• Asian-Australasian Journal of Animal Sciences
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• v.33 no.1
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• pp.53-60
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• 2020

Objective: The current study was carried out to examine the response of different levels of fat and protein in calf starter on nutrient utilisation, nitrogen metabolism, weight gain, blood parameters, and immunity level in pre-ruminant calves. Methods: Twenty four calves (5 days old) were divided into six groups in a 2×3 factorial design, with two levels of fat (10% and 14%) and three levels of protein (18%, 21%, and 24%). The calves were kept in individual pens for 120 days and fed with whole milk (1/10th of body weight) and calf starter ad-libitum. Daily dry matter intake was recorded; whereas body weight was taken on fortnightly basis to calculate average daily gain. During the growth trial blood samples were collected at 30 days interval to estimate blood glucose, albumin, total protein, total leucocyte count, total immunoglobulins and immunoglobulin G levels. A metabolic trial of seven days was carried out to find out the digestibility of different nutrients. Results: The dry matter intake was reduced (p<0.05) with higher fat and protein levels whereas feed conversion efficiency was improved (p<0.05) with higher protein level. Different levels of fat and protein in calf ration did not affect average daily gain in calves. The dry matter, organic matter, and crude protein digestibility were significantly (p<0.01) higher with increased level of protein. The nitrogen retention was also significantly higher (p<0.05) at 24% protein level, similarly the total immunoglobulin was significantly (p<0.05) high in higher protein fed groups, showed better immunity. Conclusion: The present finding suggested that 10% fat and 18% protein level of calf starter could be used in Sahiwal calves for optimum performance in terms of weight gain and immunity.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.68-76
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• 1999

A formal survey was carried out in Nharira-Lancashire areas located in Chivhu to assess the calf rearing systems practiced in smallholder dairy farming areas of Zimbabwe. A total of 47 farmers, collectively owning 305 cows and 194 calves of various breeds, participated in the survey. All the farmers allowed their calves to suckle their dams all day to obtain colostrum. The colostrums intake period was significantly (p < 0.05) shorter (5.2 vs 4.1 days) in the small scale commercial area (SSCA) compared to communal area (CA). Milk was first sold to the Nharira-Lancashire Milk Centre a day after the colostrum intake period ended. Most of the CA (91.3%) and SSCA (77.8%) farmers penned their cows and calves together at night during the colostrum intake period. Thereafter the calves were penned separate from their dams. After colostrum intake, two types of calf suckling systems were practised; twice a day suckling and twice a day then changed to once a day suckling. In both systems, suckling was allowed for 30 minutes after the cows had been hand milked. There was no significant (p < 0.05) difference in the mean weaning age of calves between the CA and SSCA (5.8 vs 5.4 months). The most common weaning method was through separation of the calves from the dams. The limitaitions to calf production in Chivhu were the prohibitively high costs of calf meals, poor feed resources during the dry season, a general lack of knowledge on calf rearing diseases and inappropriate calf housing.

• Journal of Embryo Transfer
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• v.27 no.2
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• pp.81-85
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• 2012

This study investigated the effect of birth weight on the fertility of Holstein heifers. Growth parameter (body weight) was measured at birth. Calves were analyzed as three subgroups: low (L), average (A) and high (H) birth weight (BW) calves. LBW calves were born 10 kg lighter than HBW calves. Fertility data collected included age at first breeding (AFB), number of services per conception, pregnancy rate to first artificial insemination (AI), and age at first calving (AFC). Primiparous calves in HBW are smaller compared to multiparous cows (18.3% versus 48%). Although not significantly different, LBW offspring appeared to breed faster over the service period compared with the ABW offspring that bred three weeks later on the average. The mean pregnancy rate to first AI for LBW heifers was higher (60%) than ABW (48%) and HBW (45%). HBW cows required more services per conception (2.1) than the LBW (1.7) and ABW (1.9). There were significant differences (p<0.05) in age at first calving among the different calving birth weights. Smaller birth size did not have any subsequent adverse effects on fertility. HBW offspring were more likely or tend to have worse fertility parameters.

• Korean Journal of Veterinary Service
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• v.46 no.2
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• pp.147-156
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• 2023

Between February 2020 and September 2021, a total of 452 dairy calves with diarrhea were investigated across 17 dairy farms in Gyeonggi province, Korea, using a rapid diagnostic kit. The study aimed to examine the infection rates of major pathogens causing diarrhea in dairy calves, categorizing them by season, age, and birth month. Additionally, logistic regression analysis was conducted to investigate the factors affecting the infection rate. The infection rates of the major pathogens causing infectious diarrhea in dairy calves, including bovine rotavirus, bovine coronavirus, Cryptosporidium, and E. coli, are influenced by season, age, and birth month. Bovine coronavirus and Cryptosporidium showed variations in infection rates according to season, age, and birth month, while bovine coronavirus was influenced by age and birth month, and E. coli showed variations in infection rates based on age. Furthermore, in the analysis of risk factors influencing the infection rates of these pathogens, age and birth month were identified as risk factors for bovine rotavirus, bovine coronavirus, and Cryptosporidium.

• Korean Journal of Veterinary Service
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• v.47 no.2
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• pp.81-87
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• 2024

From July to December 2022, we investigated the incidence of enteric pathogens causing diarrhea in calves under 100 days old at 22 farms across Korea. A total of 354 calves (including 247 dairy calves and 107 Korean native calves) were included. We used commercially available rapid diagnostic kits to identify five enteric pathogens, including bovine rotavirus (BRV), bovine coronavirus (BCoV), Cryptosporidium. Escherichia coli (E. coli), and Giardia. This study investigated how factors such as age, season, and birth month, which can influence the incidence of intestinal pathogens, affect the incidence of these pathogens in diarrheic dairy calves and Korean native calves. Our study found that the incidence of diarrhea-causing pathogens differed between dairy and Korean native calves. In diarrheic dairy calves, bovine rotavirus (BRV) incidence rates, correlated with season and birth month. Similarly, Cryptosporidium incidence C were associated with age and season, while Giardia incidence rates varied by season and birth month. Korean native calves, on the other hand, exhibited seasonal and birth month-related variations in BRV incidence rates, with Cryptosporidium incidence rates influenced by birth month.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.517-521
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• 2007

Questionnaire on utilization of colostrum was carried out in 33 farms. Highest milking cow numbers were 20-40 heads in 45.5% of the farms. Calf numbers were 20-40 heads in 39.4% of the dairy farms and 40-60 heads in 42.4% of the farms. The amount of colostrum production per day was 20-30 kg in 30.3% of the farms and 30-40 kg in 30.3% of the farms. Colostrum intake per calf per day was 4 kg in 45.5% farms. Surplus colostrum after intake by calf was farms (85%) was wasted in 67% of the farms. More than 90% of dairy farms recognize an necessity to use surplus colostrum. Selling price of surplus colostrum was below 1,000 won per kg at 15 dairy farms and 1,000-2,000 won per kg at 4 dairy farms. Colostrum collection and use should be done by the dairy farms of antibiotics free. Quality control of colostrum should be done by testing antibiotics, microbacterium, chemical composition, somatic cells and etc. The colostrum is subjected to cool down below $4^{\circ}C$ just after milking and process for the colostrum products.

• Journal of Practical Agriculture & Fisheries Research
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• v.13 no.1
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• pp.103-114
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• 2011

The present survey was conducted to investigate effects of weaning age on market weights of steers and calf mortality in Hanwoo. Eight hundred and sixty-two Hanwoo cow-calf operations from all nine provinces were surveyed via personal interviews. The number of farms categorized by herd (heifer plus cow) size were 188, 364, 227 and 83 for <20 heads, 20~49 heads, 50~99 heads and >100 heads, respectively. Approximate 40% of farms surveyed weaned calves at three months of age. The percentages of farms weaning calves over three months of age were 53.5%, 37.5%, 43.7% and 39.0% for <20 heads, 20~49 heads, 50~99 heads and >100 heads, respectively. The herd size did not affect market weights of Hanwoo steers. However weaning age was negatively correlated to carcass weight of Hanwoo steers, showing that as weaning age decreased, carcass weights of Hanwoo steers increased. The average calf mortality was 5.6% and the herd size did not affect calf mortality. But weaning age was shown to be positively correlated to calf mortality and the rate of diarrhea that caused calf death, suggesting that as weaning age decreased, calf mortality and the rate of diarrhea decreased. Overall, the results of present study suggest that a decrease of calf weaning age in Hanwoo can increase the profit of Hanwoo cow-calf operations by increasing carcass weight of Hanwoo steers and by decreasing calf mortality.

• Journal of Veterinary Science
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• v.22 no.5
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• pp.69.1-69.12
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• 2021

Background: Bovine group A rotavirus (BoRVA) is a major cause of severe gastroenteritis in newborn dairy calves. Only one study has investigated the G and P genotypes among dairy calves in a few regions of China, which were G6 and P[5]. Therefore, data on the prevalence and molecular characteristics of BoRVA in dairy calves in China remains limited. Objectives: The purpose of this study was to investigate the prevalence and molecular characteristics of BoRVA in dairy calves in China. Methods: 269 dairy calves diarrheic samples from 23 farms in six provinces in China were collected to detect BoRVA using reverse transcription polymerase chain reaction. Results: 71% of samples were determined to be BoRVA-positive. Two G genotypes (G6, G10) and two P genotypes (P[1], P[5]) were identified, and G6P[1] BoRVA was the predominant strain. Moreover, the VP7 and VP4 gene sequences of these dairy calf BoRVA strains revealed abundant genetic diversity. Interestingly, eight out of 17 complete G6 VP7 sequences were clustered into G6 lineage VI and analysis showed the strains were closely related to Chinese yak BoRVA strains. Conclusions: The results of this study show that BoRVA circulates widely among dairy calves in China, and the dominant genotype in circulation is G6P[1], first report on molecular characteristics of complete P[5] VP4 genes in chinese dairy calves. These results will help us to further understand the prevalence and genetic evolution of BoRVA among dairy calves in China and, thus, prevent the disease more effectively.

• 월간낙농육우
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• v.27 no.7 s.303
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• pp.192-197
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• 2007

• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.33-37
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• 2012

This study was performed to evaluate the rate of twin pregnancy and parturition in dairy cows. Calving records of Holstein dairy cows from 1998 to 2009 comprising Goyang and Paju cities herd with 20,990 calving events representing 820 twin births were used to evaluate twinning rate, calf sex ratio, periods of pregnancy and complication after parturition in single and twin births. Overall, the reported twinning rate was 3.9% in Holstein dairy cows. Rate of bicornual pregnancy (75%) was larger than that of unicornual pregnancy (25%) among cows having twin. Regardless of parity, the greatest twinning rate was observed in fall season from September to November. Calf sex ratios (male, M; female, F) were 48.0% FM, 28.9% MM, 21.5% FF and 0.9% mummifications for twin calves. Parturition type among cows having twins included normal (4.7%), premature (66.9%), delayed (9.2%), abortion (18.4%) and mummification (0.8%). The period of pregnancy in twin pregnancy (mean 272.6 days) was shorter than single pregnancy (mean 278.1 days). The retained placenta after parturition was over fourth times such as twin parturition (34.8%) higher than single parturition (8.5%) and the abomasal displacement was over two times such as twin parturition (10.2%) higher than single parturition (4.9%). The distribution of twin pregnancy with parities was high rate during the 2~3 parities. The prevalence of complication such as retained placenta and abomasal displacement with twin parturition revealed higher than single parturition.