Feed efficiency in fed F2 Nellore-Angus steers produced through embryo transfer was evaluated using two methods: residual feed intake (RFI) and NRC-based model predicted residual consumption (MPRC). Sire and family(sire) both contributed to differences in model predicted residual consumption (P = 0.036 and P < 0.001, respectively), but not in RFI (P = 0.117 and 0.455, respectively). This indicates that variation exists among the sires and families studied, and the opportunity exists to improve MPRC through selection; it also indicates these 2 evaluation methods could result in different conclusions about feed efficiency. Five aspects of temperament were also evaluated (aggressiveness, nervousness, flightiness, gregariousness, and overall temperament) on a 9-point scale shortly after weaning. Sire had a significant effect on all 5 aspects of temperament evaluated, but family was only responsible for variation in aggressiveness, nervousness, and overall temperament. Contemporary group had no effect on aggressiveness, but did contribute significantly to variation in all other temperament traits. All temperament traits were highly correlated with one another (r = 0.81 to 0.98). Recipient dam temperament was lowly correlated with gregariousness and overall temperament (r = 0.16 and 0.15, respectively), and the correlations with recipient dam temperament approached significance for aggressiveness, nervousness and flightiness. This suggests that the temperament of the recipient female may have a small effect on the temperament of the calf. This population was structured to identify QTL for economically important traits and appears to be useful to identify genetic markers for feed efficiency and animal temperament.

Feed efficiency in fed F2 Nellore-Angus steers produced through embryo transfer was evaluated using two methods: residual feed intake (RFI) and NRC-based model predicted residual consumption (MPRC). Sire and family(sire) both contributed to differences in model predicted residual consumption (P = 0.036 and P < 0.001, respectively), but not in RFI (P = 0.117 and 0.455, respectively). This indicates that variation exists among the sires and families studied, and the opportunity exists to improve MPRC through selection; it also indicates these 2 evaluation methods could result in different conclusions about feed efficiency. Five aspects of temperament were also evaluated (aggressiveness, nervousness, flightiness, gregariousness, and overall temperament) on a 9-point scale shortly after weaning. Sire had a significant effect on all 5 aspects of temperament evaluated, but family was only responsible for variation in aggressiveness, nervousness, and overall temperament. Contemporary group had no effect on aggressiveness, but did contribute significantly to variation in all other temperament traits. All temperament traits were highly correlated with one another (r = 0.81 to 0.98). Recipient dam temperament was lowly correlated with gregariousness and overall temperament (r = 0.16 and 0.15, respectively), and the correlations with recipient dam temperament approached significance for aggressiveness, nervousness and flightiness. This suggests that the temperament of the recipient female may have a small effect on the temperament of the calf. This population was structured to identify QTL for economically important traits and appears to be useful to identify genetic markers for feed efficiency and animal temperament.

The first objective was to estimate total internal fat in beef cattle based on a technique that measures kidney fat (uKFd) using real-time ultrasound (RTU). Data were obtained from 109 cattle from four studies, and animals were scanned 7 d preslaughter for uKFd and ultrasound backfat thickness. At slaughter carcass kidney fat depth (cKFd), KPH weight, and total internal fat were measured. The second objective was to characterize residual feed intake (RFI) in finishing cattle fed high grain diets and to examine the relationships with growth, ultrasound, carcass, non-carcass, and tenderness traits in two studies involving Santa Gertrudis (n = 114) steers, and Angus bulls (n = 16) and heifers (n = 16). In both experiments, RFI was calculated as the difference between actual DMI and predicted DMI. Results for the first objective indicated that RTU can be used to estimate cKFd, KPH weight and total internal fat (IFAT). Prediction equations developed to predict IFAT had R2 that ranged from 0.65 to 0.97 (P < 0.05). Results for the second objective indicate that RFI was not correlated with ADG, but was positively correlated with DMI and feed conversion ratio. Carcass 12th-rib fat depth was positively correlated with RFI in Santa Gertudis steers, such that steers with low RFI were leaner than steers with high RFI. Residual feed intake was not correlated with carcass or non-carcass composition traits in Angus bulls and heifers. Marbling and tenderness traits were not associated with RFI. Results from these studies indicate that we are able to measure IFAT with RTU, and that beef cattle producers can utilize RFI to identify animals that are more efficient with minimal impacts on growth, carcass composition and tenderness.

In this study, three chemical scrubbing processes were investigated to test their performances for removing odorous compounds in waste gases emitted from feed-drying operations. A gas chromatography with a flame ionization detector (GC/FID) and gas detector tubes were used for the identification of odorous species and their concentrations in the waste gases. Results indicate that toluene, ethyl benzene, xylenes, and styrene could be detected while their concentrations were all below the detection limits. However, trimethylamine, amine, mercaptans, ammonia, hydrogen sulfide, and acetic acid could be detected with the detector tubes. A two-stage scrubbing system with a gas flow rate of 10 L/min was used to test its performance for the odor removal. Results demonstrate that an ¡§acidic chlorination-alkaline sulfite scrubbing¡¨ process was effective. The pertinent operating conditions were found to be: (1) a pH of 6.4-6.6 and total residual chlorine of 55-85 mg/L for the acidic-chlorination solution, and (2) a pH of 8.0-8.5 for the alkaline sulfite solution with a sulfite concentration of 10,000 mg/L (as SO2). By the conditions, ammonia, trimethylamine, and amine in the odorous gas could be completely removed. A sensory measurement indicates that the odor concentration could be reduced from 17,378 to 232 after scrubbing. Cost estimation indicates that it required a chemical cost of NT$ 5.74 for removing the odors from 1,000 m3 of the gas. This study has successfully developed an economical and effective chemical scrubbing technology for the removal of odorous gas emitted from feed-drying operations. It could be applied to the treatment of odorous gases emitted from the manufacture of feeds, seafood, and other related operations.

The objectives of this study were accomplished with two experiments in growing Bonsmara bulls (N = 68) (experiment 1), and Simmental crossbred calves (N = 132) (experiment 2). Specific objectives for experiment 1 were to characterize residual feed intake (RFI) in growing bulls, and examine relationships between RFI and performance, fertility, temperament and body composition traits. In experiment 2, the objectives were to examine stocker-phase supplementation effects on feedlot feed conversion ratio (FCR) and RFI and to characterize relationships between these feed efficiency traits, and performance and carcass traits in finishing calves. In both experiments, individual feed intakes and BW were measured. Ultrasound technology was used to measure body composition in experiment 1, while actual carcass measurements taken at harvest were used for experiment 2. Experiment 1 demonstrated that temperament affected ADG and DMI, but not FCR or RFI. Residual feed intake was not phenotypically correlated to scrotal circumference or bull fertility traits. Experiments 1 and 2 demonstrated that RFI was independent of ADG and BW, but that there was a tendency (P < 0.10) for RFI to be phenotypically correlated with 12th rib fat thickness (r = 0.20 and 0.22). However, RFI was not correlated with longissimus muscle area in either experiment. Both experiments demonstrated that low RFI (< 0.5 SD below mean RFI) calves consumed significantly (20 and 22%) less feed and had improved (21%) FCR compared to calves with high RFI (> 0.5 SD above mean RFI). Results from experiment 2 suggest that RFI measured while calves are consuming high-grain diets may be less influenced by previous level of stocker supplementation compared to FCR or residual gain efficiency traits. In summary, RFI was found to be phenotypically independent of growth rate and BW, had no effect on bull fertility or temperament traits, and was less impacted by previous plane of nutrition compared to FCR.

Feed efficiency in fed F2 Nellore-Angus steers produced through embryo transfer was evaluated using two methods: residual feed intake (RFI) and NRC-based model predicted residual consumption (MPRC). Sire and family(sire) both contributed to differences in model predicted residual consumption (P = 0.036 and P < 0.001, respectively), but not in RFI (P = 0.117 and 0.455, respectively). This indicates that variation exists among the sires and families studied, and the opportunity exists to improve MPRC through selection; it also indicates these 2 evaluation methods could result in different conclusions about feed efficiency. Five aspects of temperament were also evaluated (aggressiveness, nervousness, flightiness, gregariousness, and overall temperament) on a 9-point scale shortly after weaning. Sire had a significant effect on all 5 aspects of temperament evaluated, but family was only responsible for variation in aggressiveness, nervousness, and overall temperament. Contemporary group had no effect on aggressiveness, but did contribute significantly to variation in all other temperament traits. All temperament traits were highly correlated with one another (r = 0.81 to 0.98). Recipient dam temperament was lowly correlated with gregariousness and overall temperament (r = 0.16 and 0.15, respectively), and the correlations with recipient dam temperament approached significance for aggressiveness, nervousness and flightiness. This suggests that the temperament of the recipient female may have a small effect on the temperament of the calf. This population was structured to identify QTL for economically important traits and appears to be useful to identify genetic markers for feed efficiency and animal temperament.

Feed efficiency in fed F2 Nellore-Angus steers produced through embryo transfer was evaluated using two methods: residual feed intake (RFI) and NRC-based model predicted residual consumption (MPRC). Sire and family(sire) both contributed to differences in model predicted residual consumption (P = 0.036 and P < 0.001, respectively), but not in RFI (P = 0.117 and 0.455, respectively). This indicates that variation exists among the sires and families studied, and the opportunity exists to improve MPRC through selection; it also indicates these 2 evaluation methods could result in different conclusions about feed efficiency. Five aspects of temperament were also evaluated (aggressiveness, nervousness, flightiness, gregariousness, and overall temperament) on a 9-point scale shortly after weaning. Sire had a significant effect on all 5 aspects of temperament evaluated, but family was only responsible for variation in aggressiveness, nervousness, and overall temperament. Contemporary group had no effect on aggressiveness, but did contribute significantly to variation in all other temperament traits. All temperament traits were highly correlated with one another (r = 0.81 to 0.98). Recipient dam temperament was lowly correlated with gregariousness and overall temperament (r = 0.16 and 0.15, respectively), and the correlations with recipient dam temperament approached significance for aggressiveness, nervousness and flightiness. This suggests that the temperament of the recipient female may have a small effect on the temperament of the calf. This population was structured to identify QTL for economically important traits and appears to be useful to identify genetic markers for feed efficiency and animal temperament.

Gun-drilling is one of the highly efficient tools for deep-hole making. The drilled hole possesses good size, positioning, roughness, roundness, and straightness. When the deep-hole is drilled, it is easy to cause wear at the tool-chip and tool-work interfaces at the serious condition so that the gun-drill is subjected to larger feed force. If the feed force exceeds the critical load, then the cutting edge of the gun-drill is broken. However, nowadays the device to measure the feed force in the gun-drill press is not available. This study develops a gun-drill press which possesses two new functions as follow: (1) to measure and to record the feed force during the drilling process;¡]2¡^to return the gun-drill when the feed force exceeds a set value. These two functions can be used to detect the serious breakage of the gun-drill. According to the practice drilling test, the performance of this press can be obtained. Results show that the feed force can be measured using different feed speeds. The gun-drill can stop and return to its origin position when the feed force exceeds the set value. Hence, the performance test of this new machine meets the above-mentioned functions. Using this press, the relationship between the feed force and the wear of cutting edge is investigated at the same feed speed. Results show that wear occurs on the cutting edge of the gun-drill, and the wear area increases with increasing drilling time so that the feed force is also increased. The wear grows from the outer side of the cutting edge to the inner side.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references.

No description available.