• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.2
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• pp.262-269
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• 2008

The aim of this study was to determine the effects of breeder age and stocking density on performance, carcass characteristics and some stress parameters (H-L ratio, serum glucose, cholesterol and triglyceride levels, tonic immobility test (TI), antibody production, relative asymmetry (RA) and external appearances). This experiment was carried out with 705 one-day old male broiler chicks (Ross 308) obtained from three different ages of broiler breeder (32, 48 and 61 wks). Each age group was randomly divided into two stocking density groups (11.9 and 17.5 broilers per $m^2$) with 5 replications per group. The experimental period was 6 weeks. Broilers from 32 wk-old breeders had lower initial weight (p<0.001), body weight gain of the first 3 week of rearing (p<0.01), the percentage of abdominal fat (p<0.001) and serum cholesterol level (p<0.01); higher percentage of gizzard (p<0.01) and longer TI duration (p<0.001) than those from 48 and 61 wk-old breeders. Broilers reared at 17.5 b/m2 had lower final BW, body weight gain, feed consumption, feather condition and foot health (p<0.001), higher percentage of heart, H-L ratio, serum glucose and cholesterol levels (p<0.001), and longer TI durations (p<0.001). There were no significant interactions in examined parameters except for feed to gain ratio between breeder age and stocking density.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3438-3448
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• 2021

Dynamic seals are one of the critical components of Absorber Rod Drive Mechanism of Fast Breeder Reactors, requiring separate experimental development. Their significance can't be overemphasized considering that the availability and re-usability of Control Rod Drive Mechanisms of Fast Breeder Test Reactor is governed by the failure rate of dynamic seals (bellows). For prototype and subsequent Fast Breeder Reactors in India, choice of the dynamic seal is changed to an in-house designed & developed labyrinth type V-ring seal. The present work is related to the numerical investigations carried out to gain insights into the sealing mechanism and the thermal behaviour of these seals. The results indicate that the seal geometry is very important for obtaining optimum performance. By changing the geometry of the present seal, performance enhancement by more than 50% in important indices is obtained. Further, the results point out that caution shall be exercised when the seal material & its operating temperature are changed. Also, the numerical model developed in this study will be useful for developing more robust dynamic seals in future.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1258-1265
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• 2007

Metabolizable energy (ME) required for basal metabolism, activity and growth was considered as the criterion for targeting specific increases in body weight (100 g/week) of broiler chicks during the grower phase (5-20 weeks) and its impact was evaluated on breeder performance. Broiler female chicks (460) from a synthetic dam line were randomly distributed to 4 test groups with 23 replicates of 5 birds each and housed in cages. The first group (ME-100) was offered a calculated amount of ME by providing a measured quantity of grower diet (160 g protein and 2,600 kcal ME/kg) which increased with age and weight gain (133-294 kcal/bird/day). The other three groups were offered 10 or 20% less ME (ME-90 and ME-80, respectively) and 10% excess ME (ME-110) over the control group (ME-100). From 21 weeks of age, a single breeder diet (170 g protein and 2,600 kcal ME/kg) was uniformly fed to all groups and the impact of grower ME restriction on breeder performance evaluated up to 58 weeks. The targeted body weight gain of 1,600 g in a 16-week period was achieved by pullets of the ME-100 group almost one week earlier by gaining 8.7 g more weight per week. However, pullets in the ME-90 group gained 1,571 g during the same period, which was closer to the targeted weight. At 20 weeks of age, the conversion efficiency of feed (5.21-5.37), ME (13.9-14.1 kcal/g weight gain) and protein (0.847-0.871 g/g weight gain), eviscerated meat yield, giblet and tibia weights were not influenced by ME restriction, but the weights of abdominal fat and liver were higher with increased ME intake. Reduction of ME by 10% in the grower period significantly delayed sexual maturity (169.3 d), but increased egg production (152.5 /bird) with better persistency. Improved conversion efficiency of feed, ME and protein per g egg content were also observed in this group up to 56 weeks. The fertility and hatchability at 58 weeks of age were higher in the ME-90 group compared to the control and 10% excess ME feeding. In conclusion, the present study revealed the possibility of achieving targeted weight gain in broiler growers by feeding measured quantities of ME during the rearing period with consequential benefits in breeder performance.

• Korean Journal of Poultry Science
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• v.50 no.3
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• pp.119-124
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• 2023

This study was conducted to investigate the effect of dietary levels of the metabolic energy (ME) on performance, egg quality, and hatchability of Woorimatdag breeder hens during late laying period. A total of eighty Woorimatdag breeder hens were individually housed in cages from 48 to 64 weeks of age. The hens were assigned to two groups with different dietary ME levels: 2,500 kcal/kg and 2,700 kcal/kg. Each group consisted of four replicates of ten birds. The results indicated that the dietary ME levels did not have a significant effect on the body weight and feed intake of the breeder hens. The egg production was significantly (P<0.05) higher in breeder hens fed 2,500 kcal/kg ME than in those fed 2,700 kcal/kg ME from 48 to 52 weeks of age. However, the egg production was shown to be similar values in both groups from 52 to 64 weeks of age. No significant differences were observed between groups with respect to egg weight, eggshell thickness, and eggshell strength of breeder's eggs. There was no difference in the fertility and hatchability between dietary groups. In conclusion, 2,500 kcal/kg of dietary ME could be considered to meet Woorimatdag breeder hens requirement sufficiently during late laying period.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.95-99
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• 2003

A total of 112 male and 1208 female Ross broiler breeders (30-wk-old) were used in this study to investigate whether a male to female (M/F) ratio of broiler breeder chickens may influence fertility and hatchability of hatching eggs. There were three treatments, each consisting of four pens with a size of 3.2 m ${\times}$ 6.4 m. Each pen housed approx. 100 females and 10 males to give the M/F ratio as follows: T1, 1/9; T2, 1/11; and T3, 1/13, respectively. The fertility of broiler breeder eggs ranged between 93 to 94％ at 30 wk of age. At 35 wk of age, breeder eggs from T3 tended to be less fertile (P>0.05) than those from T1 and T2. The low fertility observed in T3 at 35 wk of age further reduced to reach a statistical significance at 46 wk of age (P<0.05) when compared to those of T1 and T2. Hatchability of breeder eggs among treatments tended to follow a similar trend as shown in fertility, keeping hatchability of breeder eggs from T3 low when compared to the groups of T1 and T2. Our results indicated that the M/F ratio influenced fertility and consequently hatchability of breeder eggs. Furthermore, our study suggests that either 1/9 or 1/11 M/F ratio, but not 1/13 M/F ratio, seems suitable to sustain reproductive performance of broiler breeders throughout the laying periods.

• Korean Journal of Poultry Science
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• v.27 no.3
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• pp.181-187
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• 2000

This work was designed to investigate the performances of broiler breeder hens upon the addition were vitamin and mineral supplements in feeds. Animals were divided into for feed groups such as control, T$_1$,T$_2$and T$_3$, and each treatment has four replications. All broiler breeder hens were housed individually, and were fed with identical iso-metaboilic energy and iso-protein, except for vitamins and minerals. Different sources and levels of vitamins and minerals were added to the basic feeds according to the treatments. At the end of the experiments, general laying rate(hen days), average egg weight, hatching egg laying rate(Hen day) every day. Hatching egg weight, sterility, embryo mortality, hatching rate and chick weight were examined. Although, early laying rate in all treatment groups were reduced during cold term management, general egg laying rate was increased only T$_3$group which was contanining vitamin C. However, similar results were obtained in the rates of general and hatching egg laying. General egg laying rate were somewhat higher of Control, T$_2$and T$_3$ groups than that of T$_1$group. In addition, the laying rates of general and hatching eggs slightly improved in the T$_3$group rather than those of Control group. Egg weight was reduced with the increasing of laying rate, showing the highest in the T$_3$group. The laying rate showed significantly lower value than those of any other groups. Egg weight was about 65g in T$_3$group. The results of hatching performance for production ability of Broiler breeder hens were fed experimental diet, although the rates of non-hatched and hatched eggs increased in order of Control, T$_1$T$_2$and T$_3$groups. However, the rate of embryo mortality was declined in order Control, T$_1$T$_2$and T$_3$groups.

• Korean Journal of Poultry Science
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• v.31 no.3
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• pp.137-143
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• 2004

The fractional synthesis rates(FSR) were measured with 2l-wk and 3l-wk-old broiler breeder pullets and hens to investigate the effect of sexual maturity on FSR. The FSR were obtained from chicken tissues and blood samples using High-Performance Liquid Chromatography/Mass Spectrometry(HPLC/MS). A L-l-13C, 15N -leucine saline solution was infused by bolus injection as a tracer into broiler breeder pullets in the experiment. A rapid HPLC/MS method was developed to measure the isotopic enrichments of leucine in plasma, tissue samples, and eggs. The enrichments of stable isotope leucine incorporated into protein and the enrichments of the stable isotope free leucine were measured in liver, breast muscle and blood samples. Two sets of experiments were conducted. In experiment one, 2l-wk-old, sexually immature broiler breeder pullets were divided into groups of three and blood samples were collected at 20 or 30 min intervals until 1.5 h from initial injection. The pullets were sacrificed in groups of three at varying time intervals for 7 h after injection. The liver, breast muscle and blood samples were removed for analysis. The FSR were estimated to be 8.7l%/day for liver, 4.06％/day for breast muscle, and 5.08％/day for blood samples in 30 minutes after injection from the enrichment ratios. In experiment two, sexually matured 3l-wk-old broiler breeder hens were assorted into groups of three and blood samples were obtained at 20 or 30 min intervals for 2 h. The FSR for blood samples were determined. The broiler breeder hens were sacrificed in groups of three at various time intervals until 7 h after injection and liver, breast muscle and blood samples were removed for analysis. The FSR were calculated to be 5.96％/day for liver. Eggs were collected from five chickens daily for 10 days after large bolus injection. The average of total enrichments of stable isotope in egg albumin was increased by 0.064% at 4 days after injection and was back to normal in 7 days.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.980-983
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• 2004

A 16 week feeding trial was conducted to evaluate the effects of replacement of soybean meal (SM) by extracted cottonseed meal (CSM) on laying performance and haemoglobin levels in practical diets for breeder Japanese quail (Coturnix coturnix japonica). One hundred ninety two quails (6 weeks old) were divided randomly into eight groups. The diets were isocaloric containing 2,900 kcal/kg of ME and isonitrogenous (% 20 crude protein) as fed basis. SM was replaced by 0, 2.5, 5.0, 7.5, 10.0, 12.5, 15.0 and 17.5% of CSM, respectively. Average egg production (quail day, %; quail house, %), egg weight (g), daily feed intake (g/bird), feed efficiency ratio (g feed/g egg) data indicated no significant differences among the treatments; while, blood haemoglobin levels (% g Hb) of 7th (15.0% CSM) and 8th (17.5% CSM) group were lower than the control (0% CSM) diet (p<0.05). This experiment indicated that 17.5% CSM could replace SM (providing 44% of SM protein) in practical diets of breeder Japanese quails without any significant impairment on laying performance.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.49-55
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• 2006

An experiment was conducted to investigate the effects of feeding Bupleurum falcatum L.(BFL) on performance, blood component and hormonal secretion in broiler breeder hens. A total of 800 broiler breeder hens were allotted to four treatments(BFL ; 0, 0.5, 1.0, 2.0%) with four replications for eight weeks. Weight gain was not significantly different between the groups in growing period($20{\sim}24$ weeks), but egg production and egg mass of broiler breeder hens fed BFL were significantly(p<0.05) higher than those of the control groups in laying period($24{\sim}28$ weeks). Dietary BFL did not affect serum triglyceride concentration, whereas serum cholesterol concentration was significantly increased(p<0.05) in 2.0% BFL-fed groups. No statistical differences were found in serum glucose, Ca, P, Mg, total protein, albumin, GGT, AST, ALT and BUN concentrations. However, albumin/globulin ratio was statistically higher in BFL-fed groups compared to the control groups(p<0.05). Serum estrogen concentrations were significantly increased by feeding a diet containing 0.5% BFL, but progesterone were not influenced. Serum IGF-I of BFL groups was greater than that of control groups at 28 weeks(p<0.05). In conclusion, the results suggest that the dietary addition of BFL into broiler breeder diets improved egg production, serum estrogen and IGF-I concentration, and decreased serum cholesterol concentration and albumin/globulin ratio.