• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.983-988
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• 2007

The aim of this study was to examine the correlation between bovine casein (CN) mRNA expression levels in mammary epithelial cells and lactation period, the yields of milk proteins and other parameters. The cells were collected from each cow's milk, which contained somatic cell counts (SCC) of less than 100,000 cells/ml. The levels of ${\alpha}s1-$, ${\alpha}s2-$, ${\beta}$- and ${\kappa}$-CN mRNA expression were significantly correlated with each other in mammary epithelial cells (p<0.01). All cows produced either less than 30 kg/day/cow or a over 30 kg/day/cow level of milk yield (MY). It was shown that the CN mRNA expression levels decreased gradually from the calving period to late lactation, when MY was over 30 kg/day/cow. The SCC tended to increase gradually during the course of lactation, but it was negatively correlated with milk protein and CN yields (p<0.01) when MY was less than 30 kg/day/cow. Moreover, there was a tendency for a negative correlation between SCC and ${\alpha}s1$-CN and ${\beta}$-CN mRNA expression level, when MY was less than 30 kg/day/cow (p<0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.3
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• pp.277-286
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• 2000

A total of 21,441 milking records of biweekly test-days were collected from six dairy farms of Almarai company, Saudi Arabia to determine the effect of days open on lactation curve and milk production during the period of 1991 to 1996. These records included cows calved in two seasons: winter, for cows calved from October to March and summer, for cows calved from April to September. Season of calving did not have a significant effect on the last biweekly points of the curve, and this is due to the effect of the evaporative cooling system. Days open had a marked effect on milk production. The difference in milk yield between cows with days open <60 days and days open >150 days was 1,021 liter. Moreover, the difference in milk yield at early lactation decreased from 1,021 to 829 liter as the days open increased from 75 to 125, due to the decrease in the effect of conception on milk production with advancing lactation. These data also showed that the middle part of the curve (105-255) was the least affected part by the variation in days open because the pregnancy effect become more obvious after five months of conception. These data showed that the dairy cattle produce more than 70% of the milk yield during the first 250 days of the lactation curve.

• Korean Journal of Organic Agriculture
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• v.19 no.4
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• pp.553-563
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• 2011

This experiment was conducted to determine the effect of nattokinase (NK) additives on milk production and composition, and blood metabolites in dairy cows. The two kinds of nattokinase with high fibrinolytic activity were produced by two strains of bacteria, Bacillus amyloliquefacines (NK1) and Bacillus subtilis (NK2). Total fifteen Holstein cows (average $1.83{\pm}0.37$ parity; average milk yield $23.2{\pm}3.2$ kg/d) were randomly assigned to three treatments (5 animals per treatment). Cows were fed TMR supplemented with 0g, 100g and 100g for control, NK1 and NK2 treatment, respectively for 4 weeks. Milk yield was significantly higher (p<0.05) for NK1 (22.89 kg/d) than for control (21.07 kg/d) and NK2 (21.36 kg/d). Somatic cell counts in NK treatments were significantly lower than that in control group (58,000 vs. 21,000 and 35,000 cells/ml, control vs. NK1 and NK2). Serum ALT levels in all treatment were similar to the range of 32.00~35.83 IU/L, but AST levels in NK1 (85.67 IU/L) was significantly decreased compared with those in control and NK2 (121.67 and 117.67 IU/L respectively). Serum T-CHO levels in NK1 (145.33 mg/dl) was significantly decreased (p<0.05) compared with that in control (179.00 mg/dl) and NK2 (176.17 mg/dl). This finding showed that NK1 additives could possibly have a positive effect in lactation performance of mid-lactation dairy cows by increasing milk yield, reducing somatic cell count, improving liver function and decreasing cholesterol in blood.

• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1013-1023
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• 2022

Body condition score (BCS) at calving is a vital indicator of the effectiveness of the beginning of lactation in dairy animals. The purpose of this study was to examine the effect of BCS at calving on milk production and transition success in dairy buffaloes. Thirty-six (36) Nili Ravi buffaloes were enrolled at 40 days of expected calving and followed through 90 days of lactation. The buffaloes were categorized into three groups according to their BCS (on a scale of 1-5 with 0.25 increments) as follows: 1) low, buffaloes with BCS ≤ 3.0; 2) medium, buffaloes with BCS 3.25-3.5; and 3) high, buffaloes with BCS ≥ 3.75. All buffaloes were fed a similar diet ad libitum. The lactation diet had increased concentrate allowance according to milk yield. The results revealed that the BCS at calving did not affect milk yield; however, fat percentage (fat%) was lower in the low-BCS group. Dry matter intake (DMI) was similar among the treatment groups, although post-calving BCS loss was greater in the high-BCS group compared to the medium- and the low-BCS groups. Similarly, the buffaloes in the high-BCS group had higher non-esterified fatty acids (NEFA) concentration compared to the low- and medium-BCS groups. No cases of metabolic disorders were observed during the study. The present results suggest that the buffaloes in the medium-BCS group appeared to perform better compared to the low- and the high-BCS groups with respect to milk fat% and blood NEFA concentration.

• Animal Bioscience
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• v.36 no.2
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• pp.229-237
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• 2023

Objective: This study evaluated the effects of dandelion supplements on lactation performance, circulating antioxidative activity and plasma metabolomics in primiparous dairy cows. Methods: A total of 60 mid-lactation dairy cows (milk yield = 34.29±0.34 kg/d; days in milk = 151.72±2.36 days) were divided into 4 treatment groups randomly, comprising the addition of dandelion at 0, 100, 200, 400 g/d per head. The experiment lasted for 8 weeks with an extra 10 days' pre-feeding period. Milk and blood samples were collected, and plasma samples were selected to perform metabolomics analysis. Results: Supplementing 200 g/d of dandelion increased the yield of milk and lactose (p≤0.05). The milk somatic cell counts (p≤0.05) were lower in all dandelion groups than those in the control group. The activity of glutathione peroxidase (p≤0.05) and superoxide dismutase (p≤0.05) were increased and plasma malondialdehyde (p = 0.01) was decreased when cows were fed 200 g/d dandelion. Plasma metabolomics analysis showed that 23 hub differential metabolites were identified in the 200 g/d dandelion group. These metabolites such as ribose, glutamic acid, valine, and phenylalanine were enriched in D-glutamine and D-glutamate metabolism (p = 0.06, impact value = 1), phenylalanine, tyrosine, and tryptophan biosynthesis (p = 0.05, impact value = 0.5), and starch and sucrose metabolism (p = 0.21, impact value = 0.13). Moreover, correlation analysis showed that circulating ribose, mannose, and glutamic acid were positively related to milk yield. Conclusion: Dandelion supplementation could improve lactation performance and elevate the plasma carbohydrate and amino acids metabolism and antioxidative activity. Supplementation of 200 g/d dandelion is recommended for lactating dairy cows.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.4
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• pp.590-596
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• 1999

The effect of evaporative cooling in alleviating seasonal variations of dairy cows raised in AlMarai Dairy Farms in the Kingdom of Saudi Arabia were studied using milking record collected during the period of 1991 to 1996. The data included 13303 and 8137 records represented winter and summer calving seasons. Evaporative cooling system improved production for cows calved in summer. The least square means of milk yield were 9631 and 9556 liter for cows calved in winter and summer seasons but no significant differences (p<0.05) were observed between the yield of two seasons. No significant effect of season on calving under evaporative cooling on most of the biweekly points of the lactation curve. The farm, parity and milk level showed a significant effect on the shape of the curve. Functions of the lactation curve like initial yield, 305 MY, peak yield, time of peak and duration were estimated for each phase of the lactation curve.

• Journal of Animal Science and Technology
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• v.50 no.2
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• pp.199-208
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• 2008

This study was undertaken to investigate the effects of ruminally protected amino acids (Methionine and Lysine) on in vitro ruminal parameters, and in vivo milk yield and milk composition in mid-lactating cows. In the first in vitro experiment, there were no statistical significances between treatments in ruminal pH and dry matter digestibility during various incubation times. In the second in vivo experiment, milk yield decreased by 11.92% in control and 5.68% in the treatment respectively, but decrease rate of milk yield in the treatment was lower than control. Milk yields naturally decreased as time goes by since the DIMs(Days in milk) of the cows in experiment were in mid-lactation period. 4% FCM(Fat corrected milk) and milk protein yields also, respectively, decreased by 11.25% and 11.09% in control and 6.16% and 5.47% in the treatment as compared with the intial. Milk protein and milk fat production were higher in the treatment(0.90kg, 1.10kg) than those of control(0.66kg, 0.79kg). Milk fat content significantly increased with supplementing protected amino acids as compared to control(P<0.05). From the above results, protected amino acids were positively utilized in the performances of mid-lactating cows without inhibiting rumen fermentation. Further investigation is suggested for essential amino acid composition and intestinal digestion rate out of rumen bypass protein in dietary protein to be estimated.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1383-1389
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• 2004

The nutritive value and utilization of whole crop rice silage (WCRS), Hamasari, at yellow mature stage was determined by three studies. In first study, chemical composition, in vivo digestibility and metabolizable energy (ME) content of WCRS was determined by Holstein steers. WCRS contains 6.23% CP, its digestibility is 48.4% and estimated TDN is 56.4%. Its ME content was 1.91 Mcal/kg DM. Gross energy (GE) retention (% of GE intake) in steers is only 22.7% most of which was lost through feces (44.7% of GE intake). It takes 81 minutes to chew a kg of WCRS by steers. In another study, the effect of Hamasari at yellow mature stage at three stages of lactation (early, mid and late lactation) and two levels of concentrate (40 or 60%) on voluntary intake, ME content and ME intake, milk yield and composition using lactating Holstein dairy cows were investigated. Total intake increased with the concentrate level in early and mid lactation, but was similar irrespective of concentrate level in late lactation. WCRS intake was higher with 40% concentrate level than with 60% concentrate. ME intake by cows increased with the concentrate level and WCRS in early lactating cows with 40% concentrate can support only 90% of the ME requirement. Milk production in accordance with ME intake increased with the increase in concentrate level in early and mid lactating cows but was similar in late lactating cows irrespective of concentrate level. Fat and protein percent of milk in mid and late lactating cows were higher with for 60% concentrate than 40%, but reverse was in early lactating cows. Solids-not-fat was higher with for 60% concentrate than 40% concentrate. Finally in situ degradability of botanical fractions such as leaf, stem, head and whole WCRS, Hamasari at yellow mature stage was incubated from 0 to 96 h in Holstein steers to determine DM and N degradability characteristics of botanical fractions and whole WCRS. Both DM and N solubility, rate of degradation and effective degradability of leaf of silage was lower, but slowly degradable fraction was higher compared to stem and head. Solubility of DM and N of stem was higher than other fractions. The 48 h degradability, effective degradability and rate of degradation of leaf were always lower than stem or head. In conclusion, voluntary intake of silage ranged from 5 to 12 kg/d and was higher with low levels of concentrate, but milk yield was higher with high levels of concentrate. Fat corrected milk yield ranged from 19 to 37 kg per day. For consistency of milk, early lactating cows should not be allowed more than 40% whole crop rice silage in the diet, but late lactating cows may be allowed 60% whole crop rice silage.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.11
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• pp.1725-1731
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• 2020

Objective: An initial RNA-Sequencing study revealed that UDP-galactose-4-epimerase (GALE) was one of the most promising candidates for milk protein concentration in Chinese Holstein cattle. This enzyme catalyzes the interconversion of UDP-galactose and UDP-glucose, an important step in galactose catabolism. To further validate the genetic effect of GALE on milk protein traits, genetic variations were identified, and genotypes-phenotypes associations were performed. Methods: The entire coding region and the 5'-regulatory region (5'-UTR) of GALE were re-sequenced using pooled DNA of 17 unrelated sires. Association studies for five milk production traits were performed using a mixed linear animal model with a population encompassing 1,027 Chinese Holstein cows. Results: A total of three variants in GALE were identified, including two novel variants (g.2114 A>G and g.2037 G>A) in the 5'-UTR and one previously reported variant (g.3836 G>C) in an intron. All three single nucleotide polymorphisms (SNPs) were associated with milk yield (p<0.0001), fat yield (p = 0.0006 to <0.0001), protein yield (p = 0.0232 to <0.0001) and protein percentage (p<0.0001), while no significant associations were detected between the SNPs and fat percentage. A strong linkage disequilibrium (D' = 0.96 to 1.00) was observed among all three SNPs, and a 5 Kb haplotype block involving three main haplotypes with GAG, AGC, and AGG was formed. The results of haplotype association analyses were consistent with the results of single locus association analysis (p<0.0001). The phenotypic variance ratio above 3.00% was observed for milk protein yield that was explained by SNP-g.3836G >C. Conclusion: Overall, our findings provided new insights into the polymorphic variations in bovine GALE gene and their associations with milk protein concentration. The data indicate their potential uses for marker-assisted breeding or genetic selection schemes.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.7
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• pp.923-930
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• 2009

This study was conducted to compare three models: two random regression models with and without considering heterogeneity in the residual variances and a lactation model (LM) for evaluating the genetic ability of Holstein cows in Korea. Two datasets were prepared for this study. To apply the test-day random regression model, 94,390 test-day records were prepared from 15,263 cows. The second data set consisted of 14,704 lactation records covering milk production over 305 days. Raw milk yield and composition data were collected from 1998 to 2002 by the National Agricultural Cooperative Federation' dairy cattle improvement center by way of its milk testing program, which is nationally based. The pedigree information for this analysis was collected by the Korean Animal Improvement Association. The random regression models (RRMs) are single-trait animal models that consider each lactation record as an independent trait. Estimates of covariance were assumed to be different ones. In order to consider heterogeneity of residual variance in the analysis, test-days were classified into 29 classes. By considering heterogeneity of residual variance, variation for lactation performance in the early lactation classes was higher than during the middle classes and variance was lower in the late lactation classes than in the other two classes. This may be due to feeding management system and physiological properties of Holstein cows in Korea. Over classes e6 to e26 (covering 61 to 270 DIM), there was little change in residual variance, suggesting that a model with homogeneity of variance be used restricting the data to these days only. Estimates of heritability for milk yield ranged from 0.154 to 0.455, for which the estimates were variable depending on different lactation periods. Most of the heritabilities for milk yield using the RRM were higher than in the lactation model, and the estimate of genetic variance of milk yield was lower in the late lactation period than in the early or middle periods.