On estimating non‐additive genetic parameters in chickens 1

1. Several economically important traits in two Leghorn populations (over 9000 birds) were examined for additive and non‐additive components of genetic variance and sex‐linked effects. Data were analysed by two different statistical models based on least‐squares procedures.

2. Six different covariances were first calculated between relatives; i.e., full‐sibs, 3/4‐sisters, half‐sisters, dam‐daughters, grandam‐granddaughters and aunt‐nieces.

3. From the covariances, weighted least‐squares equations were used to obtain estimates of variance components for additive genetic, dominance, maternal and sex‐linkage effects.

4. The estimates of non‐additive components were highly variable but generally small compared with the additive genetic estimates.

5. In general this study suggests that for most traits, with the possible exception of rate of egg production, there is relatively little non‐additive genetic variation.

6. The consequences of possible negative correlations between additive effects and maternal effects are considered as they might apply to egg production in poultry.     

Production of Lambs After the Transfer of Fresh and Cryopreserved in vitro Produced Embryos from Prepubertal Lamb Oocytes and Unsorted and Sex-sorted Frozen-thawed Spermatozoa

Cumulus-oocyte complexes from hormone-stimulated 3-4-week-old (n=43) and 6-7-week-old (n=12) prepubertal lambs were matured in vitro and incubated with unsorted, or X- or Y-spermatozoa separated with a high-speed cell sorter (SX MoFlo)frozen-thawed. Presumptive zygotes were then cultured to the blastocyst stage, and transferred to recipients fresh or after cryopreservation (frozen). Oocyte cleavage was higher (p <0.05) with unsorted (515/926, 55.6%) than X- or Y-spermatozoa (261/672, 38.8% and 229/651, 35.2%, respectively) and blastocyst formation (% zygotes) by Day 9 of in vitro culture was lower (p <0.05) for X- (102/261, 39.1%) than unsorted spermatozoa (249/515, 48.3%), but did not differ between Y-spermatozoa (103/229, 45.0%) and unsorted spermatozoa, or between X- and Y-spermatozoa (p >0.05). For fresh embryos, survival to term was 50.0% (3/6) for unsorted, 0.0% (0/6) for X- and 16.7% (1/6) for Y-spermatozoa-derived embryos (p >0.05), and for frozen embryos was 4.0% (2/50) for unsorted, 9.1% (2/22) for X- and 2.9% (1/34) Y-spermatozoa-derived embryos (p >0.05). Of the two lambs born from X-spermatozoa-derived embryos, one was female (50%), and from the two Y-spermatozoa-derived lambs, both were male (100%), demonstrating that lambs can be produced after the transfer of fresh and cryopreserved IVP embryos derived from prepubertal lamb oocytes and frozen-thawed sex-sorted sperm.     

Percutaneous absorption of chemicals: developing an understanding for the treatment of disease in frogs

The permeable nature of frog skin presents an alternative route for the delivery of therapeutic chemicals to treat disease in frogs. However, although therapeutic chemicals are often topically applied to the skin of frogs, their pharmacokinetics have rarely been reported. To provide evidence to guide both candidate drug and formulation selection, we highlight factors expected to influence percutaneous absorption through frog skin, including the anatomy and physiology of the skin and the physicochemical properties of applied therapeutic chemicals. Importantly, we also highlight the effects of the formulation on percutaneous absorption, especially the inclusion of potential penetration enhancers as excipients. Finally, we collate empirical data on the topical application of various therapeutic chemicals in postmetamorphic frogs and show that, in contrast to mammalian species, even large chemicals (i.e. >500 Da) and those with a wide range of log P values (?4 through +6) are likely to be absorbed percutaneously. Topical application in frogs thus promises a convenient and effective method for delivering systemic treatments of a diverse range of chemicals; however, further experimental quantification is required to ensure optimal outcomes.     

Pattern-oriented modeling of agent-based complex systems: lessons from ecology

Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-based models. No general framework for designing, testing, and analyzing bottom-up models has yet been established, but recent advances in ecological modeling have come together in a general strategy we call pattern-oriented modeling. This strategy provides a unifying framework for decoding the internal organization of agent-based complex systems and may lead toward unifying algorithmic theories of the relation between adaptive behavior and system complexity.     

Genetic parameters for calving ease and survival at birth in Angus field data.

Calving performance records from the American Angus Herd Improvement Registry files were used to estimate variance components for calving ease and survival to 24 h. Genetic parameters for direct and maternal effects were estimated by using a sire-maternal grandsire model. Data included two independent samples of 19 and 34 herds with complete calving information. Maternal variance for calving ease was much larger than the variance for the direct effect of the sire. Maternal heritability for calving ease was .27 and .20 in the two samples of herds, respectively. Heritabilities for direct effects were .21 and .07. The genetic correlations between direct and maternal effects were -.93 and -.80. There was little genetic variation in survival at birth. Parameter estimates were within the allowable parameter space in the sample of 19 herds. Heritability for the direct effect of the sire on survival was .04. Maternal heritability was .09, and the direct-maternal correlation was -.85.     

Follicular Dynamics, Ovulation and Conception Rates in Bitches

Real-time ultrasound imaging was used in a clinical study to estimate the number of follicles of different sizes, ovulation and conception rates, and to study follicle dynamics following oestrus-induction of bitches.
Follicles were identified during late anoestrus (between 100 and 60 days prior to the pre-ovulatory LH surge) and there appeared to be a shift in the population from small follicles (1–3 mm in diameter) to large follicles (>4 mm diameter) approximately 2 days prior to the LH surge. Corpora lutea could be reliably identified although the majority were cavitated. High ovulation rates (97–100%) and pregnant rates (86–100%) were detected, and although the conception rate was approximately 70% it varied between 8 and 92%. Within the narrow range of the clinical population studied there were trends relating age to reproduction performance. Oestrus induction with a gonadotrophin regime appeared to result in large numbers of small follicles that did not ovulate, whilst when using cabergoline the number of small and large follicels and the number of copora lutea were similar to those of control cycles.     

Zu Prekler’s „rationellem Baldwirth“

Ohne Zusammenfassung f. f?chf. Dberforftmeifter. f. bahr. Regierungs- und Forftrath von Mürzburg. f. preuk. Dberforftmeifter aus Breslau. f. f?chf. Dberforftmeifter. f. bahr. Regierungs- und Forftrath von Augsburg. f. bahr. Regierungs- und Forftrath aus Regensburg. Dberj?germeifter von Braunfchweig. f. bahr. Regierungs- und Forftrath aus München. f. f?chf. Dberf?rfter. f. f?chf. Dberforftmeifter. f. f?chf. Dberforftrath. herz. braunfchweig. Forftmeifter von Blanfenburg. Direftor der fürftlich Cfterhazh’fchen Herrfchaft Spoly Parsto. fürftl. fondershauf. Dberfortmeifter. f. bahr. Redierf?rfter don Schmarzenbach. f. preuk. Dberf?rfter. f. f. Forftrath aus Brekburg. f. preuk. Dberf?rfter von Altruppin. f. hann?v. Forftmeifter von Rienburg. Forftmeifter in preuk. Schleften. f. preuk. Dberforftmeifter von Berlin. herz. aftenburg. Dberfortmeifter. f. preuk. Dberf?rfter. f. f?chf. Dberf?rfter. f. ruff. Forftfomiff?r aus Marfchau. f. preuk. Forftinfpeftor. f. f?chf. Forftinfpeftor. grokh. meimar. Forftinfpeftor von Martfuhl. f. mürttb. Dberf?rfter und Brofeffor aus Hohenheim. f. hannov. Forftmeifter aus Hammeln. Dberforftmeifter aus Sotha. herz. altenburg. Dberf?rfter aus Hummelshain. herz. altenburg. Revierf?rfter aus Milchwig. herz. altenburg. geheimer Finanzrath und Dberforftmeifter. herz. altenb. Dberforftmeifter aus Hummelshain. grokh. f?chf. geheimer Dberforftrath aus Qifenach. herz. naffau. Dberforftrath aus Miesbaden. grokh. heff. Dberforftfefret?r aus Darmftadt. f. f?chf. Dberforftmeifter.     

Einfluss Weicher Röntgenstrahlen und Mechanischer Effekte auf das Keimen von Kartoffeln

Zusammenfassung Um eine schonende Keimhemmung bei Kartoffeln der SorteBona zu erzielen, wurden Versuche mit sehr weichen R?ntgenstrahlen von 12 keV Energie durchgeführt. Sogar mit einer Bestrahlungsdosis von 10.000 bis 15.000 r wird — bei der hier angewandten weichen R?ntgenstrahlung — eine über 22 Wochen andauernde Keimhemmung erreicht ohne Verschlechterung des ?usseren Ansehens und Geschmacks. Der Schwund der Knollen wurde einzeln bis 5.000 r gemessen und mit anwachsender Dosis bis zu 15.000 r eine starke Verminderung des Schwundes erzielt. Au?erdem wurde nachgewiesen, da? durch langstündiges, vorsichtiges Rollen in der beschriebenen Versuchsanordung ebenfalls eine Keimhemmung zu erreichen ist. Es wird versucht, diese Erscheinung biologisch und rechnerisch zu deuten. Aus praktischen Gründen w?re es wünschenswert, den neuen, erw?hnten Effekt weiter zu untersuchen.

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Summary In order to bring about sparing sprout inhibition of theBona variety of potatoes experiments were undertaken with very weak X-rays of an energy of 12 keV. A radiation dose of only 10.000 to 15.000 r (with the weak X-radiation employed in this instance) was sufficient to inhibit sprouting for over 22 weeks without adversely affecting the appearance and flavour. The tuber shrinkage was individually measured up to 5.000 r and a marked reduction of shrinkage obtained with an increasing dose up to 15.000 r. It was also shown that sprouting may be inhibited by protracted, careful rolling in the described order of experiments. An attempt is made to explain this phenomenon biologically and analytically. From practical considerations it would be desirable to make a further study of the novel effect referred to.

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Résumé Pour réaliser de fa?on délicate une inhibition de la germination des pommes de terre de la variétéBona, nous avons effectué des essais de traitement par les rayons X très mous d'une énergie de 12 keV. Même l'irradition à une dose de 10.000 à 15.000 r sufit déjà — dans le cas des rayons très mous utilisés dans ces essais — pour inhiber la germination pendant 22 semaines au moins sans nuire à l'aspect ni au go?t des tubercules. La perte de poids des tubercules fut mesurée isolément jusqu'à 5000 r. Les doses croissantes jusqu'à 15.000 r réduisaient fortement la perte de poids. Il a également été constaté que dans les conditions de l'essai, un roulement très lent et doux des tubercules permet aussi de retarder la germination. Nous avons tenté d'expliquer ce phénomène au point de vue biologique et statistique. Pour des raisons pratiques, il serait désirable que l'étude de cet effet nouvellement observé soit approfondie.

     

Estimates of beef growth trait variances and heritabilities determined from field records

Variance components were estimated from field-collected performance records for use in national beef sire evaluation mixed-model programs. Estimates of residual error variances (sigma 2e), sire effect variances (sigma 2s) and dam effect variances (sigma 2d) were obtained for the American Hereford and the American Angus breeds for each of three growth traits: birth weight, weaning weight and postweaning gain. Estimates obtained for birth weight were sigma 2e, 8.43 and 9.26 kg2; sigma 2s, 1.34 and .66 kg2; and sigma 2d, 3.24 and 3.70 kg2 for the Hereford and Angus breeds, respectively. Estimates obtained for weaning weight were sigma 2e, 438.09 and 267.38 kg2; sigma 2s, 20.37 and 17.13 kg2; and sigma 2d, 162.25 and 157.28 kg2 for the Hereford and Angus breeds, respectively. Estimates obtained for postweaning gain were sigma 2e, 425.75 and 374.33 kg2; sigma 2s, 20.08 and 16.49 kg2; and sigma 2d, 41.74 and 48.61 kg2 for the Hereford and Angus breeds, respectively.     

Site and extent of nutrient digestion by sheep fed alkaline hydrogen peroxide-treated wheat straw-alfalfa hay combinations at restricted intakes.

Five crossbred wethers (58 kg) fitted with cannulas in the rumen, duodenum, and ileum were used in a 5 x 5 Latin square design to study effects of feeding combinations of alkaline hydrogen peroxide-treated wheat straw (AHP-WS) and alfalfa hay at restricted intakes on site and extent of nutrient digestion. Additionally, flows and disappearance of N and amino acids (AA) in the small intestine were regressed on alfalfa nitrogen intake (ANI) to estimate alfalfa's contribution to postruminal N and AA supplies. Diets consisted of 80:20 forage:concentrate mixtures; diet designations were 80:0, 80% AHP-WS and no alfalfa; 60:20, 60% AHP-WS and 20% alfalfa; 40:40, 40% AHP-WS and 40% alfalfa; 20:60, 20% AHP-WS and 60% alfalfa; and 0:80, no AHP-WS and 80% alfalfa. A modest positive quadratic (P less than .05) response was noted for total tract digestibility (TTD) of OM; values were 76.5% for diets 80:0 and 0:80 vs 78% for diet 40:40. Ruminal digestibility (percentage of intake) of NDF and ADF increased in a quadratic manner from 43 and 30%, respectively, for diet 0:80 to 71 and 70%, respectively, for diet 80:0. Ruminal digestibility of fiber may have been enhanced due to linear (P less than .05) decreases in liquid and particulate dilution rates, resulting in increased ruminal residence time of fiber as alfalfa hay replaced AHP-WS. Liquid and particulate dilution rates decreased linearly from 6.4 and 5.2%/h, respectively, for diet 80:0 to 5.4 and 3.4%/h, respectively, for diet 0:80. Regression analysis of N data indicated that alfalfa N had a ruminal escape value of 26%.