The dairy industry contributes significantly to anthropogenic methane emissions, which have an impact on global warming. This study aimed to investigate the effects of a dietary inclusion of brown ...seaweed Ascophyllum nodosum on enteric methane emissions (EMEs), hematological and blood biochemical profiles, and milk composition in dairy cows. Eighteen Holstein cows were divided into three groups: CON (non-supplemented cows), BS50 (50 mL of 10% A. nodosum), and BS100 (100 mL of 10% A. nodosum). In each cow, measurements of EME, dry matter intake (DMI), and milk yield (MY), as well as blood and milk sampling with respective analyzes, were performed before supplementation (P1), after 15 (P2) days, and after 30 (P3) days of supplementation. A. nodosum reduced (p < 0.05) methane production, methane yield, and methane intensity in both BS50 and BS100, and raised DMI (p < 0.05) only in BS50. Total bilirubin (p < 0.05) was higher in BS50 compared to CON cows in P2, and triacylglycerols were lower (p < 0.05) in BS50 than in CON cows in P3. Higher milk fat content was found in BS50 than in CON cows in P3. C16:0 proportions were higher (p < 0.05) in BS50 and BS100 than in CON cows, while C18:3n-3 was higher (p < 0.05) in BS100 than in BS50 and CON cows in P3. Dietary treatment with A. nodosum reduced EMEs and showed the potential to increase DMI and to improve energy status as well as milk composition in peak-lactating dairy cows.
The study aimed to determine the concentration of energy-related hormones in cow’s milk and to consider them from a public health perspective. Fourteen Holstein cows were subjected to milk and blood ...sampling on the following days in lactation (DIL): 10, 30, 60, 90, 150, 180, 210, 250 and 280 to determine milk hormones, fat and protein content and blood biochemical parameters. For the same purpose, bulk-tank milk was sampled and samples of retail m ilk with 1.5% (CM
) and 3.2% (CM
) fat was purchased. Milk insulin-like growth factor-1 (IGF-1) values were significantly lower at 90, 150, 180, 210 and 250 and significantly higher at 10, 30 and 60 DIL than lactation average (LA). Milk insulin concentrations were significantly lower at 30, 60 and 90 and higher at 210, 250 and 280 DIL than LA. Free thyroxine (fT
) level in the milk was higher at 250 DIL, while milk free triiodothyronine (fT
) concentrations were lower at 30, 60, 90 and 280 DIL, and significantly higher at 10 and 180 DIL than respective LA. Milk cortisol levels were lower at 60 and 280 DIL than LA. All measured milk hormones were significantly lower in CM
compared to CM
, bulk-tank milk and LA. An exception was the LA of IGF-1, which was significantly lower than the IGF-1 content in CM
. Blood biochemical parameters fluctuated evenly during lactation and were within the reference range. Hormone concentrations in cow’s milk fluctuate during lactation, giving milk an important role in the context of public health.
Ruminant husbandry contributes to global methane (CH
) emissions and beside its negative impact on the environment, enteric CH
emissions cause a loss of gross energy intake in cows. The study is ...aimed to estimate CH
emission and metabolic status in dairy cows via the methane concentration profile as a tool for analyzing the CH4 production pattern. The study included eighteen cows whose enteric CH
emission was measured during three consecutive days in three periods: 2 hours before (P1), 2–4 hours (P2) and 6–8 hours (P3) after the morning feeding. Based on CH
enteric emissions, cows were divided into two groups (n=6, respectively): HM (average CH
concentration: 5430.08 ± 365.92 ppm) and LM (average CH
concentration: 1351.85 ± 205.20 ppm). Following CH
measurement, on day 3, venous blood was sampled to determine the indicators of the metabolic status. HM cows had significantly higher average CH
concentrations, maximum and average CH4 peak amplitude than LM cows in all measuring periods (P1-P3), while the number of CH
peaks tended to be higher in HM than in LM cows in P2. There were no differences in the maximum and average CH
peak width and average distance among two CH4 peaks between examined groups of cows. HM cows had significantly higher total protein concentrations and significantly lower total bilirubin and NEFA concentrations than LM cows. In conclusion, HM cows have a greater number of eructations and release more CH
per eructation than LM cows, hence the differences in metabolic status are most likely related to the differences in their liver function.
Cows in the peripartal period undergo changes in thyroid hormones and are susceptible to lipomobilization and/or oxidative stress. The addition of chestnut tannins as polyphenolic compounds in the ...diet may improve feed efficiency and prevent oxidative stress-related health disorders in transition cows. However, the relationship between chestnut tannin supplementation and thyroid function, which plays an important role in metabolic regulation, has not been investigated in dairy cows. This study was conducted to investigate the effects of chestnut tannin supplementation during the close-up period on thyroid status and to evaluate the interaction between thyroid hormones and oxidative stress biomarkers in prepartum dairy cows. Forty multiparous Holstein cows were fed either a diet containing chestnut tannins (CNTs,
= 20, 1.96 g chestnut tannins/kg feed, dry matter) or a non-supplemented diet (CON,
= 20) during the last 25 ± 2 days of gestation. Blood samples were collected on the first day of study (before chestnut tannin supplementation) and d 5 before parturition to measure hormonal and oxidative stress indices. Serum concentrations of T3 (
= 0.04) and T4 (
= 0.05) were higher in CNT cows than in the CON group on day 5 before parturition. Thyroid status of CNT cows was associated with higher serum total antioxidant capacity (T-AOC,
< 0.01), activities of superoxide dismutase (SOD,
= 0.03) and glutathione peroxidase (GPx,
= 0.01), and reduced glutathione concentration (GSH,
= 0.05). Serum thiobarbituric acid reactive substances (TBARS) were lower (
= 0.04) which was associated with lower aspartate aminotransferase (AST,
= 0.02), and lactate dehydrogenase (LDH,
= 0.01) activities in the CNT than in the CON group. Estradiol and progesterone did not differ between CNT and CON cows. Chestnut tannin supplementation improves antioxidant protection, prevents oxidation-reduction processes, reduces the degree of liver cell membrane damage, and protects thyroid tissue from damage, allowing higher T3 and T4 synthesis. Considering the importance of the thyroid hormone status before parturition, mechanisms of thyroid hormone regulation in CNT-supplemented dairy cows require more detailed investigations.
The objective was to determine optimal thresholds of blood variables that are associated with liver lipid and glycogen content in dairy cows. Liver specimens of 15 Holstein dairy cows were taken 2 ...weeks postpartum (PP) and used for determination of lipid and glycogen content, respectively. Blood samples were collected weekly, starting from week 2 antepartum (AP) up to week 2 PP. Selected blood parameters and body condition scoring (BCS) were evaluated through receiver operating characteristic curve analysis as indication of fat and glycogen content in the liver. Postpartal low liver glycogen content (mode < 2.0, semiquantitative analysis of glycogen content in the liver tissue samples) can be indicated if values are higher than 0.16 mmol/L, and 3.5 mmol/L for NEFA, and glucose, respectively, and lower than 0.65 mmol/L and 17.94 μU/mL for BHBA and insulin, respectively, 2 weeks AP. Postaprtal high liver fat content (>20%, stereological quantification of fat content in the liver tissue samples) can be indicated if values are higher than 3.5 for BCS at week 2 AP. Optimal time for indicating both low liver glycogen/high fat content is 1 week PP, with LDL < cut off point set at 0.18 mmol/L and BHBA > cut off point set at 0.88 mmol/L. Established cut off values in this study can be used for indication of fat and glycogen content in the liver of dairy cows.
Highlights
More variables are reliable for indication of liver glycogen content than for indication of liver fat content.
Postpartum concentrations of LDL and BHBA can be used for indicating both high lipid liver content and low liver glycogen content.
Insulin resistance is a phenomenon which accompanies the ongoing metabolic adaptation in cows during early lactation. The aim of our study was to determine the linear correlations of HOMA ...(Homeostatic Model Assessment), QUICKI (Quantitative Insulin Sensitivity Check Index) and RQUICKI (Revised Quantitative Insulin Sensitivity Check Index) indexes of insulin resistance with the metabolic status of cows (concentration of hormones, metabolites and body condition score). The experiment included 40 Holstein-Frisian cows in the first week after calving. Indexes of insulin resistance valued: 18.68±5.43 (HOMA), 0.39±0.06 (QUICKI) and 0.45±0.06 (RQUICKI). Linear correlations were examined by testing the coefficient of correlation (r), determination (r
,%) and regression parameter beta (b) in linear equation. A negative correlation was found between HOMA and IGF-I (insulin growth factor I) (r=−0.51, r
=25.0, b=−1.1257, p<0.01). HOMA showed a positive correlation with BHB (betahidroxybutyrate) (r=0.48, r
=23.2, b=0.0234, p<0.01). A positive correlation was found between QUICKI and IGF-I (r=0.30, r
=10.0 b=46.7900, p<0.05) and cholesterol (r=0.44, r
=18.3, b=1.9021, p<0.01). In contrast, QUICKI and BHB (r=0.51, r
=27.1, b=−1.7241, p<0.01), just like QUICKI and BCS (r=0.46, r
=20.9, b=−2.424, p<0.01), showed a negative correlation. RQUICKI showed positive correlations with IGF-I (r=0.48, r
=22.8, b=28.1230, p<0.01), T4 (r=0.47, r
=22.1, b=87.142, p<0.01) and triglycerides (r=0.36, r
=13, b=0.0407, p<0.05) but negative correlations with cortisol (r=−0.36, r
=13.0, b=−9.0332, p<0.05), STH (somatotropic hormone) (r=−0.42, r
=17.3, b=−5.4976, p<0.01), BHB (r=−0.62, r
=38.3, b=−1.1872, p<0.01), total bilirubin (r=−0.58, r
=33.7, b=−7.131, p<0.01) and BCS (body condition score) (r=−0.6, r
=36.4, b=−1.8347, p<0.01). In conclusion, indexes of insulin resistance may be used to evaluate the metabolic status of cows in early lactation. RQUICKI might be the most appropriate predictor of metabolic status due to its linear relationship with most of the parameters included in homeorhetic process.
This study aimed to evaluate glucose-induced insulin response in cows exposed to different temperature-humidity index. Twenty early lactating Holstein-Friesian cows were divided into 2 equal groups ...based on season, as summer (SU) and spring (SP). SP cows were not exposed to heat stress, while SU cows were exposed to moderate or severe heat stress. Milk production was recorded daily. Starting from day 30 of lactation, intravenous glucose tolerance test (IVGTT) was carried out three times at 30-day intervals. Blood samples were taken before (basal) and after glucose infusion, and glucose and insulin were measured at each sample point. The homeostatic model assessment (HOMA) index was calculated. Milk yield from days 30 to 40 and 64 to 90 of lactation were higher in SP cows than in SU cows. Basal glucose did not differ on days 30 and 60 of lactation, while basal insulin and HOMA were lower in SU compared to SP cows. On day 90 of lactation, SU cows had higher basal glucose, whereas basal insulin and HOMA did not differ. IVGTT results revealed that glucose tolerance was affected by heat stress such that SU cows had higher glucose clearance. Insulin responses to IVGTT did not differ on days 30 and 60 of lactation. Heat stress had a marked effect on insulin secretion on day 90 of lactation, illustrated by higher increments, peak concentrations and area under the curve for insulin in SU cows. Overall, season differences in glucose tolerance depend not only on heat stress and milk production but also on the stage of lactation.
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