• Journal of Embryo Transfer
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• v.21 no.3
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• pp.199-205
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• 2006

The objective of this study was to investigate the resumption of postpartum ovarian cyclicity, and to determine the relationship between concentrations of plasma urea nitrogen (PUN) and resumption of ovarian cyclicity in Holstein cows. The cows were considered to have resumed ovarian cyclicity on the day of ovulation, if followed by regular ovarian cycles. 58.8 percentage of the cows (114/194) had normal resumption of ovarian cyclicity (resumption within 40days after calving), and 41.2% (80/194) had delayed resumption (resumption did not occur until> 40days after calving). Delayed resumption Type I (one or more ovarian cycles with luteal phase> 20days, i.e. prolonged luteal phase; 17.5%) and delayed resumption Type II (first ovulation did not occur until ${\ge}40days$ after calving, i.e. delayed first ovulation 22.7%) were the most common types of delayed resumption. 18 percentage of the cows (35/194) did not resume their ovarian cyclicity until 60days postpartum. Prolonged luteal phase and delayed first ovulation were two important ovarian dysfunctions that delayed postpartum resumption of cyclicity in dairy cows. Cows with PUN of <15, $15{\sim}19.9\;and\;{\ge}20mg/dl$ had the likelihood ratios of normal ovarian cyclicity of 0.9, 1.14 and 0.55, respectively. Thus, PUN concentration of $15{\sim}19.9mg/dl$ had a favorable association with postpartum resumption of cyclicity, whereas lower or higher PUN had a negative association with postpartum resumption of cyclicity.

• Journal of Veterinary Clinics
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• v.32 no.2
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• pp.168-173
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• 2015

This study estimated the degree of uterine inflammation and resumption of ovarian cyclicity in postpartum dairy cows. In addition, the prevalence of health problems during calving and the postpartum period was investigated. A total of 224 Holstein dairy cows from four dairy farms in Chungcheong Province were used for the study. Uterine discharge was scored on a 0 to 5 rank scale (metricheck score) using a metricheck instrument from 1 to 8 weeks postpartum and uterine cytology (neutrophil level) was examined at 4, 6 and 8 weeks postpartum to evaluate uterine inflammation. Resumption of ovarian cyclicity was evaluated based on progesterone analysis (${\geq}1ng/mL$) at 4, 6 and 8 weeks postpartum. Postpartum disorders were diagnosed by veterinarians in the research team. The metricheck score decreased linearly (p < 0.0001) from weeks 1 ($3.4{\pm}0.1$) to 4 ($2.0{\pm}0.1$) postpartum, and then remained at that level through week 8 postpartum ($1.6{\pm}0.1$, p > 0.05). The neutrophil levels determined by uterine cytology assays also decreased (p < 0.0001) from week 4 ($22.3{\pm}1.8%$) to 6 ($12.1{\pm}1.4%$) postpartum, and then remained at that level through week 8 postpartum ($9.2{\pm}1.4%$, p > 0.05). The proportion of cows exhibiting the ovarian cyclicity increased linearly (p < 0.0001) from weeks 2 (12.1%) to 8 (74.3%) postpartum. The prevalence of dystocia and retained placenta were 20.5% and 30.4%, respectively. The prevalence of ketosis, milk fever, abomasal displacement, septicemic metritis, endometritis, subclinical endometritis, pyometra, and ovarian cysts were 18.8%, 3.6%, 4.0%, 36.2%, 29.5%, 17.0%, 4.5%, and 14.7%, respectively. The prevalence of digestive problems and mastitis were 5.4% and 9.6%, respectively. The prevalence of culling and death were 4.0% and 3.6%, respectively. The prevalence of dystocia, retained placenta, septicemic metritis, endometritis, ovarian cysts, digestive problems, mastitis, and culling differed among farms (p < 0.05 to 0.01). In conclusion, proper examinations for uterine inflammation and ovarian cyclicity during 4 to 8 weeks postpartum are useful clinical tools to maintain herd reproductive health. Dystocia, retained placenta, septicemic metritis, and endometritis were predominant disorders in dairy cows of the survey area.

• Journal of Veterinary Clinics
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• v.38 no.2
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• pp.49-55
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• 2021

We aimed to identify the biological factors during the voluntary waiting period (VWP) that are associated with subsequent reproductive performance in dairy cows. Two hundred and one pregnant dairy cows had their body condition score (BCS) evaluated and blood samples taken 4 weeks before calving, at calving, and 1, 2, 4, 6, and 8 weeks after calving, to measure serum metabolite and progesterone concentrations. In addition, any peri- and postpartum disorders within 4 weeks of calving, and the mean milk yields 4 and 8 weeks postpartum, were recorded. The cows were allocated to two groups according to whether they had become pregnant or not by 120 days after calving: a pregnant group (n = 50) and a non-pregnant group (n = 151). Analyses of serum metabolite concentrations showed that the aspartate aminotransferase and γ-glutamyltransferase activities 2 weeks (p < 0.05) and the non-esterified fatty acid concentration 6 weeks (p < 0.01) postpartum were higher in the non-pregnant than in the pregnant group. However, the albumin concentrations between 2 and 8 weeks and the total cholesterol and magnesium concentrations between 4 and 8 weeks postpartum were lower in the non-pregnant group (p < 0.05). The BCS (p < 0.05) and percentages of cows that had resumed cyclicity (p < 0.001) by 6 and 8 weeks postpartum were higher in the pregnant than in the non-pregnant group, whereas the incidence of peri- and postpartum disorders was higher in the non-pregnant group (p < 0.05). In conclusion, high serum enzyme activities, which imply liver damage, imbalances in energy metabolites and magnesium, and a higher incidence of peri- and postpartum disorders, are associated with poorer reproductive performance, whereas high BCS and early resumption of cyclicity during the VWP are associated with superior reproductive performance in dairy cows.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.124-131
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• 2007

There is worldwide interest in buffalo as an animal for meeting the growing demands of meat, milk and work in the developing countries. One of the major constraints to full exploitation of the productive potential of buffalo has been its inherently low reproductive efficiency as reflected by late maturity, poor expression of oestrus, silent oestrus, irregular oestrous cyclicity, seasonality in breeding, anoestrus, low conception rate, long postpartum interval, repeat breeding etc. Ovarian cyclicity is regulated by endocrine and neuroendocrine mechanisms namely hypothalamic hormones, gonadotropins and ovarian steroids. Detailed endocrine investigations are suggested with special reference to the hypothalamo-hypophysial-ovarian axis to gain a better understanding of reproduction in buffalo and to modify it to derive the maximum benefit from this animal.

• 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.10 no.2
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• pp.229-232
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• 1997

Effects of short-term treatment with somidobove (recombinantly produced bovine somatotropin, BST) on estrous cyclicity and fertility were studied in dairy buffaloes. Twenty buffaloes of Nili-Ravi breed calving during the same season were assigned to either control (n=8) or treated group (n=12). The buffaloes of treated group received single infection (prolonged release) of 320 mg of somidobove on day-60 postpartum. The mean values for interval to first postpartum estrus, first service conception rate, services per conception, service period and calving interval for the treated group were 96.4 days, 66.7%, 1.70, 164 days and 473 days, respectively. The corresponding values for the control group were 92.5 days, 62.5%, 1.87, 135 days and 439 days. Means of all variables did not differ between control and treated group (p > 0.05). Three buffaloes of the control and four buffaloes of the treated group did not conceive at first service. Out of these, two buffaloes of control and one buffalo of treated group exhibited normal estrous cycles. It is concluded from these data that short term BST-treatment has no adverse effect on reproductive functions of dairy buffaloes.

• Reproductive and Developmental Biology
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• v.30 no.3
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• pp.213-218
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• 2006

This study was conducted to investigate the effect of abnormal ovarian cycle postpartum on subsequent reproductive performance of Holstein cows. The cows were considered to have resumed ovarian cyclicity on the day of ovulation if followed by regular ovarian cycles. Total 58.8 percentage of the cows(l14/194) had normal resumption of ovarian cyclicity(resumption within 40 days after calving), and 41.2%(80/194) had delayed resumption(resumption did not occur until >40 days after calving). Delayed resumption Type I(one or more ovarian cycles with luteal phase >20 days, i.e. prolonged luteal phase; 17.5%) and delayed resumption Type II(first ovulation did net occur until $\geq$40 days after calving, i.e. anovulation 22.7%) were the most common types of delayed resumptions. When compared with cows with a normal ovarian cycle, the cows of delayed resumption Type I had a lower 100 days AI submission conception and pregnancy rates(84.2% vs 40.0%; p<0.01, 24.0% vs 21.4% and 20.2% vs 11.1%, respectively), and longer intervals to first AI and to conception($64.7{\pm}2.79$ days vs $105.7{\pm}7.48$ days and $105.1{\pm}7.16$ days vs $133.7{\pm}11.17$ days, respectively; p<0.01). Similarly, when compared with cows with normal ovarian cycles, the cows of delayed resumption Type II had lower 100 days conception and pregnancy rates(24.0% vs 20.0% and 20.2% vs 16.3%, respectively), and longer intervals to first AI and to conception($64.7{\pm}2.79$ days vs $72.6{\pm}4.45$ days and $105.1{\pm}7.16$ days vs $120.8{\pm}12.33$ days, respectively). In conclusion, abnormal ovarian cycles postpartum adversely affected reproductive performance, including AI submission rate, pregnancy rate, interval to first AI, and calving to conception interval in Holstein cows.

• Reproductive and Developmental Biology
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• v.41 no.2
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• pp.25-31
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• 2017

Effective estrus detection and artificial insemination (AI) are necessary for profitable management of dairy herd. In current study, 45 crossbred lactating cows have been selected with the complaint of unobserved oestrus for more than sixty days postpartum. All cows had functional corpus luteum as examined by transrectal ultrasonography. Cows were treated with $PGF_2{\alpha}$ analogue and AI was performed with observed oestrus and then single dose of GnRH was administered. Similar synchronization protocol has been repeated after 14 days in cows that did not repose to first treatment. Remaining cows received additional $PGF_2{\alpha}$ after 14 days of second treatment and timed AI was performed following GnRH administration. Among 45 cows, 28.89% showed estrus after first treatment and 78.79% responded to second hormonal intervention. A higher conception rate (88.89% vs 26.66 and 72.72%) was observed in cows after triple administration of $PGF_2{\alpha}$ and timed AI. We noticed a significant differences in body condition score (BCS, 1~5 scale), postpartum period, and daily milk production between cows that either responded of non-responded following first and second hormonal treatment. In addition, there was a significant positive correlation between daily milk production and BCS, age and postpartum days, milk production and estrus/BCS, and milk production/BCS/estrus and conception rate. Depending upon the findings we conclude that hormonal intervention with $PGF_2{\alpha}$ and GnRH enhances postpartum ovarian cyclicity and help decreasing the days open of dairy herd. Therefore, this finding might provide an excellent guideline for target breeding system for profitable dairy herd management.

• Journal of Embryo Transfer
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• v.20 no.3
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• pp.279-287
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• 2005

This study was carried out to investigate resumption of ovarian cyclicity and effect of BCS on estrous response by treatment of $PGF_2a+PGF_2a+CIDR$ program on day 40 postpartum in lactating dairy cow. First $PGF_2a$ was given on day 40 postpartum, second $PGF_2a$ was given 14 days apart to cows not-responded to 1st $PGF_2a$ and then CIDR was inserted for 7 days after 5 days in cows not-responded to 2nd $PGF_2a$. The $42.9\%$ of the cows showed more than 1 ng/mL milk progesterone concentration within 10 to 30 days postpartum. About $19\%$ of the cows exhibited more than 1 ng/mL milk pro-gesterone concentration between 31 to 50 days postpartum. However $38.1\%$ of the cows have not shown more than 1 ng/mL milk progesterone up to 50 days postpartum. Estrous response to the treatment of 1 st $PGF_2a$ and 2nd $PGF_2a$ was $47.5\%$ and $52.4\%$, respectively. Combination of 1 st $PGF_2a$ and 2nd $PGF_2a$ was $75\%$ and combination of 1st $PGF_2a$+2nd $PGF_2a$+CIDR was $87.5\%$. Estrous response to the treatment of $PGF_2a+PGF_2a$ program was $61.5\%$ in cows with less than 2.50 BCS and $81.5\%$ in cows with 2.75${\~}$3.50 BCS. Estrous response to the treatment of CIDR was $40\%$ in cows with less than 2.50 BCS and $80\%$ in cows with 2.75${\~}$3.50 BCS. Estrous response to the treatment of PPC on day 40 postpartum was $76.9\%$ in cows with less than 2.50 BCS and $96.3\%$ in cows with 2.75${\~}$3.50 BCS.