Breeding Performance Research Articles

Genome-Wide Association Studies and Runs of Homozygosity Reveals Genetic Markers Associated with Reproductive Performance in Korean Duroc, Landrace, and Yorkshire Breeds

Genome-Wide Association Studies and Runs of Homozygosity Reveals Genetic Markers Associated with Reproductive Performance in Korean Duroc, Landrace, and Yorkshire Breeds

Precipitation and female experience are major determinants of the breeding performance of Canarian houbara bustards

Precipitation is one of the main triggers of reproduction in desert‐breeding birds. The unpredictability of rainfall patterns in arid environments has led species to adapt their breeding effort to episodes of abundant food after rainfall. The response is not the same for all individuals in a population, and may vary especially with the age and experience of each female. Here we investigate the effects of precipitation, temperature, body size and breeding experience, among other variables, on reproductive parameters of 20 females of Canarian houbara bustard (Chlamydotis undulata fuertaventurae), an endangered desert bird endemic of the eastern Canary Islands. Precipitation and breeding experience were the main determinants of female breeding performance. Higher rainfall determined an increase in nesting rate, and earlier autumn rains caused an advancement of nesting to October, allowing the breeding season to be extended to eight months. This favoured an extraordinary increase in productivity in more rainy breeding seasons, with 15 times more females nesting in the two most rainy winters than in dry years. In addition, females with more breeding experience showed a higher tendency to breed, higher nest attempt and fledging success, and longer breeding season, which allowed them to rear more chicks. A female even double brooded successfully in the same season, which, considering that chicks remain with the mother for up to six months, indicates a great capacity to optimise reproductive investment, by adapting to highly variable rainfall regimes. In recent decades, the eastern Canary Islands have undergone a process of aridification, and climate models predict a medium‐term increase in the frequency and duration of drought periods. Thus, Canarian houbaras are particularly vulnerable to climate change, so measures are urgently needed to reduce their mortality and improve the quality of their habitat, in order to favour their reproduction and prevent their extinction.

Comparative study on slaughter performance, meat quality, and rumen microbiota of Hainan Dong goat and its hybrid with Nubian goat.

The Hainan Dong goat (DG) is a local meat breed widely raised in Hainan, China because of its good adaptability to local hot and humid weather. However, the growth rate of these DG is much slower than that of commercialised breeds improved in European countries, resulting in poor carcase characteristics, including smaller slaughter weight and carcase weight, which have become increasingly prominent. In recent decades, Nubian goats have been continuously imported into China to improve the production performance of local breeds. In this study, the effects of breed on growth performance, carcase and meat quality, and ruminal microbiota were analysed in 40 goats, including 20 DGs and 20 hybrid F3 offspring generated by crossing the DG and Nubian hybrids (NH). All the goats were averagely aged 90 days and weighed at 11 ± 1.34 kg. They were assigned to two treatments, with three replicates per treatment. The two groups were fed the same diet for 90 days before slaughter. The results showed that the average daily gain, F/G ratio, slaughter weight, and carcase weight of the NH group were higher than those of the DG group (p < 0.05). However, tube circumference, meat-to-bone ratio, and eye muscle pH were lower in the NH group than in the DG group (p < 0.05). The NH group showed a smaller fibre crosssectional area and fibre diameter, but a larger fibre density than the DG group (p < 0.05). Bacteroidetes and Firmicutes were the most dominant phyla in the two groups; however, the two breeds had different ruminal microbial communities. In the present study, the differences in growth performance between two groups of goats under the same feeding environment and feed conditions were compared. The correlation between feed sources and rumen flora has been demonstrated, and the results of this study show that the same diet has similar effects on rumen microorganisms, which in turn have related effects on growth and production performance. In summary, hybrids can improve the growth and slaughter performance of local breeds, which may be related to changes in the rumen microorganisms. This study revealed that crossbreeding of Nubian goats with Dong goats has the potential to be used in a wide range of applications owing to its effectiveness in increasing production efficiency.

Comparative evaluation of the efficacy of three GnRH analogues in induced breeding of stinging catfish, Heteropneustes fossilis under hatchery conditions

Evaluating the breeding performance of cultivable fish using gonadotropin-releasing hormone (GnRH) analogues is crucial for optimizing reproductive efficiency and enhancing the sustainability of aquaculture practices. However, there is a lack of understanding regarding which GnRH analogue performs best under hatchery conditions for stinging catfish. Therefore, this study was conducted to assess the breeding performance of stinging catfish (Heteropneustes fossilis) using three commercially available GnRH analogs: Wova-FH, Ovaprim, and Easy-spawn. For this purpose, an experiment was set up in a commercial hatchery by dividing the samples into three groups, each treated with one of the analogs: Wova-FH, Ovaprim, or Easy-spawn. In the experiment, a ratio of 1.5:1 male to female was maintained, and 1 mL syringes were used to inject the analogs. The results showed that the spawning induction efficiency differed among the three inducing agents. Compared to Ovaprim and Easy-spawn, Wova-FH-treated H. fossilis exhibited higher breeding success in all measured aspects. Specifically, Wova-FH achieved a latency period of 8 h, an ovulation rate of 87.25%, a fertilization rate of 89.33%, a hatching rate of 88.85%, and an incubation period of 16 h. In comparison, Ovaprim and Easy-spawn had incubation periods of 18 h and 24 h, respectively. In Ovaprim-induced individuals, the latency period was approximately 8.30 h, with an ovulation rate of 82.08%, a fertilization rate of 86.75%, and a hatching rate of 85.97%. In contrast, the Easy-spawn-induced individuals had a latency period of 9 h, an ovulation rate of 27.50%, a fertilization rate of 27.10%, and a hatching rate of 26.15%. Significant differences (p &amp;lt; 0.05) were observed among the treatments in both the ovulation rate, fertilization rate, latency period incubation period, and hatching rate. The findings suggest that Wova-FH is a superior alternative to Ovaprim and Easy-spawn for GnRH analogs in the induced breeding programs of H. fossilis, offering optimal yield.

Comparative analysis of production performance, carcase traits, and meat quality in yearling beef of Limousine, Sardo-Bruna, and their crosses

The aim of this study was to compare animal performance and meat quality of a local cattle breed of Sardinia Island with specialised meat purebred or obtained by crossbreeding. For this purpose, 10 Sardo-Bruna (SB; 5 males, 5 females), 10 Limousine (L; 5 males, 5 females) and 10 Limousine × Sardo-Bruna crossbreed (L × SB; 5 males, 5 females) were compared simultaneously from 12 to 20 ± 1 (mean ± SEM) months old. During the trial, body weight (BW) was recorded once a month for estimating the average daily gain (ADG). At slaughter, carcase measurements, pH and colour traits were recorded from the left side of the carcase. Proximate composition, fatty acid (FA) profile, cooking and drip losses were evaluated using the Longissimus thoracis et lumborum muscle. The SB group showed a lower cold carcase yield compared to L and L × SB genetic types. Males had a higher ADG, slaughter weight, hot and cold carcase weights, hot and cold carcase yields, and cooking losses than females. Females group showed a higher intramuscular fat content and rib fat thickness compared to males. No relevant differences among genetic types and between sexes were observed for meat and fat colours and pH. Concerning the FA profile, SB genetic type evidenced a higher oleic acid content and a better nutritional index than other genetic types while males had a higher PUFA content than females. In conclusion, the results of this study showed that the Limousine breed can be effectively used to enhance carcase yield of local breed without effects on meat quality.

Effect of Age on the Body Parameters, Scrotum, Seminal Characteristics, Spermatozoa Integrity and Sexual Behavior in Ganjam Buck

Background: Bucks raised for breeding purposes receive no special attention and are raised at random without following the correct selection process. Besides, the fertility of the male bucks is never addressed. Goat breeders have noted a sharp decline in the reproductive efficiency of Ganjam goats, associated with a lengthened kidding interval, fewer successful pregnancies and decreased twining frequency. The measurement of male fertility parameters is crucial for estimating the breeding performance of any species since males contribute 50% of the reproductive efficiency. Methods: Six Ganjam bucks of age 1.5(B1), 2(B2), 2.5(B3), 3.5(B4), 4(B5) and 4.5(B6) years procured after selection on the basis of their body morphometry and sexual behaviour were maintained under optimum management practice. They were trained for semen collection. For study on effect age on the semen qualities, they were classified into two age groups and ejaculates were collected during two phases. Bucks of age below 3 were considered under Age group I and bucks older than 3 years were assigned Age group II. Twelve ejaculates from each buck were collected, six ejaculates between the month of July to August and six ejaculates during October to November. The total of 72 ejaculates was evaluated for the study of seminal characteristics. Besides, the external body parameters, scrotal parameters and sexual behaviour of the bucks were also recorded before each semen collection. Result: The bucks of age group II were found to be having significantly higher (p less than 0.01) body weight, mean body length and average value of chest girth than age group I bucks in the present study. The mean value of scrotal width of the bucks of age group II was significantly higher (p less than 0.01) as compared to that of age group I. The mean value of abnormalities of the bucks of age group II was significantly higher (p less than 0.01) than that of age group I. The mean value of acrosome integrity and MBRT of the bucks of age group II was significantly higher (p less than 0.05) to that of age group I. The present study will be helpful in the selection of Ganjam buck at appropriate age for breeding purpose basing on their body parameters, scrotum, seminal characteristics, spermatozoa integrity and sexual behavior.

Risk factors underlining reproductive performance in smallholder beef cattle herds of South Africa

Improving the historically low reproductive performance of beef cattle in smallholder systems is essential for its productivity and profitability. Therefore, identifying and addressing risk factors associated with low performance in this system present an opportunity for improvement. The study aimed to evaluate the effect of animal and management risk factors on pregnancy rate (PR), fetal and calf loss (FC), calving interval (CI) and days open (DO) in smallholder beef cattle farms. A multi-stage selection approach was conducted in five provinces of South Africa. Cow records (3694) collected from 40 smallholder herds over two years (2018–2019) were analysed. Data on animal and herd management factors including body condition score (BCS), cow age class, breed type, lactation status, culling old/non-productive cows, record-keeping, and breeding and calving seasons were recorded. The GLIMMIX procedure was computed to determine risk factors associated with performance indicators (PR, FC, CI and DO). Risk factors highly associated with performance were breed type, BCS, cow-age class and breeding/calving season (P ≤ 0.05). Indicators FC, DO and CI increased with decreased BCS, autumn calving seasons, and in first calvers and aged cows. Whereas, PR increased with increasing odds of BCS and breeding seasons between December-March, November-February and January-March. Optimizing reproductive performance in smallholder beef cattle herds may involve managing cow body condition, breeding with adapted genotypes and synchronizing breeding with favourable seasons. Therefore, record keeping and regular monitoring of herd nutrition, climate and breed performance may be significant in improving reproductive performance in smallholder herds.

Carcass size, not source or taxon, dictates breeding performance and carcass use in a burying beetle.

Small vertebrate carcasses represent critical resources for many terrestrial organisms, including burying beetles, which rely on carcasses for survival and breeding. Carcass attributes can influence the reproduction of burying beetles, yet most studies on their breeding ecology have used laboratory-reared carcasses of limited sizes. We conducted breeding and feeding experiments using a wide size range of lab (laboratory mice) and wild carcasses (wild mammals, birds and reptiles) to investigate how carcass size, source and taxon affect various breeding outcomes (e.g. clutch size, brood size and brood mass) of the burying beetle Nicrophorus nepalensis. Our results reveal a hump-shaped relationship between carcass size and breeding performance, with optimal breeding outcomes occurring on medium-sized carcasses. Furthermore, despite the variation in carcass tissue nutritional composition, breeding outcomes and larval growth did not differ between the two carcass sources or among the three wild carcass taxa. Finally, we found a larval quality-quantity trade-off across the range of carcasses examined, with carcass size shaping the larval life-history traits. Overall, these results elucidate how carcass resources may influence the breeding performance of burying beetles. Importantly, our study provides solid evidence validating decades of research using lab carcasses to study the reproductive ecology of burying beetles.

Merinos in Poland – an analysis of breeding condition, selected performance traits and perspectives for the protection of genetic resources in relation to the country’s total sheep population

The purpose of the study was to analyse the breeding condition and performance traits of merino sheep belonging to three breeds in 2008-2022. The experimental material consisted of data derived from annual reports published by the Polish Sheep Breeding Association on breeding of three merino breeds: Polish Merino, Coloured Merino, old-type Polish Merino and data on the number and distribution of flocks, as well as data on the implementation of the sheep genetic resources protection programme from the database of the National Research Institute of Animal Production covering the period of the last 15 years. Analysing the population size over the last 15 years, significant changes were observed in the breed structure of the Merino sheep population. The implementation of conservation programmes and the opportunity to obtain subsidies for conservation breeds have had an impact on the breeding of these breeds in our country. Currently, the largest share of the merino sheep population is represented by the old-type Polish merino. Merino breeding has a regional and large-scale profile, concentrated in the historical areas of their maintenance, in Wielkopolska and Kujawy, usually in flocks of about 100 dams. Reproduction rates expressed by maternal prolificacy were found to be in line with the breed pattern. The Polish merino and the old-type Polish merino were distinguished by similar parameters of reproductive traits and higher fertility as well as rearing indices than those of the coloured merino. The coloured merino is the breed with the highest fertility and breeding performance. Body weight of lambs was higher for the white varieties. However, reproductive and meat performance indices show the potential of merino sheep in the context of lamb production, which is currently the main focus of sheep production in Poland.

Study of Growth Performance and Carcass Quality of Different Broiler Breeds

Study of Growth Performance and Carcass Quality of Different Broiler Breeds

Comparative Analysis of Classification and Segmentation Performance of Different Dog Breeds Based on Mask R-CNN

The classification of different image data is a common task in real life, which has been achieved as early as convolutional neural networks. With the emergence of R-CNN (Region CNN), simple classification tasks began to develop towards object detection tasks, followed by various segmentation tasks. After Faster R-CNN [4], Mask R-CNN [3] achieved instance segmentation while detecting objects. This algorithm model needs to distinguish different target objects in the image panel and learn a large number of characteristics to represent the details of each target object. In dog data images, there are differences and similarities in the characteristics of dog species, such as fur color, texture, and body shape. So in this article, the author selected and created two different dog datasets, representing targets with significant differences and similarities in features. Compare and analyze the performance of Mask R-CNN object detection and instance segmentation using these two dog datasets.

Evaluating performance, intestinal lesions, and immunity related genes in heritage and modern broiler breeds during a necrotic enteritis challenge

In this comparative study, the differential responses of heritage (ACRB; Athens Canadian Random Bred) and modern (Cobb) broilers to a necrotic enteritis (NE) challenge were evaluated. The design was a 2×2 factorial with breed (ACRB and Cobb) and challenge (non-challenged and NE-challenged) as main factors. On day (d) of hatch, 96 male chicks (48 ACRB and 48 Cobb) were allocated to 4 experimental groups with 8 replicate cages and 3 birds/cage. On d 14, birds in the NE-challenged groups were orally gavaged with 3,000 Eimeria maxima sporulated oocysts followed by 2 doses of ∼1×108 CFU of Clostridium perfringens on d 19 and 20. On d 21, 2 birds/cage were necropsied to score NE lesions, and spleen and cecal tonsils (CT) samples were collected from 1 bird/cage for assessing mRNA abundance. Challenged ACRB birds exhibited reduced growth performance and relative growth performance compared to challenged Cobb birds. There was no significant interaction between breed and challenge during the challenge period (d 14-21) for mortality. However, there was a challenge main effect (P ≤ 0.05) on mortality as manifested by greater NE-associated mortality compared to non-challenged birds. No significant breed × challenge interaction or breed main effect on lesion scores were observed in the duodenum, jejunum, and ileum. NE-challenged Cobb birds exhibited greater mRNA abundance of IL-18, TNFα, TLR1.2, TLR2.1, CCR5, CCR6, CCL20, and AvBD1 in CT compared to NE challenged ACRB birds. There was a significant breed × challenge interaction effect on mRNA abundance of IL-10, AvBD13, NK-Lysin, and LEAP2 in the spleen. Moreover, a main effect of breed was observed in IL-1β, IL-18, TNFα, TLR2.1, CCR5, CCL20, and NK-Lysin where ACRB birds had higher mRNA abundance than Cobb birds (P ≤ 0.05). The observed differences in performance, pathology, and mRNA abundance between ACRB and Cobb broilers during the NE challenge highlight the distinct immune response profiles of heritage and modern breeds, emphasizing the need for breed-specific nutritional, managerial, and genetic selection programs for modulating immune responses during enteric disease challenges.

Effect of Administering Serially Diluted Suprecur and Motilium (Dopamine Blocker) on the Breeding Performance of Clarias gariepinus

This study was designed to determine the effect of using serially diluted Buserelin acetate (Suprecur), which is a luteinizing hormone-releasing hormone analogue (LHRHa) with dopamine antagonist (Motilium) on the latency period, fecundity, percentage fertilization and percentage hatching of Clarias gariepinus. Treatments administered include 50ug/l, 40ug/l, 20ug/l and 10ug/l of Suprecur in tandem with 5mg/kg of Motilium. Metrics obtained include egg numbers, latency period, fertilization rate, hatching rates, and survival to first feeding. The results obtained demonstrated that the use of Suprecur (LHRHa) together with dopamine antagonist (Motilium) successfully induced ovulation in the experimental Clarias gariepinus broodfish. The highest fecundity was from the treatment T40 There was no significant difference in egg weights stripped from each treated group. The application of 50 µg/kg of Suprecur with 5mg/kg of Motilium resulted in earlier synchronization of ovulation (Latency period; 12 hours). Results of the fertilization percentage indicated that an increase in the dose of LHRHa did not significantly affect the fertilization rate in treated groups of broodfish. Overall superiority of 50 µg/kg of Suprecur plus 5mg/kg of Motilium in spawning induction was proved by significantly high hatchability, 83.56%. Broodstock used for the 40µg/kg dose had the highest fecundity. There was no significant correlation (p&gt;0.05) between the water quality parameters and the breeding parameters. In conclusion, the result obtained clearly indicates an overall superiority of using 50 µg/kg of Suprecur together with 5mg/kg of Motilium to induce spawning with regard to the recorded high hatchability percentage.

Enhancing fuel breed-burn performance in a sodium-cooled fast reactor using a novel reactivity control method

This study aims to enhance the fuel cycle and fissile breeding performance of a sodium-cooled fast breeder reactor (FBR) by utilizing minor actinides (MAs) as a means of reactivity control alongside partially-inserted control rods. Choosing the PFBR-500 as the reference design, four core models, designated as Cases A, B, C, and D, utilizing various proportions of minor actinides (MAs) were built and simulated using OpenMC. The MA concentrations were optimized to compensate for the withdrawal of control rods and ensure the same initial reactivity for all cores. Burnup analysis over 365 EFPDs revealed a significant increase in cycle length and burnup for the modified cores along with a modest rise in breeding ratio. Notably, Case C, employing 3.45 wt.% MAs in the 88 inner-core fuel subassemblies achieved an extra 62.25 EFPDs cycle length, a 33.74% rise in single-cycle burnup, and a 3.86% increase in breeding gain compared to the reference. Loading MAs into the inner-core region proved to be more effective in enhancing both fertile-to-fissile conversion (thus extending the cycle length and fuel burnup) and transmutation than utilizing MAs throughout the core due to greater neutron flux at the core center. While Case D utilizing 2.2 wt.% MAs both in the inner and outer core fuel subassemblies had the highest overall MA loading, it demonstrated lower increments in cycle length, burnup, and breeding gain compared to Case C. Case C also exhibited the highest overall destruction rate (approximately 24%/y) for Np and Am isotopes, and successfully transmuted around 24.08 kg 237Np, 9.33 kg 241Am and 3.82 kg 243Am over the course of a single year. The addition of MAs also achieved a slight flattening of the axial and radial flux profile and a decrease in the flux peaking factor. However, it slightly lowered the beta-effective, Doppler constant, and control rod assembly worth, and shifted the coolant void reactivity worth to the positive side.

Performance, Feeding Behavior, and Nutrient Utilization of Different Goat Breeds Fed Creep Feed

Introduction: Feed is one of the main factors to improve animal production. The utilization of feed is depended on quality, quantity, type, breed, and rate of passage of feed. This study aimed to evaluate the performance, feeding behavior, and nutrient utilization of growing Etawah crossbred and Senduro goats fed different forms of starter concentrate of creep feed. Materials and methods: Twelve local growing goats were used in this study, consist of six Etawah crossbred and six Senduro goats with average body weight 20 ± 1.57 kg from both sex, fed different forms of creep feed for three month. This study was designed by factorial randomized completely block design 2x2. The first factor was type of creep feed form (mash and pellet), and the second factor was the type of goat breeds (Etawah crossbred and Senduro). The complete ration consisted of 70% creep feed containing black soldier fly (BSF) meal and BSF oil plus 30% elephant grass. The variables observed were feeding behavior nutrient consumption, digestibility, blood metabolites, and performance. Results: The results showed that there was no interaction between the creep feed forms and the goat breeds in all variables. The form of creep feed had a significant effect on prehension and mastication and the pellet form had higher prehension and mastication compare to mash from but it had no significant effect on nutrient consumption and digestibility. Performance and blood metabolites were same in all treatments, except for the feed efficiency of Senduro goats had higher than Etawah crossbred goats. Conclusion: In conclusion, giving creep feed containing BSF larvae meal and oil in starter concentrate as pellet forms resulted a lower prehension and higher mastication, but has higher prehension and lower mastication for mash type. The performance and blood metabolites were are not different in all treatment groups.

Determining the optimal level and the effect of different zinc sources on performance, egg quality and the immune system of laying hens at the end of the production period.

Trace elements, such as zinc, magnesium and copper, are essential for improving the performance and health of broiler breeders and the development of chicken embryos. These elements are integral to various proteins involved in metabolism, hormone secretion and the immune system, necessitating their inclusion in small amounts in poultry diets. This study aimed to determine the optimal level and effect of different zinc sources on performance, egg quality and the immune system of laying hens at the end of the production period. The experiment involved 520 Lohmann LSL laying hens, aged 80 weeks, divided into 13 treatments with 5 replications and 8 birds per replication. The hens were fed diets supplemented with 40, 60 and 80mg/kg of zinc from various sources: mineral zinc oxide, mineral zinc sulphate, organic zinc chelated with glycine and organic zinc chelated with an organic acid. Key parameters measured included body weight, egg weight and immune response. The basal diet contained 63.58mg/kg of zinc, with the requirement per the Lohmann LSL guideline being 80mg/kg. Zinc supplementation significantly increased body weight in the second month, with 80mg/kg being the optimal dose. Zinc oxide notably increased egg weight compared to the control. The hens utilized zinc from all sources, resulting in weight gain and improved parameters such as egg quality. Immune parameters were also positively influenced by zinc supplementation. Zinc supplementation at appropriate levels enhances the performance and egg quality of laying hens, particularly at the end of the production period. It improves bioavailability, enriches eggs and mitigates age-related declines in productivity.

Effects of Intermittent Harem Mating on Parturition-induced Stress and Success Rate of Weaning in C57BL/6JNarl Mice.

Improving the effectiveness of mating schemes for large-scale production of mice is an ongoing challenge in animal facilities. Continuous mating, which requires fewer breeding cages than intermittent mating, has traditionally been used to take advantage of postpartum estrus for efficient production. However, the continuous mating scheme lacks flexibility because it cannot immediately accommodate the reduced needs of mice when production levels are high. In this study, we compared reproductive performance, fecal corticosterone metabolite (FCM) level as a stress indicator, and mouse mortality between the continuous trio (CT) and intermittent quad (IQ) mating schemes. The weaning rates in the IQ scheme were higher than those in the CT scheme (98.8% compared with 85.3%). The FCM levels in IQ female breeders were lower during the first 5 d after parturition than those in CT female breeders. The FCM levels in postpartum females housed with 2 adult mice were significantly higher on days 1, 3, and 5 after giving birth than those of females housed alone. This suggests that the presence of cage mates may induce stress responses in postpartum females. Increasing the individual cage area did not reduce the FCM levels of female breeders when accompanied by cage mates after parturition. In addition, the incidence of dystocia and mortality was lower in IQ breeders than in CT breeders. In summary, this breeding trial suggests that compared with the continuous mating scheme, the intermittent mating scheme improves the welfare of postpartum females with normal breeding performance in the C57BL/6JNarl production colony.

Breeding biology of Great White Pelican Pelecanus onocrotalus at Lake Tana, Ethiopia

Great White Pelicans, once thriving at Lake Shala, have faced a decline in breeding pairs at Lake Abijata due to increased salinity and overfishing. A study at Lake Tana Biosphere, from December 2020 to December 2021, aimed to understand their breeding biology, which had not been previously documented. We conducted intensive searches for nests and monitored them during incubation and post-hatching to assess reproductive success. The study found pelicans breed year-round, with peaks from late December to March and June to July. The average clutch size was 2.14, with egg dimensions averaging 90.33 mm in length and 58.70 mm in breadth and a mean weight of 173.68 g. No significant differences were observed in these measurements, but a positive correlation was found between egg length, weight, and breadth and weight. However, no correlation existed between length and breadth. Out of 98 eggs, 84 hatched, resulting in 80 and 91.5 % hatchability rates across two breeding seasons, averaging 85.71 %. The hatching success rate did not differ significantly between seasons. Unfortunately, only 37 pelicans reached the pre-fledging stage, indicating a high mortality rate of 63 %. The study concluded that the breeding performance of Great White Pelicans at Lake Tana is poor, with human disturbance, overfishing, and predation on nestlings posing significant threats to their nesting success. This highlights the need for conservation efforts to address these challenges and protect the species.

Effects of Dietary Levels of Vitamin E on Broiler Breeder Performance

Effects of Dietary Levels of Vitamin E on Broiler Breeder Performance

Effects of increasing SID lysine and metabolizable energy levels in lactation diets fed to young and mature sows.

The objective was to evaluate increasing standard ileal digestible (SID) lysine (Lys) and metabolizable energy (ME) above recommended inclusion levels fed to young (parity 1-2) and mature (parity 3-5) lactating sows. A total of 741 sows (371 parity 1-2, 370 parity 3-5) were fed in a 2×2 factorial arrangement of treatments in a randomized complete block design. Factors included SID Lys (0.85% vs 1.11%) and ME (3.18 Mcal/kg vs 3.33 Mcal/kg). Diets were formulated to deliver 62g of SID Lys at 0.85% inclusion and 23.2 Mcal of energy to sows that consume 7.30kg of complete feed per day. Overall, sows consumed 61g/d SID Lys and 22.6 Mcal/kg, but because of nutrient intake differences between young and mature sows, outcome variables were analyzed separately and not statistically compared. There were no differences for either SID Lysine or ME treatment in lactation feed intake (P ≥ 0.27) or change in body weight (P ≥ 0.19) for young sows. Young sows fed 3.33 Mcal/kg ME had 0.31 fewer post-cross foster mortalities (P < 0.01) resulting in weaned litters that were 4.06kg heavier (P < 0.01) than litters from young sows fed 3.18 Mcal/kg ME. Young sows fed 1.11% SID Lys and 3.33 Mcal/kg ME had the fewest (P ≤ 0.03) sows bred by d 7 compared to all other treatments. There was an interaction (P = 0.03) for wean-to-estrus-interval for young sows were young sows fed 1.11% SID Lys and 3.33 Mcal/kg ME were at least 3.27 days longer than young sows fed 0.85% SID Lys and 3.33 Mcal/kg ME or 1.11% SID Lys and 3.18 Mcal/kg ME. Young sows fed 3.33 Mcal/kg ME had a nearly 7% improvement in lactation G:F (0.40 vs 0.43; P < 0.01) compared to young sows fed 3.18 Mcal/kg ME. The percentage of mature sows fed 1.11% SID Lys bred by day 7 was 7.0 percentage units less (P = 0.06) when fed 3.33 Mcal/kg ME compared to 3.18 Mcal/kg ME. Feed efficiency of mature sows fed 1.11% SID Lys (0.38) was 7.89% greater (P < 0.01) than mature sows fed 0.85% SID Lys (0.35). Increasing either SID Lys or ME energy to young and mature sows had little influence on sow or pig performance, but simultaneously increasing both SID Lys and metabolizable energy negatively impacted subsequent breeding performance.