• Journal of Nutrition and Health
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• v.30 no.1
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• pp.3-11
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• 1997

This study was conducted to investigate the effects of protein levels and casein/whey ratios on organ growth and protein metabolism in early weaned rats. Premature rats weaned by the 17th day were fed six semipurified synthetic, isocaloric and gel diets that contained three levels (low, medium and high) and two different combinations(casein/whey ; 80 : 20 or 20 : 80) of milk protein for 8 days. On the 25th day postpartum, frest weigth and DNA, RNA and milk protein contents in brain, liver, kidney and muscle were determined to ascertain organ and cellular growth. Futher, with a view to ascertain protein metabolism and renal functions, serum total protein, $\alpha$-amino N, urea N, and creatinine and creatinine and urinary urea N, creatinine and hydroxproline were determined. Total DNA contents of brain, liver and kidney, which may represent as an index of cell numbers in those organs were significantly decreased in the rats fed diets containing low level protein regardless of casein/whey ratio. However, as fat as the rats fed high protein diets were concerned, their fresh weight, protein contents and GFR of kidney were significantly increased. Furthermore, nitrogen components, $\alpha$-amino N, urea N and creatinie in serum and urine were also increassed. Another observation was that high casein/whey ratio significantly facilitated accumulation of porteins in muscle and kidney and urinary hydorxyproline excretion, not affecting the DNA content of those organs. This study showed that low(8%) or high(32%) contents of protein had less desirable effects either on protein metabolism or on organ cellular growth in prematurely weaned rats, whereas there were no effects on general growth and bone strength.

• Journal of Animal Science and Technology
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• v.58 no.8
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• pp.30.1-30.12
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• 2016

Background: The effect of choline chloride supplementation through forced drinking combined with concentrate diets containing Ca-fish oil on milk production and milk composition of Etawah Grade goats was evaluated. Choline chloride is an essential component in ruminant diets as it is required for fat metabolism. Method: The experiment was conducted in a completely randomized block design with three types of treatments and eight replications. The trial had two successive experimental periods; the first, during the eight weeks of late pregnancy, and the second, during the first 12 weeks of lactation. Twenty-four Etawah Grade does in the second gestation period were divided into three treatment groups. Commercial choline chloride 60 % in corncobs-based powder was used as a source of choline chloride. The treatments were no supplementation (control) and supplemented with either 4 g or 8 g/2days of choline chloride. Choline chloride was given to the animals through a forced drinking technique, after dissolving it in 60 ml drinking water. The initial body weight of does was $38.81{\pm}3.66kg$. The does were penned individually, and were given fresh chopped King Grass ad libitum and 700 g/day of concentrate diets containing Ca-fish oil, starting eight weeks prior to expecting kidding and continuing for 12 weeks of parturition. Results: All nutrient intakes were not significantly different (p > 0.05) among the treatments during the late pregnancy and the lactation periods. Supplementation did not affect (p > 0.05) the average daily gains and feed conversion ratio during pregnancy but gave effects (p < 0.05) on the average daily gains, feed conversion ratio and income over feed cost during lactation. The highest average daily milk yields and 4 % fat corrected milk yields were found in goats supplemented with 4 g/2days of choline chloride and increased by 17.00 % and 24.67 %, respectively, compared to the control. Moreover, milk composition percentage and milk constituent yields improved significantly (p < 0.05) in those supplemented with 4 g/2days of choline chloride. Conclusion: The supplementation of 4 g/2days of choline chloride through forced drinking increased milk yields, the 4 % fat corrected milk yields, milk composition, milk constituent yields, and improved feed conversion ratio and income over feed cost of Etawah Grade goats.

• Journal of Nutrition and Health
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• v.29 no.8
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• pp.899-907
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• 1996

This study was conducted to examine how Korean women mange energy metabolism during lactation. Eighteen women recruited were healthy, had normal pregnancies and were required to breast-feed their babies exclusively for at least 12wks. During the study period, all subjects were visited and interviewed five times : 3d, 9d, 4wk, 8wk, and 12wk lactation. Body composition variables were analyzed by a bioelectrical impedance method, energy intakes were assessed by using the inventory-weighing method, energy expenditure were determined by recording daily activities, and milk energy output was investigated from the amount of milk production and the gross energy content of milk. The subjects consumed less energy than current recommended allowance all over the study period, but compatible with fairly adequate lactational performance. They responded the additional energy stress of lactation by enhancing metabolic efficiency, increasing energy intakes, reduction physical activities and mobilizing body reserves. Another finding in this study was that the reduction in body fat-free mass may be the one way that women meet the energy demands of lactation like the reduction in body fat mass. The results from this study suggest that current recommended additional energy need during lactation, 2.09MJ/d(500kcal/d), is too high for healthy Korean women. Our data also indicate that the changes of body composition and energy balance at earlier postpartum are extremely different from those at later periods.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.812-818
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• 2009

This study evaluated the effects of live yeast and yeast cell-wall mannan-oligosaccharide supplementation onperformance and nutrient digestibility during early lactation in cows fed a diet based on a mixture of corn silage and alfalfa hay as forage sources. Eight multiparous Holstein dairy cows (average days in milk, 27${\pm}$6) were used in a replicated 4${\times}$4 Latin square design. Diets contained 45% forage and 55% concentrate on a dry matter (DM) basis and treatments were: i) basal diet without additive (Control), ii) basal diet with 32 g/d of mannan-oligosaccharides (MOS), iii) basal diet with $1.2{\times}10^{10}$ colony forming units per day (cfu/d) of live yeast (Saccharomyces cerevisiae CNCM 1-1077; SC), and iv) basal diet with a mixture of MOS (32 g/d) and SC ($1.2{\times}10^{10}$ cfu/d; MOS+SC). Treatments had no effect (p>0.05) on DM intake and yields of milk, 3.5% fat-(FCM) and energy-corrected milk (ECM), and on milk fat percentage, body condition score and blood metabolites. Compared with the Control, only supplementation of SC resulted in numerically higher yields of FCM (41.9 vs. 40.1 kg/d) and ECM (41.8 vs. 40.3 kg/d), and milk fat percentage (3.64 vs. 3.43%). While the MOS diet had no effects on performance compared to the Control, the combination treatment MOS+SC increased milk protein percentage (p<0.05). Also, the MOS supplementation, both alone or in combination with SC, numerically increased milk fat percentage. The SC supplementation increased apparent digestibility of DM and crude protein while the MOS supplementation did not affect digestibility. Concentrations of total volatile fatty acids (VFA) and ruminal pH were similar across treatments. Overall results indicated that supplementation of MOS produced variable and inconsistent effects on rumen metabolism and performance, whereas SC supplementation improved nutrient digestibility and numerically increased FCM and ECM yields, which could not be enhanced by the combined supplementation of MOS+SC. According to our experimental condition, there was no effect of MOS alone or in combination with SC on dairy cow performance.

• Animal Bioscience
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• v.34 no.4
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• pp.759-769
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• 2021

Objective: This study aimed to investigate the effect of stocking density on the behavior, productivity, and metabolism of periparturient Holstein cows as well as calf performance. Methods: A total of 48 periparturient cows were randomly assigned into three groups at 28 days (±3 days) before their expected calving date. The stocking densities of the groups, relative to the standard cubicle and feed bunk number, were i) 80% (13 cows), ii) 100% (16 cows), and iii) 120% (19 cows). Lying and rumination behavior was recorded using electronic data loggers and HR-Tags from d -21 ("d-" means days before calving) until the calving date, d 0. Lying time was assessed to determine the diurnal total hours spent lying per day. Rumination time was averaged in 2 hours interval periods over 24 hours during the experimental period. Results: Cows in the 80% group spent more time lying and ruminating between d -21 and d -7 and tended to ruminate more between d -14 and d 0. Calcium levels tended to be higher for cows in the 80% group, no other observable differences were found in monitored blood parameters. Moreover, 3.5% fat corrected milk and energy corrected milk yields were higher in 80% group in the first month of lactation. No other observable differences were found in the yield and composition of colostrum and milk in the first 10 months of lactation. The growth and performance of calves in the first week of life was not affected by stocking density of the dams. Conclusion: We concluded that lower stocking density may increase lying and ruminating behavior of prepartum Holstein cows. However, this did not translate into improved productivity and metabolism.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.8
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• pp.1181-1188
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• 2014

The aim of this study was to evaluate protein expression patterns of liver in response to subacute ruminal acidosis (SARA) induced by high-concentrate diet. Sixteen healthy mid-lactating goats were randomly divided into 2 groups and fed either a high-forage (HF) diet or a high-concentrate (HC) diet. The HC diet was expected to induce SARA. After ensuring the occurrence of SARA, liver samples were collected. Proteome analysis with differential in gel electrophoresis technology revealed that, 15 proteins were significantly modulated in liver in a comparison between HF and HC-fed goats. These proteins were found mainly associated with metabolism and energy transfer after identified by matrix-assisted laser desorption ionization/time of flight. The results indicated that glucose, lipid and protein catabolism could be enhanced when SARA occurred. It prompted that glucose, lipid and amine acid in the liver mainly participated in oxidation and energy supply when SARA occurred, which possibly consumed more precursors involved in milk protein and milk fat synthesis. These results suggest new candidate proteins that may contribute to a better understanding of the mechanisms that mediate liver adaptation to SARA.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1600-1608
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• 2005

The study was carried out to evaluate the effect of exogenous bovine somatotropin on water metabolism in relation to mammary function in early lactation of crossbred Holstein cattle. Ten, 87.5% crossbred Holstein cattle were divided into two groups of 5 animals each. At day 60 of lactation, the control group was given placebo while animals in the experimental group were given recombinant bovine somatotropin (rbST) by subcutaneous injection with 500 mg of rbST (14-days prolonged-release rbST). In rbSTtreated animals, milk yield increased 19.8%, which coincided with a significant increase in water intake (p<0.01), while DM daily intake was not different when compared to the control animals. Water turnover rate as absolute values significantly increased (p<0.05), while the biological half-life of water did not change in rbST-treated animals. Total body water (TBW) and total body water space (TOH) as absolute values significantly increased (p<0.01) in rbST-treated animals, while it was decreased in the control animals. Absolute values of empty body water (EBW) markedly increased (p<0.05), which was associated with an increase in the extracellular fluid (ECF) volume. Absolute values of plasma volume and blood volume were also significantly increased (p<0.05) in rbST-treated animals. The increase in mammary blood flow in rbST-treated animals was proportionally higher than an increase in milk production. The plasma IGF-1 concentration was significantly increased (p<0.01) in rbST-treated animals when compared with those of control animals during the treatment period. Milk fat concentration increased during rbST treatment, while the concentrations of both protein and lactose in milk were not affected. The present results indicate that rbST exerts its effect on an increase in both TBW and EBW. An increased ECF compartment in rbST-treated animals might partly result from the decrease in fat mass during early lactation. The action of rbST on mammary blood flow might not be mediated solely by the action of IGF-1 for increase in blood flow to mammary gland. An elevation of body fluid during rbST treatment in early lactation may be partly a result of an increase in mammary blood flow in distribution of milk precursors to the gland.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.651-658
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• 2009

Four multiparous lactating Holstein cows fitted with rumen cannulae were fed diets varying in the amount and source of rumen-degradable carbohydrates (starch vs. sucrose) to examine their effects on rumen fermentation, nitrogen metabolism and lactation performance. A $4{\times}4$ Latin square with four diets and four periods of 28 days each was employed. Corn starch and sucrose were added to diets and corn starch was replaced with sucrose at 0 (0 S), 2.5 (2.5 S), 5.0 (5.0 S) 7.5% (7.5 S) of diet dry matter in a total mixed ration (TMR) containing 60% concentrate and 40% forage (DM basis). Replacing corn starch with sucrose did not affect (p>0.05) ruminal pH which averaged 6.41, but the ruminal pH for 7.5 S decreased more rapidly at 2 h after morning feeding compared with other treatments. Sucrose reduced ($p{\leq}0.05$) ruminal $NH_3-N$ concentration (13.90 vs. 17.09 mg/dl) but did not affect peptide-N concentration. There was no dietary effect on total volatile fatty acids (110.53 mmol/L) or the acetate to propionate ratio (2.72). No differences (p>0.05) in molar proportion of most of the individual VFA were found among diets, except for the molar proportion of butyrate that was increased ($p{\leq}0.05$) with the inclusion of sucrose. Total branched chain volatile fatty acids tended to increase ($p{\geq}0.051$) for the control treatment (0 S) compared with the 7.5 S treatment. Dry matter intake, body weight changes and digestibility of DM, OM, CP, NDF and ADF were not affected by treatments. Sucrose inclusion in the total mixed ration did not affect milk yield, but increased milk fat and total solid percentage ($p{\leq}0.05$). Sucrose tended ($p{\geq}0.063$) to increase milk protein percentage (3.28 vs. 3.05) and reduced ($p{\leq}0.05$) milk urea nitrogen concentration (12.75 vs. 15.48 mg/dl), suggesting a more efficient utilization of the rapidly available nitrogen components in the diet and hence improving nitrogen metabolism in the rumen.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.351-359
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• 2015

Twelve multiparous Holstein dairy cows in mid-lactation were selected for a replicated $4{\times}4$ Latin square design with a $2{\times}2$ factorial arrangement to investigate the effects of corn and soybean meal (SBM) types on rumen fermentation, N metabolism and lactation performance in dairy cows. Two types of corn (dry ground [DGC] and steam-flaked corn [SFC]) and two types of SBM (solvent-extracted and heat-treated SBM) with different ruminal degradation rates and extents were used to formulate four diets with the same basal ingredients. Each period lasted for 21 days, including 14 d for adaptation and 7 d for sample collection. Cows receiving SFC had a lower dry matter (DM) and total N intake than those fed DGC. However, the milk yield and milk protein yield were not influenced by the corn type, resulting in higher feed and N utilization efficiency in SFC-fed cows than those receiving DGC. Ruminal acetate concentrations was greater and total volatile fatty acids concentrations tended to be greater for cows receiving DGC relative to cows fed SFC, but milk fat content was not influenced by corn type. The SFC-fed cows had lower ruminal ammonia-N, less urea N in their blood and milk, and lower fecal N excretion than those on DGC. Compared with solvent-extracted SBM-fed cows, cows receiving heat-treated SBM had lower microbial protein yield in the rumen, but similar total tract apparent nutrient digestibility, N metabolism measurements, and productivity. Excessive supply of metabolizable protein in all diets may have caused the lack of difference in lactation performance between SBM types. Results of the present study indicated that increasing the energy degradability in the rumen could improve feed efficiency, and reduce environmental pollution.

• Animal Bioscience
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• v.36 no.11
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• pp.1666-1684
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• 2023

Objective: Our objective was to examine the relationships of supplemental rumen-protected lysine (RPL) or lysine + methionine (RPLM) on lactational performance, plasma amino acids (AA) concentration, and nitrogen use efficiency of lactating dairy cows by using a meta-analysis approach. Methods: A total of 56 articles comprising 77 experiments with either RPL or RPLM supplementation were selected and analyzed using a mixed model methodology by considering the treatments and other potential covariates as fixed effects and different experiments as random effects. Results: In early lactating cows, milk yield was linearly increased by RPL (β₁ = 0.013; p<0.001) and RPLM (β₁ = 0.014; p<0.028) but 3.5% fat-corrected milk (FCM) and energy-corrected milk (ECM) (kg/d) was increased by only RPL. RPL and RPLM did not affect dry matter intake (DMI) but positively increased (p<0.05) dairy efficiency (Milk yield/DMI and ECM/DMI). As a percentage, milk fat, protein, and lactose were unchanged by RPL or RPLM but the yield of all components was increased (p<0.05) by feeding RPL while only milk protein was increased by feeding RPLM. Plasma Lys concentration was linearly increased (p<0.05) with increasing supplemental RPL while plasma Met increased (p<0.05) by RPLM supplementation. The increase in plasma Lys had a strong linear relationship (R² = 0.693 in the RPL dataset and R² = 0.769 in the RPLM dataset) on milk protein synthesis (g/d) during early lactation. Nitrogen metabolism parameters were not affected by feeding RPL or RPLM, either top-dress or when supplemented to deficient diets. Lactation performance did not differ between AA-deficient or AA-adequate diets in response to RPL or RPLM supplementation. Conclusion: RPL or RPLM showed a positive linear relationship on the lactational performance of dairy cows whereas greater improvement effects were observed during early lactation. Supplementing RPL or RPLM is recommended on deficient-AA diet but not on adequate-AA diet.