• Journal of Embryo Transfer
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• v.25 no.1
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• pp.21-27
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• 2010

The increase in the total number of cows on farms, which breed Korean Native Cattle (KNC), is associated with many problems. In particular, the services per conception and calving interval have increased. In this study, we examined the effect of dietary supplementation with vitamin and mineral complex on the estrus rate, pregnancy rate, gestation length, and birth weight of KNC calves. Multiparous or primiparous KNC were divided into 3 groups with 40 heads per group. Experimental group 1 was administered a consisting of 35,000 IU vitamin A, 100 IU vitamin E, 200 mg $\beta$-carotene, 200 mg Zn methionine, and 1.5 mg Se. Experimental group 2 was administered a vitamin complex (100 g/day) consisting of 100 IU vitamin E and 200 mg $\beta$-carotene. In the case of multiparous KNC, the estrus detection rate in the control group was 90.0% and those in the experimental groups were 75.0% to 95.0%. However, the first-service pregnancy rate after parturition in the control group was 41.2%, which was significantly lower than that in the experimental groups (71.0% to 76.7%; p<0.05). The average duration of pregnancy in the group supplemented with the vitamin complex was days, which was similar to that in the case of the control group. The birth weight of calves from cows fed with vitamin complex was 25.3 to 27.0 kg, which was similar to that in the case of the control group (25.2 to 26.0 kg). In the case of primiparous KNC, no differences in the estrus rate, pregnancy rate, gestation length, or the birth weight of calves were noted between the groups. Thus, dietary supplementation vitamin and mineral complex have no effect on the reproductive efficiency in primiparous cows, but the pregnancy rate was observed to have increased in multiparous KNC with these supplements.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.3
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• pp.336-340
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• 1999

Age at maturity was studied in 661 Nili Ravi buffaloes maintained at six dairy farms in Pakistan. The mean age at maturity in the overall data from the six farms was $976.49{\pm}9.2$ days. Significantly lower mean age at maturity $(957.93{\pm}10.68\;days)$ was observed at Military Dairy Farm, Khyber Okara, Military Daiiy Farm, Punjnad and Livestock Research Station, National Agricultural Research Centre, Islamabad (Group I) compared to $(1015.26{\pm}17.39\;days)$ other three Military Dairy Farms, Peshawar, Nowshera and Rawalpindi (Group II). The advantages associated to early age at maturity were as following. Male and female calves were heavier $(38.35{\pm}0.17\;and\;31.84{\pm}15kg,\;respectively)$ in Group I as compared to $(29.27{\pm}0.26\;and\;26.27{\pm}0.26kg)$ in Group II. Milk yield per lactation was significantly higher in Group I $(1912{\pm}12\;lit.)$ as compared to $(1833.36{\pm}16.56\;lit.)$ in Group II. Lactation length was significantly longer $(284.41{\pm}1.23\;days)$ in Group I as compared to $(277.77{\pm}2.02\;days)$ in Group II. Dry period and service period were significantly shorter $(241.59{\pm}4.18\;and\;217.05{\pm}4.95\;days,\;respectively)$ in Group I as compared to $(306.39{\pm}78\;and\;280.95{\pm}9.32\;days)$ in Group II. The mean age at first calving and sex ratio were low ($1282.75{\pm}10.14$ days and 100 ♀ ♀:130.7 ♂ ♂) in Group I as compared to ($1308.7{\pm}16.44$ days and 100 ♀ ♀:152.15 ♂ ♂) in Group II but the differences were non significant.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.3
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• pp.277-286
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• 2000

A total of 21,441 milking records of biweekly test-days were collected from six dairy farms of Almarai company, Saudi Arabia to determine the effect of days open on lactation curve and milk production during the period of 1991 to 1996. These records included cows calved in two seasons: winter, for cows calved from October to March and summer, for cows calved from April to September. Season of calving did not have a significant effect on the last biweekly points of the curve, and this is due to the effect of the evaporative cooling system. Days open had a marked effect on milk production. The difference in milk yield between cows with days open <60 days and days open >150 days was 1,021 liter. Moreover, the difference in milk yield at early lactation decreased from 1,021 to 829 liter as the days open increased from 75 to 125, due to the decrease in the effect of conception on milk production with advancing lactation. These data also showed that the middle part of the curve (105-255) was the least affected part by the variation in days open because the pregnancy effect become more obvious after five months of conception. These data showed that the dairy cattle produce more than 70% of the milk yield during the first 250 days of the lactation curve.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.4
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• pp.486-495
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• 2012

Twenty four periparturient cows were used to determine the effects of DCAD on acid-base balance, plasma and urine mineral concentrations, health status, and subsequent lactation performance. Each group of 12 cows received either a diet containing -100 DCAD or +100 DCAD for 21 d prepartum. Both anionic and cationic groups were divided into two groups, one received a +200 DCAD and the other +400 DCAD diet for 60 d postpartum. Prepartum reduction of DCAD decreased DMI, urinary and blood pH, urinary concentrations of Na or K and increased plasma and urinary Ca, Mg, Cl and S. Also cows fed -100 DCAD diet consumed the most dry matter in the first 60 d after calving. Postpartum +400 DCAD increased milk fat and total solid percentages, urinary and blood pH and urinary Na and K concentrations, but urinary Ca, P, Cl and S contents decreased. Greater DMI, FCM yields were observed in cows fed a diet of +400 DCAD than +200 DCAD. No case of milk fever occurred for any diets but feeding with a negative DCAD diet reduced placenta expulsion time. In conclusion, feeding negative DCAD in late gestation period and high DCAD in early lactation improves performance and productivity of dairy cows.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.8
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• pp.1031-1040
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• 2011

The objective of this study was to characterize factors influencing genetic improvement of dairy cattle for milk production at farm level. Data were accumulated from 305-day milk yields and pedigree information from 1,921 first-lactation dairy cows that calved from 1990 to 2007 on 161 farms in Central Thailand. Variance components were estimated using average information restricted maximum likelihood procedures. Animal breeding values were predicted by an animal model that contained herd-year-season, calving age, and regression additive genetic group as fixed effects, and cow and residual as random effects. Estimated breeding values from cows that calved in a particular month were used to estimate genetic trends for each individual farm. Within-farm genetic trends (b, regression coefficient of farm milk production per month) were used to classify farms into 3 groups: i) farms with negative genetic trend (b<-0.5 kg/mo), ii) farms with no genetic trend (-0.5 kg/$mo{\leq}b{\leq}0.5$ kg/mo), and iii) farms with positive genetic trend (b>0.5 kg/mo). Questionnaires were used to gather information from individual farmers on educational background, herd characteristics, farm management, decision making practices, and opinion on dairy farming. Farmer's responses to the questionnaire were used to test the association between these factors and farm groups using Fisher's exact test. Estimated genetic trend for the complete population was $0.29{\pm}1.02$ kg/year for cows. At farm level, most farms (40%) had positive genetic trend ($0.63{\pm}4.67$ to $230.79{\pm}166.63$ kg/mo) followed by farms with negative genetic trend (35%; $-173.68{\pm}39.63$ to $-0.62{\pm}2.57$ kg/mo) and those with no genetic trend (25%; $-0.52{\pm}3.52$ to $0.55{\pm}2.68$ kg/mo). Except for educational background (p<0.05), all other factors were not significantly associated with farm group.

• Journal of Veterinary Clinics
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• v.28 no.2
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• pp.267-270
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• 2011

Ovarian tumors in cows are uncommon and most are granulosa cell tumors. Bovine ovarian fibromas are extremely rare and tend to occur in older animals. This paper reports the case of a large ovarian mass found in a primiparous dairy cow which had shown no sign of cycling after calving. The mass continued to increase in size as detected during six-month serial observations by ultrasonography. An ovariectomy was subsequently performed and the growth was diagnosed as an ovarian fibroma by gross and microscopic examination. This case is the first report of an ovarian fibroma observed in a living dairy cow.

• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.394-400
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• 2016

The objective of this study was to estimate the environmental factors affecting milk ${\beta}$-hydroxybutyric acid (BHBA) and acetone (Ac) concentrations in Holstein cattle. A total of 264,221 test-day records collected from the Korea Animal Improvement Association (KAIA) during the period of 2012 to 2014 were used in this study. Analysis of variance (ANOVA) was performed to determine the factors significantly affecting ketone body concentrations. Parameters considered in the model were season of test, season of calving, parity, lactation stage, and milk collecting time (AM and PM). According to the ANOVA, the $R^2$ for milk BHBA and Ac were 0.5226 and 0.4961, respectively. 'Season of test' showed a considerable influence on ketone body concentration. Least square (LS) means for milk BHBA concentrations was the lowest ($39.04{\mu}M$) in winter while it increased up to $62.91{\mu}M$ in summer. But Ac concentration did not significantly change along with 'season of test'. The means of milk BHBA and Ac concentrations were high at first lactation stage, low around second lactation stage, and then gradually increased. Cows milked in the morning had lower mean BHBA and Ac concentrations ($48.49{\mu}M$ and $121.69{\mu}M$, respectively) in comparison to those milked in the evening ($53.46{\mu}M$ and $130.42{\mu}M$, respectively). The LS means of BHBA and Ac slightly increased over parities. These results suggest that proper maintenance of milk collection, herd management programs, and evaluation of ketone body levels in milk should be considered for the efficient management of resistance to ketosis.

• Journal of Embryo Transfer
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• v.28 no.4
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• pp.319-324
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• 2013

This study was conducted among 120 different breed cows at selected areas of Sirajgonj district from March to July 2010 to compare the reproductive performance of crossbred and Desi cows at farmer's level. The results showed that the average daily milk yield of Desi, Shahiwal ${\times}$ Desi, Friesian ${\times}$ Desi and Jersey ${\times}$ Desi cows was $2.3{\pm}0.2$, $4.9{\pm}0.9$, $6.0{\pm}1.0$ and $5.7{\pm}0.9$ liters, respectively. The milk yield of crossbred cows ($5.5{\pm}0.6$ liters/day) was significantly (p<0.01) higher than Desi cows ($2.3{\pm}0.2$ liters/day). The average age at puberty of Shahiwal ${\times}$ Desi, Friesian ${\times}$ Desi and Jersey ${\times}$ Desi was significantly (p<0.01) lower than that of Desi breed. The crossbred cows had significantly (p<0.01) lower pubertal age ($20.4{\pm}1.2$) than Desi ($25.9{\pm}1.1$). The age at first calving in Desi cows was significantly (p<0.01) higher ($37.6{\pm}1.1$ months) than crossbred cows ($31.2{\pm}1.3$ months). The average gestation length of Desi, Shahiwal ${\times}$ Desi, Friesian ${\times}$ Desi and Jersey ${\times}$ Desi was $289.9{\pm}1.4$, $285.0{\pm}0.0$, $285.0{\pm}4.2$ and $282.1{\pm}2.4$ days, respectively. It is suggested that the overall reproductive performance of Friesian ${\times}$ Desi, Jersey ${\times}$ Desi and Shahiwal ${\times}$ Desi cows were better than that of Desi cow.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.119-124
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• 2007

Milk components analysis was carried out milk yield(MY), milk fat(MF), milk protein(MP), milk urea nitrogen(MUN), milk solid(MS), day of non-pregnant condition(DNPC), and days of primipara(DPRI) involved. Dairy farms were divided high, middle and low groups according to the standard records for milk components. Examination records were divided by farm, parity, year, season and month, the number of samples were 28,957. MUN concentration was below 12 mg and when the MPP was below 3.0%, the days of non-pregnant condition were $94{\pm}10.77$ days but concentration of MUN was under 12 mg and when MPP was above 3.2%, longer period of non-pregnant condtion of $181.3{\pm}9.25$ was noted. The days of gestation of the first calving cow was $495.9{\pm}9.04$ days when the concentration of MUN was below 12mg/dl and MPP was under 3.0%. If the concentration of MUN was 12 mg/dl and when the MPP was over 3.2%, the days of gestation were $511.0{\pm}8.36$ days. It was believed that the concentrations of MPP and MUN have significant effects on the days of non-pregnant condition and the days of gestation. Determination of MY, MF, MS, and MUN was Milkoscan $4,000{\sim}5,000$ Serier(FOSS Electric Co., Copenhagen, Denmark). MUN standard concentration was 12-18(mg/dl) similar to blood urea nitrogen(BUN). Mutual relationship of milk components(MF, SCC, MY, DNPC, MS) and MUN concentration was low in regression analysis.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.266-275
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• 2022

The impact of heat stress (HS) on reproductive performance and its problems in cows remains to be investigated in Bangladesh. The study was, therefore, aimed to evaluate the effect of HS on fertility and reproductive health problems of dairy cows in a selected area of Bangladesh. A total of 1,095 cows from 500 farms were included in this study. The climate-related data were recorded daily basis for every month in a year and temperature-humidity index (THI) values were calculated to determine the level of HS. Concurrently, data on fertility parameters [number of services per conception (NSC), conception rate (CR) and calving to the first service interval (CFSI)], and reproductive problems were collected through a pre-defined questionnaire. The results show that crossbred [Native x Holstein-Friesian, (HF)] cows were more vulnerable (p < 0.05) to a magnitude of HS effects considering physiological parameters of cows [age, body condition score (BCS), parity and milk yield]. Regarding fertility, HS had no effect on NSC, CR and CFSI in both native and crossbred cows (p > 0.05). The findings on the reproductive problems indicate that HS had significant influence on the prevalence of anestrus (χ² = 21.814, p < 0.05) and retained placenta (χ² = 24.632, p < 0.05) in cows. Of note, the prevalence of repeat breeding syndrome was 2.5 folds higher in stress condition than in no stress condition. Abortion and dystocia were not influenced by HS. In conclusion, HS does not influence the fertility parameters of cows studied; however, anestrus and retained placenta are likely to occur under HS conditions in cows.