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《The Journal of Applied Poultry Research》2014,23(1):34-40
The characteristics of broiler hatching eggs have the potential to effect broiler posthatch growth and processing yield. The association of set egg weight (SEW), length of incubation (LI), and mean daily percentage of incubational weight loss (MDPEWL) of embryonated Ross × Ross 708 broiler hatching eggs with subsequent posthatch BW and processing yield was investigated. Sixty Ross × Ross 708 broiler hatching eggs were randomly set on each of 8 replicate tray levels of an incubator. Weight loss of individual embryonated eggs between 0 and 10.5, 10.5 and 18.5, and 0 and 18.5 d of incubation was determined for the calculation of MDPEWL. Furthermore, on 18.5 d of incubation, embryonated eggs were transferred to a hatcher unit where they were individually monitored for hatch every 12 h for determination of LI. Chicks were placed in corresponding replicate floor pens and were grown out from 0 (21.5 d of incubation) to 49 d posthatch. Live bird BW as a percentage of SEW on 21.0 d of incubation and d 0 and 49 posthatch, and bird sex on d 49 posthatch were determined. After commercial processing, carcass weight as a percentage of SEW, and carcass, abdominal fat pad, wings, breast muscle, tenders, drumsticks, and thighs weights as percentages of live BW were determined. Bird BW on 21.0 d of incubation and on d 0 and 49 posthatch were positively correlated or interrelated with SEW. Between 0 and 10.5 d of incubation, MDPEWL was negatively correlated with absolute and relative BW on 21.0 d of incubation, absolute BW on d 0 posthatch, and relative tenders weight. Further, LI was positively correlated with absolute and relative BW on 21.0 d of incubation and d 0 posthatch, but was negatively correlated with relative (percentage of live BW) carcass weight on d 49 posthatch. The MDPEWL of modern strain broiler hatching eggs should be closely monitored, particularly during the first half of incubation, for the regulation of LI and hatchling BW and for their potential effects on processing yield characteristics. 相似文献
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Ross River Virus (RRV) was believed to be the cause of acute illness in four horses around the Bellarine peninsula in south-west Victoria, Australia. The horses presented with clinical signs including petechial haemorrhages, lymphadenopathy, distal limb swelling and reluctance to move. Fibrinogen was also elevated in three of the four horses. Whilst no virus was isolated, serological testing revealed elevated RRV IgM titres in all horses indicating acute infection. The outbreak occurred at a time when a known RRV vector, the mosquito Aedes camptorhynchus was recorded at very high levels in the region. This report is one of very few to attribute specific signs of disease to RRV in horses in conjunction with serological evidence of infection. Aust Vet J 2008;86:367-370. 相似文献
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Ross公鸡的管理目标是培育质高量足的种公鸡,以在19周按时与母鸡混群,并在整个产蛋期都有个好的受精率。质高意味着公鸡整个生产期都能维持高水平的受精率;量足则表示23周时至少有占母鸡数量8%￣10%之间的合格公鸡可供选择。从现有的实践经验看,培育、管理优秀公鸡的办法并非十 相似文献
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《The Journal of Applied Poultry Research》2014,23(3):494-500
The cost of energy-contributing ingredients has increased over the last several years. Defining minimum dietary energy specifications for broilers is a strategy to mitigate high diet cost. Two experiments were conducted to evaluate the effects of diets with graded concentrations of AMEn fed to Hubbard × Cobb 500 (experiment 1) and Ross × Ross 708 (experiment 2) male broiler chicks from 14 to 28 d of age. Both experiments were identical in experimental procedures with the exception of genetic strain. Broilers were fed a common corn-soybean meal-based starter diet from 1 to 13 d of age. At 14 d of age, dietary treatments were provided with 1 of 6 concentrations of AMEn (3,000, 3,030, 3,060, 3,090, 3,120, and 3,150 kcal/kg). In experiment 1, BW gain, feed intake, and FCR of Hubbard × Cobb 500 broilers decreased linearly with increasing AMEn. Linear broken-line response of FCR was estimated at 3,062 kcal of AMEn/kg based on broken-line methodology. In experiment 2, Ross × Ross 708 broilers did not respond to graded concentrations of energy, as indicated by linear and quadratic regression of BW gain, feed intake, caloric conversion, and FCR data. Therefore, Hubbard × Cobb 500 male broilers respond to AMEn from 14 to 28 d of age and may be fed diets formulated at 3,062 kcal of AMEn/kg without loss of performance. Conversely, growth performance of Ross × Ross 708 male broilers was not affected by varying AMEn (3,000 to 3,150 kcal/kg) from 14 to 28 d of age. In addition, the response to AMEn may not be as pronounced with the modern broiler compared with broilers used in previous research. 相似文献
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J. W. Ng’ambi S. M. Maoba D. Norris M. S. Malatje C. A. Mbajiorgu 《Tropical animal health and production》2009,41(1):11-16
Two experiments were conducted to determine the effect of dietary lysine to crude protein ratio on performance of male Ross
308 broiler chickens. In each experiment the diets were isocaloric and isonitrogenous but with different lysine to crude protein
ratios. A complete randomized design was used in both experiments, the starter (1–21 days) and grower (22–42 days) experiments.
The three starter diets, based on lysine to crude protein ratios, were L0 (0.055), L1 (0.066) and L2 (0.077), while grower diets were L3(0.047), L4(0.061) and L5(0.074). A quadratic type equation was used to determine ratios for optimum growth rate, feed conversion ratio, breast meat
yield and breast meat nitrogen content. Dietary lysine to crude protein ratios of 0.066 and 0.077 supported optimum growth
rate and feed conversion ratio, respectively, during the starter period. Dietary lysine to crude protein ratios of 0.073,
0.073, 0.069 and 0.079 supported optimum growth rate, feed conversion and breast meat yield and nitrogen content during the
grower phase. Dietary lysine to crude protein ratio had no effect on diet intake and digestibility. The results indicate that
at each phase a single dietary lysine to crude protein optimized both growth rate and feed conversion ratio. However, the
ratio for optimum breast meat yield was lower than that for optimum growth rate and feed conversion ratio. These findings
have implications on ration formulation for broiler chickens. 相似文献
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K. Benyi O. Acheampong-Boateng D. Norris M. Mathoho M. S. Mikasi 《Tropical animal health and production》2009,41(8):1707-1713
The effects of skip-a-day feeding for 14 days during the starter or grower period or for 28 days during both periods followed
by ad libitum feeding to market age on the growth performance of two strains of broiler chickens, Ross 308 and Hybro, were studied over
7 weeks. Ross was superior to Hybro in weight gain, final body weight and feed conversion but consumed more feed. Overall,
feed restriction reduced feed intake, weight gain and body weight in all feed - restricted birds. Also, the 14-day feed-restricted
birds gained more weight and were heavier than the 28-day restricted ones. Feed restriction neither improved feed conversion
nor reduced abdominal fat but decreased mortality rate. Strain | treatment interaction significantly affected only feed intake.
It is suggested that for broiler chicken production in the tropics Ross 308 could be used and feed restricted for 14 days
during the starter or grower period. 相似文献
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K. Benyi O. Acheampong-Boateng D. Norris T. J. Ligaraba 《Tropical animal health and production》2010,42(7):1421-1426
The effects of feed removal for 6, 8, or 10 h during the day from 8 to 28 days of age followed by ad libitum feeding to market
age on the growth performance of two strains of broiler chickens, Ross 308 and Hubbard, were studied over 7 weeks. Ross 308
was superior to Hubbard in weight gain and final body weight but consumed more feed and deposited more abdominal fat. Overall,
daily feed removal reduced feed intake and improved feed efficiency in all feed-restricted birds, and the longer the period
of feed removal the better the efficiency of utilization, but it had no significant effect on weight gain and market weight.
It is suggested that for broiler production in the tropics, Ross 308 could be used on a 10-h daily feed removal program from
8 to 28 days of age. 相似文献