• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.369-375
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• 2003

The ultrasonography was performed in 77,924 subestrous dairy cows from 680 dairy farms at 57 districts. The cows were examined for confirmation of resumption of ovaries and uterus after 30 days postpartum, for early pregnancy diagnosis after 30 days post-insemination, confirmation of pregnancy at 8 month post-insemination, and for diagnosis of reproductive dysfunctions, respectively. The results of reproductive examination by ultrasonography in 77,924 dairy cows were ovarian disorders 35,452 (46.8%), uterine disorders 10,721 (13.8%), pregnancy and pregnant failure 24,044 (30.8%), adhesion of reproductive tracts 167 (0.2%), freematins 13 (0.01%) and others 6,527 (8.4%) cows, respectively. The 13,732 (49.6%) cows out of 27,694 cows were treated for silent heat or error of estrus detection, 3,473 (12.5%) cows for follicular cysts, 815 (3.0%) cows for luteal cysts, 606 (2.2%) cows for inactive ovaries, 4 (0.01%) cows for granulosa cell tumors, and 6,455 (23.3%) cows for endometritis, respectively. The indices of reproductive efficiencies before (2001-08-10) and after (2003-07-20) periodical examination of reproductive status were as follows; the mean intercalving interval were shortened from 471 days to 383 days, the mean interval calving to conception were shortened from 187 days to 99 days, the mean interval calving to first service were shortened from 105 days to 67 days, the mean cows showing heat by 60 days postpartum were increased from 33% to 89%, the mean conception rate to first service were increased from 43% to 68%, and the mean service per conception were shortened from 2.6 times to 1.8 times, respectively. These results suggest that periodical examination of reproductive status would be useful for the improvement of the reproductive performance in dairy cows.

• Journal of Veterinary Clinics
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• v.31 no.5
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• pp.382-388
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• 2014

The objective of this study was to determine the risk factors associated with pregnancy following 3 synchronization protocols in dairy cows. Data were collected on 1,952 cows from 22 dairy farms, including synchronization protocols ($PGF_{2{\alpha}}$ + estradiol benzoate [PG+EB], Ovsynch, and CIDR-ovsynch), cow parity, body condition score (BCS), and dates of previous calving, insemination and conception. The odds ratio (OR) for pregnancy were analyzed by logistic regression using the LOGISTIC procedure in SAS. The analysis revealed that farm (p = 0.005), cow parity (p = 0.0001), BCS (p < 0.005), and AI season (p < 0.05) significantly affected and calving to AI interval tended to affect (p < 0.1) the probability for pregnancy. Although synchronization protocols did not affect the probability for pregnancy (p > 0.05), cow parity and synchronization protocols showed a significant interaction (p < 0.005); the OR (0.60) was significantly lower (p < 0.0001) for multiparous cows compared to primiparous cows using PG+EB, whereas the OR (1.44) tended to be higher (p < 0.1) for multiparous cows compared to primiparous cows using the Ovsynch, and the probability for pregnancy did not differ between multiparous and primiparous cows using the CIDR-ovsynch (p > 0.05). Cows with BCS ${\geq}$ 3.00 were more likely pregnant (OR: 1.41) compared with cows having BCS ${\leq}$ 2.75, whereas cows inseminated during summer had a lower OR (0.73) compared with those inseminated during spring. Cows with a calving to AI interval > 150 days were more likely to be pregnant (OR: 1.20) compared with cows with a calving to AI interval ${\leq}$ 150 days. In conclusion, the OR for pregnancy following synchronization protocols in dairy cows was affected by farm, parity, BCS, calving to AI interval of the cow, and AI season, and there was a significant interaction between cow parity and synchronization protocols; the OR for pregnancy was lower for multiparous cows compared with primiparous cows using the PG+EB protocol.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.1
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• pp.1-6
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• 2004

The 490 and 380 performance records of Karan Fries and Karan Swiss cows developed through crossbreeding followed by inter-se mating were evaluated for production, reproduction performance and disposal rate. Duration of study (1982-92) was grouped into five periods (1982-83; 1984-85; 1986-87; 1988-89; 1990-92) and each year was divided into four seasons (Winter: Dec.-Jan.; Spring: Feb.-March; Summer: April-June; Rainy: July-Sept.; Autumn: Oct.-Nov). Data were also classified according to sire and level of inbreeding. The least squares means of FLY (first lactation yield -305 days), FLL (first lactation length), FSP (first service period), FDP (first dry period), FCI (first calving interval ), MY/FLL (milk yield per day of first lactation length), MY/FCI (milk yield per day of first calving interval), EBV (expected breeding value) and EBE (expected breeding efficiency) were $3,173{\pm}82$ kg, $34611{\pm}$days, $143{\pm}11$ days, $75{\pm}6$ days, $423{\pm}11$ days, $10.6{\pm}0.2$ kg, $8.9{\pm}0.2$ kg, $3,380{\pm}26$ kg, and $88.2{\pm}1.3$% respectively in Karan Fries. Corresponding estimates in Karan Swiss cows were $2,616{\pm}82$ kg, $328{\pm}8$ days, $148{\pm}12$ days, $103{\pm}9$ days, $435{\pm}13$ days, $8.9{\pm}0.2$ kg, $7.2{\pm}0.3$ kg, $2,924{\pm38}$ kg and $86.0{\pm}3.8$% respectively. The effect of sire was significant on FLY, MY/FLL, MY/FCI and EBV in both the herd (p<0.01). The 10 and 15% sires showed superiority (FLY) over herd average of 11 and 7% in Karan Fries and 32 and 21% in Karan Swiss cattle respectively. Inbreeding has adversely and significantly (p<0.05) affected the FLY, MY/FLL, MY/FCI and survivability of Karan Fries females; FDP and disposal through culling of Karan Swiss heifers. The Karan Fries heifers with inbreeding above 12.5% performed 16% lower FLY to herd average. The effect of season of calving was significant on FLL, FSP and FCI (p<0.05) in Karan Fries. Summer calvers ($361{\pm}12$) were have higher lactation length and autumn calvers ($329{\pm}14$) had minimum. Period of calving significantly influenced the FSP, FCI, MY/FLL and MY/FCI in Karan Fries and FLY, MY/FLL and MY/FCI in Karan Swiss. Production efficiency traits in Karan Fries herd witnessed higher yield in the last two periods whereas, Karan Swiss heifers showed fluctuating performance. The findings suggested judicious use of available genetic variability, keeping of inbreeding under safer level and managemental interventions for the consistent improvement of both herds.

• Journal of Embryo Transfer
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• v.22 no.2
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• pp.111-114
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• 2007

This study was carried out to investigate the reproductive performance of average (less than 10,000 liters milk in 305 days) and high yielding (more than 10,000 liters milk in 305 days) Holstein cattle at commercial dairy herds (n=22). Data on milk progesterone (10 to 60 days postpartum), days to post-partum estrous, days to post-partum conception, service per conception and calving interval were recorded for two consecutive years. Post-partum milk progesterone concentration and days to reach peak milk progesterone concentration were similar in high and average yielding cows. High yielding cows took more days to show signs of first postpartum estrous than average yielding cows. Post-partum conception was 20 days earlier in average yielding cows than high yielding cows. Artificial insemination per conception was similar between average and high yielding cows. Calving interval was 26.9 days longer in high yielding cows compared to average yielding cows. In conclusion, better reproductive and feeding management may help improve the reproductive performance of high yielding dairy cattle in commercial dairy farms.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.5
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• pp.470-474
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• 1998

Data on the first lactation performance traits of $F_1$, $F_2$ and $F_3$ crosses covering the period from 1972 to 1995 of a total of 803 dairy cows of three genetic grades maintained at Livestock Production Research Farm, Indian Veterinary Research Institute, Izatnagar were analysed. Three genetic grades were 1/2 Friesian + 1/2 Hariana (FH), 1/2 Friesian + 1/4 Brown Swiss and 1/4 Hariana (FBH) and 1/2 Friesian+ 1/4 Jersey + 1/4 Hariana (FJH). Age at first calving increased by 7% and 8% in $F_2$ and $F_3$, respectively, over the $F_1$ in FH. The reduction in age at first calving at $F_2$ and $F_3$ levels by 2-7% over the $F_1$ was observed in FBH and FJH. The lactation milk yield of $F_1$, $F_2$ and $F_3$ crosses was $1,943{\pm}100.3$, $2202{\pm}120.5$ and $1,925{\pm}123.2kg$ in FH; $2,014{\pm}76.7$, $2,264{\pm}91.5$ and $2,096{\pm}123.9kg$ in FBH and $2,005{\pm}87.0$, $2,414{\pm}94.4$ and $2,093{\pm}121.1kg$ in FJH, respectively. The lactation milk yield improved by 12-20% in $F_2$ crosses in various genetic grades. The performance of $F_1$ was, however, maintained in FH $F_3$ crosses, it improved by 4% in FBH and FJH $F_3$ crosses. The lactation lengths and calving intervals were nearly the same for $F_1$, $F_2$ and $F_3$ crosses in FH while lactation lengths and calving intervals were reduced by 3-11% in $F_2$ and $F_3$ crosses in FBH and FJH genetic grades. The milk yield/day of lactation length and milk yield/day of calving interval increased by 16-35% in $F_2$ and 2-14% in $F_3$ over the $F_1$ in various genetic grades. It is recommended that a sufficiently large effective population size of these three genetic grades be maintained by inter se matings and rigorous selection of sires so for developing a genetic base population for new breed development.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.6
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• pp.820-826
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• 2018

Objective: The purpose of this retrospective study was to investigate the relationship between temperature-humidity index (THI), season, and conception rate (CR) of Holstein cows in central Taiwan. Methods: The mean performance and number of observations were statistically evaluated for various parameters, including age at first service, number of days open, gestation length, CR, and calving interval for different parities. Results: The results indicate that the mean age at first service was 493.2 days; the gestation length was similar across all cows of different parities, ranging from 275.1 to 280.7 days. The overall CR of all inseminations was significantly lower in multiparous cows ($47.26%{\pm}0.22%$) than in heifers ($57.14%{\pm}0.11%$) (p<0.05). At THI>72 and during the hot season (from June to November), CRs for multiparous cows were significantly reduced compared to that for heifers, while the ratio remained unchanged among heifers for all seasons. Conclusion: To achieve a high CR, lactating cows should be bred in winter and spring (from December to May) from the start of the seasonal breeding program, whereas the heifer should be allowed to breed in summer and fall under the subtropical climate in Taiwan.

• Journal of Veterinary Clinics
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• v.1 no.1
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• pp.25-31
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• 1984

The effects of progesterone releasing intravaginal device (PRID) on the fertility levels in dairy cows were studied in 2 experiments. In experiment I, 70 lactating cows at 45 days postpartum were allotted to 3 groups and the treatments imposed were either： 1: Untreated control, 2: PRID with a capsule containing long of oestradiol benzoate (ODB) attached, inserted for 12 days, 3: PRID inserted for 12 days with long of prostaglandin F$\_$2${\alpha}$/ administration 24 h before PRID removal. Treated cows were inseminated 56 h after PRID removal and at an observed oestrus during the subsequent 48-day period. The control group was inseminated at an observed oestrus during this 60-day period. In experiment II, 60 ovarian disorder cows were divided into 5 groups and PRID+ODB inserted for 12 days. 1: atrophied ovary, 2: smooth ovary, 3: persistent corpus luteum, 4: follicular cyst, 5: luteal cyst. Treated cows were inseminated 56 h after PRID removal and at an observed oestrus over a period from the first insemination to 46 days. The results obtained were as follows: 1. The device produced a vaginal discharge in some animals. In experimenet I : 2. For treatments 2 and 3, respectively, conception rates to the fixed time insemination were 45% and 52%. 3. The conception rates of cows inseminated to the fixed time insemination and at an observed oestrus during a 60-day period were 65%, 86% and 91% for control, treatment 2 and 3, respectively. 4. Mean interval from calving to conception and inseminations per conception were 133, 91 and 86 days and 2.4, 2.1 and 1.9 for control, treatments 2 and 3, respectively. In experiment II； 5. The conception rates to the fixed time insemination for each group 20, 50, 70, 20 and 50%, respectively. 6. The total conception rates for the 48 days period of each group were 60, 70, 100, 60 and 90%, respectively. 7. The inseminations per conception of each group were 2.8, 2.1, 1.4, 2.7 and 1.9, respectively.

• Animal Bioscience
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• v.34 no.8
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• pp.1303-1308
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• 2021

Objective: The objective of this study was to define a new composite trait for Holstein dairy cows and evaluate the possibility of joint improvement in milk and fertility traits. Methods: A data set consisting 35,882 fertility related records (days open [DO], calving interval [CI], and number of services per conception [NSC], and total milk yield in each lactation [TMY]) was collected from 1998 to 2016 in Polish Holstein-Friesian breed herds. In this study TMY, DO, CI, and lactation length of each cow was used to obtain composite milk and fertility traits (CMF). Results: Moderate heritability (0.15) was estimated for composite trait that was higher than heritability of female fertility related traits: DO 0.047, CI 0.042, and NSC 0.014, and slightly lower than heritability of TMY 0.19. Favourable genetic correlations (-0.87) were estimated between CMF with TMY. Spearman rank correlation coefficients between breeding value of CMF with DO, CI, and TMY were high (>0.94) but with NSC were moderate (0.64). Selection on CMF caused favourable correlated genetic gains for DO, CI, and TMY. Different selection indices with different emphasis on fertility and milk production were constructed. The amount of correlated genetic gains obtained for DO and total milk production according to selection in CMF were higher than of genetic gains obtained for DO and TMY in selection indices with different emphasis on milk and fertility. Conclusion: The animal selection only based on a composite trait - CMF proposed in current study would simultaneously lead to favourable genetic gains for both milk and fertility related traits. In this situation CMF introduced in current study can be used to overcome to limitations of selection index and CMF could be useful for countries that have problems in recording traits, especially functional traits.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.3
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• pp.419-426
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• 1992

After the virtual eradication of cattle during World War II, Papua New Guinea herds were rebuilt with Shorthorn and Aberdeen Angus cattle from Australia. These, and Red Sindhi and Sahiwal, imported in 1952, were considered unsuitable breeds. In 1954, Department of Agriculture, Stock and Fisheries imported three Brahman bulls and three heifers from Texas and in 1960 began importations of Afrikaner from Queensland. In Central Province, Brahmans were crossed with Angus and at Erap (Morobe) the hottest place in Papua New Guinea, Shorthorns were crossed with Afrikaners. In 1965, Brahman and Brahman-cross were sent to Erap. Records of breeding and growth rates were collected for use in upgrading in cattle of the basis of performance, not pedigree. The data are not ideal for genetic analysis, since no control groups were maintained. Birth weights (BWT), weaning weights (WWT) and calving intervals (CI) were analysed for the period 1969-1978. After exclusion of unsatisfactory data, 2,514 calf records were used, including both breeds from 1969 to 1973, but only Brahman-cross subsequently. Breed mean BWT ranged only from 30.6 to 33.8 kg. As Brahman content increased, BWT decreased and WWT increased; within a genotype, there was a negative maternal effect of high Brahman content on BWT and a positive effect on WWT which ranged from 138 to 174 kg. Afrikaner calves had heavier BWT but lighter WWT. As expected, bulls were heaviest, heifers lightest and mature cows bore and reared heavier calves. Calving interval (405 days, equivalent to 90% calving) was unaffected by breed but 4-year old cows averaged 423 days. Breed differences in BWT and WWT are consistent with the body of literature on performance of Brahmans and Afrikaners. Since cattle tick are not present and internal parasites are insignificant at Erap, the superiority of Brahmans indicates that they were better at utilizing the mediocre quality grazing of the Markham Valley or were more heat tolerant. Performance selection over ten years resulted in the virtual elimination of Afrikaners, with the final genotype approximately 9/16 Brahman, 3/8 Shorthorn and 1/16 Afrikaner.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.10
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• pp.1347-1352
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• 2000

The objectives of the study were to examine non-genetic factors that influence somatic cell counts in dairy cattle and to estimate the genetic parameters of somatic cell counts. A total of 34, 097-test day somatic cell count records were obtained from the Zimbabwe Dairy Services Association (ZDSA). The data were from 5, 615 Holstein daughters of 390 sires and 2, 541 dams tested between May 1994 and December 1998. First lactation cows contributed 22, 147 records to the data set, while 11, 950 records were from second and later parity cows. The model for analysis included fixed effects of month of calving, year of calving, stage of lactation, calving interval and test date. Milk yield and age on test day were fitted in the model as covariates. The additive genetic effects pertaining to cows, sires and dams and the residual error were the random effects. The Average Information Restricted Maximum Likelihood algorithm was used for analysis. The heritability of somatic cell scores was low at $0.027{\pm}0.013$ for parity one cows and $0.087{\pm}0.031$ for parity two and above. Repeatability estimates were $0.22{\pm}0.01$ and $0.30{\pm}0.01$ for the two lactation groups, respectively. Genetic and phenotypic correlations between the somatic cell scores and test day milk production were small and negative. It seems that there is no genetic link between somatic cell counts and milk yield in Holstein cattle in Zimbabwe. The results also seem to indicate that somatic cell count is a trait that is mainly governed by environmental factors.