• Asian-Australasian Journal of Animal Sciences
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• v.23 no.1
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• pp.1-6
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• 2010

The objectives of this study were to i) investigate genetic performance for linear type traits of individual Holstein dairy cows, especially focusing on comparative traits, and to estimate genetic variances for these traits using actual data, and ii) compare genetic performance and improvement of progeny by birth country of the cows. Linear type traits defined with five comparative traits on this study were general stature composite (GSC), dairy capacity composite (DCC), body size composite (BSC), foot and leg composite (FLC), and udder composite (UDC). These traits were scored from 1 to 6 with 1 = poor, 2 = fair, 3 = good, 4 = good plus, 5 = very good and 6 = excellent. Final scores (FS) were also included in this study. Data used was collected from the years 2000 to 2004 by the Korea Animal Improvement Association (KAIA). Only data of more than five tested cows by herd appraisal date and by sires having more than ten daughters were included to increase the reliability of the data analyses. A total of 30,204 records of the selected traits, which was collected from 26,701 individuals having pedigree information were used. Herd appraisal date, year of age, lactation stage (grouped by month), and time lagged for milking (in hours) were assumed as fixed effects on the model. Animal additive genetic effects considering pedigree relationship and residual errors were assumed with random effects. Year of age at appraisal date was classified from one to nine years of age, assigning the value of nine years of age for animals that were greater than or equal to nine years of age. From our results, the estimate for heritability was 0.463, 0.346, 0.473, 0.290, and 0.430 on GSC, DCC, BSC, FLC and UDC, respectively. The estimate for FS heritability was 0.539. The greatest breeding values for GSC were estimated for Canada, with the breeding values for American lines increasing for 10 years starting in 1989 but tending to decrease after that until 2004. For DCC, the breeding values for American and Canadian lines showed similar patterns until 1999, after which the breeding values for the American lines declined sharply. For BSC, data from Korea, Canada and the USA followed similar trends overall except when the breeding values of the American lines decreased starting in 1999. Overall, the methods used to evaluate genetic performance in this study were acceptable and allowed for the discovery of differences by country of genetic origin, likely due in part to the American use of selection indexes based primarily on milk yield traits until methods for evaluating other traits began to emerge.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.10
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• pp.1525-1538
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• 2007

Because of the increasing evidence of potential benefits of conjugated linoleic acid (CLA) on human health, there is a need to investigate its status in commercial dairies and develop feeding strategies to enhance the content and supply of CLA in milk and milk products. A two-year experiment was conducted to study the status of milk fat c-9, t-11 CLA on four selected commercial dairy farms in Utah (two) and Idaho (two), USA. Farms A and C grazed cows on pasture and supplemented with 7.0 kg/cow per day of their respective grain mixes during summer, while conserved forage and grain mix was fed during winter. Farm B fed a total mixed diet all year, with 10% of diet dry matter as fresh cut pasture during summer. Farm D had 1/3 of its cows grazed on pasture and supplemented with a total mixed diet during summer, while the rest were fed a total mixed diet. All cows in Farm D were fed a total mixed diet during winter. Farms A, B, C, and D had on average 80, 400, 150, and 500 milking cows, respectively, with Holstein or its crosses as the major breed. On a year-round basis, Farms A and C produced milk with 60% or more milk fat c-9, t-11 CLA and transvaccenic acid (TVA) contents than Farm B. Similarly, Farm D produced 30% or more c-9, t-11 CLA and TVA in milk than Farm B. Milk fat content of CLA and TVA was 150-200% more during summer compared with winter. Individual cows varied from 0.16 to 2.22% in milk fat c-9, t-11 CLA contents and 89% of the cows had c-9, t-11 CLA contents between 0.3 and 1.0% of milk fat. Individual cow variation was larger on Farms A and C compared with Farm D, with least variation on Farm B. Variation was larger in summer than in winter. The bulk tank milk c-9, t-11 CLA content varied from 0.27 to 1.35% of milk fat. Cows on Farms A and C produced similar or higher amounts of milk fat c-9, t-11 CLA on a daily basis even though their milk yield was lowest among the dairies. Concentration and supplies of c-9, t-11 CLA and TVA were highest from June through September and lowest from February through April, which should be the months for targeting improvement in the content and supply of milk fat c-9, t-11 CLA and TVA.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.3
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• pp.373-377
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• 2007

Alfalfa silage and corn silage are the major dairy feeds in most dairy operations in Michigan, USA. In recent years, the need to improve digestible fiber and dry matter intake of forages to meet the nutrient requirements of high yielding dairy cows and the willingness to plant corn specifically for silage has led plant breeders to focus on the brown mid-rib (BMR) trait. The objective of this study was to investigate the effect of different ratio of alfalfa to BMR corn silage and ration level of forage neutral detergent fiber (NDF) on animal performance of lactating cows in the Upper Peninsula of Michigan. This study was conducted at the Upper Peninsula Experiment Station of Michigan State University in Chatham, Michigan, USA. Two different ratios of forage type (high alfalfa silage/low BMR corn silage, AS, and high BMR corn silage/low alfalfa silage, BMRCS) and two different dietary NDF contents (27% NDF, 27 = low forage/high grain feeding, and 33% NDF, 33 = high forage/low grain feeding) were used. The experimental design was a $4{\times}4$ Latin Square with 20 milking cows (12 multiparous and 8 primiparous). This trial had four 21-day periods with 14 d adaptation and 7 d data collection. Milk yield and body condition score (BCS) on the AS-27, BMRCS-27 and BMRCS-33 treatments were significantly (p<0.05) higher than on the AS-33 treatment. Dry matter intake of the AS-27 and BMRCS-27 treatments was significantly (p<0.05) higher than for the AS-33 and BMRCS-33 treatments. Milk urea nitrogen (MUN) on the AS-33 treatment was significantly (p<0.05) higher than on the other diet treatments. A key finding of this study was that the BMRCS-33 (higher amounts of brown mid-rib corn silage than alfalfa silage, high forage and low grain feeding diet at 33% NDF) led to the equal highest milk production whilst having the equal lowest dry matter intake. This study demonstrated that the diet with higher ratio of highly digestible NDF forage such as brown mid-rib corn silage to alfalfa silage could lower grain feeding in the ration.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.248-262
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• 1987

This experiment was conducted to study plant characteristics and dry matter production of several rice varieties. The results are summarized as follows. 1. Culm length was gradually shortened as varieties were improved and showed significant decrease in Japonica X Indica hybrids. 2. Panicle length seems to be shortened as varieties changed from group I to group III. However, varieties in group IV had longer panicle length in spite of shortening tendency in other groups. 3. Leaf blade length was decreased as varieties improved, but leaf blade width was increased. 4. Panicle exertion showed significant decrease as varieties improved. 5. Number of panicles per square meter among Japonica varieties was gradually increased and similar to the number of spikelets per panicle. Number of spikelets on Indica X Japonica hybrids were higher than Japonica varieties, whereas 1,000 kernel weight was slightly decreased. 6. Dry weight of leaf sheath and culm, and leaf blade was highest at the time of heading and the weight of panicle showed significant increase between 10 and 20 days after heading. 7. The maximum crop growth ratios of leaf blade, stem and panicles were attadined at the stage of heading, booting and milking, respectively. 8. The distribution ratio of dry matter was higher in leaf blade than in stem at the tillering stage. At the heading stage, the distribution ratio of dry matter was higher in order of culm, leaf blade and panicle. At the maturing stage, the ratio was higher in order of panicle, stem and laf blade. 9. Correlation coefficients among grain yield, harvest index, and biological yield were all significant and they were positive.

• Korean Journal of Animal Reproduction
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• v.24 no.1
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• pp.19-33
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• 2000

Eighty dairy farms (38 farms responded) in Palmerston North area of New Zealand were questioned by mail questionnaire on: 1) general characteristics, 2) milk yield and feed supplementary, 3) reproductive efficiencies (12 questions) and 4) reproductive disorders (12 questions) from February to July, 1998. Among those 4 items, the reproductive efficiencies (3) and disorders (4), various diseases and culling rates were surveyed and analyzed for Korean dairy farmers (especially in Cheju island) and compared with New Zealand. The results are as follows: 1. Fifteen farms in 38 dairy farms relied entirely on artificial insemination, the rest of 23 dairy farms (60.5%) raised 5∼6 bulls to increase conception rate. The dairy farmers in Palmerston North used artificial insemination from Oct 4th to Dec 10th for 42.8 days, and then used bulls from that point to coming Jan 10th for 41.4 days. The submission rate within 3, 6 and 10 weeks following the initiation of AI season was 84.7, 93.9 and 97.9% respectively. 2. The average age of heifers at the first estrus, pregnancy and calving was 11.0, 18.0 and 24.7 months respectively, and an average 1.4 estrus cycles were required for conception. The intervals of estrus recurrence and the following conception after calving were 38 and 68 days respectively. 3. Among inseminated cows, calving, abortion and empty cow was 90.9, 1.6 and 7.4% respectively. Calving rate decreased according to increasing farm size, while the number of empty cows decreased. 4. Stillbirth, retained placenta and delivery abnormalities were 5.3, 3.7 and 5.5% respectively, not different depend on herd size. 5. The incidence of milk fever, grass tetany, and ketosis was 3.6, 3.0 and 1.0%, respectively. The delivery abnormality and mastitis treated with medicine were 3.1 and 6.7%, but decreased according to farm size. Lameness was 8.6% on average, but over 10% in farms which has more than 400 milking cows. 6. Among the culled cows (15.5% of the total), those culled due to an old age, lameness and other diseases were 2.9, 1.8 and 4.3% respectively and those culled due to low milk production, reproductive abnormality reduced with farm size. 7. Compared with the data collected in Korea, the reproductive efficiency was better, and lameness, metabolic problem and culling rate were higher in New Zealand