Estimates of Mean Differences Necessary for Significance between Pigs in Group Feeding Experiments

1939 ◽  
Vol 1939 (1) ◽  
pp. 157-161
Author(s):  
H. O. Hetzer ◽  
G. W. Brier
Keyword(s):  
Feeding Experiments ◽  
Group Feeding ◽  
Mean Differences

Fattening studies with cross-bred (European×Zebu) bulls: 1. Performance on diets of native hay and concentrate

1978 ◽  
Vol 90 (2) ◽  
pp. 425-429 ◽  
Author(s):  
P. B. O'Donovan ◽  
A. Gebrewolde ◽  
B. Kebede ◽  
E. S. E. Galal
Keyword(s):  
Weight Gain ◽  
Feed Intake ◽  
Live Weight ◽  
Maximum Temperature ◽  
Research Station ◽  
Live Weight Gain ◽  
The Third ◽  
Feeding Experiments ◽  
Group Feeding ◽  
Feeding Trials

SummaryTwo group-feeding and one individual-feeding experiments were made for 112 and 182 days, respectively, with 76 cross-bred and eight Zebu bulls. Simmental, Friesian and Jersey sire breeds were mated to three Ethiopian Zebu breeds, namely Boran, Horro and Barca, while Zebu bulls were included for comparison purposes in Expt 3. The trials were conducted in confinement at Holetta Research Station, located at 2400 m elevation and having a mean maximum temperature range of 18·7–24 °C. In the group-feeding trials (Expts 1 and 2) a common diet was fed, consisting of native hay (30%) molasses (20%) and a concentrate supplement. In the third experiment, two diets containing 30 and 50% native hay were supplemented by concentrate and fed individually to eight Simmental and eight Friesian cross bulls, while eight Zebus served as a control.The average daily gains, feed intake and conversion did not differ markedly between Simmental and Friesian crosses, but lower values were generally found for Jersey crosses. Cross-breds outgained Zebus, consumed more feed and converted it more efficiently to live-weight gain. Performance differences were noted between the Zebu breeds as well as some evidence of sire × dam breed interactions. Significantly higher gains were achieved with the low than with the high roughage diet.

A note on feed-lot performance of Grey Shirazi sheep

1970 ◽  
Vol 12 (4) ◽  
pp. 677-680 ◽  
Author(s):  
K. Ghorban ◽  
A. A. Mozafar ◽  
N. Sefidbakht ◽  
E. Simhaee
Keyword(s):  
Feeding Experiments ◽  
Different Seasons ◽  
Group Feeding

SUMMARYIdentical group-feeding experiments (each of 90 days duration) were conducted in the summer and in the winter of 1968. The purpose was to study the feed-lot performance of the Grey Shirazi breed on high- and low-concentrate diets with or without diethylstilboestrol (DES) in two different seasons of the year. Lambs on the high-concentrate diet gained more than those on the low-concentrate diet both in summer and in winter. On both diets lambs performed better under cold than under warm conditions. There was no difference when DES was given orally with the above two rations.

Reply to note by E. J. Sheehy on methods of experimentation in animal nutrition

1934 ◽  
Vol 24 (2) ◽  
pp. 335-339
Author(s):  
George Dunlop
Keyword(s):  
Animal Nutrition ◽  
Weight Curve ◽  
Feeding Experiments ◽  
Group Feeding

The note by E. J. Sheehy on a method of correction in the weight curve of certain animals in group-feeding experiments(l) has been brought to the author's notice.

The influence of processing and of certain crude enzyme preparations on the utilisation of cereals by pigs

1964 ◽  
Vol 6 (2) ◽  
pp. 237-244 ◽  
Author(s):  
G. S. Burnett ◽  
E. L. Neil
Keyword(s):  
Enzyme Preparation ◽  
Crude Enzyme ◽  
Or Efficiency ◽  
Enzyme Preparations ◽  
Feeding Experiments ◽  
Food Utilisation ◽  
Group Feeding ◽  
Feeding Trials ◽  
Pig Performance ◽  
Better Than

1. Three group feeding trials and two individual feeding experiments, involving a total of 202 pigs from 8 to 10 weeks of age to bacon weight, were conducted to determine the effect of processing (steaming, followed by rolling and grinding) of maize and barley on pig performance. The effect of supplementation of raw and processed cereal diets with two crude enzyme preparations was also studied.2. Processing of maize or barley had no significant effects on rate of growth or efficiency of food utilisation in pigs fed on diets containing a proportion of bran and pollard, or of pigs fed on diets in which maize or barley constituted the entire cereal portion.3. Neither enzyme preparation affected pig performance.4. The growth rate and efficiency of food utilisation of pigs given diets high in maize were significantly better than for those given diets high in barley.

Effect of a pen in group-feeding trials: modelling data from suckler cows

2008 ◽  
Vol 146 (4) ◽  
pp. 381-387 ◽  
Author(s):  
L. JAUHIAINEN ◽  
M. MANNINEN ◽  
J. ÖFVERSTEN
Keyword(s):  
Simulation Study ◽  
Mixed Model ◽  
Intraclass Correlation ◽  
Live Weight ◽  
Experimental Unit ◽  
Mixed Model Approach ◽  
Feeding Experiments ◽  
Single Animal ◽  
Group Feeding ◽  
Feeding Trials

SUMMARYThis paper provides information on the extent and containment of intraclass correlation (ICC) concerning group-feeding trials on suckler cows. The research comprised the re-analysis of six previously reported experiments and a parallel simulation study. ICC coefficients were estimated for eight variables. They were seen to be higher in experiments on bulls compared with those on cows and more notable in the measurements of live weight gain compared with final weight. Moreover, the ICC coefficients were generally high for all variables measuring behavioural patterns. The simulation study showed that using a single animal as an experimental unit could be valid in certain situations, but it could not be extended to cover all the cases. The simulation study also showed that the common mixed model approach had significant problems when the ICC was slight. In general, the research strengthened the arguments that much more effort should be placed on the planning and statistical analysis of group-feeding experiments, especially in behavioural studies.

Analyzing Observed Composite Differences Across Groups

Methodology ◽  
2013 ◽  
Vol 9 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Holger Steinmetz
Keyword(s):  
Monte Carlo ◽  
Structural Equation Modeling ◽  
Measurement Invariance ◽  
Structural Equation ◽  
Monte Carlo Study ◽  
Equation Modeling ◽  
Factor Loadings ◽  
Latent Mean Differences ◽  
Partial Invariance ◽  
Mean Differences

Although the use of structural equation modeling has increased during the last decades, the typical procedure to investigate mean differences across groups is still to create an observed composite score from several indicators and to compare the composite’s mean across the groups. Whereas the structural equation modeling literature has emphasized that a comparison of latent means presupposes equal factor loadings and indicator intercepts for most of the indicators (i.e., partial invariance), it is still unknown if partial invariance is sufficient when relying on observed composites. This Monte-Carlo study investigated whether one or two unequal factor loadings and indicator intercepts in a composite can lead to wrong conclusions regarding latent mean differences. Results show that unequal indicator intercepts substantially affect the composite mean difference and the probability of a significant composite difference. In contrast, unequal factor loadings demonstrate only small effects. It is concluded that analyses of composite differences are only warranted in conditions of full measurement invariance, and the author recommends the analyses of latent mean differences with structural equation modeling instead.

Insecticidal bait development for control of Musca Domestica L.

2020 ◽  
pp. 28-30
Author(s):  
Mikhail A. Levchenko ◽  
Keyword(s):  
Musca Domestica ◽  
Poultry Farm ◽  
Laboratory Studies ◽  
Scientific Center ◽  
Insecticidal Effect ◽  
Invasive Diseases ◽  
Previous Level ◽  
Group Feeding ◽  
Livestock Building ◽  
Production Conditions

The control of houseflies (Musca domestica L.) in veterinary surveillance premises is an important measure for the welfare of animals against infectious and invasive diseases. For this purpose, the most effective chemical insecticides are used. To prevent possible resistance to them, bait insecticides with two active binary ingredients from different chemical classes are used. The work was carried out in the laboratory of the Tyumen Scientific Center and in the production conditions of ZAO Pyshminskaya Poultry Farm. This material presents the main stages in the development of a prototype of the insecticidal bait Mukhnet AX containing two insecticides: 1.5% acetamiprid and 6% chlorfenapir. For this purpose, adults of houseflies Musca domestica L. 3-5 days old were used. Under laboratory conditions, effective rational doses of the above insecticides were determined by group feeding, feeding and by the method of assessing food insecticidal baits when fighting flies from 0.00002 to 4% concentrations. According to the results of laboratory studies, it was found that the optimal doses causing 100% death of insects were 0.5% for acetamiprid and 2% for chlorfenapir. The insecticidal efficiency of the developed bait Mukhnet AH against flies in production conditions on the first day after the treatment of the livestock building was 91.25%. The insecticidal effect of the measures taken lasted for at least 6 days. The restoration of the number to the previous level of the number of insects occurred after 10 days. Based on the results obtained, the Method of using the composition of an insecticidal bait agent in the fight against Musca domestica was proposed and patented.

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