• Korean Journal of Animal Reproduction
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• v.12 no.2
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• pp.91-96
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• 1988

A study was conducted to improve breeding efficiency of dairy and beef cows on Cheju Island. Milk progesterone and plasma progesterone profiles were determined by using radioimmunoassay techniques during the oestrus cycle, onset on oestrus and during the gestation period. Progesterone connections in milk were very low during the oestrus with a means value of 2.4ng/ml and 4.6ng/ml at the onset of oestrus but gradually declined at 4 to 9 hr after oestrus. In the cyclic cow, milk progesterone concentraitons in the early part of the cycle, ranged from 3 to 5ng/ml and increased from 6.0 to 11.6ng/ml on day 13 to 21 of cycle. Milk progesterone concentrations of pregnancy cows ranged from 5.0 to 40ng/ml during the gestation and grom basal line to 3.5ng/ml for nonpregnant cows. Plasma progesterone concentrations of beef during pregnancy period ranged form 3.0 to 33ng/ml and basal levels ranged from 0 to less than 2.5ng/ml for non-pregnant beef cows.

• Journal of Veterinary Clinics
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• v.25 no.2
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• pp.136-138
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• 2008

On a dairy farm, a Holstein cow had consistently shown an intersucking behavior within the milking herd. It has been considered as one of several behavioral disorders primarily coming from feeding management failure during weaning period. Due to their behavior, injured teats of other milking cows could decrease milk production. Through tongue surgery, by producing a convex shape of the dorsum of the tongue after suturing the excised ventral region, the intersucking behavior was forcefully corrected and disappeared thereafter within the dairy herd without any complications.

• Journal of agriculture & life science
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• v.43 no.4
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• pp.15-20
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• 2009

The transition from pregnancy to lactation, commonly referred to as the "transition period" is characterized by dramatic changes in metabolic processes and their regulation in order to prepare the dairy cow for parturition and lactogenesis. An important adaptation to lactation is the increase in gluconeogenesis by the liver to meet the tremendous increase in demand of glucose for lactose synthesis, and the accumulation of lipid in adipose tissue during pregnancy, its mobilization that begins prior to lactation and the dramatic increase in plasma NEFA concentration early lactation. Epinephrine and insulin, the homeostatic regulators of metabolism are responsible for the adaptations of lipid and carbohydrate metabolism in support of milk production along with mobilization of body fat to meet overall energy demands because dry matter intake is insufficient to meet these demands during early lactation.

• Journal of Animal Science and Technology
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• v.65 no.2
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• pp.459-472
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• 2023

Korea is currently developing country-specific emission factors to support the 2050 zero-carbon campaign. Dairy cattle represent one of the largest livestock industries in Korea, and the industry is estimated to continue increasing because of an increase in milk demand. However, country-specific emission factors for dairy cattle are currently only available for calculating methane (CH₄) emissions from enteric fermentation. Two experiments were conducted to evaluate CH₄ and nitrous oxide (N₂O) fluxes from sawdust-bedded barn in dairy cow and steer, as well as dairy cattle manure composting lots. The greenhouse gas (GHG) fluxes were quantified using the open-chamber method and gas chromatography. CH₄ fluxes from steer, dairy cow, and manure compost were 27.88 ± 5.84, 36.12 ± 10.85, and 259.44 ± 61.78 ㎍/head/s, respectively. N₂O fluxes from steer, dairy cow, and manure compost were 14.04 ± 1.27, 4.11 ± 1.57, and 3.97 ± 1.08 ㎍/head/s, respectively. The result of this study can be used to construct country-specific data for GHG emissions from manure management. Thus, the application of mitigation strategies can be prioritized based on the GHG profile and targeted source.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.6
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• pp.957-964
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• 2020

Objective: An experiment was conducted to determine the effect of partial replacement of soybean meal (SBM) by white lupine seeds (WLS) on milk yield and quality, feed efficiency and rumen fermentation of high-yielding dairy cows. Methods: Thirty multiparous cows of two breeds (20 Holstein and 10 Czech Pied cows) in early mid-lactation received three diets (treatments) in a 3×3 Latin square design with a 28-d period. The dietary treatments were as follows: CON (control total mixed ration with SBM, no WLS), WLS30 (30% of the SBM was replaced, on a dry matter basis, by WLS), and WLS50 (50% of the SBM was replaced by WLS). Results: Feed intake by the cows was not affected (p = 0.331) by the diets. Milk production decreased with increasing proportions of WLS in the diet. Cows fed WLS50 yielded approximately 1 kg/d (p<0.001) less milk than cows fed the CON diet. The proportions of milk fat (p = 0.640), protein (p = 0.507), and lactose (p = 0.709) were not altered by the diet. For milk fat, feeding with WLS50 reduced the proportion of total saturated fatty acids (p<0.001) and increased the proportion of total monounsaturated fatty acids (p<0.001), mainly through oleic acid (p<0.001). No differences were found in feed efficiency, body weight, and blood plasma metabolites between groups. Rumen ammonia-N levels tended (p = 0.087) to increase with increasing proportions of WLS in the diet, whereas no effect of diet on rumen pH was found (p = 0.558). Conclusion: We did not identify the safe range within which raw WLS can efficiently replace SBM in the diet of high-producing dairy cows. In contrast, even partial replacement of SBM by WLS favorably changed the milk fatty acid profile.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.5
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• pp.825-835
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• 2020

Objective: The aim of the present study was to investigate the effect of dietary zinc supplementation of Friesian cows on chemical-nutritional and aromatic properties of Caciocavallo cheese after 7 days (C₇) and 120 days (C₁₂₀) of ripening. Methods: Twenty eight Friesian cows, balanced for parity, milk production and days in milk, were randomly assigned to 2 groups. The control group (CG) was fed with a conventional complete diet, while the experimental group (zinc group, ZG) received a daily zinc supplementation of 60 mg for kg of dry complete feed. During the experimental period, the milk yield was monitored and samples of milk and caciocavallo cheese were collected and analyzed for chemical-nutritional composition and aromatic profile. Results: The enrichment of dairy cows diet with zinc, did not influence milk yield and composition, however a marked reduction of somatic cell count was evidenced. Both in milk and cheese the ZG samples were characterized by a lower concentration of satured fatty acids and an increase in oleic, vaccenic and rumenic acids. The aromatic profile of dairy products was also positively affected by dietary zinc intake, with an increase in concentration of carboxylic acids, esters and lactones. Conclusion: The present results suggest a positive role of dietary zinc intake in improving the quality of bovine milk and related cheese, in particular for the increase in concentration of bioactive fatty acids such as rumenic acid. The changes evidenced in cheese through the analysis of the volatile profile, would be consistent with the development of interesting organoleptic properties, although further evaluations should be performed to confirm the consumer acceptability of these changes.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.658-664
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• 2002

This study was conducted to determine a proper feeding regime for lactating Holstein cows during the warm season in Taiwan. In Feeding Trial, 21 lactating Holstein cows were randomly allotted into three feeding regimes in a Completely Randomized Design. The feeding regimes were roughage fed ad libitum along with concentrate fed either twice daily (2C) or four times daily (4C), and total mixed ration (TMR) for 8 weeks. No significant differences among the three feeding regimes were found in body weight changes, and intakes in terms of dry matter, crude protein and net energy. For milk yield and 4% FCM yield, 4C were higher than the other two feeding regimes (p<0.05). No significant differences were found in milk compositions or differences noted in the yields of the respective milk components. TMR was worse than 2C and 4C (p<0.05) in milk production efficiencies in terms of dry matter intake per kg milk yield, crude protein intake per kg milk protein yield, as well as dry matter intake, net energy intake and crude protein intake per kg 4% FCM yield. Three ruminally fistulated Holstein dry cows were randomly assigned into the same three feeding regimes in a 3${\times}$3 Latin Square Design. No significant differences were found among the feeding regimes in ruminal pH, ammonia nitrogen, total VFA concentration, molar percentages of VFA, and acetic acid: propionic acid ratio (C$_2$/C$_3$). Taken all together, roughage fed ad libitum and concentrate fed four times daily was the better feeding regime for lactating cows during the warm season in Taiwan.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.821-827
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• 2002

The purpose of this study was to evaluate the effect of protected fat and heat-extruded soybean meal on the lactation performance of Holstein cows. Twenty-four cows, consisting of 20 lactating cows and 4 rumen-fistulated dry cows, were randomly allocated into four groups with 5 lactating cows and 1 fistulated cow in each group. A replicated 4${\times}$4 Latin square design with four 21 day periods, including 14 days of adaptation and 7 collection days within each period was employed. The experiment was a 2${\times}$2 arrangement, with or without heat-extruded soybean meal and protected fat inclusion. The dietary treatments consisted of supplements of (a) soybean meal (the control), (b) heat-extruded soybean meal, (c) protected fat, and (d) heat-extruded soybean meal and protected fat. The results showed that there were no significant differences in feed intake, milk yield, milk protein content, milk lactose content and body weight change between the dietary treatments. However, cows supplemented with protected fat showed a significantly increased (p<0.05) milk fat yield, 3.5% FCM and total solid yield. The increase in undegradable intake protein (UIP) via heat extruded soybean meal supplement significantly decreased the urea nitrogen concentration in the blood (p<0.05). Dietary fat inclusion significantly increased the blood cholesterol concentration (p<0.01) and decreased the ruminal pH value (p<0.01). Increased dietary UIP significantly decreased the ammonia nitrogen concentration in the rumen (p<0.01), but did not significantly influence the pH and VFA molar percentage in the rumen. It appears that dietary protected fat inclusion could improve milk fat and solid content. Increased dietary undegradable intake protein through heat extruded soybean meal did not improve milk yield. But it could alleviate the adverse effect of decreased milk protein due to dietary fat supplementation. Increased UIP could also decrease the ammonia nitrogen concentration in the rumen and plasma urea nitrogen concentration in the blood.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.3
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• pp.315-318
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• 2006

Associations were analysed between polymorphisms localized in intron 3 of the growth hormone gene (GH-MspI) and milk production traits of 543 China Holstein cows. A PCR-RFLP method was used for identification of genotypes. The following frequencies of genotypes and alleles were found: 0.77, 0.21 and 0.02 for +/+, +/- and -/-, respectively, and 0.87 and 0.13 for $GH^+$ and $GH^-$, respectively. Significant differences between herds were observed in the frequencies of both genotypes and alleles. The results of least squares analysis showed that in all three lactation phases the GH +/+ cows yielded most milk (p<0.01 for lactation I and p<0.05 for lactations II and III), whereas +/- cows showed higher milk fat content than +/+ individuals (p<0.05 for lactation I and II, and p<0.01 for lactation III). The +/+ cows yielded more fat than +/- individuals (p<0.01 only in lactation I). The +/+ cows yielded more milk protein than +/- individuals (p<0.01 for lactation I, II, and III). The +/+ cows produced milk of higher protein content than that of +/- individuals (p<0.05 only in lactation II). Based on these results, we conclude that the +/+ of GH locus should be the favored genotype in China Holstein cow breeds for use in marker-assisted selection programmes.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.3
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• pp.309-314
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• 2006

The present investigation was undertaken to study the milkability characteristics of Holstein cows. Out of 6,660 initial records 4,607 records were finally included in the analysis after deleting some records with an abnormal range of values for the traits considered. These 4,607 Holstein cows belonged to a total of 122 herds located in a province in Korea. The 'LactoCorder' instrument was used to electronically record the milkability traits at the milking parlor. A total of 19 traits were studied which were broadly classified into milk yield, milking speed, milking time and the electrical conductivity related traits. The SAS 9.1 statistical software was used to carry out analyses. The average maximum milk flow per minute was 3.21 kg/min, while the average milking speed during the main milking process (DMHG) had a mean value of 2.30 kg/min. The total milk yield was 14.14 kg, 62% of which was milked during the first three minutes of the milking. The average total milking time was 8.23 min. Among the three phases of the main milking process, the time of stable milk flow had the longest time (2.97 min) followed by the time at the decline phase (2.62 min). The average time taken to reach the plateau phase was 1.08 min, which can still be reduced further through improved managemental practices. Among milk yield traits, milk yield during the first two (MG2) and three (MG3) minutes of milking had high positive correlation with milking speed traits and negative correlations with almost all the milking time traits except time of incline in milk flow from 0.5 kg/min till the attainment of the plateau phase (tAN). Milking speed traits had negative correlations with total milking time, time at main milking process, time at plateau and with the time at decline. Since there was medium to high negative correlation between the milking speed and the time at plateau, there is a need for selection of cows which have intermediate milking speed so that it could require less milking time and also the optimum (higher and longer) plateau time. Proper pre-stimulation and avoiding over milking will help in further reducing the milking time and thus will add to the net profit of the farmer.