Association between quarter-level milk somatic cell count and intramammary bacterial infection in late-lactation Irish grazing dairy cows.

The objectives of our study were to describe quarter-level prevalence of intrammamary infection (IMI), to evaluate the performance of commonly used somatic cell count (SCC) thresholds for the diagnosis of quarter-level IMI, and to determine those with maximized sensitivity (Se) and specificity (Sp) for identifying quarter-level IMI as defined by positive aerobic culture in late-lactation grazing dairy cows. In this observational study, quarter milk samples were collected from all cows in 21 commercial spring-calving, pasture-based Irish dairy herds. Total SCC determination and aerobic bacterial culture were performed in 8,177 quarter milk samples obtained between 238 and 268 d in milk from 465 primiparous and 1,609 multiparous cows. The Se and Sp of SCC thresholds used for diagnosis of IMI were evaluated against the gold standard aerobic culture separately for all, primiparous, and multiparous cows. The overall prevalence of bacteriologically infected quarters was 6.3%, and it was higher among primiparous (11.3%) than multiparous cows (5.5%). However, considering all samples, quarter-level SCC was higher for multiparous than for primiparous cows (195,250 ± 21,422 vs. 115,940 ± 26,260 cells/mL). Associated Se and Sp for the 200,000 cells/mL threshold were 59.2% and 88.0% for all, 52.7% and 95.4% for primiparous, and 62.9% and 85.9% for multiparous cows, respectively. Receiver operating characteristic curve analyses determined the thresholds that optimized the Se and Sp of a positive bacterial culture: 101,000 cells/mL for all cows [Se = 80.0%; Sp = 76.4%; area under the curve (AUC) = 0.84], 61,000 cells/mL for primiparous (Se = 87.1%; Sp = 84.0%; AUC = 0.90), and 101,000 cells/mL for multiparous (Se = 80.9%; Sp = 72.6%; AUC = 0.83). The results indicate that the 200,000 cells/mL threshold was inefficient in identifying late-lactation quarter-level IMI (low Se) in the studied herds where the main etiological agent was Staphylococcus aureus. Suggested quarter-level SCC thresholds have the potential of serving as a supporting tool for dry cow therapy decisions and warrant further study in late-lactation cows from spring-calving, pasture-based herds with S. aureus as the main pathogen causing IMI.

Maximum speed exposures in Australian rules football: do methods matter?

This study compared weekly near-to-maximum speed exposure data when determined via different methods and criteria. Forty-seven professional Australian rules football (AF) players undertook pre-season sprint assessments (PSSA) via 3 × 50 m maximal efforts using 10 Hz GPS over two consecutive seasons. The same technology was used continually during the in-season to identify maximum speeds attained in training and matches. Weekly near-to-maximal speed (MS) exposure counts were aggregated for speeds ≥80%, ≥85%, ≥90% and ≥95% of their individual maximum for both determination approaches. Weekly near-to-MS exposures was lower (p < 0.0001) when determined from in-season monitoring for ≥80% (-1.26; CI: -1.58 to -0.93), ≥85% (-0.78; CI: -0.97 to -0.59), ≥90% (-0.42; CI: -0.53 to -0.32), and ≥95% (-0.09; CI: -0.12 to -0.06) versus PSSA, with no effect of playing position (P ≥ 0.161). Although ≥80% and ≥85% near-to-maximum speed exposure data was meaningfully influenced by the determination method, the effect was somewhat trivial at higher speed criteria (≥90% and ≥95%) often considered important for performance gains and injury risk reduction purposes. Maximum speed determination methods therefore may be used interchangeably, and discrete sprint assessments may not be necessary for this purpose.

Emulsion-Based Postbiotic Formulation Is Comparable to Viable Cells in Eliciting a Localized Immune Response in Dairy Cows With Chronic Mastitis.

Bovine mastitis is a disease with a multi-etiological nature, defined as an infection and inflammation of the udder. Mastitis represents a significant ongoing concern in the dairy industry, leading to substantial losses in profits and revenue for farmers worldwide. The predominant causes of bovine mastitis include the pathogens Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis, and Escherichia coli. Antibiotic administration is currently the main treatment option for mastitis. However, there is a pressing need for alternative therapies to treat and prevent the disease, especially with the emergence of antibiotic-resistant, mastitis-causing pathogens, resulting in antibiotic treatment failure. One such example is live bio-therapeutics (also known as probiotics), such as Lactococcus lactis DPC3147. The efficacy of this live bio-therapeutic has been demonstrated in several previous trials by our group. The most recent of these trials showed that an emulsion-based formulation of this strain was as effective as a commercial antibiotic formulation in treating sub-clinical and clinical cases of bovine mastitis. Here, we report the results of a follow-up field trial, in which we sought to gain insight into the mechanism of action of such live bio-therapeutics, focussing on chronic mastitis cases. We treated 28 cows with chronic mastitis with two separate emulsion-based formulations containing either viable L. lactis DPC3147 cells (15 cows) or heat-killed L. lactis DPC3147 cells (13 cows). We then evaluated the efficacies of the two formulations (two treatment groups) in terms of stimulating a localized immune response (quantified by measuring IL-8 concentrations in milk collected from udders affected by mastitis) and efficacies in terms of cure rates (quantified by reductions in somatic cell counts and absence of pathogens). We demonstrate that the presence of heat-inactivated bacteria (a postbiotic) was as effective as the live bio-therapeutic in eliciting a localized immune response in cows with chronic mastitis. The response to heat-killed cells (postbiotic) reported herein could have beneficial implications for farmers with regard to prolonging the shelf life of such emulsion-based formulations containing heat-killed cells of L. lactis DPC3147 for curing cows with mastitis.

The Impact of Seasonality in Pasture-Based Production Systems on Milk Composition and Functionality.

Seasonal calving, pasture-based dairy systems are widely practiced in countries with a temperate climate and plentiful rainfall such as Ireland and New Zealand. This approach maximizes milk production from pasture and, consequently, is a low-cost, low-input dairy production system. On the other hand, the majority of global milk supply is derived from high input indoor total mixed ration systems where seasonal calving is not practiced due to the dependence on ensiled silages, grains and concentrated feeds, which are available year-round. Synchronous changes in the macro and micronutrients in milk are much more noticeable as lactation progresses through early, mid and late stages in seasonal systems compared to non-seasonal systems-which can have implications on the processability and functionality of milk.

A Live Bio-Therapeutic for Mastitis, Containing Lactococcus lactis DPC3147 With Comparable Efficacy to Antibiotic Treatment.

Bovine mastitis is an ongoing significant concern in the dairy and agricultural industry resulting in substantial losses in milk production and revenue. Among the predominant etiological agents of bovine mastitis are Staphylococcus aureus, Streptococcus uberis, Streptococcus dysgalactiae, and Escherichia coli. Currently, the treatment of choice for bovine mastitis involves the use of commercial therapeutic antibiotic formulations such as TerrexineTM, containing both kanamycin and cephalexin. Such antibiotics are regularly administered in more than one dose resulting in the withholding of milk for processing for a number of days. Here, we describe the optimization of a formulation of Lactococcus lactis DPC3147, that produces the two-component bacteriocin lacticin 3147, in a liquid paraffin-based emulsion (formulation hereafter designated 'live bio-therapeutic') for the first time and compare it to the commercial antibiotic formulation TerrexineTM, with a view to treating cows with clinical/sub-clinical mastitis. Critically, in a field trial described here, this 'ready-to-use' emulsion containing live L. lactis DPC3147 cells exhibited comparable efficacy to TerrexineTM when used to treat mastitic cows. Furthermore, we found that the L. lactis cells within this novel emulsion-based formulation remained viable for up to 5 weeks, when stored at 4, 22, or 37°C. The relative ease and cost-effective nature of producing this 'live bio-therapeutic' formulation, in addition to its enhanced shelf life compared to previous aqueous-based formulations, indicate that this product could be a viable alternative therapeutic option for bovine mastitis. Moreover, the single-dose administration of this 'live bio-therapeutic' formulation is a further advantage, as it can expedite the return of the milk to the milk pool, in comparison to some commercial antibiotics. Overall, in this field trial, we show that the live bio-therapeutic formulation displayed a 47% cure rate compared to a 50% cure rate for a commercial antibiotic control, with respect to curing cows with clinical/sub-clinical mastitis. The study suggests that a larger field trial to further demonstrate efficacy is warranted.

The "Grass-Fed" Milk Story: Understanding the Impact of Pasture Feeding on the Composition and Quality of Bovine Milk.

Milk is a highly nutritious food that contains an array of macro and micro components, scientifically proven to be beneficial to human health. While the composition of milk is influenced by a variety of factors, such as genetics, health, lactation stage etc., the animal's diet remains a key mechanism by which its nutrition and processing characteristics can be altered. Pasture feeding has been demonstrated to have a positive impact on the nutrient profile of milk, increasing the content of some beneficial nutrients such as Omega-3 polyunsaturated fatty acids, vaccenic acid, and conjugated linoleic acid (CLA), while reducing the levels of Omega-6 fatty acids and palmitic acid. These resultant alterations to the nutritional profile of "Grass-Fed" milk resonate with consumers that desire healthy, "natural", and sustainable dairy products. This review provides a comprehensive comparison of the impact that pasture and non-pasture feeding systems have on bovine milk composition from a nutritional and functional (processability) perspective, highlighting factors that will be of interest to dairy farmers, processors, and consumers.

Pasture Feeding Changes the Bovine Rumen and Milk Metabolome.

The purpose of this study was to examine the effects of two pasture feeding systems-perennial ryegrass (GRS) and perennial ryegrass and white clover (CLV)-and an indoor total mixed ration (TMR) system on the (a) rumen microbiome; (b) rumen fluid and milk metabolome; and (c) to assess the potential to distinguish milk from different feeding systems by their respective metabolomes. Rumen fluid was collected from nine rumen cannulated cows under the different feeding systems in early, mid and late lactation, and raw milk samples were collected from ten non-cannulated cows in mid-lactation from each of the feeding systems. The microbiota present in rumen liquid and solid portions were analysed using 16S rRNA gene sequencing, while ¹H-NMR untargeted metabolomic analysis was performed on rumen fluid and raw milk samples. The rumen microbiota composition was not found to be significantly altered by any feeding system in this study, likely as a result of a shortened adaptation period (two weeks' exposure time). In contrast, feeding system had a significant effect on both the rumen and milk metabolome. Increased concentrations of volatile fatty acids including acetic acid, an important source of energy for the cow, were detected in the rumen of TMR and CLV-fed cows. Pasture feeding resulted in significantly higher concentrations of isoacids in the rumen. The ruminal fluids of both CLV and GRS-fed cows were found to have increased concentrations of p-cresol, a product of microbiome metabolism. CLV feeding resulted in increased rumen concentrations of formate, a substrate compound for methanogenesis. The TMR feeding resulted in significantly higher rumen choline content, which contributes to animal health and milk production, and succinate, a product of carbohydrate metabolism. Milk and rumen-fluids were shown to have varying levels of dimethyl sulfone in each feeding system, which was found to be an important compound for distinguishing between the diets. CLV feeding resulted in increased concentrations of milk urea. Milk from pasture-based feeding systems was shown to have significantly higher concentrations of hippuric acid, a potential biomarker of pasture-derived milk. This study has demonstrated that ¹H-NMR metabolomics coupled with multivariate analysis is capable of distinguishing both rumen-fluid and milk derived from cows on different feeding systems, specifically between indoor TMR and pasture-based diets used in this study.

Effect of pasture versus indoor feeding systems on quality characteristics, nutritional composition, and sensory and volatile properties of full-fat Cheddar cheese.

The purpose of this study was to investigate the effects of pasture-based versus indoor total mixed ration (TMR) feeding systems on the chemical composition, quality characteristics, and sensory properties of full-fat Cheddar cheeses. Fifty-four multiparous and primiparous Friesian cows were divided into 3 groups (n = 18) for an entire lactation. Group 1 was housed indoors and fed a TMR diet of grass silage, maize silage, and concentrates; group 2 was maintained outdoors on perennial ryegrass only pasture (GRS); and group 3 was maintained outdoors on perennial ryegrass/white clover pasture (CLV). Full-fat Cheddar cheeses were manufactured in triplicate at pilot scale from each feeding system in September 2015 and were examined over a 270-d ripening period at 8°C. Pasture-derived feeding systems were shown to produce Cheddar cheeses yellower in color than that of TMR, which was positively correlated with increased cheese ß-carotene content. Feeding system had a significant effect on the fatty acid composition of the cheeses. The nutritional composition of Cheddar cheese was improved through pasture-based feeding systems, with significantly lower thrombogenicity index scores and a greater than 2-fold increase in the concentration of vaccenic acid and the bioactive conjugated linoleic acid C18:2 cis-9,trans-11, whereas TMR-derived cheeses had significantly higher palmitic acid content. Fatty acid profiling of cheeses coupled with multivariate analysis showed clear separation of Cheddar cheeses derived from pasture-based diets (GRS or CLV) from that of a TMR system. Such alterations in the fatty acid profile resulted in pasture-derived cheeses having reduced hardness scores at room temperature. Feeding system and ripening time had a significant effect on the volatile profile of the Cheddar cheeses. Pasture-derived Cheddar cheeses had significantly higher concentrations of the hydrocarbon toluene, whereas TMR-derived cheese had significantly higher concentration of 2,3-butanediol. Ripening period resulted in significant alterations to cheese volatile profiles, with increases in acid-, alcohol-, aldehyde-, ester-, and terpene-based volatile compounds. This study has demonstrated the benefits of pasture-derived feeding systems for production of Cheddar cheeses with enhanced nutritional and rheological quality compared with a TMR feeding system.

Quality characteristics, chemical composition, and sensory properties of butter from cows on pasture versus indoor feeding systems.

This study evaluated the effects of 3 widely practiced cow feeding systems in the United States, Europe, and Southern Hemisphere regions on the characteristics, quality, and consumer perception of sweet cream butter. Fifty-four multiparous and primiparous Friesian cows were divided into 3 groups (n=18) for an entire lactation. Group 1 was housed indoors and fed a total mixed ration diet (TMR) of grass silage, maize silage, and concentrates; group 2 was maintained outdoors on perennial ryegrass-only pasture (GRS); and group 3 was maintained outdoors on a perennial ryegrass/white clover pasture (CLV). Mid-lactation butter was manufactured in triplicate with milk from each group in June 2015 (137±7d in milk) and was analyzed over a 6-mo storage period at 5°C for textural and thermal properties, fatty acid composition, sensory properties, and volatile compounds. The nutritional value of butters was improved by pasture feeding, and butter from pasture-fed cows had significantly lower thrombogenicity index scores compared with butters from TMR-fed cows. In line with these results, pasture-derived milks (GRS and CLV) produced butter with significantly higher concentrations of conjugated linoleic acid (cis-9,trans-11) and trans-ß-carotene than TMR butter. Alterations in the fatty acid composition of butter contributed to significant differences in textural and thermal properties of the butters. Total mixed ration-derived butters had significantly higher hardness scores at room temperature than those of GRS and CLV. Onset of crystallization for TMR butters also occurred at significantly higher temperatures compared with pasture butters. Volatile analysis of butter by gas chromatography-mass spectrometry identified 25 compounds present in each of the butters, 5 of which differed significantly based on feeding system, including acetone, 2-butanone, 1-pentenol, toluene, and ß-pinene. Toluene was very significantly correlated with pasture-derived butter. Sensory analysis revealed significantly higher scores for GRS-derived butter in several attributes including "liking" of appearance, flavor, and color over those of TMR butter. Partial least square regression plots of fatty acid profiles showed clear separation of butter derived from grazed pasture-based perennial ryegrass or perennial rye/white clover diets from that of a TMR system, offering further insight into the ability of fatty acid profiling to verify such pasture-derived dairy products.

Effect of pasture versus indoor feeding systems on raw milk composition and quality over an entire lactation.

The aim of this study was to investigate the effects of different feeding systems on milk quality and composition. Fifty-four multiparous and primiparous Friesian lactating cows were divided into 3 groups (n=18) to study the effects of 3 feeding systems over a full lactation. Group 1 was housed indoors and offered a total mixed ration diet (TMR), group 2 was maintained outdoors on a perennial ryegrass pasture (referred to as grass), and group 3 was also grazed outdoors on a perennial ryegrass/white clover pasture (referred to as clover). Bulk milk samples were collected from each group at morning and afternoon milkings once weekly from March 11 to October 28 in 2015. Milk from pasture-fed cows (grass and clover) had significantly higher concentrations of fat, protein, true protein, and casein. The pasture feeding systems induced significantly higher concentrations of saturated fatty acids C11:0, C13:0, C15:0, C17:0, C23:0, and unsaturated fatty acids C18:2n-6 trans, C18:3n-3, C20:1, and C20:4n-6 and a greater than 2-fold increase in the conjugated linoleic acid C18:2 cis-9,trans-11 content of milk compared with that of the TMR feeding system. The TMR feeding system resulted in milks with increased concentrations of C16:0, C18:2n-6 cis, C18:3n-6 cis, C22:0 C22:1n-9, and C18:2 cis-10,trans-12. Principal component analysis of average fatty acid profiles showed clear separation of milks from the grazed pasture-based diets to that of a TMR system throughout lactation, offering further insight into the ability to verify pasture-derived milk by fatty acid profiling.

The anatomic pattern of biliary atresia identified at time of Kasai hepatoportoenterostomy and early postoperative clearance of jaundice are significant predictors of transplant-free survival.

OBJECTIVE: The goals of this study were to describe the clinical and anatomic features of infants undergoing Kasai portoenterostomy (KPE) for biliary atresia (BA) and to examine associations between these parameters and outcomes. METHODS: Infants enrolled in the prospective Childhood Liver Disease Research and Education Network, who underwent KPE were studied. Patients enrolled in a blinded, interventional trial were excluded from survival analysis. Primary endpoints were successful surgical drainage (total bilirubin less than 2 mg/dL within the first 3 months), transplant-free survival (Kaplan-Meier), and time to transplant/death (Cox regression). RESULTS: KPE was performed in 244 infants (54% female; mean age: 65 ± 29 days). Transplant-free survival was 53.7% and 46.7% at 1 and 2 years post-KPE. The risk of transplant/death was significantly lower in the 45.6% of patients who achieved successful bile drainage within 3 months post-KPE (HR: 0.08, P < 0.001). The risk of transplant/death was increased in patients with porta hepatis atresia (Ohi type II and III vs type I; HR: 2.03, P = 0.030), nonpatent common bile duct (Ohi subtype: b, c, and d vs a; HR: 4.31, P = 0.022), BA splenic malformation syndrome (HR: 1.92, P = 0.025), ascites > 20 mL (HR: = 1.90, P = 0.0230), nodular liver appearance compared to firm (HR: = 1.61, P = 0.008), and age at KPE ≥ 75 days (HR: 1.73, P < 0.002). Outcome was not associated with gestational age, gender, race, ethnicity, or extent of porta hepatis dissection. CONCLUSION: Anatomic pattern of BA, BASM, presence of ascites and nodular liver appearance at KPE, and early postoperative jaundice clearance are significant predictors of transplant-free survival.

Insemination factors affecting the conception rate in seasonal calving Holstein-Friesian cows.

Differences in conception rate to first service between artificial inseminations (AI) carried out by commercial AI operators (CAI) or do-it-yourself operators (DIY), between natural service (NAT) and AI, between different AI sires, and between fresh and frozen-thawed semen, on Irish commercial dairy farms, were studied using logistic regression. The study comprised 12,933 potential first inseminations from 77 spring-calving dairy herds. The data were recorded during 1999 and 2000. Amongst the total, 4,394 cows had repeated records across the two years. Adjustment variables included: herd, year, parity, calving period, calving to service interval, herd size, proportion of North American Holstein-Friesian genes, peak milk yield, semen fresh or frozen-thawed status, AI sire and a cow history variable to account for the correlation structure that may exist between performance records of cows present in both years of the study. Interactions of interest were tested but were non-significant. No significant association was observed between the category of AI operator and the likelihood of conception rate to first service (PREG1). The variation in PREG1 observed within the category of operator (CAI and DIY) was investigated using the Levene test for homogeneity of variance. There was no difference between the level of variation observed within CAI and DIY operators. There were significant differences in the likelihood of PREG1 between different AI sires. Amongst the 40 most commonly used AI sires, 3 sires had a lower likelihood of PREG1 (P < 0.05) when compared to the reference AI sire (sire with PREG1 similar to the mean of the group). There was a tendency for a reduced likelihood of PREG1 with the use of fresh semen compared to frozen-thawed semen (OR = 0.80, P = 0.067). Amongst the adjustment variables in the model, those significantly associated with the likelihood of PREG1 included the herd, calving period, calving to first service interval and peak milk yield. No significant difference in the likelihood of PREG1 was observed between AI and NAT.