• Asian-Australasian Journal of Animal Sciences
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• v.5 no.3
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• pp.435-438
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• 1992

Data were collected on productive and reproductive performance of different $F_1$ crossbred cows (Deshi cows joined by A.I. to Sindhi, Sahiwal, Jersey or Holstein-Friesian Bull semen) reared by farmers in and around the Bangladesh Agricultural University campus at Mymensingh. The traits considered were birth weight, age at first heat, age at first calving, gestation length, post-partum heat period, milk yield, lactation length, dry period and calving interval. Data were analyzed statistically using a completely randomized design and Duncan's Multiple Range Test to compare and determine the significance of between individual group means. It was observed that the Holstein $\times$ Deshi had the highest birth weight (21.4 kg) followed by Sahiwal (17.6 kg), Jersey (16.7 kg) and Sindhi (16.1 kg). Shortest age at first heat (854 and 920 days) and age at first calving (1002 and 1201 days) were found for the Jersey $\times$ Deshi and Holstein $\times$ Deshi crosses respectively. The post-partum heat period were significantly different between breeds with Jersey and Holstein sired calves having the shortest intervals. There was no difference in the gestation length of the four crosses. Holstein $\times$ Deshi and Jersey $\times$ Deshi cows gave the highest milk yields due to longer lactation periods and higher daily milk production. Similarly, Holstein $\times$ Deshi and Jersey $\times$ Deshi crosses had significantly shorter dry periods and Jersey $\times$ Deshi had a shorter calving interval. From this study it may be concluded that exotic genotypes such as Holstein-Friesian and Jersey can perform very well under rural conditions in Bangladesh.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.159-163
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• 2004

Data pertaining to first lactation records of 316 Murrah buffaloes, progeny of 47 sires, maintained at NDRI Farm for a period of 18 years were analysed to construct selection indices and to examine their robustness by changing the relative economic values of different economic traits. A total of 120 selection indices were constructed for three sets of relative economic values ( 40 for each set) considering different combinations of seven first lactation traits viz. age at first calving (AFC), first lactation 305 day or less milk yield (FLMY), first lactation length (FLL), first calving interval (FCI), milk yield per day of first lactation length (MY/FLL), milk yield per day of first calving interval (MY/FCI) and milk yield per day age at second calving (MY/ASC). The three sets of relative economic values were based on economic values of different traits, 1% standard deviation of different traits and regression of different traits on FLMY. The 'optimum' indices for the first two sets had five traits each namely AFC, FLMY, FLL, FCI and MY/ASC giving improvement in aggregate genotype of Rupees 269.11 and Rs. 174.88, respectively. The accuracy of selection from both indices was 70.79 and 69.39%, respectively. The 'best' selection index from the third set of data again had five traits (AFC, FLMY, FLL, FCI and MY/FLL) giving genetic gain of Rs. 124.16 and accuracy of selection of 71.81%. The critcal levels or break-even points for FLMY for varying levels of AFC and FCI estimated from the "optimum index" suggested the need of enhancement of present production level of the herd or reduction of AFC or FCI. It was concluded that economic values of various first lactation traits were the most appropriate to construct selection indices as compared to other criteria of assigning relative economic weights in Murrah buffaloes.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.230-238
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• 2021

This study attempted to determine the characteristic features of postpartum dairy cows during their return to estrus. Moreover, it investigated the effects of abnormal ovarian cycles (AOC) on subsequent reproductive performance and the relationship between normal ovarian cycles (NOC) and the blood urea nitrogen (BUN) level postpartum. Incidentally, 56.3% of the Holstein cows and 66.7% of the Jersey cows had NOC, whereas the 43.7% and 33.3% of the Holstein and Jersey, respectively, had AOC. Within 100 days of calving, the cows with AOC had significantly lower rates of artificial insemination (AI) submission as well as pregnancy and a significantly longer interval to first AI, as compared to that in the cows with NOC. Additionally, the cows with NOC had a significantly higher first AI conception rate than that in the cows with AOC. In this study, of the 32 Holstein cows, 8 resumed their ovarian cycle within 20 days of calving, 10 resumed the cycle with 21-40 days of calving, 8 within 41-60 days of calving, while the remaining 6 did not resume their ovarian cycles until 60 days postpartum. Furthermore, the likelihood ratios of incidence of NOC are 0.93, 1.94, and 0.38, respectively, in the groups with BUN levels < 15, 15-19.9, and ≥ 20 mg/dl. In conclusion, AOC postpartum adversely affects reproductive performance such as AI submission rate, pregnancy rate, interval to first AI and first AI conception rate; moreover, an increase or decrease in the BUN levels beyond 15-19.9 mg/dL leads to the AOC postpartum.

• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.280-285
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• 2008

This study evaluated the correlation between the body condition score (BCS) during prepartum, calving and postpartum periods and the reproductive performance of Korean brown cattle. The BCSs of 33 cows who underwent 73 calvings over a two and a half period [the parities of the cows ranged from 1 to 4 ($mean{\pm}SD,\;2.0{\pm}0.9$)] were scored at months 2 and 1 prepartum, calving, and every month postpartum until month 7. A marked prepartum loss of BCS in the month preceding calving was noted. The correlations between the interval from calving to conception and the month 1 prepartum, calving and months 1 and 2 postpartum BCSs were analyzed by Pearson correlation analysis. The correlation between the interval from calving to conception and the prepartum body condition loss was also evaluated. The interval from calving to conception correlated positively with the month 1 prepartum BCS (r = 0.389, P = 0.0007) and the prepartum body condition loss (r = 0.488, P < 0.0001) but did not correlate significantly with the BCS at calving (r=-0.070, P=0.56) or months 1 (r=0.107, P=0.37) or 2 (r=0.102, P=0.39) postpartum. The prepartum body condition loss correlated positively with the month 1 prepartum BCS (r=0.587, P<0.0001). In conclusion, the month 1 prepartum BCS may be a good criterion for predicting subsequent reproductive performance. Moreover, the prevention of obesity and/or excessive prepartum body condition loss may result in higher fertility in Korean brown cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.11
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• pp.1516-1519
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• 2001

The data consisted of 369 lactation records for calvings over a sixteen-year period (1972-1987) and included only cows that had normal milk records. The data were analysed using a linear model containing the fixed effects of parity, year of calving and season of calving. The least squares means${\pm}$S.E. were $1,273{\pm}58.4kg$ for milk yield, and for post-partum body weight (kg) at 2, 3 and 4 months after calving were $343.40{\pm}3.96$, $346.10{\pm}4.10$ and $352.54{\pm}4.26$, respectively. With the exception of season of calving, the effects of parity and year of calving were significant (p<0.01) on the performance of the animals. Thus, the mean-milk yields 1162, 1351 and 1350, were similar for pre-, peak- and post rainy seasons, respectively. On the other hand, as parity increased from 1 to 3, milk yield also increased, but thereafter, there was a gradual decline in milk yield. Similarly, post-partum body weight also increased with parity. However, no consistent pattern for year effect was observed which probably was a reflection of the variation in climatic conditions, or forage quality and/or availability. The phenotypic correlations between milk yield and post-partum body weights were negative and small (ranging from -0.01 to -0.08). However, high milk production in cows was associated with longer calving interval. The implications from the phenotypic correlations are suggestive of one or two possibilities. Firstly, selection for increased body weight may actually result in decreased milk yield. Also, a substantial genetic antagonism may exist between milk yield and fertility in the crossbred cows. Therefore, it is important that selection to improve milk production should take into consideration the reproductive performance of the cows.

• 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.13 no.6
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• pp.837-841
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• 2000

The study was conducted at semi urban area in Bangladesh. It was based on a field survey by a prepared questionnaire. Various milking and reproduction performance were analyzed. The effects of grazing hour were found significant on age at weaning (AW) (p<0.001), age at first heat (AFH) (p<0.001), age at first conception (AF conception) (p<0.001), age at first calving (AF calving) (p<0.001), post partum heat period (PPHP) (p<0.001), calving interval (CI) (p<0.001), lactation length (LL) (p<0.001) and total lactational production (TLP) (p<0.001). The effects of concentrate feed were significant on AW (p<0.01), AFH (p<0.01), AF conception (p<0.001), AF calving (p<0.001), PPHP (p<0.001) CI (p<0.001), LL (p<0.001) and TLP (p<0.001). The effects of management level were significant on AW (p<0.001), PPHP (p<0.01), CI (p<0.001), daily milk yield (DMY) (p<0.05) and TLP (p<0.001). The overall mean values were $251.88{\pm}2.97$ days for AW, $37.29{\pm}0.33$ months for AFH, $38.43{\pm}0.34$ months for AF conception, $47.62{\pm}0.34$ months for AF calving, $1.30{\pm}0.02$ number of services per conception (NSPC), $191.57{\pm}3.92$ days for PPHP, $17.02{\pm}0.15$ months for CI, $2.49{\pm}0.06kg$ for DMY, $247.23{\pm}3.51$ days for LL and $590.40{\pm}15.00kg$ for TLP.

• Journal of Veterinary Clinics
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• v.36 no.1
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• pp.68-73
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• 2019

We determined the risk factors for displacement of the abomasum (DA), and the relationships between DA and postpartum disorders, milk yield, and reproductive performance in dairy cows. Initially, we identified the risk factors for DA using data regarding cow health and calving season from 2,208 lactations. Then, we compared the incidence of postpartum disorders, culling, death, and reproductive performance between cows with DA and their control herdmates (each n = 57). In addition, serum metabolites concentrations and milk yield were compared between cows with DA and controls (each n = 33). Ketosis (odds ratio [OR] = 9.27, p < 0.0001) and twin calves (p = 0.06) increased the risk of DA. Cows with a parity of three had a higher risk (OR = 5.23, p < 0.01) of DA than primiparous cows. Serum total cholesterol concentration was lower but non-esterified fatty acid, ${\beta}-hydroxybutyrate$, and alanine aminotransferase concentrations were higher after calving in cows with DA than in controls (p < 0.05). The removal rate from the herd by 2 months after calving was higher (p < 0.05) but milk yield 1 and 2 months after calving (p < 0.01) and the rate of first insemination by 150 days postpartum were lower (hazard ratio = 0.49, p < 0.05) in cows with DA than controls. In conclusion, higher parity, twin calves, and ketosis are risk factors for DA in dairy cows, which is associated with a higher removal rate from the herd, lower milk yield, a longer calving to first insemination interval, and unfavorable levels of metabolites related to energy and liver function.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.3
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• pp.427-433
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• 1992

Reproduction and growth to weaning were compared for Brahman crossbred (BX) and a local strain of South-East Asian cattle, "Javanese Zebu" (JZ) and their reciprocal crosses at "Erap" in the humid equatorial lowlands of Papua New Guinea. Forty heifers of each breed were mated continuously, half to bulls of each breed, for five years. BX calved first at 35 months while JZ calved at 31 months. Subsequent calving intervals were very short, at 370 and 341 days. JZ cows weighed about two thirds of the BX cattle at each stage of reproduction. Birth weights and growth to weaning were : BX 35 kg and 0.68 kg/d ; BX male $\times$ JZ female 29.3 kg and 0.53 kg/d ; JZ male $\times$ BX female 30.8 kg and 0.61 kg/d ; JZ 25 kg and 0.50 kg/d. The combination of small cow size, short calving interval and rapid calf growth resulted in the BX male $\times$ JZ female being the most efficient producer, in kg of calf weaned per cow mated per year while the reciprocal cross was the least efficient ; both straight-breds were equal and intermediate. These data show that indigenous equatorial cattle may not be inferior under good grazing conditions. For all traits, breed interactions (heterosis) was small and non-significant.

• Journal of Veterinary Clinics
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• v.33 no.6
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• pp.351-355
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• 2016

This study was conducted to investigate reasons for culling of Chungcheong dairy herds and to investigate the relationships between cow parity, interval from calving to culling, or season and culling reasons. Lactation data from 826 cows on 9 dairy farms from 2013 to 2015, including reasons for culling, dates of birth, last calving, and culling, were analyzed. The overall culling rate was 29.8% (246/826), with mammary problems (23.2%) being the most prevalent reason for culling, followed by infertility (14.2%) and downer cow syndrome (11.0%). The culling rate varied among farms (18.8-43.1%, p < 0.05), but was greater in parity $4{\leq}(40.7%)$ than parities 1, 2, or 3 (17.9-23.6%), whereas the rate was less frequent during mid lactation (21.1%) than in early (36.2%) or late (42.7%) lactation. Moreover, the culling rate was greater during summer (35.8%) than other seasons (20.3-23.2%). Mammary problems, downer cow syndrome, and metabolic disorders were the more common reasons for culling during early lactation, whereas infertility was predominant during late lactation. Our data show that the culling rate in Chungcheong dairy herds was associated with cow parity, interval from calving to culling, and season, with the main reasons for the removal of cows from dairy herds being mammary problems, infertility, and downer cow syndrome.