Supplementing selenium yeast to diets with adequate concentrations of selenium: Selenium status, thyroid hormone concentrations and passive transfer of immunoglobulins in dairy cows and calves

2009 ◽  
Vol 89 (1) ◽  
pp. 111-122 ◽  
Author(s):  
K M Koenig ◽  
K A Beauchemin
Keyword(s):  
Thyroid Hormone ◽  
Dairy Cows ◽  
Whole Blood ◽  
Dry Matter ◽  
Basal Diet ◽  
Passive Transfer ◽  
Selenium Yeast ◽  
Maternal Supplementation ◽  
Selenized Yeast ◽  
Se Status

The objective of this study was to investigate whether supplementing organic Se yeast to diets with relatively high basal concentrations of Se was more effective than inorganic Se for improving Se status of dairy cows and their calves. Forty Holstein cows (primiparous and multiparous) were fed total mixed rations (TMR) supplemented with 0.3 mg kg-1 of Se (dry matter basis) as either selenized yeast (Se yeast) or sodium selenite from 60 d before the expected calving date until 60 d in milk (DIM). Cows were fed diets containing 0.38 to 0.40 mg Se kg-1 with no supplemental Se for 90 d before receiving the dietary Se treatments. The Se concentration of the TMR supplemented with Se ranged from 0.62 to 0.81 mg kg-1. Blood was collected from cows at 60 and 30 d before the expected calving date, at calving, and at 15, 30 and 60 DIM, and from their calves at 24 h and 56 d of age. Milk was collected at calving (colostrum) and at 15, 30 and 60 DIM. At birth, calves were removed from the dam and fed colostrum in an amount equivalent to 10% of their body weight within 12 h. Whole blood Se concentration averaged 11% greater (P < 0.05) in cows fed Se yeast compared with selenite (291 vs. 262 ± 4.5 ng mL-1) and serum Se concentration averaged 13% greater in cows fed Se yeast (128 vs. 113 ± 5.3 ng mL-1). Maternal supplementation of Se yeast increased (P < 0.05) the Se status of calves by increasing whole blood (252 vs. 211 ± 16 ng mL-1), serum (94 vs. 75 ± 4.7 ng mL-1), and colostrum (245 vs. 174 ± 5.8 ng mL-1) Se concentration by 19, 25 and 41%, respectively. There was, however, no beneficial effect (P > 0.10) of Se source on thyroid hormone concentrations or the passive transfer of immunoglobulins to the calf. Supplemental organic Se yeast increased the Se status of dairy cows and the transfer of Se to their calves even though the Se concentration of the basal diet was adequate (? 0.3 mg kg-1). Key words: Selenized yeast, selenium, thyroid hormone, immunoglobulin, dairy cows

scholarly journals Effects of Dietary Alkyl Polyglycoside Supplementation on Lactation Performance, Blood Parameters and Nutrient Digestibility in Dairy Cows

Animals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 549
Author(s):  
Xiaoli Zhang ◽  
Chunyu Jiang ◽  
Qinghua Gao ◽  
Duanqin Wu ◽  
Shaoxun Tang ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Milk Fat ◽  
Dry Matter ◽  
Basal Diet ◽  
Nutrient Digestibility ◽  
Blood Metabolites ◽  
Ionic Surfactant ◽  
Lactation Performance ◽  
Positive Effects ◽  
Alkyl Polyglycoside

This study evaluated the effects of alkyl polyglycoside (APG), which is a non-ionic surfactant, on lactation performance, nutrient digestibility and blood metabolites in dairy cows. Twenty dairy cows were randomly divided into four groups and fed a basal diet that included pelleted concentrate, distillers grains, and fresh limpograss. The four treatments included 0, 5.5, 11 and 22 mL APG per kg of pelleted concentrate on a dry matter basis; treatments were defined as APG0, APG5.5, APG11, and APG22, respectively. Dry matter intake was not affected by APG supplementation. There was an increase in milk yield (from 13.96 to 16.71 kg/day) and increases in milk fat (quadratic, p = 0.04), protein (quadratic, p = 0.10), and lactose concentrations (linear, p = 0.07) with increasing APG supplementation. In addition, APG supplementation increased (p ≤ 0.03) the milk fat, protein, solid non-fat, and total solid yields, while the lactose yield increased (linear, p = 0.01) as the APG level increased. Dietary APG supplementation had no effect on nutrient digestibility and blood metabolites. It was concluded that the addition of APG at doses up to 22 mL/kg of pelleted concentrate had positive effects on the milk composition in dairy cows.

scholarly journals Impact of long-term supplementation of zinc and selenium on their content in blood and hair in goats

2011 ◽  
Vol 56 (No. 2) ◽  
pp. 63-74 ◽  
Author(s):  
L. Pavlata ◽  
M. Chomat ◽  
A. Pechova ◽  
L. Misurova ◽  
R. Dvorak
Keyword(s):  
Blood Plasma ◽  
Whole Blood ◽  
Average Concentration ◽  
The Other ◽  
Control Group ◽  
Selenium Yeast ◽  
Hair Samples ◽  
The Impact ◽  
Se Status

This paper evaluates the impact of long-term supplementation of different forms of zinc (Zn) and selenium (Se) on the content of these substances in the blood and hair of goats. Two analogous supplementation experiments were performed. 37 goats divided into four groups were used in the first trial with the Zn supplementation. Group A (n = 10) was a control group (with no Zn administered). A further three groups (B, C, D) were supplemented with Zn in various forms. Group B (n = 9) with zinc oxide, Group C (n = 9) with zinc lactate and Group D (n = 9) with zinc chelate. The second trial with Se supplementation was carried out on 20 goats divided into four groups. Group E (n = 5) was a control group. The other three groups were administered Se. Group F (n = 5) was supplied with a selenium lactate-protein complex, Group G (n = 5) with sodium selenite and Group H (n = 5) with selenium yeast. Three months later blood and hair samples were taken from all animals and Zn and Se concentrations were determined in whole blood, plasma, and hair. Glutathione peroxidase (GSH-Px) activity was determined in the Se supplementation trial group. At the end of the trial the Zn concentrations in plasma and whole blood were without major differences between the groups. The plasma concentration of Zn did not increase from the initial value at the start of the trial. In hair the average concentration of Zn was 95.2&ndash;100.0 mg/kg<br />in all groups. No conclusive relation was confirmed between the values of Zn in hair and its concentration in blood. The Se concentration in whole blood (&micro;g/l) at the end of trial in supplemented groups (F &ndash; 188.8 &plusmn; 24.6; G &ndash; 197.2 &plusmn; 10.9; H &ndash; 190.1 &plusmn; 26.3) was significantly higher (P &lt; 0.01) than in the control group (E &ndash; 103.1 &plusmn; 23.5). Similarly, the activity of GSH-Px (&micro;kat/l) was significantly higher in all supplemented groups (F &ndash; 872.3 &plusmn; 94.8; G &ndash; 659.5 &plusmn; 176.4; H &ndash; 839.8 &plusmn; 150.8) than in the control group (E &ndash; 379.1 &plusmn; 63.5). Se content in hair (&micro;g/kg) was higher also in all trial groups (F &ndash; 242.3 &plusmn; 41.5; G &ndash; 200.5 &plusmn; 46.9; H &ndash; 270.0 &plusmn; 106.8) than in the control group (E &ndash; 174.7 &plusmn; 38.0). However, it was significantly (P &lt; 0.05) higher only in Group F. A conclusive correlation was identified between the Se concentration in whole blood and its content in hair (r = 0.54; P &lt; 0.05; n = 20). Based on the results it can be concluded that none of the supplemented forms of Zn increased its concentration in blood, plasma and hair. On the other hand, the administration of Se led to an increase in the Se concentration in blood, increased the activity of GSH-Px in whole blood and the Se content in hair. Based on the proven correlation and regression relation between the Se concentration in blood and its content in hair, hair can be considered as a suitable material for the diagnosis of long-term Se status in goats. Goats with sufficient Se status are those that have more than 160 &micro;g/kg of Se in hair dry weight.

scholarly journals Comparison of organic and inorganic forms of selenium in the mother and kid relationship in goats

2012 ◽  
Vol 57 (No. 8) ◽  
pp. 361-369 ◽  
Author(s):  
L. Pavlata ◽  
L. Mišurová ◽  
A. Pechová ◽  
R. Dvořák
Keyword(s):  
Glutathione Peroxidase ◽  
Whole Blood ◽  
Sodium Selenite ◽  
Dry Matter ◽  
Control Group ◽  
Individual Trial ◽  
Significant Difference ◽  
The Individual ◽  
Se Status

The goal of the experiment was to compare the effect of four different forms of selenium (Se) &minus; sodium selenite (SS), lactate-protein selenium complex (SL), selenium enriched yeast (SY), and selenium-proteinate (SP) supplemented to pregnant goats on Se concentration and glutathione peroxidase (GSH-Px) activity in the blood of goats on the day of delivery and also on Se concentration and GSH-Px activity in the blood of newborn kids. The experiment involved 33 pregnant goats of White Short-haired breed. The supplementation started 6 weeks before the parturition. The goats were divided into 5 groups: control group&nbsp;C, not supplemented, and 4 trial groups (SL, SP, SS, SY), which received Se in the above stated forms by the means of supplemented pellets (300 g per animal per day) at a rate 900 &mu;g Se/kg of dry matter. The average Se concentrations in the blood of the goats were 79.6 &mu;g/l in group C, 152.6 &mu;g/l in group SL, 167.1&nbsp;&mu;g/l in group SP, 144.9 &mu;g/l in group SS, and 152.9 &mu;g/l in group SY. Selenium concentrations in all 4 trial groups were significantly higher (P &lt; 0.01) than in control group, however no significant difference was found between individual trial groups. Likewise, the activity of GSH-Px in goat blood increased significantly in all supplemented groups compared to the controls; however we did not discover any significant differences in activity of GSH-Px between the individual selenium-supplemented groups. The Se concentrations in the blood of kids were significantly (P &lt; 0.01) higher in the selenium-supplemented groups (SL &ndash; 94.9&nbsp;&mu;g/l, <br />SP &ndash; 87.5 &mu;g/l, SS &ndash; 87.6 &mu;g/l, SY &ndash; 92.5 &mu;g/l) than in the control group (C &ndash; 49.4 &mu;g/l), but we did not discover any differences between the individual experimental groups. The activity of GSH-Px in the blood of the kids tended towards higher values in the supplemented groups than in the control group, but the values were significantly higher (P &lt; 0.05) only in groups SY and SL. We have found significant correlation between GSH-Px activity and Se concentration in the blood of goats (r = 0.86) and newborn kids (r = 0.95). Likewise, there was significant correlation between Se concentration in the blood of goats and their kids (r&nbsp;= 0.74). We discovered that the kids are reaching physiologically only about 60% of Se status in whole blood in comparison with their mothers. Our results are suggesting that all the above forms of Se were similarly utilised and transferred into the foetus in the goats. &nbsp;

scholarly journals Pengaruh Suplementasi Lemak Terproteksi Terhadap Konsumsi dan Kecernaan Nutrien Sapi Perah Friesian Holstein

2018 ◽  
Vol 16 (1) ◽  
pp. 34 ◽  
Author(s):  
Ahmad Pramono ◽  
Aditya Yusuf ◽  
Susi Dwi Widyawati ◽  
Hari Hartadi
Keyword(s):  
Organic Matter ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Dry Matter ◽  
Basal Diet ◽  
T Test ◽  
Test Analysis ◽  
Fat Supplementation ◽  
Breeding Center ◽  
Organic Matter Digestibility

<span lang="EN">The research aims to evaluate protected fat supplementation to Friesian Holstein (FH) dairy cattle digestibility based on diet digestibility (dry matter and organic matter consumption; dry matter and organic matter digestibility). The reseach was conducted for 12 weeks, at the Breeding Center for Dairy Cattle (BBPTU-SP) Baturraden. The material used is 12 FH dairy cows. The experiment consists of two treatment i.e. P0: basal diet and P1: basal diet + 3% protected fat supplementation. Each treatment was repeated 6 times. Data were analyzed by independent samples t-test analysis. Result showed that fat protected supplementation had no effect on dry matter and organic matter consumption; dry matter and organic matter digestibility.</span>

scholarly journals The application of a selenium fertiliser for the correction of marginal deficiencies in grazing sheep

1999 ◽  
Vol 70 (3) ◽  
Author(s):  
S.W.P. Cloete ◽  
F.E. Van Niekerk ◽  
M. Young ◽  
G.D. Van der Merwe ◽  
J. Clark
Keyword(s):  
Whole Blood ◽  
Sodium Selenite ◽  
Dry Matter ◽  
Liver And Kidney ◽  
Poorly Soluble ◽  
Se Deficiency ◽  
Ram Lambs ◽  
Grazing Sheep ◽  
Lamb Growth ◽  
Se Status

A commercial fertiliser, consisting of a poorly soluble barium selenate core with a coating of highly soluble sodium selenite, was evaluated in 2 trials for the provision of selenium (Se) to grazing sheep. The fertiliser was administered at a level of 1 kg per hectare to 3 of 6 kikuyu paddocks during 1995 and 1996 in Trial 1, while the other paddocks were left untreated. The Se status of SA mutton merino ram lambs, as reflected by whole blood, liver and kidney Se concentrations, was elevated (P<0.01) for at least 5 months after application of the fertiliser. Whole blood and liver Se concentrations of animals grazing unfertilised control paddocks were indicative of a subclinical Se deficiency at times (<100 ng Se/mℓ whole blood and <300 mg Se/kg liver dry matter). In Trial 2, 4 of 7 paddocks on which an oat fodder crop was established were treated with the Se fertiliser during 1995 and 1997. The remaining 3 paddocks were left unfertilised as controls. Groups of 10-15 pregnant SA mutton merino ewes were introduced to these paddocks within 2 weeks of parturition. These ewes and their progeny utilised these paddocks for a mean (+SD) period of 41+8 days after parturition. The whole blood Se concentrations of these ewes and their offspring were elevated (P < 0.01) relative to their contemporaries utilising control paddocks. No suggestion of a subclinical Se deficiency was discernible in animals grazing control paddocks, although whole blood Se levels approached 100 ng Se/mℓ during 1997. The application of Se fertiliser did not result in improvements in ewe reproduction or lamb growth. There was a suggestion of an improvement (P = 0.21) in mean (+SE) lamb survival on paddocks receiving Se fertiliser compared to control paddocks (71.5 + 4.6 % vs 62.2 + 5.3 % respectively).

scholarly journals Effect of Feeding Improved Grass Hays and Eragrostis tef Straw Silage on Milk Yield, Nitrogen Utilization, and Methane Emission of Lactating Fogera Dairy Cows in Ethiopia

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1021
Author(s):  
Shigdaf Mekuriaw ◽  
Atsushi Tsunekawa ◽  
Toshiyoshi Ichinohe ◽  
Firew Tegegne ◽  
Nigussie Haregeweyn ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Methane Emission ◽  
Dry Matter ◽  
Basal Diet ◽  
Nitrogen Utilization ◽  
Dry Matter Intake ◽  
Eragrostis Tef ◽  
Tropical Regions ◽  
Natural Pasture

The nutritionally imbalanced poor-quality diet feeding is the major constraint of dairy production in tropical regions. Hence, alternative high-quality roughage-based diets are required to improve milk yield and reduce methane emission (CH4). Thus, we tested the effects of feeding natural pasture hay, improved forage grass hays (Napier and Brachiaria Hybrid), and treated crop residues (Eragrostis tef straw) on nutrient digestibility, milk yield, nitrogen balance, and methane emission. The eight lactating Fogera cows selected for the experiment were assigned randomly to a 4 × 4 Latin square design. Cows were housed in well-ventilated individual pens and fed a total mixed ration (TMR) comprising 70% roughage and 30% concentrate. The four roughage-based basal dietary treatments supplemented with formulated concentrate were: Control (natural pasture hay (NPH)); treated teff straw silage (TTS); Napier grass hay (NGH); and Brachiaria hybrid grass hay (BhH). Compared with the control diet, the daily milk yield increased (p < 0.01) by 31.9%, 52.9%, and 71.6% with TTS, NGH, and BhH diets, respectively. Cows fed BhH had the highest dry matter intake (8.84 kg/d), followed by NGH (8.10 kg/d) and TTS (7.71 kg/d); all of these intakes were greater (p = 0.01) than that of NPH (6.21 kg/d). Nitrogen digestibility increased (p < 0.01) from the NPH diet to TTS (by 27.7%), NGH (21.7%), and BhH (39.5%). The concentration of ruminal ammonia nitrogen was higher for cows fed NGH than other diets (p = 0.01) and positively correlated with plasma urea nitrogen concentration (R² = 0.45). Feeding TTS, NGH, and BhH hay as a basal diet changed the nitrogen excretion pathway from urine to feces, which can help protect against environmental pollution. Estimated methane yields per dry matter intake and milk yield were decreased in dairy cows fed BhH, NGH, and TTS diets when compared to cows fed an NPH diet (p < 0.05). In conclusion, feeding of TTS, NGH, and BhH roughages as a basal diet to lactating dairy cows in tropical regions improved nutrient intake and digestibility, milk yield, nitrogen utilization efficiency, and reduced enteric methane emission.

scholarly journals Elevated thyroid hormone caused by high concentrate diet participates in hepatic metabolic disorders in dairy cows

2021 ◽  
Author(s):  
Qu Chen ◽  
Chen Wu ◽  
Zhihao Yao ◽  
Liuping Cai ◽  
Yingdong Ni ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Thyroid Hormone ◽  
Dairy Cows ◽  
Dry Matter ◽  
Metabolic Disorders ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Fatty Acid Synthase ◽  
Thyroid Hormone Receptor ◽  
Serum Triglyceride ◽  
Lactating Dairy Cows

Abstract Background Feeding a high concentrate diet is widely used to satisfy high milk yields, however, if used over a longer term it can cause metabolic disorders. Abnormal secretion of hormones is one of the important causes of metabolic disorders caused by high concentrate diet, however, the related research is still limited. In total, 12 mid-lactating dairy cows were randomly assigned to HC group (60% concentrate of dry matter, n = 6) or LC group (40% concentrate of dry matter, n = 6). All cows were slaughtered at the 21st day, and blood and liver samples were collected. Results Compared with LC group, HC group showed reduced serum triglyceride (TG), free fatty acid (FFA), total cholesterol (TC), low density lipoprotein (LDL-C), and increased liver glycogen and glucose (P < 0.05). Real-time PCR results showed that genes related to gluconeogenesis, namely, glucose-6-phosphatase (G6PC) and phosphoenolpyruvate carboxykinase 1 (PCK1) were significantly upregulated and accompanied greater gluconeogenic protein expression in HC group (P < 0.05). The expression of hepatic genes and proteins related to lipogensis, including sterol regulatory element-binding protein 1 (SREBP1), long-chain acyl-CoA synthetase 1 (ACSL1), and fatty acid synthase (FAS) were downregulated in HC group (P < 0.05). However, the expression of genes and proteins related to β-oxidation, including carnitine palmitoyltransferase 1α (CPT1α) and peroxisome proliferator activated receptor α (PPARα) were significantly increased in HC group (P < 0.05). The levels of serum cortisol, thyroxin (T4), triiodothyronine (T3), free triiodothyronine (FT3) and liver FT3 elevated significantly in HC group (P < 0.05). Moreover, the expression of thyroid hormone receptor (THR) upregulated at gene and protein levels (P < 0.05). Conclusions Taken together, this study first reports that abnormal secretion of TH induced by high concentrate diet participates in metabolic disorders, and it regulates glycometabolism and lipid metabolism through its actions on the liver in lactating dairy cows.

Milk production responses to turnips fed to dairy cows in mid lactation

1998 ◽  
Vol 38 (2) ◽  
pp. 117 ◽  
Author(s):  
P. J. Moate ◽  
D. E. Dalley ◽  
K. Martin ◽  
C. Grainger
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Dry Matter ◽  
Rumen Fluid ◽  
Basal Diet ◽  
Milk Composition ◽  
Control Group ◽  
Physical Form ◽  
Yield Responses ◽  
Dietary Treatments

Summary. Recently, many dairy farmers in Victoria have grown turnips as a summer fodder crop for lactating dairy cows. This paper reports on a 1 month experiment in which cows were individually fed indoors, and milk yield responses to feeding combinations of turnips and barley were measured. Forty cows in mid lactation were evenly allocated to 5 treatment groups. The control group were offered a basal diet of pasture hay and pasture silage which is similar to that available on many Victorian dairy farms during summer. Cows in the other 4 groups were offered the basal diet and various combinations of turnips and/or barley. Marginal milk responses from barley, turnips and a 50 : 50 mixture of turnips and barley were 0.62, 0.49 and 0.59 L/kg dry matter of supplement eaten. Milk composition of all groups was similar. Despite diets differing greatly in the proportions and physical form of dietary constituents, the mean milk production of each group was accurately predicted by their mean dry matter intake. Measurement of plasma minerals (calcium, magnesium, sodium, potassium and phosphorus) and rumen fluid pH showed that dietary treatments caused some significant (P<0.05) differences but all values were within the normal range. In this experiment, the milk production responses from barley, turnips and combinations of barley and turnips were similar. Since the cost of turnips is generally about half that of barley, it is concluded that turnips are an economic alternative to barley as a feed supplement for summer milk production.

The impact of dietary cation anion difference (DCAD) on the acid-base balance and calcium metabolism of non-lactating, non-pregnant dairy cows fed equal amounts of different anionic salts

2007 ◽  
Vol 74 (3) ◽  
pp. 311-322 ◽  
Author(s):  
Carl-Christian Gelfert ◽  
S Leonie Loeffler ◽  
Sven Frömer ◽  
Maike Engel ◽  
Helmut Hartmann ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Whole Blood ◽  
Calcium Metabolism ◽  
Dry Matter ◽  
Blood Parameters ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
The Impact ◽  
Serum And Urine

We evaluated the impact of the dietary cation-anion difference (DCAD) on the influence of anionic salts (AS) on the metabolism of dairy cows using a study-design that included control of feed intake. Ten mature, non-lactating, non-pregnant, Holstein-Friesian-crossbreed cows received 2000 mEq of either one of the seven anionic salts tested, two combinations of the anionic salts or water as control via a rumen cannula. Salts and controls were assigned in a 10×10 Latin square design. Whole blood, serum and urine samples were taken during treatment (TP) and washout period. Samples of whole blood were tested for pH, base-excess and bicarbonate concentrations. In urine, pH and net acid-base excretion (NABE) were analysed. Calcium was measured in serum and urine. According to the different batches of hay, five groups of DCAD were created regarding cluster analysis. Changes in urine and blood parameters were statistically analysed for each DCAD group separately. The different DCAD had an impact on the amount of change in acid-base balance (ABB) and calcium metabolism and for how long these changes lasted. In the DCAD group receiving the highest amount of AS (239 mEq/kg dry matter with AS), changes of ABB were only noticeable in urine and these changes only differed from day zero in the first week of TP (P<0·05). In the other four groups changes of ABB were also visible in blood parameters, but only on a few days of TP did the deviations differ significantly (P<0·05) from day zero. Changes of ABB parameters in urine samples were more pronounced than those in blood and differed clearly from day zero (P<0·05). Parallel to the changes of ABB, calcium concentrations in these samples were significantly increased (P<0·001) in all DCAD groups. Except for the highest DCAD group, ionized calcium concentrations changed over time (P<0·020). However, the differences were very small and only differed from day zero on a few TP days. We conclude that the DCAD of a dairy cow's diet has an important impact on the effect of AS on ABB and calcium metabolism with respect to the duration and amount of change. The target regions of DCAD should be clearly below 100 mEq/kg dry matter to ensure the desired effect on ABB and calcium metabolism. Extremely negative DCAD should be avoided to minimize the risk of clinical acidosis induced by AS.

scholarly journals Effect of duodenal infusions of leucine on milk yield and plasma amino acids in dairy cows

2010 ◽  
Vol 55 (No. 9) ◽  
pp. 351-358 ◽  
Author(s):  
M. Richter ◽  
J. Svobodová ◽  
L. Křížová ◽  
J. Třináctý ◽  
P. Homolka
Keyword(s):  
Amino Acids ◽  
Dairy Cows ◽  
Milk Yield ◽  
Dry Matter ◽  
Basal Diet ◽  
Experimental Period ◽  
Plasma Amino Acids ◽  
Maize Silage ◽  
Subsequent Period ◽  
Period 2

Four high-yielding lactating Holstein cows fitted with duodenal cannulas were used in the experiment. Cows were divided into 2 groups &ndash; control (Control) with leucine deficiency and experimental (Leucine) with a leucine supplement. The experiment was divided into 4 periods of 7 days, each consisting of a 3-day preliminary period followed by a 4-day experimental period. In the first period, 2 cows were assigned to Control and the remaining 2 to Leucine. In the subsequent period the cows were switched to the other treatment. Cows were fed individually twice daily the basal diet based on maize silage, lucerne hay and supplemental mixture. Infusions of amino acids in Leucine consisted of methionine (12.6 g/day), lysine (20.7 g/day), histidine (10.7 g/day) and leucine (19.3 g/day). The composition of amino acid infusate in Control was the same except for leucine that was replaced with monosodium L-glutamate. The intake of dry matter was not affected by the treatment (P &gt; 0.05). No effect of leucine infusion on milk yield and composition was observed (P &gt; 0.05), nevertheless the concentration of protein and casein in milk tended to be higher in Leucine (38.3 and 31.3 g/kg) than in Control (37.4 and 30.4 g/kg, respectively, P &lt; 0.1). The yield of milk components was not affected by the treatment (P &gt; 0.05). Duodenal infusion of leucine resulted in a decreased plasma level of isoleucine in Leucine compared to Control (P &lt; 0.01). Concentrations of leucine, cysteine and citrulline tended to be higher and the concentration of tyrosine tended to be lower in Leucine in comparison with Control (P &lt; 0.10).

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