• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.909-914
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• 2005

This study was conducted to estimate phenotypic and genetic parameters of body condition score (BCS) and reproductive traits in Hanwoo cows. DFREML procedures were applied to obtain variance-covariance components and heritability estimates with single or two-trait models. Estimates of phenotypic correlations of BCS at service with BCS at calving was 0.16 and 0.26 with calving interval, 0.08 with gestation length, and 0.06 with number of services per conception, respectively. Estimates of phenotypic correlation of BCS at calving was 0.10 with calving interval, 0.13 with gestation length, and 0.10 with number of services per conception, respectively. Estimates of phenotypic correlation were low and negative, -0.11 between calving interval and gestation length and -0.13 between gestation length and number of services per conception. Estimates of direct genetic correlation were -0.06, between BCS at service and BCS at calving, 0.37 between BCS at service and BCS at weaning, and -0.18 between BCS at calving and BCS at weaning. Estimates of direct genetic correlation of days from calving to the 1st service were 0.17 with number of services per conception and -0.21 with BCS at service. Estimates of direct genetic correlation for BCS at calving were -0.02 with number of services per conception and -0.08 with BCS at service. Estimates of direct genetic correlation for BCS at weaning were 0.02 with number of services per conception and -0.07 with BCS at service. Estimates of direct heritability from single trait analyses were 0.13 for BCS at service, 0.20 for BCS at calving, 0.02 for BCS at weaning, and 0.20 for number of service per conception, respectively. Estimates of direct heritability were 0.20 for birth weight and 0.10 for weaning weight.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.369-374
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• 1999

One hundred forty cows that have claw disorder have been used to study the association between lameness and reproductive disorders. Weak estrus owing to ovarian hypoplasia (41.4%) followed by follicular cyst (39.3%) was more frequent than any other disorders. Two hundred ninety-four cows have been used to study the association between lameness and calving to first service and calving to conception intervals depending on lactations, claw disease and floor conditions. And a comparison of number of services per conception between cows with lameness and cows free from lameness was carried out. The calving to first service intervals were significantly increased from average 78 to 102.5 days and calving to conception intervals were significantly increased from 109.6 to 150.6 days in cows with lameness. The calving to first service and calving to conception intervals were not significant different between lactations in cows with lameness. In comparison of calving to first service and calving to conception intervals in cows with lameness depending on claw disease and floor conditions, there was no significant difference. The average number of services per conception was increased from 1.73 to 2.57 in cows with lameness. Service numbers were more frequent during second lactation (3.0 services) but there was no significant difference between lactations in cows with lameness. Therefore, it is likely that the management of lameness is important factor on proper health control of cows and the cows with lameness show decreased fertility.

• Journal of Embryo Transfer
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• v.26 no.2
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• pp.91-96
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• 2011

The purpose of this study was to evaluate the effects of days open on subsequent reproductive performance following to estrus synchronization in the 114 lactating dairy cows. The animals were divided into two groups according to the time of estrus synchronization; viz, ${\leq}$ 85 days, and > 85 days postpartum, respectively. The estrus synchronization protocol consisted of insertion of a controlled internal drug release (CIDR) device containing 1.9 g progesterone with an injection of 250 ${\mu}g$ gonadorelin (Day 0), an injection of $PGF_2{\alpha}$ and removal of the device on Day 7, an injection of 250 ${\mu}g$ GnRH on Day 9, and TAI 17 h later. Pregnancy diagnosis was determined at 30 to 60 days after TAI using both ultrasonography and rectal palpation. The body condition score (BCS) gradually increased over the postpartum period. In estrus synchronized cows until 85 days, conception rate on first service, number of service per conception, interval from estrus synchronization to conception, and interval from calving to conception were not significantly different among two farms (P>0.05). In estrus synchronized cows after 85 days postpartum, conception rate on first service, number of service per conception and interval from calving to conception were significantly different ($P{\leq}0.05$) between herds A and B (26.8 vs 50.0%; $2.1{\pm}1.35$ vs $1.37{\pm}0.54$ times, $237.3{\pm}97.8$ vs $164.7{\pm}69.3$ days, respectively). In estrus synchronized cows after 85 days postpartum interval from estrus synchronization to conception was greater (P<0.01) in herd B than in herd A ($63.6{\pm}57.4$ vs $26.1{\pm}24.9$). These results indicate that the time of estrus synchronization for maximized the reproductive performance is before 85 days postpartum and feeding and management is important factor for high reproductive performance.

• Journal of Embryo Transfer
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• v.24 no.2
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• pp.127-130
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• 2009

The purpose of this study was to determine the effect of cows parity and calving seasons on the subsequent reproductive performance of the herd of Korean native cows raised under the same condition. With the parity of the cows ranged 1 to 4 (mean: 1.9), significant associations were found between parity and calving interval (p<0.05). Calving interval of the primiparous cows group was 395.0 ${\pm}$ 16.5 days, which was the longest calving interval among the four groups. On the other hand, calving interval of the second parity group was 333.7 ${\pm}$ 3.6 days. The primiparous cows had tendencies that long interval from calving to conception and small number of service per conception relatively when compared with the multiparous cows. In the case of calving season, the interval from calving to first service was short in summer and winter relatively. The interval from calving to conception in summer was the shortest in four seasons. The number of service per conception was larger in spring and winter and smaller in summer and autumn. Calving in spring showed delayed reproductive performance and calving in summer showed desirable reproductive performance.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.331-334
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• 2003

The assessment of reproductive potentials of female gayal under semi-intensive management was conducted with 18 animals in Bandarban hilly area of Bangladesh. Age at first estrous (days), age at first conception (days), length of estrous cycle (days), number of service per conception (natural), gestation period (days), age at first calving (days), and calving interval (natural service) (days) of gayal were $598.2{\pm}168.44$, $723{\pm}169.94$, $21.86{\pm}2.93$, 1.41, $296.05{\pm}3.87$, $1014.42{\pm}260.32$ and $465{\pm}80.48$ respectively. Daily milk yield and lactation length of gayal were $304.98{\pm}30.46ml/day$ and $116.67{\pm}8.08days$. Gayal male calves had higher birth weight (19.67 kg) than female calves (15.58 kg) in first lactation. Birth weight increases in second and third lactation than first lactation in both male and female calves. Highest conception rate observed in winter season and 70.60% successful conception occur when service was given within 21-30 h of estrous. Maximum number of female gayal use to come in estrous in winter and calved in monsoon and autumn. Cervicitis and irregular heat were the most reproductive problems followed by metritis, case of abortion, anestrous and repeat breeding. From this study it was observed that the reproductive performance of gayal is very close with the domestic cattle. It may use as beef cattle for the hilly regions of Bangladesh.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.191-200
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• 2002

This study was conducted to estimate the effects of environmental factors on certain reproductive traits in Korean cattle on the basis of data from Korean Cattle Improvement Areas which were surveyed from 1986 to 1995. Results obtained were summarized as follows ; 1. Least square means of the reproductive traits estimated were 466.11${\pm}$5.72 days for age at 1st service, 480.10${\pm}$6.15 days for age at 1st conception, 742.79${\pm}$7.48 days for age at 1st calving, 64.97${\pm}$1.42 days for days at 1st service postpartum, 72.06${\pm}$1.73 days for days open, 355.93${\pm}$1.92days for calving interval, 285.38${\pm}$0.42 days for gestation length and 1.21${\pm}$0.02 days for number of services for conception, respectively. 2. The ranges of the least squares means for the districts were 447.62${\pm}$5.94-490.72${\pm}$5.94 days for age at 1st service, 464.27${\pm}$6.38-505.20${\pm}$6.39 days for age at 1st conception, 721.91${\pm}$7.85-772.75${\pm}$7.80 days for age at 1st calving, 62.27${\pm}$1.55-68.97${\pm}$1.74days for days at 1st service postpartum, 69.74${\pm}$1.97-74.36${\pm}$2.27days for days open, 352.71${\pm}$2.18-359.64${\pm}$2.09 days for calving interval, 284.52${\pm}$0.42-286.04${\pm}$0.47days for gestation length and 1.11${\pm}$0.02-1.30${\pm}$0.02 days for number of services for conception, respectively. 3. Age at 1st service was latest in the cows with Basic Register and tended to be earlier for the more advanced registers. The number of services per conception tended to increase for the more advanced registers. 4. Days at 1st service postpartum was longest in the 2nd parity and tended to be shorter with the advancement of parity. The number of services per conception tended to decrease with the advancement of parity. 5. As the calving year advances from 1987 to 1995, days at 1st service postpartum, days open and calving interval tended to be longer, and number of service per conception tended to increase. 6. Days at 1st service postpartum, days open and calving interval were shorter in the cows that calved in spring and summer than in the cows that calved in fall and winter. The number of services per conception was larger in the cows that cocalved in fall and winter than the cows that calved in spring and summer.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.4
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• pp.321-323
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• 1995

Observations were recorded regarding various fertility parameters on 26 Jersey donor cows following superovulation under tropical conditions. These cows, in their mid-luteal phase were treated with 2,500-3,000 i.u. PMSG or 28-40 mg FSH followed by $500{\mu}g$ $PGF_{2{\alpha}}$ injection 48-60 hours later, to induce oestrus. The cows were bred artificially twelve hours following standing oestrus. Embryo collection was carried out 7 days after oestrus. $PGF_{2{\alpha}}$ was injected to each donor cow after embryo recovery to regress the corpora lutea. Fertility data($PGF_{2{\alpha}}$-Oestrus interval, services per conception, days between embryo collection and successful service and any pathololgical condition) were recorded. $PGF_{2{\alpha}}$-Oestrus interval and correlation (r) between number of corpora lutea and $PGF_{2{\alpha}}$-Oestrus interval were $30.9{\pm}6.3$ and 0.17, respectively. Of 26 treated donors, 19 conceived within a period of $91.7{\pm}18.8$ days after embryo recovery. Average services per conception were $2.3{\pm}0.3$. Only two cows developed metritis which conceived after treatment with antibiotics. These observations indicated no profound adverse effect of superovulation on subsequent reproduction of donor cows, except some effect on services per conception, under tropical conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.4
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• pp.519-526
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• 2019

Objective: We determined the risk factors limiting first service conception (FSC) rate in dairy cows and their economic impact. Methods: Data were collected from 790 lactations regarding cow parity, peri- and postpartum disorders, body condition score (BCS), reproductive performance, and expenses associated with reproductive management (treatment, culling, and others). Initially, we identified the risk factors limiting FSC rate in dairy cows. Various biological and environmental factors, such as herd, cow parity, BCS at 1 month postpartum and first artificial insemination (AI), resumption of cyclicity within 1 month of calving, year, AI season, insemination at detected estrus or timed AI, peri- and postpartum disorders, and calving to first AI interval, were evaluated. Next, we evaluated the economic impact of the success or failure of FSC by comparing the expense associated with reproductive management until conception between cows that did or did not conceive at their first service. Results: Cows with BCS <3.0 had a lower probability of conceiving at first insemination (odds ratio [OR] = 0.64, p<0.05) than cows with $BCS{\geq}3.0$. Cows inseminated during summer were less likely to conceive (OR = 0.44, p<0.001) than cows inseminated during spring. Cows with peri- or postpartum disorders were less likely to conceive (OR = 0.55, p<0.001) than cows without disorders. Survival curves generated using MedCalc showed an 81 day extension in the mean interval between calving and conception in cows that failed to conceive over those that did conceive at first insemination. Cows failing conceive required additional expenditure on reproductive treatment ($55.40) and other management ($567.00) than cows that conceived at first insemination. Conclusion: Lower BCS, hot weather at first insemination, and peri- and postpartum disorders are risk factors limiting FSC, which result in an economic loss of $622.40 per dairy cow.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.1
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• pp.26-30
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• 2006

The study was undertaken to investigate the validity of milk urea concentration as an index of the reproductive performances in crossbred Karan-Fries (Holstein Friesian${\times}$Tharparkar) cows under farm condition. Milk urea was analysed in noon milk samples (1200 to 1300 h) to interrelate with the interval from parturition to first service, number of insemination per conception, first service conception rate and service period. Milk progesterone (P4) was analysed in noon milk samples on the day 1, 10, 20 and 30 post insemination to study the effect of milk urea concentration on early embryonic mortality. The interval from parturition to first service was found significantly (p<0.01) higher ($77.2{\pm}5.5$ days) when milk urea concentration was ${\geq}63.4mg/dl$. The average milk urea concentrations (mg/dl) were found $42.1{\pm}2.5$, $47.9{\pm}1.5$ and $50.3{\pm}3.1$, respectively in cows that conceived at $1^{st}$, $2^{nd}$ and $3^{rd}$ insemination. However, the variation was not statistically significant. The first insemination conception rate was found significantly (p<0.05) higher (68.8%) when milk urea level was ${\leq}32.4mg/dl$. The service period was found significantly (p<0.05) higher ($125.4{\pm}8.8$ days) when milk urea concentration was ${\geq}45.1mg/dl$. The milk P4 level indicated that the cows, those were detected as non-pregnant on day 60 post insemination were initially pregnant but the pregnancy was terminated sometime during the day 30 to 60 post insemination. The study indicates that the milk urea values may be used as an index of reproductive performances in dairy herd when individual animals are not being monitored for nutritional status. The altered milk urea values may be utilised by the farmers as ready reference to rectify the protein and energy nutrition in cows to achieve the better reproductive performances in herd.

• Journal of Animal Science and Technology
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• v.46 no.1
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• pp.31-38
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• 2004

Data from five Hanwoo breeding farms were collected to analyze the effects of parity, season, nutrition and reproduction on body conditions of heifers and cows and to analyze the relationships of body conditions with reproductive performances and body growth. Analytic models included farms and parity which were run through SAS to estimate least squares means and correlation coeflicients between traits body condition scores(BCS) of I(very emaciated) through 9(very obese) scale at service and at calving. calving interval, days to rebreeding, gestation length. number of services per conception. Overall averages were 4.55 for BCS at service, 5.42 for BCS at calving. 406.7days of calving interval, 287.7days of gestation length, 66.2days from calving 10 first service and 1.78 times of services per conception. Number of services per conception was 1.50${\sim}$1.74 times for the cows of BCS 5 or under and 2.00${\sim}$3.00 for those of BCS 6 or higher. Body weight of calves from cows observed averaged 23.3kg at birth and 70.7kg at weaning. 57 percent of cows showed BCS 4${\sim}$5 at service while 46 percent of those showed 5${\sim}$6 at calving. Estimated phenotypic correlation coefficients of BCS at service with BCS at calving, calving interval, gestation length, number of services per conception were low but positive: 0.16, 0.26. 0.08 and 0.06. respectively. Phenotypic correlations of BCS at calving with calving interval, gestation length and number of services per conception were estimated to be also low and positive: 0.10, 0.13 and 0.10. respectively. However, phenotypic correlations between calving interval and gestation length, and between gestation length and number of services per conception were negative but low as - 0.11 and- 0.13 each.