• Nutrition Research and Practice
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• v.10 no.2
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• pp.198-205
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• 2016

BACKGROUND/OBJECTIVES: A healthy diet has been reported to be associated with physical development, cognition and academic performance, and personality during adolescence. This study was performed to investigate the relationships among milk consumption and academic performance, learning motivation and strategies, and personality among Korean adolescents. SUBJECTS/METHODS: The study was divided into two parts. The first part was a survey on the relationship between milk consumption and academic performance, in which intakes of milk and milk products and academic scores were examined in percentiles among 630 middle and high school students residing in small and medium-sized cities in 2009. The second part was a survey on the relationships between milk consumption and learning motivation and strategy as well as personality, in which milk consumption habits were collected and Learning Motivation and Strategy Test (L-MOST) for adolescents and Total Personality Inventory for Adolescents (TPI-A) were conducted in 262 high school students in 2011. RESULTS: In the 2009 survey, milk and milk product intakes of subjects were divided into a low intake group (LM: ${\leq}60.2g/day$), medium intake group (MM: 60.3-150.9 g/day), and high intake group (HM: ${\geq}151.0g/day$). Academic performance of each group was expressed as a percentile, and performance in Korean, social science, and mathematics was significantly higher in the HM group (P < 0.05). In the 2011 survey, the group with a higher frequency of everyday milk consumption showed significantly higher "learning strategy total," "testing technique," and "resources management technique" scores (P < 0.05) in all subjects. However, when subjects were divided by gender, milk intake frequency, learning strategy total, class participation technique, and testing technique showed significantly positive correlations (P < 0.05) in boys, whereas no correlation was observed in girls. Correlations between milk intake frequency and each item of the personality test were only detected in boys, and milk intake frequency showed positive correlations with "total agreeability", "organization", "responsibility", "conscientiousness", and "intellectual curiosity" (P < 0.05). CONCLUSION: Intakes of milk and milk products were correlated with academic performance (Korean, social science, and mathematics) in Korean adolescents. In male high school students, particularly, higher milk intake frequency was positively correlated with learning motivation and strategy as well as some items of the personality inventory.

• Journal of Nutrition and Health
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• v.24 no.3
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• pp.219-229
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• 1991

The longitudinal changes on human milk volume per day and lactational performance of 23 Korean lacto-ovo-vegetarians(primiparae=11, multiparae=12) from 0.5 to 5 months after parturition have been studied by test weighing method. The human milk volume per day tended to increase during lactation. The mean volume (SD, ml/day) at 0.5, 1, 2, 3, 4, 5 months were 502(102), 692(127), 697(100), 684( 125), 757(52), 703(70), respectively. The overall mean volume was 661$\pm$132ml/day. The peak milk volume during the lactation was observed at most lactating women at the 1st month. The distributions of the individual mean volume during the first 5 months of lactation were found over 750m1(8.7% ), 650-750ml(47.9% ), 550-650m1(2l.7% ), and 450-550ml(2l.7% ) The number of feeding per day was 8.1 ($\pm$1.0) at 0.5 months postpartum, which was consistently decreased. However, the mean volume per feeding was increased from 62($\pm$9.5)ml at 0.5 month to 112($\pm$13.3)ml at 5 months postpartum. The milk volume was correlated with the peak volume. and maternal age. but not with weight before delivery. maternal height and birth weight. No differences of milk volume and lactational performance between facto-ovo-vegetarian and nonvegetarian women were observed. This study suggests that the human milk volume cited in the recommended dietary allowances for Koreitns is over estimated.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.8
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• pp.1137-1143
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• 2013

To evaluate lactation performance and changes in plasma and fecal lipopolysaccharide (LPS) concentrations in response to the supplementation of Saccharomyces cerevisiae fermentation product (SC), two dairy farms were selected. On each farm, 32 cows in early to mid lactation (21 to 140 DIM) were blocked by parity and days in milk (DIM), and randomly assigned to one of the two treatments within block (Control or 56 g SC/cow/d). Effect of SC on lactation performance (daily) and changes in blood and fecal LPS level were examined on d 0 and 28 of supplementation. The results showed that SC supplementation increased lactation performance of dairy cows on both farms. On Farm 1, milk production, 3.5% fat corrected milk (FCM), and yield of milk fat and protein were greater (p<0.01) for cows supplemented with SC. Supplementation of SC increased percentage milk fat (p = 0.029) from 81 to 110 DIM. There was no significant effect (p>0.05) of SC supplementation on percentage of milk protein, dry matter intake and feed efficiency. On Farm 2, cows supplemented with SC had a greater (p<0.05) milk yield, percentage of milk fat and milk protein, yield of milk fat and protein, 3.5% FCM and feed efficiency. Supplemental SC had no effect on LPS concentrations in feces (p>0.05) while it trended to reduce (p = 0.07 or 0.207) the concentration in plasma. The results indicate that supplemental SC can increase lactation performance of dairy cattle and has potential for reducing plasma LPS concentration.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.9
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• pp.1327-1333
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• 2007

Lactose synthase catalyses the formation of lactose which is the major osmole of bovine milk and regulates the milk volume. Alpha-lactalbumin (${\alpha}$-LA) is involved in the synthesis of lactose synthase in the mammary gland. Therefore ${\alpha}$-LA is regarded as a plausible candidate gene for the milk yield trait. To determine whether ${\alpha}$-LA is associated with milk performance traits, 1,028 Chinese Holstein cows were used to detect polymorphisms in the ${\alpha}$-LA by means of single-strand conformation polymorphism (SSCP). Two nucleotide transitions were identified in the 5'flanking region and intron 3 of ${\alpha}$-LA. Associations of such polymorphisms with five milk performance traits were analyzed using a general linear model procedure. No significant associations were observed between these polymorphisms and the five milk performance traits (p>0.05). RH mapping placed ${\alpha}$-LA on BTA5q21, linked most closely to markers U63110, CC537786 and L10347 (LOD>8.3), which is far distant from the region of the quantitative trait locus (QTL) on bovine chromosome 5 for variation in the milk yield trait. In summary, based on our findings, we eliminated these SNPs from having an effect on milk performance traits.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.1
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• pp.25-29
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• 1991

Performance and production of twenty lactating Holstein cows fed diets containing either soybean meal or fish meal as the primary protein source were compared in a continuous or split feeding scheme. At 1 wk prepartum four groups of five animals were placed on each experimental diet. Animals assigned to the continuous feeding scheme were continued on these diets for 10-wk postpartum. At 4 wk postpartum, the diets for the groups assigned to switching protein sources were changed. These treatments were continued for another 6 wk. Milk production and dietary intakes were recorded daily. Milk constituents were measured every 2 d. Cows weights, rumen fluid samples and jugular blood samples were collected weekly. Data showed no effect of early lactation diet on cow performance or milk characteristics. Overall, compared to the soybean meal diet, the fish meal diet lowered the milk fat percent and increased production of milk per unit of dry matter ingested. No differences were observed for volatile fatty acid content of rumen fluid, blood mineral content, milk protein, somatic cell count, 4%-fat corrected milk, dry matter intake, or body weight.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.11
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• pp.1516-1519
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• 2001

The data consisted of 369 lactation records for calvings over a sixteen-year period (1972-1987) and included only cows that had normal milk records. The data were analysed using a linear model containing the fixed effects of parity, year of calving and season of calving. The least squares means${\pm}$S.E. were $1,273{\pm}58.4kg$ for milk yield, and for post-partum body weight (kg) at 2, 3 and 4 months after calving were $343.40{\pm}3.96$, $346.10{\pm}4.10$ and $352.54{\pm}4.26$, respectively. With the exception of season of calving, the effects of parity and year of calving were significant (p<0.01) on the performance of the animals. Thus, the mean-milk yields 1162, 1351 and 1350, were similar for pre-, peak- and post rainy seasons, respectively. On the other hand, as parity increased from 1 to 3, milk yield also increased, but thereafter, there was a gradual decline in milk yield. Similarly, post-partum body weight also increased with parity. However, no consistent pattern for year effect was observed which probably was a reflection of the variation in climatic conditions, or forage quality and/or availability. The phenotypic correlations between milk yield and post-partum body weights were negative and small (ranging from -0.01 to -0.08). However, high milk production in cows was associated with longer calving interval. The implications from the phenotypic correlations are suggestive of one or two possibilities. Firstly, selection for increased body weight may actually result in decreased milk yield. Also, a substantial genetic antagonism may exist between milk yield and fertility in the crossbred cows. Therefore, it is important that selection to improve milk production should take into consideration the reproductive performance of the cows.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.5
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• pp.677-684
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• 2003

Twenty eight multiparous lactating cows were utilized in an experiment to evaluate the response to an exogenous fibrolytic enzyme on their lactational performance during early lactation period (in terms of milk production, milk composition, feed intake, milking efficiency, body weight change) and the exact time of this response. Cows were randomized into two groups (14 each) with similar parities and were fed a concentrate ration of barley, ground corn, soybean meal, and wheat bran and roughage ration of alfalfa hay. One of the two groups was supplemented with the fibrolytic enzyme immediately after parturition up to 100 post partum. The experiment was of two phases with 50 days each. The enzyme, which has a cellulase/hemicellulase activity (derived from Trichoderma group), was added to the concentrate part of the ration in a dry powder form. Milk production, 3.5% fat corrected milk, energy corrected milk were higher (p<0.05) for cows fed treated diet. At the same time, No differences were observed in percentages of milk components, feed intake, body weight, body weight change, or rectal temperature for the whole experimental period or during any of the two phases. Efficiency of milk production was higher (p<0.05) for treatment group cows than for that of the control ones. However, efficiency was better during the second phase than during the first phase. Feeding enzyme treated diets to dairy cows improved lactational performance during early 100 day of the lactation period. However, the first 50 days of lactation looked to be the critical.

• Animal Bioscience
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• v.36 no.10
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• pp.1546-1557
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• 2023

Objective: The present study aimed to evaluate the effects of extruded and unextruded feeding on the performance, milk composition, digestibility and ruminal fermentation of dairy cows through a meta-analysis. Methods: The database was compiled from 53 studies in Scopus and PubMed. The data were analyzed using a random effects model in OpenMEE software. Extruded feed was grouped as the experiment group while and the others as control group. The bias of publication in the main parameter of dairy performance was evaluated by a funnel plot. Results: The result showed that extruded feed enhanced the milk yield, dry matter and crude protein digestibility, butyrate and valerate acid production (p<0.05). Meanwhile, the extruded feed significantly decreased the milk fat and protein concentration (p<0.05). Also, the iso-butyrate and iso-valerate in unextruded feeding was significantly higher than the extruded feed (p<0.05). Conclusion: It was concluded from the meta-analysis that extruded feed effectively improved the milk production and milk lactose concentration, dry matter and protein digestibility, but not the milk fat and protein concentration.

• Journal of Animal Science and Technology
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• v.65 no.3
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• pp.588-595
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• 2023

The aim of this study was to investigate the effects of heat stress on milk traits in South Korea using comprehensive data (dairy production and climate). The dataset for this study comprised 1,498,232 test-day records for milk yield, fat- and protein-corrected milk, fat yield, protein yield, milk urea nitrogen (MUN), and somatic cell score (SCS) from 215,276 Holstein cows (primiparous: n = 122,087; multiparous: n = 93,189) in 2,419 South Korean dairy herds. Data were collected from July 2017 to April 2020 through the Dairy Cattle Improvement Program, and merged with meteorological data from 600 automatic weather stations through the Korea Meteorological Administration. The segmented regression model was used to estimate the effects of the temperature-humidity index (THI) on milk traits and elucidate the break point (BP) of the THI. To acquire the least-squares mean of milk traits, the generalized linear model was applied using fixed effects (region, calving year, calving month, parity, days in milk, and THI). For all parameters, the BP of THI was observed; in particular, milk production parameters dramatically decreased after a specific BP of THI (p < 0.05). In contrast, MUN and SCS drastically increased when THI exceeded BP in all cows (p < 0.05) and primiparous cows (p < 0.05), respectively. Dairy cows in South Korea exhibited negative effects on milk traits (decrease in milk performance, increase in MUN, and SCS) when the THI exceeded 70; therefore, detailed feeding management is required to prevent heat stress in dairy cows.

• Agribusiness and Information Management
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• v.6 no.2
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• pp.32-39
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• 2014

The goal of this research was to develop a portable system that could be used to evaluate the quality of milk in real time at a raw milk production site. A real-time portable quality evaluation system for raw milk was developed to enable non-destructive quality evaluation of somatic cell count (SCC), fat, protein, lactose, and total solid (TS) in milk samples. A prediction model of SCC, fat, protein, lactose, and TS was constructed using partial least squares (PLS) and 200 milk samples were used to evaluate the prediction performance of the portable quality evaluation system and high performance spectroscopy. Through prediction model development and verification, it was found that the accuracy of high performance spectroscopy was 90% for SSC, 96% for fat, 96% for protein, 91% for lactose, and 97% for TS. In comparison, the accuracy of the portable quality evaluation system was relatively low, at 90% for SSC, 95% for fat, 92% for protein, 89% for lactose, 92% for TS. However, the measurement time for high performance spectroscopy was 10 minutes for 1 sample, while for the portable quality evaluation system it was 6 minutes. This means that the high performance spectroscopy system can measure 48 samples per day (8 hours), while the portable quality evaluation system can measure 80 (8 hours). Therefore, it was found that the portable quality evaluation system enables quick on-site quality evaluation of milk samples.