Field trial on glucose-induced insulin and metabolite responses in Estonian Holstein and Estonian Red dairy cows in two herds

<p>Abstract</p> <p>Background</p> <p>Insulin secretion and tissue sensitivity to insulin is considered to be one of the factors controlling lipid metabolism <it>post partum</it>. The objective of this study was to compare glucose-induced blood insulin and metabolite responses in Estonian Holstein (EH, n = 14) and Estonian Red (ER, n = 14) cows.</p> <p>Methods</p> <p>The study was carried out using the glucose tolerance test (GTT) performed at 31 ± 1.9 days <it>post partum</it> during negative energy balance. Blood samples were obtained at -15, -5, 5, 10, 20, 30, 40, 50 and 60 min relative to infusion of 0.15 g/kg BW glucose and analysed for glucose, insulin, triglycerides (TG), non-esterified fatty acids (NEFA), cholesterol and β-hydroxybutyrate (BHB). Applying the MIXED Procedure with the SAS System the basal concentration of cholesterol, and basal concentration and concentrations at post-infusion time points for other metabolites, area under the curve (AUC) for glucose and insulin, clearance rate (CR) for glucose, and maximum increase from basal concentration for glucose and insulin were compared between breeds.</p> <p>Results</p> <p>There was a breed effect on blood NEFA (<it>P </it>< 0.05) and a time effect on all metabolites concentration (<it>P </it>< 0.01). The following differences were observed in EH compared to ER: lower blood insulin concentration 5 min after glucose infusion (<it>P </it>< 0.05), higher glucose concentration 20 (<it>P </it>< 0.01) and 30 min (<it>P </it>< 0.05) after infusion, and higher NEFA concentration before (<it>P </it>< 0.01) and 5 min after infusion (P < 0.05). Blood TG concentration in ER remained stable, while in EH there was a decrease from the basal level to the 40^thmin nadir (<it>P </it>< 0.01), followed by an increase to the 60^thmin postinfusion (<it>P </it>< 0.01).</p> <p>Conclusion</p> <p>Our results imply that glucose-induced changes in insulin concentration and metabolite responses to insulin differ between EH and ER dairy cows.</p

Voxel anthropomorphic phantoms: Review of models used for ionising radiation dosimetry

Computational anthropomorphic phantoms have k e n used since the 1970s for dosimetric calculations. Realistic geometries are required for this operation, resulting in the development of ever more accurate phantoms. Voxel phantoms, comisting of a set of smail-volume elements, appeared towards the end of the 1980s, and significantly improved on the original mathematical models. Voxel phantoms are models of the human body, obtained using compnted tomography (CT) or magnetic resonance images (MRI). These phantoms are an extremely accurate representation of the human anatomy. This article provides a review of the literatnre available on the development of these phantoms and their applications in ionising radiation dosimetry. The bibliographical stndy has shown that there is a wide range of phantoms, covering various characteristics of the general population in terms of sex, age or morphology, and that they are used in applications relating ta al1 aspects of ionising radiation. © 2004 EDP Sciences

Methionine balanced diet improves performances and biosynthetic traffic in mammary epithelial cell

International audienceMethionine (Met) or energy supplementation increase milk protein and fat yields in cow. Here we investigated whether this could be explained by increasing flow of milk components in the secretory pathways of mammary epithelial cells. Multiparous Alpine goats (mid lactation, n=47), grouped by levels of expression of CSN1S1, were assigned to 4 treatments in a randomised complete block design. Treatments were: LE (Low Energy), LEMet (LE, balanced Met), AE (Adequate Energy) and AEMet (AE, balanced Met) for 5 weeks. Diets consisted in a fixed amount of hay per group with individual amount of energy concentrates (LE vs AE: 1.47 vs 1.54 Mcal/kg DM). Isopropyl ester of 2-hydroxy-4-methylthio butanoic acid (HMBi 0.24% concentrate DM) was incorporated in the LEMet and AEMet concentrates based on 100% cow Met requirement. Goats (n=23) were slaughtered and mammary tissue was processed for Western blotting using secretory compartment specific markers. In goats fed Met balanced diets, milk protein yield and casein content significantly increased (P=0.01), as was previously observed in cow. The amount of the endoplasmic reticulum (ER) markers Calnexin and ERLIN2 decreased (20%, P≤0.05) in goats fed the LE diet. Met balanced diets had the opposite effect on both markers (20%, P≤0.05) and on protein disulphide isomerase (45%, P≤0.05). These observations are in agreement with a positive effect of Met on the activity of the ER, the site where milk specific proteins and lipids are synthesised. On the other hand, a specific marker of the exit site of the Golgi apparatus and secretory vesicles formation (AP1) decreased with the LE diet (25%, P≤0.05) and its highest level was found in goats fed Met balanced diet at AE supply. Concerning ßCOP, a marker of intra Golgi transport, its variation clearly evoked a decrease in membrane transport at LE diets. These data show that energy level has a direct impact on membrane traffic in the secretory pathway of mammary epithelial cell while suggesting that Met improves ER activity and has the tendency to further promote intracellular transport of milk components and, ultimately, their secretion

Methionine balanced diet improves performances and biosynthetic traffic in mammary epithelial cell

International audienceMethionine (Met) or energy supplementation increase milk protein and fat yields in cow. Here we investigated whether this could be explained by increasing flow of milk components in the secretory pathways of mammary epithelial cells. Multiparous Alpine goats (mid lactation, n=47), grouped by levels of expression of CSN1S1, were assigned to 4 treatments in a randomised complete block design. Treatments were: LE (Low Energy), LEMet (LE, balanced Met), AE (Adequate Energy) and AEMet (AE, balanced Met) for 5 weeks. Diets consisted in a fixed amount of hay per group with individual amount of energy concentrates (LE vs AE: 1.47 vs 1.54 Mcal/kg DM). Isopropyl ester of 2-hydroxy-4-methylthio butanoic acid (HMBi 0.24% concentrate DM) was incorporated in the LEMet and AEMet concentrates based on 100% cow Met requirement. Goats (n=23) were slaughtered and mammary tissue was processed for Western blotting using secretory compartment specific markers. In goats fed Met balanced diets, milk protein yield and casein content significantly increased (P=0.01), as was previously observed in cow. The amount of the endoplasmic reticulum (ER) markers Calnexin and ERLIN2 decreased (20%, P≤0.05) in goats fed the LE diet. Met balanced diets had the opposite effect on both markers (20%, P≤0.05) and on protein disulphide isomerase (45%, P≤0.05). These observations are in agreement with a positive effect of Met on the activity of the ER, the site where milk specific proteins and lipids are synthesised. On the other hand, a specific marker of the exit site of the Golgi apparatus and secretory vesicles formation (AP1) decreased with the LE diet (25%, P≤0.05) and its highest level was found in goats fed Met balanced diet at AE supply. Concerning ßCOP, a marker of intra Golgi transport, its variation clearly evoked a decrease in membrane transport at LE diets. These data show that energy level has a direct impact on membrane traffic in the secretory pathway of mammary epithelial cell while suggesting that Met improves ER activity and has the tendency to further promote intracellular transport of milk components and, ultimately, their secretion

Nitrogen efficiency and amino acid requirements in dairy cattle

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Decreased lactose percentage in milk associated with quarter health disorder and hyperketolactia, a proxy for negative energy balance, in dairy cows

ABSTRACT: Several studies have described variations in lactose content (LC) in dairy cows during udder quarter health disorder or negative energy balance (NEB). However, their joint effects on LC have never been described. This was the aim of a longitudinal observational study performed on 5 Quebec dairy farms using automatic milking systems. Quarter milk samples were collected every 14 d from 5 to 300 DIM. Quarter health status was described by combining SCC level (SCC− or SCC+: 0.19 mM = BHB++. A total of 14,505 quarter cisternal milk samples were collected from 380 lactating cows. The quarter LC was analyzed using a mixed linear regression model with the following fixed effects: quarter health status, parity, time interval between last milking and sampling, quarter milk yield (in kg/d), DIM, and herd. A random quarter intercept with a repeated measures correlation structure and a cow random intercept were also specified. The LC of SCC+ quarters was lower (−0.17 ± 0.013 percentage points) compared with LC of SCC- quarters for both primiparous and multiparous cows. Of the 162 bacterial species identified, only 8 species had a prevalence greater than 4.0%, and just 5 of them were associated with a reduction in LC: Staphylococcus aureus, Staphylococcus chromogenes, Streptococcus dysgalactiae, Staphylococcus epidermidis, and Staphylococcus simulans. Cows identified as BHB+ and BHB++ in early lactation had a lower LC (−0.05 ± 0.019 and −0.13 ± 0.020 percentage points, respectively) compared with BHB− cows. For BHB++ cows, in both parity groups the decrease in LC (−0.20 ± 0.025 percentage points) was higher in SCC+ quarters compared with SCC− quarters. Moreover, the additive effect of the quarter health status and NEB on milk LC was greater with larger increases in BHB. Our findings highlight the necessity to jointly take into consideration both quarter health status and milk BHB concentration when using LC as a biomarker for NEB

Immediate and residual effects on milk yield and composition of decreasing levels of udder emptying during milking in dairy cows

International audienceThe quantity of milk accumulated in the udder, under extended milking intervals, could reduce milk yield, with residual effects on following milking intervals. Aim of the trial was to modify the quantity of milk stored in the udder over one milking interval, by decreasing udder emptying (100, 70, 40, and 0% ), in order to describe the short-term effects on milk yield and composition. 16 dairy cows averaging 41 kg/d of milk were assigned to treatments 100, 70, 40, and 0% according to a Latin square design with four 7 -d periods. Cows were milked twice daily at 0700 and 1730. Treatments were applied at the morning milking called MO. Changes in milk yield and composition were assessed on the 7 following milking (Ml to M7), using the mixed procedure of SAS with milking as repeated measures. The quantity of milk collected at Ml milking linearly increased as udder emptying decreased at MO. Nevertheless, because of milk accumulation in the udder, MO+Ml milk yield was quadratically depressed by -1.5, -5.3, -12.9 kg with 70,40 and 0% treatments, respectively. Residual effects on milk yield were only observed for 40 and 0% treatments on M2 and M3 milking and did not differ between 40 and 0% treatments. Milk fat content increased only for treatment 0% at Ml and for treatments 40 and 00/o at M2. Milk lactose content was lower for treatments 40 and 0% at Ml and only for treatment 0% till M4. Lower milk: protein contents were observed from M2 till M5 milking for either treatment 40 or 0% or both. Till M5 milking, somatic cell score linearly increased as udder emptying decreased at MO. In conclusion, a 70%-emptying milking at one milking did not alter milk yield and composition in dairy cows. Residual effects on milk yield and composition were only observed for higher amounts of milk: accumulated in the udder