• Asian-Australasian Journal of Animal Sciences
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• v.25 no.9
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• pp.1338-1350
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• 2012

This review focuses on the nutritional effects from birth until age at first calving on growth, mammary developmental changes, and first-lactation milk yield in heifer calves. The advancement in the genetic potential and the nutritional requirements of the animals has hastened the growth rate. Genetic selection for high milk yield has suggested higher growth capacity and hence increasing nutritional inputs are required. Rapid rearing by feeding high energy or high concentrate diets not only reduces the age of sexual maturity but also lowers the time period of attaining the age of first calving. However, high energy diets may cause undesirable fat deposition thereby affecting future milk yield potential. Discrepancies exist whether overfed or overweight heifers at puberty can influence the mammary development and future milk yield potential and performance. The data on post-pubertal nutritional management suggested that body weight at calving and post-pubertal growth rate is important in first lactation milk yield. There is a continuous research need for strategic feeding that accelerates growth of dairy heifers without reduction in subsequent production. Nutritional management from birth, across puberty and during pregnancy is critical for mammary growth and for producing a successful cow. This review will mostly highlight studies carried out on dairy breeds and possible available opportunities to manipulate nutritional status from birth until age at first calving.

• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.303-306
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• 1998

This study was carried out to investigate the effect of time of feeding to pregnant holstein cows on calving time during a day. The investigation revealed that feeding at 18:00∼04:30 resulted in 87.8%(9＋15h) and 80.7% (12＋12h) of the cows calving, whereas the traditional 08:00 and 18:00 feeding resulted in 57.9%(9＋15h) and 51.8%(12＋12h) of them calving during the day period(p＜0.001). Especially, between 06:00∼11:00 and 16:00∼17:00, 38.5% and 19.6% of cows calving during the day period were investigated.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.466-469
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• 2002

The data on 512 Hariana cows, progeny of 20 sires calved during period from 1974 to 1993 maintained at Government Livestock Farm, Hisar were considered for the estimation of genetic parameters. The means for first lactation milk yield (FLY), wet average (WA), first lactation peak yield (FPY), first lactation milk yield per day of first calving interval (MCI) and first lactation milk yield per day of age at second calving (MSC) were 1,141.58 kg, 4.19 kg/day, 6.24 kg/day, 2.38 kg/day and 0.601 kg/day, respectively. The effect of period of calving was significant (p<0.05) on WA, FPY and MCI while the effect of season of calving was significant only on WA. Monsoon calvers excelled in performance for all the production efficiency traits. The effect of age at first calving (linear) was significant on all the traits except on MCI. Estimates of heritabilty for all the traits were moderate and ranged from 0.255 to 0.333 except for WA (0.161). All the genetic and phenotypic correlations among different production efficiency traits were high and positive. It may be inferred that selection on the basis of peak yield will be more effective as the trait is expressed early in life and had reasonably moderate estimate of heritability.

• Korean Journal of Veterinary Research
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• v.19 no.1
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• pp.63-67
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• 1979

In order to investigate modified Hayden test for mastitis test milk Samples from 120 cows (total 470 of quarters) were tested by this method. The tests were performed by different lactation age group, different calving frequency and their total quarters. Comparision of results were made between the modified Hayden method and the California Mastitis Test. The results obtained were as follows: 1. Ratio of results of mastitis test between modified Hayden method and California Mastitis Test was 1.1:1.0. 2. Incidence rate of mastitis in different Lactation age group shown 78.5% in 7 to 9 year group, 50% in 4 to 6 year age group and 37.5% in up to 3 year age group, respectively. 3. Incidence rate of mastitis with calving frequency, were 13.5% in 1 to 2 calving frequency group, 83.3% in 3 to 4 calving frequency group and 63.6% in 5 to 6 calving frequency group respectively. 4. Mastitis ratio between rear quarters and front quaters were 1.7:1.0. 5. It is probable that modified Hayden was more sensitive than the California mastitis test in detecting subclinical and clinical mastitis.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.5
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• pp.503-508
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• 1996

The data analysed consisted of records on lactation length (LL), total lactation yield (TLY), estimated 305-day yield (305 DY), days dry (DDRY), age at frist calving (AFC) and calving interval (CI) of 448 Friesian $\times$ Bunaji halfbreds that calved over a twenty-three year period (1967-1989) at the National Animal Production Research Institute, Shika, Nigeria. Least squares means of LL, TLY, 305DY, DDRY, AFC and CI were 250 days, 1,988 kg, 2,420 kg, 102 days, 35 months and 390 days, respectively. Parity, season and year of calving significantly affected LL, TLY (p < 0.01) and 350DY (p < 0.05), but not CI. DDRY was affected by season of calving only (p < 0.05). It was therefore concluded that the Shika Friesian $\times$ Bunaji crossbreeding programme was successful and beneficial in that the $F_1$ crosses calved at a younger age, produced twice as much milk, had longer lactations and slightly shorter calving intervals than the indigenous Bunaji.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.2
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• pp.161-164
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• 1999

Dairy performances of Pabna cows and its crossbreds with Sahiwal (SL) and Friesian (F) in the Baghabarighat dairying area of Bangladesh were evaluated. Four SL and three F sires were used for the crossbreeding. The exotic sire effect of individuals on their daughters were also evaluated in this study. It showed that the genetic group had a significant (p<0.05) effect on birth weight, age at first heat, calving interval, lactation length and lactation yield. The lowest birth weight (17.9 kg), longest age at first heat (39.2 m) and calving interval (16.3 m) shortest lactation length (199 d) and lowest lactation yield (728 L) were found in Pabna cows. The highest birth weight (22.5 kg). shortest age at first heat (25.5 m) and calving interval (13.7 m), longest lactation length (253 d) and highest lactation yield (1936 L) were found in the F crossbreds. Within the same breed, the effect of individual sire was significant (p<0.05) on age at first heat, lactation length and lactation yield. Individual sire effects of SL bulls differed significantly (p<0.05) but F sires had a non-significant (p>0.05) effect on calving interval in their progeny. The fat % and SNF % in milk and number of services required for conception did not differ (p>0.05) among inter-and intra- breed sire groups.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.3
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• pp.347-354
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• 2017

Objective: The effects of the pre- and postpartum supplementation of cows with Se on their plasma P4 concentrations after calving were investigated. Methods: Thirty-four Holstein cows were used to investigate the effects of dietary selenium supplementation on the postpartum recovery of the luteal function in cows. Selenium-rich yeast (containing 300 ppm selenium) was mixed with total mixed ration fed to 17 pregnant cows from 30 days before they were due to calve (10 g yeast daily) to 100 days after calving (20 g yeast daily). The control cows (n = 17) were fed the same amount of ordinary yeast. The cows' plasma progesterone concentrations were determined every two days using an enzyme immunoassay after calving. Results: Feed intake (total digestive nutrient, crude protein), milk production, body weight and the biochemical properties of blood plasma did not differ between the two groups; however, the plasma selenium concentrations of the supplemented animals were significantly greater than those of the controls at and after calving. The postpartum plasma progesterone concentrations of the selenium-yeast-supplemented group increased earlier than those of the control group. Moreover, during the estrus cycle after the 3rd ovulation or ovulation with estrus between 60 to 80 days after calving, the selenium-supplemented cows exhibited greater progesterone concentrations than the control cows. Conclusion: Selenium supplementation promotes the postpartum progesterone production of cows.

• Korean Journal of Veterinary Research
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• v.59 no.1
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• pp.1-8
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• 2019

We aimed to identify predictive markers of peri- and postpartum disorders in dairy cows. Data regarding peri- and postpartum disorders, serum metabolites, body condition score (BCS), and rectal temperature, were collected from 227 dairy cows, which were allocated to healthy (n = 57) and diseased (n = 170) groups. Serum non-esterified fatty acid (NEFA) concentration was higher in diseased than healthy cows 4 weeks before (p < 0.01) and immediately after (p = 0.05) calving. Serum alanine aminotransferase (AST) activity was higher (p < 0.05) in diseased than healthy cows 1 and 2 weeks after calving, whereas total cholesterol (TCH) concentration was lower (p < 0.05-0.0001) in diseased cows 4 weeks before, and after calving. BCS was higher (p < 0.05) in diseased than healthy cows 4 weeks before calving, but lower (p < 0.01) in diseased cows 8 weeks after calving. Rectal temperature was higher (p < 0.05-0.01) in diseased than healthy cows between 2 and 14 days postpartum. In conclusion, high serum NEFA and AST concentrations and lower TCH concentration during the peripartum period, and high prepartum BCS and postpartum rectal temperature, could be used as biomarkers to predict the subsequent development of peri- and postpartum disorders.

• Journal of Veterinary Clinics
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• v.34 no.3
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• pp.222-224
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• 2017

A retrospective study was designed to determine whether there were any differences in prepartal blood biochemical parameters between cows developed subclinical ketosis (SCK) and non-SCK cows. Data on blood biochemistry from 33 Holstein parturient cows (15 SCK and 18 non-SCK cows) in one farm for one year, were compared. Plasma beta-hydroxybutyrate, non-esterified fatty acid and glucose concentrations were utilized in the diagnosis of SCK and showed significant differences between SCK and non-SCK cows after calving. Before calving, however, only plasma total cholesterol concentration in SCK cows was significantly lower than that in non-SCK cows. Consequently, it seems that lower plasma total cholesterol concentration before calving is related to the occurrence of SCK immediately after calving.

• Korean Journal of Veterinary Research
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• v.62 no.2
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• pp.15.1-15.8
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• 2022

The objective of this study was to identify risk factors for repeat breeder dairy cows and their impact on reproductive performance. The characteristics of 1,504 cows, including their peripartum health, nutrition, production, and reproduction, were collected. Cows with metabolic disorder were significantly more likely (odds ratio [OR], 2.47; p < 0.001) and cows with clinical endometritis tended to be more likely (OR, 1.35; p < 0.1) to become repeat breeders than cows without metabolic disorder and clinical endometritis, respectively. Cows initially inseminated > 80 days after calving were less likely (OR, 0.78; p < 0.05) to become repeat breeders than cows initially inseminated ≤ 80 days after calving. As a result, repeat breeding in dairy cows resulted in a 90 day longer (p < 0.0001) mean interval from calving to pregnancy. In conclusion, postpartum metabolic disorder, clinical endometritis, and a short interval from calving to initial insemination were risk factors for repeat breeder dairy cows, resulting in a severely impaired reproductive performance.