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T-Stór is Teagasc’s Open Access Repository, maintained by the Teagasc Library Service. Stór is the Gaelic word for Repository or Store or Warehouse, and T-Stór is an online “store” of Teagasc Research outputs and related documents. T-Stór collects preserves and makes freely available scholarly communication, including peer-reviewed articles, working papers and conference papers created by Teagasc researchers. Where material has already been published it is made available subject to the open-access policies of the original publishers. About Teagasc
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Modelling the production, profit, and greenhouse gas emissions of Irish sheep flocks divergent in genetic meritCONTEXTSheep production industries face the challenge of increasing farm production and profit while reducing environmental impacts. OBJECTIVESGenetic selection using multi-trait breeding indices can be used to improve flock productivity, profitability, and greenhouse gas (GHG) emissions intensities (kg CO2-eq /kg of product), however validation of the improved performance of animals ranked higher on breeding indices at a flock level is required. METHODSPhenotypic data from 387,580 production records of animals born between 2018 and 2020 of known genetic merit in commercial flocks were inputted to an established bio-economic model. Two contrasting flocks were compared, a flock of ewes ranked High (top 20%) on the Irish replacement Index bred with rams ranked High on the replacement and terminal indices, and a flock of ewes ranked Low (bottom 20%) on the Irish replacement Index bred with rams ranked Low on the replacement and terminal indices. The two flocks were then simulated using life cycle assessment to estimate the GHG emissions profile for both systems. RESULTS AND CONCLUSIONFlock weaning rates were 1.70 and 1.53 lambs weaned per ewe presented for breeding for the High and Low genetic merit flocks, respectively. The flock of High genetic merit ewes sold 0.17 more lambs per ewe, equating to 3.29 kg more lamb carcass per ewe, than the flock of Low genetic merit ewes; lambs from the High genetic merit flock were also sold at an earlier age. The greater production of the High genetic merit flocks resulted in an additional €18/ewe net profit than the Low genetic merit flock. Although total flock GHG emissions were higher for the High genetic merit flock, GHG emissions intensities were lower at 21.7 and 23.3 kg CO2-eq /kg lamb carcass sold for the High and Low genetic merit flocks, respectively. The lower emissions intensity of the High genetic merit flock was due to the dilution effect of higher lamb production and lambs being drafted for slaughter ealier. SIGNIFICANCEThe results suggest Irish sheep producers can make substantial profit gains through selection according to the national breeding indices while also reducing their environmental impact, and farmers should consider genetic merit when purchasing their rams, particularly sires of replacement ewe lambs.
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High-Pressure Processing on Whole and Peeled Potatoes: Influence on Polyphenol Oxidase, Antioxidants, and Glycaemic IndicesPolyphenol oxidase (PPO) inactivation in five whole and peeled Irish potato cultivars was investigated using high-pressure processing (HPP) at 400 MPa and 600 MPa for 3 min. PPO activity was significantly lower in most of the HPP-treated samples, while the highest PPO inactivation was observed after HPP at 600 MPa. No significant (p > 0.05) changes were observed on the total phenolic content and antioxidant activity of all the HPP-treated potatoes. Regarding individual phenolic acids, chlorogenic acid was decreased significantly (p < 0.05) in all studied varieties with a concomitant increase (p < 0.05) in caffeic and quinic acid. Similarly, ferulic acid was also increased (p < 0.05) in all studied varieties after the HPP treatment, while there was a variation in rutin and 4-coumaric acid levels depending on the cultivar and the sample type. Anthocyanins in the coloured whole potato varieties (i.e., Kerr’s Pink and Rooster), tentatively identified as pelargonidin-O-ferulorylrutinoside-O-hexoside and pelargonidin-O-rutinoside-O-hexoside, also exhibited significantly (p < 0.05) higher levels in the HPP-treated samples as opposed to those untreated. Glycaemic indices of the potatoes treated with HPP did not differ with the corresponding untreated cultivars.
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Migration of Cefquinome Antibiotic Residues from Milk to Dairy ProductsThe aim of this study was to investigate the distribution of cefquinome in different dairy products during the processing of naturally contaminated milk or spiked milk. The analysis of cefquinome residues in milk, skimmed milk, buttermilk, whey, cream, butter, curd, and cheese samples was performed using a water:acetonitrile solvent extraction and C18 dispersive solid-phase extraction (d-SPE) clean-up, followed by ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC–MS/MS) determination. The target concentration of cefquinome was achieved in the spiked milk (100 µg kg−1). During its processing, the antibiotic migrated primarily with the skimmed milk as opposed to cream (ratios of 3.6:1 and 2.8:1 for experiments A and B, respectively), and with the buttermilk during butter manufacture (ratios of 6.9:1 and 4.6:1), but was equal in the curd and whey during the manufacture of cheese. In the milk collected from treated animals, the measured concentration of cefquinome was considerably high (approx. 5000 µg kg−1). The results obtained from the dairy products were similar to those obtained in the spiked study (ratios of 8.2:1 and 3.1:1 for experiments A and B, respectively, during the separation of skimmed milk and cream; 6.0:1 and 5.0:1 for A and B, respectively, during the separation of buttermilk and butter). However, during cheesemaking, cefquinome migrated with the whey after cutting the curd, with ratios of 0.54:1 and 0.44:1 for experiments A and B, respectively. The difference in the migration of cefquinome between curd and whey in spiked and animal studies is probably due to the different concentration levels in the two different experiments. The results of this study showed that, in dairy products manufactured from milk containing cefquinome residues, the drug migrated primarily with the high-water-containing fractions.
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Rehydration Properties of Whey Protein Isolate Powders Containing Nanoparticulated ProteinsThe rehydration properties of original whey protein isolate (WPIC) powder and spray-dried WPI prepared from either unheated (WPIUH) or nanoparticulated WPI solutions were investigated. Nanoparticulation of whey proteins was achieved by subjecting reconstituted WPIC solutions (10% protein, w/w, pH 7.0) to heat treatment at 90 °C for 30 s with no added calcium (WPIH) or with 2.5 mM added calcium (WPIHCa). Powder surface nanostructure and elemental composition were investigated using atomic force microscopy and X-ray photoelectron spectroscopy, followed by dynamic visualisation of wetting and dissolution characteristics using environmental scanning electron microscopy. The surface of powder particles for both WPIUH and WPIC samples generally appeared smooth, while WPIH and WPIHCa displayed micro-wrinkles with more significant deposition of nitrogen and calcium elements. WPIH and WPIHCa exhibited lower wettability and solubility performance than WPIUH and WPIC during microscopic observation. This study demonstrated that heat-induced aggregation of whey proteins, in the presence or absence of added calcium, before drying increases aggregate size, alters the powder surface properties, consequently impairing their wetting characteristics. This study also developed a fundamental understanding of WPI powder obtained from nanoparticulated whey proteins, which could be applied for the development of functional whey-based ingredients in food formulations, such as nanospacers to modulate protein–protein interactions in dairy concentrates.
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Changes to the Oligosaccharide Profile of Bovine Milk at the Onset of LactationNumerous bioactive components exist in human milk including free oligosaccharides, which represent some of the most important, and provide numerous health benefits to the neonate. Considering the demonstrated value of these compounds, much interest lies in characterising structurally similar oligosaccharides in the dairy industry. In this study, the impacts of days post-parturition and parity of the cows on the oligosaccharide and lactose profiles of their milk were evaluated. Colostrum and milk samples were obtained from 18 cows 1–5 days after parturition. Three distinct phases were identified using multivariate analysis: colostrum (day 0), transitional milk (days 1–2) and mature milk (days 3–5). LS-tetrasaccharide c, lacto-N-neotetraose, disialyllacto-N-tetraose, 3’-sial-N-acetyllactosamine, 3’-sialyllactose, lacto-N-neohexaose and disialyllactose were found to be highly affiliated with colostrum. Notably, levels of lactose were at their lowest concentration in the colostrum and substantially increased 1-day post-parturition. The cow’s parity was also shown to have a significant effect on the oligosaccharide profile, with first lactation cows containing more disialyllacto-N-tetraose, 6’-sialyllactose and LS-tetrasaccharide compared to cows in their second or third parity. Overall, this study identifies key changes in oligosaccharide and lactose content that clearly distinguish colostrum from transitional and mature milk and may facilitate the collection of specific streams with divergent biological functions.
