• 농업과학연구
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• 제42권3호
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• pp.245-251
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• 2015

Records of 490,767 cows collected from 1990 to 2012 by dairy herd milk test of National Agriculture Cooperative Federation The pedigree of dairy cattle were provided by Korea Animal Improvement Association. The data were used to analyze the longevity of dairy cows with the life traits such as days in milk, number of lactation, productive life, and life span. The data were also used to investigate genetic relationship of these longevity traits with profitability of dairy cows, including heritability and genetic correlation. The profitability was calculated with simulation of milk income and production costs for individual cows. Days in milk among the traits had -0.287, -0.572 and -0.536 of genetic correlation with number of lactations, productive life and lifespan, respectively. The heritabilities of life span, number of lactations, productive life, and days in milk were found to be 0.045, 0.047, 0.059 and 0.081, respectively. Genetic correlations of profit with productive life, number of lactations, and days in milk were identified as 0.072, 0.080, 0.098 and 0.101. These results suggested that days in milk was most desirable traits to represent longevity of Holstein dairy cattle. In general, since longevity and profitability were close genetic relationship each other, genetic improvement of longevity is necessary for better profitable cows.

• Journal of Nutrition and Health
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• 제37권9호
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• pp.809-816
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• 2004

The purpose of this study was to evaluate the effect of maternal nutritional status and health behaviors on the concentrations of minerals (Zn, Fe, Ca) and the immunological substances (lactoferrin, sIgA, Iysozyme) in breast milk. Breast milk was collected from 193 healthy Korean women from obstetric clinics and postpartum care centers in Seoul. : 99 colostrum (1 - 5 days postpartum), 33 transitional milk (6 - 10 days postpartum), 61 mature milk (11 - 50 days postpartum). The concentrations of minerals and immunological substance were highest in colostrum and decreased with lactational period. Concentrations of Zn and Fe reduced significantly from colostrum to mature milk, however, Ca concentration stayed constant throughout the lactational period. Contents of lactoferrin, sIgA, and lysozyme were significantly lower in mature milk than in colostrum. Mother's nutritional status, assessed by prepregnancy BMI, had an effect only on colostrum, but not on transition and mature milk. Fe concentration of colostrum was significantly lower in underweight (prepregnancy BMI < 18.5) than in overweight mothers (prepregnancy BMI $\geq$ 23.0). Also lower tendency was observed for sIgA and lysozyme contents, even though the difference was not statistically significant. Pregnancy weight gain had no effect on the breast milk component. Since nutritional factors had some effect on colostrum, the health behaviors of mothers providing colostrum were assessed. The mother's behavior of smoking, drinking, morning sickness, parity, disease, nutrient supplement use had no significant effect on the breast milk component, however, Zn, sIgA, and lysozyme were the somewhat affected components by maternal health behavior.

• Asian-Australasian Journal of Animal Sciences
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• 제14권6호
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• pp.747-753
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• 2001

In this study, the Italian milk recorded buffalo population from 1974 to 1996 was analysed with the purpose to estimate genetic and environmental variability and provide genetic parameters for the most important economic traits. High variability between herds was evident due to the poor knowledge of feeding requirements and husbandry technology in this species compared to cattle. Age at first calving was reduced by 57 days during the considered years following efforts made in better feeding and management from 1990; on the contrary, calving interval has increased by 17 days as a consequence of forcing buffaloes to calve in spring, in order to have the peak milk yield when milk is much better paid. Average milk yield increased by 1853 kg during these years, while lactation duration was reduced by 30 days. Season of calving has no effect on all traits. Calving order has a positive effect on milk yield especially because older cows produce more milk in shorter lactations. Heritability for the age at first calving and calving interval was 0.26 and 0.05 respectively. Heritability of productive traits, milk yield and duration of the lactation was 0.19 and 0.13 respectively, with repeatabilities of 0.40 and 0.26. Genetic trend for milk yield was 2.1 kg milk/year for the bulls and 1 kg for all population. The high genetic variability of milk production as well as duration of the lactation, indicates that there are good opportunities for genetic improvement when including these traits in a selection scheme. The low genetic trend registered over 15 years of recording activity can be explained by the fact that neither progeny testing was performed or selection schemes were implemented, due to the difficulties to use artificial insemination in buffalo.

• Asian-Australasian Journal of Animal Sciences
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• 제31권10호
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• pp.1542-1549
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• 2018

Objective: Because lactation periods in dairy cows lengthen with increasing total milk production, it is important to predict individual productivities after 305 days in milk (DIM) to determine the optimal lactation period. We therefore examined whether the random regression (RR) coefficient from 306 to 450 DIM (M2) can be predicted from those during the first 305 DIM (M1) by using a RR model. Methods: We analyzed test-day milk records from 85,690 Holstein cows in their first lactations and 131,727 cows in their later (second to fifth) lactations. Data in M1 and M2 were analyzed separately by using different single-trait RR animal models. We then performed a multiple regression analysis of the RR coefficients of M2 on those of M1 during the first and later lactations. Results: The first-order Legendre polynomials were practical covariates of RR for the milk yields of M2. All RR coefficients for the additive genetic (AG) effect and the intercept for the permanent environmental (PE) effect of M2 had moderate to strong correlations with the intercept for the AG effect of M1. The coefficients of determination for multiple regression of the combined intercepts for the AG and PE effects of M2 on the coefficients for the AG effect of M1 were moderate to high. The daily milk yields of M2 predicted by using the RR coefficients for the AG effect of M1 were highly correlated with those obtained by using the coefficients of M2. Conclusion: Milk production after 305 DIM can be predicted by using the RR coefficient estimates of the AG effect during the first 305 DIM.

• 한국축산식품학회지
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• 제21권2호
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• pp.156-162
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• 2001

The quality changes of UHT market milk product were investigated by the season and storage conditions. Throughout the year, standard plate counts(SPC) wasnt increased significantly during storage at 5$\pm$1 and 7$\pm$1$^{\circ}C$ for 10 days. And except for summer, SPC was lower than 20,000 cfu/ml after storage at 10$\pm$1$^{\circ}C$ or 10 days. But SPC was rapidly increased from 3 days at 15$\pm$1$^{\circ}C$, and there was gas forming by yeast growth after storage at 30$\pm$1$^{\circ}C$. Values of pH and titratable acidity of market milk products were 6.49 to 6.71 and 0.155 to 0.16%, respectively. pH and titratable acidity were a lot changes at the temperature over 15$\pm$1$^{\circ}C$, and milk products showed a curd at 30$\pm$1$^{\circ}C$. Carbohydrate of market milk product had little difference throughout the year, whereas fat, protein and total solids of market milk products in autumn showed a little higher value than that of other seasons. There were no changes of milk composition during storage periods, but carbohydrate was decreased a little after storage over 20$\pm$1$^{\circ}C$.

• Journal of Animal Science and Technology
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• 제55권6호
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• pp.489-500
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• 2013

Daily milk yields on test days were estimated using morning or afternoon partial milk yields collected by official agencies and the accuracy of the estimates was determined. Test-day data for milk yields consisted of 3,156,734 records of AM/PM partial milking measurements of 255,437 milking Holstein cows from 3,708 farms collected from December 2008 to April 2013. A linear regression model (LRM) was applied to estimate daily milk yields using alternate AM/PM milk yield records within lactation stages, milking intervals, and parities on every daily milk yield. The alternate statistical approach was a non-linear hierarchical model (NHM) in which Brody's growth function was implemented by reflecting an animal's physiological milk production cycle. When compared with LRM, daily milk yields predicted by the NHM were assumed to be functionally related to day in milk (or lactation) stage, milking intervals, and partial milk yields. Since the results were in terms of accuracies based on comparisons of different statistical models, accuracies of estimates of daily milk yields by NHM were close to those determined by the LRM. The average of these accuracies was 0.94 for AM partial milk yields and 0.93 for PM partial milk yields for first calving cows. However, the accuracies of AM/PM milk yield estimations from cows under a calving stage higher than the first parity were 0.96 and 0.95, respectively. Correlations between the estimated daily milk yields and the actual daily milk yields ranged from 0.96~0.98. These accuracies were lower for unbalanced AM/PM milking intervals and the first calving cows. Overall, prediction of daily milk yields by NHM would be more appropriate than by LRM due to its flexibility under different milk yield-related circumstances, which provides an idea of the functional relationship between milking intervals and days in milk with daily milk yields from statistical viewpoints.

• 한국가축번식학회지
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• 제3권2호
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• pp.57-63
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• 1979

In this study, pooled whole semen and diluted semen with skim milk lactose solution and yolk skim milk lactose solution were inseminated at 6 and 7 days interval during 90 days. Egg production, fertility and hatchability were investigated. The results obtained from this study are summarized as following: 1. The average fertility of 57.8% for whole semen was clearly higher than that of 35.2% for diluted semen during 90 days insemination trial. 2. The highest fertility was a, pp.ared from 35 to 99 days after insemination for the whole semen, but from 28 to 60 days for the diluted semen during 90 days insemination trial. 3. In case of 7 days insemination interval, highest fertility of 86.6 and 70.0% for the whole semen and the diluted semen was a, pp.ared on 2 days after insemination and thereafter the fertility was gradually decreased according to passage of insemination. The lowest fertility of 35.0 and 0.0% for the whole semen and diluted semen was a, pp.ared on 1 day after insemination. 4. In case of 6 days insemination interval, highest fertility of 80.0 and 55.8% for the whole semen and the diluted semen was also a, pp.ared on 2 days after insemination and thereafter the fertility was slowly decreased according to passage of insemination. However, lowest fertility of 25.0 and 20.0% for the whole semen and the diluted semen was a, pp.ared on 0 day after insemination. 5 It suggests that there was no difference in fertility between the skim milk lactose and the yolk skim milk lactose dilutors. 6. In case of whole semen, average fertility of 7 days insemnaition interval was a, pp.rently lower than that of 6 days, however there was no difference in fertility between 6 and 7 days insemination interval. 7. Insemination interval of 6 and 7 days and passage day after insemination did not alter egg production and hatchability of fertilized egg production and hatchability of fertilized egg in both whole and diluted semen.

• Asian-Australasian Journal of Animal Sciences
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• 제12권4호
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• pp.585-589
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• 1999

Six crossbred goats in their 2nd or 3rd lactation, were administered bromocryptine at 5 mg/day during early lactation of 15-20 days (period I) and thereafter again at an interval of 13 days, bromocryptine was given for 5 days (period II). Blood samples were collected before (-5, -4, -3, -2, -1) during (1, 2, 3, 4, 5) and after (+1, +2, +3, +4, +5) administration of bromocryptine in both the periods of study. In period I, administration of bromocryptine resulted in a decrease in milk yield to the extent of 16..8% in comparison to before treatment, and 28.5% after the cessation of treatment. The glucose content of blood increased (p<0.01) as the milk yield decreased without any change in NEFA concentration. During period II of bromocryptine treatment the milk yields did not change in spite of a decline in prolactin level, perhaps the effect of previous treatment was prolonged. A decline in protein and lactose content of milk after bromocryptine treatment in both the periods of study, when prolactin level also declined suggests a role of prolactin in protein synthesis and also a depressing effect on lactose synthesis.

• Journal of Dairy Science and Biotechnology
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• 제40권4호
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• pp.151-162
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• 2022

Although many developed countries (USA, Canada, and several EU countries) allow raw milk cheese to be aged more than 60 days, these countries have strict standards for the aging conditions, such as temperature, of raw milk cheese. Spiking experiments were conducted with Camembert cheese made from raw milk, to assess the microbiological safety of raw milk cheese aged for more than 60 days. We spiked Escherichia coli O157:H7 into raw milk with different inoculation levels (high, medium, and low). Camembert cheese was prepared from the inoculated raw milk, then aged in an incubator for up to 9 weeks (63 days). There were no significant differences in pH and water activity (aW) between uninoculated cheese and cheese samples inoculated with E. coli O157:H7 (p<0.05). The pH and aWof the Camembert cheese decreased throughout the storage period. In conclusion, E. coli O157:H7 did not affect the pH and aW of the cheese samples. Cell counts were conducted every week using the agar-plating method. Inoculated cells were completely eliminated, especially in Camembert cheese, after 60 days, and the reduction rate of cells was much faster in Camembert cheese.

• Asian-Australasian Journal of Animal Sciences
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• 제19권5호
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• pp.627-631
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• 2006

The objective of this study was to evaluate the association of genetic differences in the bovine leptin gene and milk yield, reproduction, body condition score (BCS), and plasma glucose level in Iranian Holstein cows. In total, two hundred and thirty eight cows were used and genotyped for a restricted fragment length polymorphism at the leptin gene locus. Two genotypes, AA and AB, have been distinguished which have the frequencies of 0.89 and 0.11, respectively. The genotypes were distributed according to the Hardy - Weinberg equilibrium ($x^2$ = 0.733). During the first 12 wk of lactation, milk yield and composition, live weight, BCS and plasma glucose were measured in 50 cows. Data were analyzed based on a repeated measures ANOVA. During this period, milk yield and composition, live weight, BCS and plasma glucose level were similar among the genotypes. The first cumulative 60-d milk yield, 305-d milk yield, days to first breeding, days open and days from first breeding to conception using previous lactation records were also analyzed using Standard Least Square within mixed models. Fixed effects were year, season, parity and age at calving, and sire. For the reproductive traits the cumulative first 60-d milk yield was also added to the model. Animal was fitted as a random effect. A significant association was detected between the RFLP-AB genotype and 305-d milk yield (p<0.05). The first 60-d cumulative milk yield was similar for the two genotypes (p = 0.21) and tended to be higher in the heterozygous cows. The heterozygous genotypes at the above mentioned locus had a trend to better reproductive performance than the homozygous. The results demonstrate that the RFLP B-allele can yield a higher 305-d milk production with a trend to better reproductive performance.