic cell count and prevalence of intramammary infection in dairy goats.

UNLABELLED: Abstract AIM: The objective of the study was to determine if dairy goats selected as having either Low or High estimated breeding values for somatic cell count (EBV SCC) would differ in prevalence of intramammary infection (IMI). METHODS: The EBV SCC for all does in two dairy goat herds were calculated based on the three or four herd test results for somatic cell count (SCC) from the preceding lactations. Within each herd does were categorised into six age groups (i.e. 2, 3, 4, 5, 6 and >6 years old) and ranked on EBV SCC. Approximately the top (High group; n=149) and bottom (Low group; n=148) 12.5% of the does within each age group within each herd had milk samples collected from each gland on one calendar day for subsequent microbiology. The presence of any IMI or IMI due to a major pathogen at goat level was modelled using a GLM with a binomial link function. RESULTS: There was no difference between the High and Low groups in terms of age, days in milk at the time of sampling or in the proportion of the Saanen breed. Mean EBV SCC was -1.0 (SD 0.4) vs 0.8 (SD 0.4) for the Low and High groups, respectively, and there was no overlap in EBV SCC between groups. Goats in the Low group had lower prevalence of any IMI than those in the High group (0.67 (95% CI=0.58-0.76) vs 0.81 (95% CI=0.74-0.88); p=0.002). Goats in the High group were 8.4 (95% CI=1.9-38.0) times more likely to have IMI due to a major pathogen infection than goats in the Low group (p=0.006). CONCLUSIONS: Does with a high EBV SCC had a higher prevalence of any IMI and were more likely to have an IMI due to a major pathogen than does with a low EBV SCC. Thus selection for EBV SCC is likely to result in a lower SCC and also lower prevalence of IMI.

Diagnosis and treatment of subclinical mastitis in early lactation in dairy goats.

The objectives of the study were to define the sensitivity and specificity of the California Mastitis Test (CMT) in determining the presence of intramammary infection in postpartum dairy goats and to determine whether antibiotic therapy increased bacteriological cure rate and lowered somatic cell count (SCC) compared with untreated controls. A CMT was performed and milk samples were collected for bacteriology from 211 glands of 106 does between 0 and 10 d after kidding. From a population of 3,239 glands from goats in 4 commercial herds, goats with one or both glands with a CMT score of >1 and from which bacteria were isolated were either assigned to be treated with 3 intramammary infusions at 12-h intervals of 75 mg of sodium ampicillin and 250 mg of sodium cloxacillin (n=57 glands) or left as untreated controls (n=49 glands). Milk samples were collected again 14 ± 3 and 21 ± 3 d later for bacteriology and SCC determination. Composite milk yield, goat SCC, length of lactation, and survival data were collected. A partial budget was constructed to assess the cost effectiveness of treatment. At a cut point of greater than trace, the sensitivity, specificity, and positive and negative predictive values of the CMT were 0.74, 0.74, 0.42, and 0.92, respectively. Treatment increased the bacteriological cure rate compared with no treatment [30/57 (53%) vs. 6/49 (12%)], but there was a pathogen by treatment interaction whereby treatment increased cure proportion in glands infected with minor, but not major, pathogens. Treatment reduced the foremilk gland-level SCC [1,595 (95% CI=1,106-2,300) vs. 3,028 (95% CI=2,091-4,385) geometric mean (× 1,000) cells/mL] but not the SCC at goat level [1,596 (95% CI=1,219-2,090) vs. 1,488 (95% CI=1,132-1,955) geometric mean (× 1,000) cells/mL] compared with no treatment. Milk yield, risk of removal from the herd, and length of lactation were not altered by treatment. Treatment resulted in a loss of NZ$20.39/doe. It was concluded that use of the CMT as a screening test resulted in a higher likelihood of finding a gland that would be infected than selecting a gland at random. Treatment increased bacteriological cure rate and reduced SCC at gland level compared with no treatment. However, at goat level, milk yield, SCC, and survival were not altered, resulting in no economic benefit of treatment.

Composition and distribution of fatty acids in triglycerides from goat infant formulas with milk fat.

Most infant formulas use vegetable oils in place of milk fat to provide an overall fatty acid profile similar to that of breast milk. Vegetable oils have 5 to 20% saturated fatty acids in the sn-2 position of triglycerides unless they are modified by interesterification. Interesterification is increasingly used for the fat for infant formulas to raise the level of saturated fatty acids in the sn-2 position to 40 to 60%. The objective of this study was to verify an alternative approach to providing the appropriate fatty acid profile, including in the sn-2 position, for a goat infant formula. In this method, 55% of total fat was made from goat milk fat and 45% from a mixture of unmodified high oleic sunflower, canola, and sunflower oils in a ratio of 44:30:26. The fatty acid profile was measured by gas-liquid chromatography and the relative percentage of fatty acids in the sn-2 position of triglycerides was measured via partial deacylation with Grignard reagent using trimethylsilyl derivatives of monoacylglycerols. Mixing goat milk fat with vegetable oils produced a formula with a profile of essential fatty acids and a ratio of linoleic:alpha-linolenic fatty acids within the required interval of 5 to 15:1 recommended for infant formula. The proportion of palmitic acid in the sn-2 position was 31%.

Effects on adhesion molecule expression and lymphocytes in the bovine mammary gland following intra-mammary immunisation.

Changes to adhesion molecule expression and lymphocyte populations were evaluated in alveolar mammary tissue collected from cows following an immunisation protocol that involved intra-mammary inoculation to induce an IgA response in mammary secretions. The right quarters of the udder were immunised; the left side acted as a control. Antibody titres in secretions showed that at least two animals responded with antigen-specific IgA. Numbers of T-lymphocytes were 4-fold higher in immunised glands compared with controls (P<0.05). IgA-, IgM- and IgG-positive cell numbers were significantly higher (P<0.01) in immunised glands compared with controls in three of the four cows. No mucosal addressin molecule-1 (MAdCAM-1), vascular cell-adhesion molecule-1 (VCAM-1) or peripheral node addressin (PNAd) protein expression was detected on smaller venules that stained positively for von Willebrand factor in alveolar mammary tissues, from either immunised or control glands. Both VCAM-1 and PNAd were detected on smaller venules in supramammary lymph nodes, however, there was no significant difference between immunised and control glands. Quantification of MAdCAM-1 mRNA showed very low expression in both immunised and control alveolar tissue compared with Peyer's patch positive-control tissue. These findings suggest that the bovine mammary gland is capable of a mucosal antibody response; however, MAdCAM-1 is not involved with lymphocyte homing to the mammary gland in this species.

Vitamin D status is not associated with the risk of hospitalization for acute bronchiolitis in early childhood.

The association between vitamin D status and susceptibility to acute lower respiratory tract infection (ALRI) was studied in young Canadian children. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were measured in patients aged 1-25 months admitted to hospital with uncomplicated ALRI (primarily viral bronchiolitis) as well as in healthy, similarly aged patients without a history of hospitalization for ALRI (controls). Serum 25(OH)D concentrations were similar among cases and controls (77.0 versus 77.2 nmol l(-1); P=0.960), and there was no case-control difference in the prevalence of vitamin D insufficiency using two thresholds (<40 nmol l(-1): 4.7 versus 1.5%, P=0.365; <80 nmol l(-1): 51.6 versus 56.9%, P=0.598). Vitamin D status was not associated with the risk of hospitalization for ALRI in this population.

cDNA microarray analysis reveals that antioxidant and immune genes are upregulated during involution of the bovine mammary gland.

We have used cDNA microarray analysis to identify genes that play a role in bovine mammary involution. Involution was induced by termination of milking, and alveolar tissue was collected from 48 nonpregnant Friesian cows in mid lactation sacrificed at 0, 6, 12, 18, 24, 36, 72, and 192 h (n = 6/group) postmilking. The most highly upregulated genes were those associated with oxidative stress. Quantitative real-time reverse-transcription PCR analysis confirmed that mRNA expression of spermidine/spermine N(1)-acetyltransferase was increased by 24 h, superoxide dismutase 2 and metallothionein 1A by 36 h, and glutathione peroxidase by 72 h postmilking. The mRNA expression of the host defense proteins lactoferrin and lingual antimicrobial peptide were increased by 192 h postmilking. A dramatic increase in the protein expression of lactoferrin by 192 h postmilking was also detected by Western analysis. Decreased mRNA expression of the milk protein genes alpha(S1)-, beta-, and kappa-casein, and alpha-lactalbumin were early events in the process of involution occurring within 24 to 36 h postmilking, whereas beta-lactoglobulin mRNA was decreased by 192 h postmilking. Decreases in alpha-lactalbumin and beta-lactoglobulin protein levels in alveolar tissue occurred by 24 and 192 h postmilking, respectively, and the cell survival factors beta1-integrin and focal adhesion kinase were decreased by 72 and 192 h postmilking, respectively. The results demonstrate that in the bovine mammary gland, decreased milk protein gene expression and cell survival signaling are associated with multiple protective responses to oxidative stress that occur before the induction of immune responses and mammary epithelial cell apoptosis during involution.

Adhesion molecule expression in the bovine mammary gland.

The bovine mammary gland requires lymphocytes for immune protection of the gland from foreign pathogens and, in addition, to transfer immune protection to the neonate via colostrum and milk. The process of homing primed lymphocytes to tissues is mediated by the interaction of cell-adhesion molecules displayed on the surface of lymphocytes and counter receptors displayed on the vascular endothelium. This study was conducted to identify the cell-adhesion molecules involved in homing lymphocytes to the bovine mammary gland at four different physiological stages; pregnant, colostral, lactation and involution. The expression and distribution of adhesion molecules in alveolar tissues and supramammary lymph nodes from the mammary glands of healthy cows was determined in situ by immunohistochemical analysis and compared with bovine Peyer's patch, used as a typical mucosal-associated lymphoid tissue and positive control. The mucosal addressin molecule, MAdCAM-1, was not detected in bovine mammary tissues at any of the four different physiological stages. Absence of MAdCAM-1 expression was verified by quantitative real-time RT-PCR analysis. Transcription levels of MAdCAM-1 mRNA were found to be more then 5 x 10(3)-fold lower in mammary alveolar tissues compared with bovine Peyer's patch tissues. In contrast to MAdCAM-1, phase-dependent protein expression of VCAM-1 was detected in both mammary alveolar tissues and the supramammary lymph nodes, with the highest expression observed in colostral phase cows. The protein expression in mammary alveolar tissues was limited to larger venules, although in colostral phase cows, VCAM-1 was also detected around the alveoli perimeter. In the supramammary lymph node, VCAM-1 protein was observed on both small and large venules. PNAd was detected in supramammary lymph nodes at all physiological stages of the mammary gland; however, it was not found in mammary alveolar tissues. Lymphocytes expressing beta7 were not detected in mammary tissues and lymphocytes expressing CD62L were only observed in the supramammary lymph nodes. Overall the data suggest that MAdCAM-1 and VCAM-1 are not involved in homing lymphocytes to the bovine mammary gland; whereas, VCAM-1 and PNAd may have this role in the supramammary lymph node.

Mineral retention in three-week-old piglets fed goat and cow milk infant formulas.

Goat milk and cow milk are commonly used in infant formula preparations and, as such, understanding the nutritional characteristics of infant formulas made from these milks is important. In this study, a goat milk infant formula was compared with an adapted (whey-enhanced) cow milk infant formula with respect to mineral absorption and deposition using the 3-wk-old piglet as a model for the 3-mo-old infant. Equal numbers of piglets (n = 8) were fed either the goat milk formula or the cow milk formula. The mineral composition of the prepared goat milk formula was higher than that of the prepared cow milk formula for most minerals, including calcium (75.1 vs. 56.7 mg/100 mL) but excluding iron, which was higher in the prepared cow milk formula (0.92 vs. 0.74 mg/100 mL). The amounts of calcium, phosphorus, and manganese absorbed by the piglets were significantly higher for the goat milk formula, whereas the amounts of zinc, iron, and magnesium absorbed were significantly higher for the cow milk formula. Apparent mineral absorption, relative to intake, was statistically higher in the cow milk formula for calcium and phosphorus, although the actual differences were very small (less than 1.3%). For copper, zinc, iron, and magnesium there was no significant difference between treatments in apparent mineral absorption, whereas for manganese, absorption was higher for the goat milk infant formula. The absolute mineral deposition was higher in piglets fed the goat milk formula for calcium, phosphorus, and manganese, whereas iron deposition was higher in the piglets fed cow milk formula. For all other minerals tested, there were no significant differences between treatments. The goat milk infant formula provided a pattern of mineral retention in the 3-wk-old piglet very similar to that of the adapted cow milk infant formula. The minor differences observed between the 2 appeared to be due to the different mineral contents of the 2 formulas.

True ileal amino acid digestibility of goat and cow milk infant formulas.

Goat milk is used as an alternative to cow milk for the production of infant formulas. However, little is known about the protein quality and, specifically, about the digestible AA pattern of goat milk formulas compared with their cow milk counterparts. In this study, the true ileal AA digestibility of a goat milk infant formula was compared with a premium cow milk infant formula. The 3-wk-old piglet was used as a model for the 3-mo-old infant. Both milk formulas were prepared as described by the manufacturer, with titanium dioxide added as an indigestible marker. The formulas were fed to the piglets over a 2-wk trial period. Digesta from the terminal ileum were collected post euthanasia and analyzed for AA content, along with samples of the formulas. True AA digestibility was determined after correcting for endogenous AA loss at the terminal ileum of pigs fed an enzyme-hydrolyzed casein-based diet, followed by ultrafiltration (5,000 Da) of the digesta. Total urine and feces collection was also undertaken to determine the nitrogen retention from the diets. The true ileal AA digestibility was similar between the goat and cow milk infant formulas for all AA except Gly and Trp. There was no significant difference in the nitrogen retention of piglets fed the two different formulas. The goat milk infant formula and the premium cow milk infant formula were similar in terms of protein quality.

Reduction in heat-induced gastrointestinal hyperpermeability in rats by bovine colostrum and goat milk powders.

Male Sprague-Dawley rats were assigned to one of three dietary groups [standard diet (Cont; n = 8), standard diet plus bovine colostrum powder (BColost 1.7 g/kg; n = 8), or goat milk powder (GMilk 1.7 g/kg; n = 8)] to determine the ability of these supplements to reduce gastrointestinal hyperpermeability induced by heat. Raising core body temperature of rats to 41.5 degrees C increased transfer of (51)Cr-EDTA from gut into blood 34-fold relative to the ambient temperature value (P < 0.05) in the Cont group of rats, indicative of increased gastrointestinal permeability. Significantly less (P < 0.01) (51)Cr-EDTA was transferred into the blood of rats in either the BColost (27% of Cont) or GMilk group (10% of Cont) after heating, showing that prior supplementation with either bovine colostrum or goat milk powder significantly reduced the impact of heat stress on gastrointestinal permeability. The changes in the BColost group were not significantly different than those of the GMilk group. The potential mechanism of the protective effect of bovine colostrum and goat milk powders may involve modulation of tight junction permeability, because both powders were able to maintain transepithelial resistance in Madin Darby canine kidney cells challenged with EGTA compared with cells maintained in media only. The results show that bovine colostrum powder can partially alleviate the effects of hyperthermia on gastrointestinal permeability in the intact animal. Moreover, goat milk powder was equally as effective as bovine colostrum powder, and both may be of benefit in other situations where gastrointestinal barrier function is compromised.

Mammary blood flow does not limit milk yield in lactating goats.

There is a close relationship between mammary blood flow (MBF) and milk production, but whether MBF is limiting milk yield has not been determined. Five lactating goats received close arterial (external pudic) infusion of PBS or the nitric oxide donor diethylamine NONOate (0.5 mg/h; NONate) for 6 h, according to a crossover design. Goats were hand milked (with oxytocin) every 2 h starting 2 h before and ending 6 h after the end of the infusion. In one goat, a transit time flow probe was implanted around the infused and noninfused artery, whilst in another goat a flow probe was implanted around the infused artery only. Infusion of PBS did not affect MBF or milk production. As with previous results (Lacasse et al., 1996), NONate induced a rapid increase (up to 250% of preinfusion level) in MBF in the infused gland only. Mammary blood flow was still above the preinfusion level at the end of the infusion period. Despite this increase in MBF, NONate did not affect milk production. Milk yield ratio (infused/noninfused gland) averaged 1.20, 1.12, and 1.17 for the preinfusion, infusion and post infusion periods, respectively. Similarly, protein, fat and lactose yields were not affected by PBS or NONate infusion. These results provide no support to the contention that increasing MBF can enhance milk production.

Stat5 phosphorylation status and DNA-binding activity in the bovine and murine mammary glands.

The transcription factors Stat5a and Stat5b are mediators of prolactin signalling in mammary epithelial cells, and are thought to play a role in lactogenesis. In cultured cells, activation of Stat5 activity through phosphorylation results in Stat5 binding to the promoters of at least some of the milk protein genes, thereby stimulating their transcription. However, the mammary biology of Stat5 differs between species, and the role of Stat5 in the bovine mammary gland is not fully understood. We have generated an antibody that specifically recognises the phosphorylated forms of Stat5a and Stat5b and used it to compare the levels of phosphorylated Stat5 with Stat5 DNA-binding activity in bovine and murine mammary tissue. Both Stat5 DNA-binding activity and phosphorylation status in the bovine mammary gland were at near-maximal levels at late pregnancy (27-35 days prior to calving), when at least three of the major milk proteins are not highly expressed. In addition, these studies revealed significant animal-to-animal variation in the level of Stat5 activity in both species. The results are consistent with a role in terminal differentiation of mammary epithelial cells. They also suggest that the stimulation of high-level expression of milk protein genes in the bovine mammary gland is not through activation of the prolactin receptor-Jak2-Stat5 pathway.

Effects of mammary engorgement and feed withdrawal on microvascular function in lactating goat mammary glands.

The responses of the mammary microvasculature in lactating goats (n = 8) during feed withdrawal (18-20 h) and mammary engorgement (26-28 h of milk accumulation) were compared using an indicator-dilution technique with FITC-albumin and [(14)C]sucrose as the intravascular and diffusible indicators, respectively. Feed withdrawal and mammary engorgement caused a 50-60% decrease in mammary arterial flow and in the permeability-surface area product (PS) values for sucrose. Only feed withdrawal increased the mean transit time [from 17.3 to 30.0 s, SE of the difference (SED) = 2.16, P < 0.01] of FITC-albumin, whereas only mammary engorgement reduced sucrose extraction (0.63 to 0.51, SED = 0.04, P < 0.05). Mammary engorgement also caused a substantial reduction in the sucrose-accessible extravascular space from 92 to 44 ml (SED = 15.2, P < 0.01). In a separate experiment using five goats, milking after mammary engorgement did not immediately restore arterial flow or sucrose extraction, indicating that the effect of milk accumulation was not mediated simply via increased intramammary pressure. In conclusion, feed withdrawal resulted in slower flow in the capillary bed but apparently no change in capillary recruitment, whereas mammary engorgement caused capillary derecruitment.

Effects of pasture allowance on the yield and composition of milk from cows of different beta-lactoglobulin phenotypes.

The objective of this study was to determine whether the differences in the composition of milk from cows of different beta-lactoglobulin beta-LG) phenotypes are affected by the amount of pasture available and, hence, pasture dry matter intake. Twenty-two Friesian cows of each of the AA and BB variants of the beta-LG phenotype were subjected to ad libitum grazing or restricted grazing in crossover experiments during spring (early lactation, approximately 60 d in milk) and summer (mid to late lactation, approximately 180 d in milk). Milk samples were collected from each cow at the end of each 8-d treatment period and analyzed for composition. Cows of the AA variant of the beta-LG phenotype had higher concentrations of whey protein and beta-LG, but lower concentrations of casein (CN), alpha-CN, kappa-CN (summer only), and BSA, than cows of the BB variant. Compared with cows with a restricted allowance, cows grazing ad libitum had higher milk yields and concentrations of protein, casein, whey protein, and all individual proteins except BSA and immunoglobulin. There were no interactions between effects of pasture allowance and phenotype on milk yield or composition. The data show that having adequate pasture for grazing cows is important not only to maximize milk yield, but also to optimize concentrations of protein and casein, and hence the manufacturing potential of milk. Further, the differences in composition of milk from cows of differing beta-LG phenotypes persisted during short-term restrictions in pasture allowance, and between spring and summer.