The Effect of Dietary Energy and Protein Levels on Production in Breeding Female Ostriches.

1. In a study spanning two breeding seasons, we assessed the effect of different dietary energy and protein levels on body mass, body condition, and egg production of female ostriches. 2. During the first breeding season, groups were given diets with energy concentrations of 8.5, 9.5 and 10.5 MJ/kg dry mass (DM) metabolisable energy (ME) and protein concentrations of 135, 150 and 165 g/kg. In the second breeding season, groups were given diets with ME of 7.5, 8.5 and 9.5 MJ/kg and protein contents of 105, 120 and 135 g/kg. 3. Body mass of birds on diets of 7.5 and 8.5 MJ/kg ME decreased significantly in the course of the breeding season compared with birds fed on diets with higher energy contents and body measurements decreased, suggesting a loss of body condition. 4. Females fed on diets containing only 7.5 MJ/kg ME produced significantly fewer eggs at significantly longer intervals, resulting in fewer chicks hatched. 5. There was no significant difference in egg mass, initial chick mass, chick survival to one month of age and body mass of chicks at one month. 6. Dietary protein concentrations had no effect on egg production, egg mass, hatchability, initial chick mass, chick survival or chick mass at one month old. 7. The female ostriches regained their original body mass during the 4-month rest period between breeding seasons, but significant differences in some parameters during the second breeding season suggest that they may not have fully recovered their body condition. 8. A dietary energy content of 7.5 MJ/kg proved to have an adverse effect on egg production by breeding female ostriches, and it may be concluded from this study that a diet containing 8.5MJ ME/kg DM and 105 g/kg protein should be regarded as the minimum that can be used for breeding female ostriches without compromising egg production

The Effect of Dietary Energy and Protein Levels on Body Condition and Production of Breeding Male Ostriches (Struthio cemelus domesticus).

In a study over two breeding seasons we assessed the effect of different energy and protein levels in the diet of male ostriches on their body weight, body condition and the fertility of the eggs produced by their females. During the first season, the birds were fed diets with energy levels of 8.5, 9.5 or 10.5 MJ metabolisable energy (ME)/kg dry matter (DM) and 13.5, 15.0 or 16.5% protein. Corresponding lysine concentrations were 6.5, 7.5 and 8.5 g/kg. In the second breeding season the groups were fed diets with energy levels of 7.5, 8.5 and 9.5 MJ ME/kg and protein levels of 10.5, 12.0 and 13.5%. Corresponding lysine concentrations were 4.9, 5.9 and 6.9 g/kg. During the first breeding season the weight of all birds increased, but the weight of those fed the 8.5 MJ ME/kg DM diet was significantly lower at the end of the season than that of birds fed diets containing 9.5 and 10.5 MJ ME/kg DM. During the second season the trend in the case of the 8.5 and 9.5 MJ ME/kg diets was the same as in the previous season, but a significant decrease in weight occurred in birds fed the 7.5 MJ ME/kg DM diet. A general loss in body condition occurred at all energy levels. In contrast, protein level in the diets had no significant effect on any parameters measured. There were no trends or significant differences in the production of fertile eggs with any of the experimental diets. We concluded from this study that levels of 8.5 MJ ME/kg DM and 10.5% protein in the diet of breeding male ostriches are sufficient if maintenance in weight is the main criteria for formulating rations

Collisions of solitons and vortex rings in cylindrical Bose-Einstein condensates

Interactions of solitary waves in a cylindrically confined Bose-Einstein condensate are investigated by simulating their head-on collisions. Slow vortex rings and fast solitons are found to collide elastically contrary to the situation in the three-dimensional homogeneous Bose gas. Strongly inelastic collisions are absent for low density condensates but occur at higher densities for intermediate velocities. The scattering behaviour is rationalised by use of dispersion diagrams. During inelastic collisions, spherical shell-like structures of low density are formed and they eventually decay into depletion droplets with solitary wave features. The relation to similar shells observed in a recent experiment [Ginsberg et al. Phys Rev. Lett. 94, 040403 (2005)] is discussed

Comparison of estimates of feed energy obtained from ostriches with estimates obtained from pigs, poultry and ruminants

(South African J of Animal Science: 2000, 30, Supplement 1: 13 -14

Hatch traits of artificially incubated ostrich eggs as affected by setting position, angle of rotation and season

High levels of hatching failure in artificially incubated ostrich eggs cause considerable loss of income for the industry. In the 2015 - 2016 breeding seasons, between 846 and 1 549 egg records were used to determine the effect of various setting positions during artificial incubation. Fresh eggs were placed in trolleys in the setter that were turned automatically hourly through 60 degrees or 90 degrees. The additional treatments as factorial design included eggs set horizontally for five weeks in the setter; in horizontal position for three weeks and vertically for two weeks; and vertically for five weeks. These treatments were repeated over two production years to represent the seasons, namely winter (June to August), spring (September to November), and summer (December). Late embryonic mortalities improved significantly in eggs that were set to turn through 90 degrees (0.16 ± 0.02) compared with those set to turn through 60 degrees (0.28 ± 0.02), regardless of season and setting position. The preferred way of setting ostrich eggs would therefore be vertically in a trolley that turns hourly through 90 degrees with the air cell upwards to utilize incubator space optimally

Factors Related to Shell Deaths During Artificial Incubation of Ostrich Eggs.

The ostrich industry experiences a high rate of embryonic mortalities during artificial incubation of eggs. Embryonic deaths were studied from data recorded on 37 740 fertile eggs incubated artificially during the 1998–2005 breeding seasons. Roughly 10 000 eggs that sustained embryonic mortalities were classified according to the stage and nature of death, i.e. before 21 days of incubation, after 21 days of incubation, deaths after pipping and rotten eggs. Although infection may have played a role in ~1300 rotten eggs, no detailed knowledge of the pathogens involved was available. The remainder of deaths could not be related to pathogens and the deaths were thus generally referred to as non-infectious. The overall level of embryonic mortality in all the eggs studied was 28.5 %. Overall embryonic mortality was affected by incubator, with higher levels (57.0 %) found in eggs incubated in an African Incubator® and also in eggs that were transferred between incubators during incubation (38.1 %). Overall embryonic mortality also increased in eggs produced by older females. Eggs produced in the autumn had the highest level of embryonic mortality at 53.6 %, whereas eggs produced in the winter had a marginally higher level of embryonic mortalities of 29.2 % compared with eggs produced during summer (27.4 %). Eggs produced by South African (SA) Black males crossed to Zimbabwean Blue females had high levels of embryonic losses of 45.7 %. The embryonic mortality of eggs produced by SA Blacks or Zimbabwean Blue breeding birds subjected to pure breeding was similar at ~33–34 %, but embryonic mortality was improved in eggs produced by Zimbabwean Blue males crossed to SA Black females (27 %). Embryonic mortality was increased in eggs that were set directly (32.0 %) or subjected to longer than 6 days of storage (43.5 %). Embryonic mortality was affected by year. The results that were obtained will assist in determining non-infectious factors that have a negative effect on hatching success. Steps can thus be taken to eliminate such factors that may compromise hatching success

Changes in the Air Cell Volume of Artificially Incubated Ostrich Eggs.

A total of 2160 images of candled, incubated ostrich eggs were digitized to determine the percentage of egg volume occupied by the air cell at different stages of incubation. The air cell on average occupied 2.5% of the volume of fresh eggs. For eggs that hatched successfully, this volume increased to an average of 24.4% at 41 days of incubation, just prior to hatching. Air cell volume at 29 days of incubation for infertile eggs (19.3%) was significantly higher when compared to dead-in-shell (DIS) eggs (14.3%) and eggs that hatched (13.8%). There was a significantly larger air cell volume in eggs that hatched normally compared with DIS eggs at 41 days of incubation (28.3% vs. 21.7%, respectively). No differences in air cell volume were observed up to day 17 of incubation for eggs that hatched normally between eggs that exhibited high, average or low rates of water loss, but from 20 days of incubation the air cell volume was significantly larger for high weight loss eggs. However, for the DIS eggs, air cell volume was consistently larger in eggs that exhibited high rates of water loss. Air cell volume was largely independent of adult strain (SA Black or Zimbabwean Blue) or whether chicks were assisted to hatch. Although some subtle differences in air cell size were detected between hatched and DIS chicks during this study, it is unlikely to find useful application in the broader industry

Genetic Parameters for Ostrich Incubation Traits in South Africa.

Data obtained from a pair-mated ostrich flock located at Oudtshoorn, South Africa, were used to estimate genetic parameters for egg weight (EWT), weight of day-old chicks (CWT), water loss to 21 (WL21) and 35 (WL35) days of incubation, and pipping time (PT) for between 13 806 and 19 913 artificially incubated ostrich eggs during the 2003 – 2006 production years. Data were initially analysed as single traits using ASREML. Covariance components and ratios were subsequently derived from two-trait analyses. Single-trait estimates of heritability (h2) were 0.46 ± 0.08 for EWT, 0.34 ± 0.07 for CWT, 0.34 ± 0.07 for WL21, 0.27 ± 0.06 for WL35 and 0.16 ± 0.04 for pipping time. Estimates of maternal genetic effects (m2) were 0.23 ± 0.12 for EWT and 0.29 ± 0.10 for CWT. A maternal permanent environmental effect amounted to 0.25 ± 0.10 for EWT, 0.12 ± 0.09 for CWT, 0.25 ± 0.04 for WL21 and 0.30 ± 0.04 for WL35. Genetic correlations with EWT amounted to -0.21 ± 0.13 for WL21 and to -0.12 ± 0.14 for WL35. Corresponding correlations with CWT were -0.43 ± 0.07 and -0.54 ± 0.11. Parameters indicate that it should be possible to alter evaporative water loss of ostrich eggs by genetic selection. A feasible selection strategy, however, needs to be devised as it is challenging to effect genetic change in a trait with an intermediate optimum