• Journal of Veterinary Clinics
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• v.31 no.4
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• pp.272-277
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• 2014

This retrospective study evaluated the effect of somatic cell count (SCC) in milk during early lactation on reproductive performance in dairy cows. Data were collected on 774 cows from six dairy farms, including cow parity, dates of previous calving, artificial insemination, pregnancy diagnosis, incidence of postpartum endometritis, reproductive performance (the intervals from calving to first insemination and conception), milk production and SCC. Data on 774 lactations were grouped based on the average first 3 months postpartum linear somatic cell score (SCS) as T1 (< 3.0, n = 521), T2 (3.0 ${\leq}$ and < 4.0, n = 113), and T3 (${\geq}$ 4.0, n = 140) groups. The odds ratio (OR) for the probability of endometritis increased 1.6 (p < 0.05) and 3.2 times (p < 0.0001) in the T2 and T3 groups, respectively, compared with that in the T1 group. The hazard of first insemination by 150 days in milk (DIM) was lower in the T3 group (hazard ratio [HR]: 0.76, p < 0.01) than in the T1 group. First insemination conception rate did not differ among the 3 groups (28.7-34.2%, p > 0.05). The hazard of pregnancy by 365 DIM in the T3 group was lower (HR: 0.75, p < 0.05 respectively) than in the T1 and T2 groups. The SCS during 4 to 7 months postpartum differed (p < 0.0001) among the 3 groups. Farm and cow parity were important risk factors for higher SCS (${\geq}$ 4.0). Multiparous cows were more likely to have a higher SCS (OR: 2.26, p = 0.0005) compared with primiparous cows. In conclusion, higher SCS (${\geq}$ 4.0) during early lactation was associated with decreased reproductive performance of dairy cows.

• Journal of agriculture & life science
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• v.50 no.5
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• pp.173-182
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• 2016

This study was aimed to identify the phenotypic relationships between calving interval and lactation curve parameters in Korean Holstein cow. The data of 36,505 lactation records was obtained from the Dairy Herd Improvement program run by Dairy Cattle Improvemnet Center of National Agricultural Federation of Korea. All lactation records were collectied from the multiparous cows calving between 2011 to 2013. The estimated lactation curves were drawn using Wood model based on actual milk yield records, and NLIN Procedure of SAS program (ver. 9.2). General linear multivariate models for calving interval, 305-d milk yield, lactation parameters(A, b, c), persistency, peak day, and peak yield included fixed effects of calving year-season (spring, summer, fall and winter) and parity(2, 3 and 4). For calving interval, 305-d milk yield, lactation parameters(A, b, c), persistency, peak day and peak yield, all two fixed effect(calving year-season, parity) were significant(p<0.05). The estimated lactation functions using Wood model for 2, 3, and 4 parity were yt=24.66t0.175e-0.00302t, yt=24.69t0.192e-0.00334t, and yt=24.22t0.200e-0.00341t, respectively. Phenotypic correlation (partial residual correlation) between calving interval and 305-d milk yield, A, b, c, persistency, peak day, and peak yield were 0.093, -0.014, 0.028, -0.046, 0.099, 0.085, and 0.052, respectively. To conclude, if calving interval increase then ascent to peak, persistency, peak day and peak yield are increase, and descent after peak is decrease. So, total 305-d milk yield is increase.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.6
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• pp.801-806
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• 2016

The objectives of this study were to evaluate the effects of different supplemental levels of Saccharomyces cerevisiae fermentation product (SCFP; Original XP; Diamond V) on lactation performance in Holstein dairy cows under heat stress. Eighty-one multiparous Holstein dairy cows were divided into 27 blocks of 3 cows each based on milk yield ($23.6{\pm}0.20kg/d$), parity ($2.88{\pm}0.91$) and day in milk ($204{\pm}46d$). The cows were randomly assigned within blocks to one of three treatments: 0 (control), 120, or 240 g/d of SCFP mixed with 240, 120, or 0 g of corn meal, respectively. The experiment was carried out during the summer season of 2014, starting from 14 July 2014 and lasting for 9 weeks with the first week as adaption period. During the experimental period, average daily temperature-humidity index (measured at 08:00, 14:00, and 20:00) was above 68, indicating that cows were exposed to heat stress throughout the study. Rectal temperatures tended to decrease linearly (p = 0.07) for cows supplemented with SCFP compared to the control cows at 14:30, but were not different at 06:30 (p>0.10). Dry matter intake was not affected by SCFP supplementation (p>0.10). Milk yield increased linearly (p<0.05) with increasing levels of SCFP. Feed efficiency (milk yield/ dry matter intake) was highest (p<0.05) for cows fed 240 g/d SCFP. Cows supplemented with SCFP gained (p<0.01) body weight, while cows in the control lost body weight. Net energy balance also increased linearly (p<0.01) with increasing levels of SCFP. Concentrations of milk urea nitrogen (p<0.01) decreased linearly with increasing levels of SCFP, while no difference (p>0.10) was observed among the treatments in conversion of dietary crude protein to milk protein yield. In summary, supplementation of SCFP alleviated the negative effect of heat stress in lactating Holstein dairy cows and allowed cows to maintain higher milk production, feed efficiency and net energy balance. Effects of SCFP were dose-dependent and greater effects were observed from higher doses.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.565-576
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• 2020

Recently, Jersey cattle was introduced and produced by embryo transfer to Korea. This study was conducted to investigate the differences of milk compositions between Jersey and Holstein cows and the relationship between days in milk (DIM) and milk compositions during early lactation. Data were collected from twelve lactating cows from Department of Animal Resources Development at National Institute of Animal Science. Cows in parity 1 were used, and calved at spring from April to March of 2017. All cows were housed in two sections within a free-stall barn, which divided into six from each breed, and received a basal total mixed ration. Milk samples of each cow were collected at 3 DIM and 30 DIM for analyzing the milk compositions, including fatty acids (FA), amino acids and minerals. Total solids, citrate, and milk urea nitrogen level were differed between the breeds (p < 0.05). As DIM went from 3 to 30, milk protein, total solids, and somatic cell count decreased (p < 0.05), but lactose increased in all breed milk (p < 0.05). Citrate and free fatty acid (FFA) elevated in Jersey milk (p < 0.05), whereas reduced in Holstein milk (p < 0.05). Proportions of some individual FA varied from the breeds. Myristic (C14:0), palmitic (C16:0), and arachidonic acid (C20:4) in milk from all cows were higher at 3 DIM than at 30 DIM (p < 0.05). Also, stearic (C18:0) and oleic acid (C18:1) were lower at 3 DIM than at 30 DIM (p < 0.05), and the C18:1 to C18:0 ratio was significantly differed in DIM × breed interactions (p < 0.05). The contents of the individual amino acids did not differ from the breeds. Calcium, phosphorous, magnesium, and zinc (Zn) contents was significantly increased in Holstein milk than Jersey milk at 3 DIM. Also, K and Zn concentrations were higher in Holstein milk than in Jersey milk at 30 DIM (p < 0.05). It was concluded that Jersey cows would produce more effective milk in processing dairy products and more proper energy status compared with Holstein cows in early lactation under the same environmental and nutritional conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1699-1707
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• 2000

Thirty-one multiparous Bos indicus${\times}$Bos taurus cows were offered concentrate supplements based on (1) 2 kg wheat bran; (2) 4 kg wheat bran; and (3) concentrate (30 maize: 67 wheat bran) at 0.5 kg per 1.0 kg milk produced, in a one year study in India. All supplements also contained 2 parts of a mineral mixture and 1 part salt. Cows were allocated to treatments at calving on parity (2nd and 3rd calf) with 13, 8 and 10 cows respectively in treatments 1, 2 and 3. They were individually fed for whole lactation, the basal diet being ad libitum berseem clover plus 2 kg wheat straw in the cool season/winter (period 1) and chopped maize in summer (period 2). Diets with berseem offered TDN and CP contents of 67.6, 18.2; 65.5, 16.8; and 67.5, 16.8 percent; and with maize fodder 62.6, 12.0; 62.6, 12.5; and 63.3, 12.5 percent for treatments 1, 2 and 3, respectively. Total dry matter (DM) intakes (1) 9.9 kg, (2) 10.9 kg and (3) 11.1 kg DM/day and intake of nutrients (TDN, CP) increased with level of supplementation (p<0.01), but effects of treatment on animal performance were not significant. Cow milk yields averaged (1) 7.9 kg, (2) 8.1 kg and (3) 8.8 kg milk/day (p>0.05) for lactation lengths of 252, 270 and 220 days (p>0.05) and cows gained +7.3; +8.1; and +12.0 kg respectively over their lactation (p>0.05). Wheat bran was used effectively as the sole energy component in concentrates for lactating dairy cows. Its use could potentially reduce feed costs and demands for cereal grain. Reduced concentrate levels may be considered if green forages of high nutrient content are fed ad libitum. Associated economic advantages or disadvantages require further evaluation.

• Journal of Veterinary Clinics
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• v.19 no.4
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• pp.391-396
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• 2002

cows, in order to suggest a means for the improvement of milk production. A total of 30 Holstein cows (3rd to 5th of parity) were used and assigned to two groups according This study investigated blood biochemical values between high and low yielding dairy to milk production levels at 15, 30, 60 and 90 days postpartum. Milk production of group A was less than an average of 27 kg/day and that of group B was an average of 30 kg/day. Blood samples were collected by jugular venipuncture from each cow six times at 15 days before the anticipated calving date, within 12 hours postpartum (0 days) and at 15, 30, 60 and 90 days after calving. In serum mineral concentrations, group B was consistently higher than group A in both Mg and Ca. Inorganic phosphorus concentrations showed a little fluctuation between the groups at antepartum and at postpartum, but group B was significantly higher than group A at 15 and 30 days after calving (p < 0.05). In serum biochemical values cholesterol concentrations were consistently higher in group B except at 0 days. BUN and glucose concentrations did not differ between the groups. The concentration of vitamin A of group B was significantly higher than group A at 15 days before the anticipated calving date and at 15 days postpartum (p < 0.01), but at 30, 60 and 90 days postpartum vitamin A concentration of both groups were similar. Vitamin E concentration did not differ between the groups during the experimental period. Results of this study suggest that raising the levels of Mg, Ca, Pi and vitamin A in serum would be effective in increasing milk production of low producing cows.

• Korean Journal of Organic Agriculture
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• v.25 no.1
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• pp.219-231
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• 2017

The aim of this study was to determine the effects of feeding of different organic diets (based on fatty acid contents) on CLA and fatty acid concentration of raw milk. Total two hundred and ninety Holstein cows were divided into control, treatment 1 and treatment 2 groups according to the parity and milk yield. Control diet was contained higher C16:00, C18:2 and SFA. Treatment 1 diet was higher in C18:1, C18:2, UFA and treatment 2 diet was higher in MUFA and C18:3 and PUFA. The results indicated that the C16:0 concentration in raw milk was greater in the group of treatment 2 than in control and treatment 1 (p<0.05). The concentration of CLA in treatment 2 was higher compared to treatment 1 and control groups (p<0.05). The ration of n-3/n-6 was higher in treatment 2 group compared with control and treatment 1 (p<0.05). In conclusion, feeding 100% of grass feed for dairy cows increases CLA and n-3 content in milk. From now on, basis on our study, development of functional milk will increase a health of children and old people.

• Journal of Embryo Transfer
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• v.19 no.1
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• pp.1-10
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• 2004

These studies were carried out to improve the reproductive efficiency through embryos transfer of Hanwoo IVM/IVF embryos. Following routine IVM/IVF procedure, oocytes and zygotes were cultured far 40 to 44 h in CRlaa medium with BSA. Then 2 to 8-cell embryos were removed the cumulus cell and were cultured in CRlaa medium containing 10% fatal bovine serum and 2.5 mM taurine in 5% $O_2$ and 5% $CO_2$ at 38.5$^{\circ}C$. The fresh embryos of the morulae and blastocysts cultured for 6 to 9 days in vitro or the frozen-thawed embryos were transferred into recipients. The pregnancy rates of the blastocyst produced for 6, 7, 8, and 9 days in vitro culture were 59.4, 68.2, 66.0 and 100%, respectively. In the developmental stage, pregnacy rates of early blastocysts (61.1%), blastocysts(64.7%) and expanded blastocysts(69.5%) were higher than that of morulae stage(20.0%). The pregnancy rates according to the corpus luteum grades of A, B and C in recipients were 73.6, 62.9 and 50.0%, respectively. Effects of donor-recipients synchrony of after day 2, 1 and 0, before day 1 and 2 on the pregnancy rates were 35.7, 65.5, 72.6, 67.9 and 60.0%, respectively. Pregnancy rates of the body condition score of recipients $\leq$2(71.3%) were higher than those of $\geq$3.0 score(40.0%). The pregnancy rates according to the parity of recipients when embryo was transferred to cow(70.6%) was higher than in heifer(59.1%). The pregnancy rates according to hormone treatment before embryo transfer were 69.9% in hCG + GnRH administration group and 63.0% in control group. Fresh and frozen-thawed embryos on the pregnancy rates were 70.6 and 36.4%, respectively. Pregnancy rates in single and AI+single was 90.0% and 64.8%. Pregnancy rates in twin induction was better than in single. These results indicate that pregnancy rates after transfer were affected on the embryo ages, donor-recipient synchrony, body condition score of recipients, corpus luteum status, parity and hormone treatment to recipients.

• Korean Journal of Agricultural Science
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• v.21 no.1
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• pp.45-53
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• 1994

This study was conducted to estimate the genetic and environmental effects on lactation yield and milk compositions in Holstein cows. The data analysis were the records of 159 cows rearing at Nation Animal Breeding Institute from 1990 to 1991. The least square means were estimated on milk and fat yield in lactation yield, and the percent of fat, protein, solids-not-fat and total solid in milk composition. The results obtained are summarized as follows: 1. The average yield of milk and fat in 305 days were $7,26.56{\pm}3,57.24$ and $254.65{\pm}44.94Kg$ and the percent of fat, protein, solids-not-fat and total solid were $3.69{\pm}0.43$, $3.32{\pm}0.41$, $9.15{\pm}0.49$ and $12.75{\pm}0.96$ and the coefficients of variation were 18.68, 17.64, 11.88 and 12.34% for milk yield, fat yield, fat percent and protein percent, respectively. 2. The effect of sires was highly significant at 1% level in milk and fat yield and fat percent, and significant at 5% level in protein and total solid percent. Among the sires, B, L and O sire were superior in milk yield with 7,571.22, 7,499.11 and 7,420.58 Kg, and A, F and K sire were superior in protein percent with 3.75, 3.64 and 3.65, respectively. 3. The effect of parity was highly significant at 1% level in milk yield, and significant at 5% level in fat yield. Among the parities, the 3rd parity was superior in milk and fat yield with 7,634.54 and 274.98 Kg, and the 4th and over was superior in fat and protein percent with 3.90 and 3.50, respectively. 4. The effect of calving seasons was highly significant at 1% level in milk yield, and significant at 5% level in fat yield, and the percent of fat, protein and total solid. Among the calving seasons, spring and winter were superior in milk yield with 7,310.31 and 7,364.57 Kg, also spring and winter were superior in protein percent with 3.68 and 3.52, respectively.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.335-346
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• 2004

Factors associated with milk urea nitrogen on milk yield and milk composition were investigated in this study regarding feeding management and Physiological status of lactating cows. The data for 3 years between 1999 and 2002 for this study were collected from 129,645 cows by Korean Agricultural Cooperatives Federation. The objectives of this study were to describe the relationships between milk urea concentrations and seasonal factors, cow factors and production of milk, milk fat, protein and somatic cell score(SCS). Milk urea was highest in summer and it also showed a nonlinear association with milk yield. Milk yield was higher at milk urea concentrations of 21 ${\sim}$ 24mg/dl, however it decreased at higher level of milk urea concentrations than 24mg/dl. Milk urea was higher with increased parities of cows and in particular, at 3 to 4 parities. There was a negative association between milk urea and SCS in milk. SCS in milk was lowest at milk urea concentrations of 2l${\sim}$24mg/dl. Milk fat and milk protein were greatly affected by days in milk(DIM), year of birth, season and milk urea concentrations, respectively. While milk urea increased in summer, milk fat and protein were decreased. Milk protein decreased according to longer days in milk. With regard to the influences of parity, milk protein in overall was negatively correlated to milk urea in all lactations, however the extent of decrease of milk protein at high concentrations of milk urea was bigger at third lactation. The balanced supply of energy and protein to the animals might have greatly affected the urea concentrations and protein content of milk.