This paper presents results of determination of certain quality parameters and its phenotypic correlation in eggs originated from extensively reared gray variety of Guinea fowl. A total of 150 egg collected by sampling 30 eggs in each of five analyzed laying months were used for egg quality evaluation and statistical analysis by methods of descriptive statistics and simple linear correlation. Average egg weight, shape index and shell thickness was 38.14 g, 76.03% and 0.49 mm, respectively.

The aim of this study was to evaluate selected egg quality traits depending on the laying period of pearl grey guinea fowl hens reared in semi-intensive system. In each of three evaluation terms (the second, fourth and sixth month of laying period) 40 eggs were collected, with the total of 120 eggs were used for quality evaluation. Methods of descriptive analysis and one-way ANOVA were used for data analysis. Overall values of three evaluation terms for egg weight, shell thickness, yolk to albumen ratio, Haugh units and yolk colour were 40.63 ± 0.27 g, 0.50 ± 0.01 mm, 0.58 ± 0.01, 75.37 ± 0.41 and 12.74 ± 0.11, respectively, whereas overall values of shell, albumen and yolk proportion were 15.32 ± 0.15, 53.75 ± 0.16 and 30.94 ± 0.17%, respectively. Significant differences were found for values of egg quality traits depending on the laying period, but the average value was generally comparable with literature data reported for similar rearing conditions for this Guinea fowl variety.

Cilj rada bio je da se ispitaju vrijednosti parametara inkubacije(gubitak mase, oplođenost, valivost uloženih i oplođenih jaja, te ukupan, rani,srednji i kasni embrionalni mortalitet) rasplodnih jaja različite mase teškog linijskoghibrida Cobb 500. Ukupno je ispitano 600 jaja podijeljenih u četiri jednake grupe(n=150) prema njihovoj masi: 57,5 – 62,5 (S); 62,6 – 67,5 (M); 67,6 – 72,5 (L) i 72,6 –77,50 g (XL), a vrijednosti parametara inkubacije određene su i statistički obrađenestandardnim metodama. Masa jaja uticala je statistički značajno na gubitak masejaja tokom inkubacije (p<0,05), pri čemu je taj gubitak bio veći kod jaja manje (grupaS 11,10% i grupa M 11,40%) u odnosu na jaja veće mase (grupa L 10,42% i grupaXL 10,31%). Valivost uloženih jaja u grupama S, M, L i XL iznosila je 76,0; 75,3;78,7 i 66,0%, redom, a oplođenih 82,0; 81,3; 82,5 i 71,7%, redom, pri čemu nijeustanovljena statistički značajna razlika (p>0,05). Masa jaja nije statistički značajnouticala na razliku u vrijednostima mortaliteta embriona, iako je kod jaja grupe XLustanovljena viša vrijednost ukupnog, ranog i kasnog mortaliteta u odnosu na ostalegrupe jaja. Rezultati ovog istraživanja ukazuju na niže vrijednosti valivosti i višimortalitet embriona u inkubaciji jaja izrazito velike mase u odnosu na ostale grupe,zbog čega izboru jaja za nasad treba posvetiti posebnu pažnju i u pogledu mase.

The aim of this study is to determine whether the site of oviposition has an impact on the results of incubation of broiler hatching eggs. In order to determine this, eggs laid in the nest, eggs laid in the nest and then placed on the floor to cool and eggs laid on the floor were compared. All eggs had a visually clean shell, including eggs laid on the floor. A total of 1,800 eggs from a 59-week-old Cobb 500 parent flock were examined, divided into three groups (n = 600) with 4 replicates (150 eggs per replicate). Compared to nest eggs, floor eggs had significantly higher weight loss (p0.05), lower hatchability of set eggs and total embryonic mortality (p0.01), as well as a lower number of first grade chicks per incubator tray (p0.05). The percentage of contamination differed significantly between groups and it was the highest in floor eggs and the lowest in nest eggs (p0.01). Nest eggs placed on the floor did not differ statistically significantly from nest and floor eggs in hatchability, total mortality and number of first grade chicks per incubator tray, although these eggs achieved more favourable results compared to floor eggs (p0.05). The applied treatments did not affect the weight and length of the chicks (p0.05). This research confirmed that floor eggs, despite their clean shell, have lower hatchability and a higher percentage of contamination than nest eggs, which emphasizes the importance of maintaining hygiene in nests and preventing the appearance of floor eggs in order to ensure the maximum number of eggs suitable for incubation.

Abstract:The aim of study was to examine the values of the incubation parameters (weight loss, fertilization, hatchability of placed and fertilized eggs, total, early, middle and late embryonic mortality) of eggs of different weights in brolier hybrid Cobb 500. In total, 600 eggs were divided into four equal groups (n = 150 each) according to their weight: 57.5-62.5 g (S); 62.6-67.5 g (M); 67.6-72.5 g (L) and 72.6-77.50 g (XL). Values of incubation parameters were determined and statistically processed by standard methods. The weight of eggs significantly influenced the loss of egg weight during incubation (p<0.05), with this loss being higher in smaller eggs (group S 11.10% and group M 11.40%) compared to larger eggs (group L 10.42% and group XL 10.31%). Hatchability of all eggs in groups S, M, L and XL was 76.0; 75.3; 78.7 and 66.0%, respectively, and for fertilized it was 82.0; 81.3; 82.5 and 71.7%, respectively, with no significant difference (p>0.05). The weight of eggs did not significantly affected the difference in embryo mortality values, although in the XL egg group a higher value of total, early and late mortality was found, compared to other groups. The results of this study indicate lower hatchability and higher mortality of embryos in eggs of extremely large weight, compared to other groups, which indicates that special attention should be given to the selection of hatching eggs in terms of their weight.

A total of 3,600 floor eggs from a 59-week-old Cobb 500 parent flock were collected to examine the effects of shell cleanliness and cleaning treatment on incubation results. The eggs were divided into two equal groups according to the cleanliness of the shell: eggs with a visually clean shell (clean eggs) and eggs with a dirty shell (dirty eggs). Depending on the cleaning treatment, clean and dirty eggs were divided into three equal groups: eggs that were not cleaned at all (intact), eggs that were cleaned with metal wire (scraped eggs) and eggs that were washed (washed eggs). Cleaning treatment significantly affected egg weight loss (p = 0.057). The hatchability of set eggs was under significant influence of egg cleanliness (p = 0.018), while the hatchability of fertile eggs was under significant influence of egg cleanliness (p = 0.003) and cleaning treatment (p = 0.029). Significant influence of shell cleanliness (p = 0.000) and cleaning treatment (p = 0.000) on egg contamination was also observed. Early, middle and total embryonic mortality were not significantly influenced by shell cleanliness and cleaning treatment, in contrast to late mortality which was under significant influence of egg cleanliness (p = 0.028). The number of first grade chicks per incubator tray was significantly influenced by egg cleanliness (p = 0.018). Chick weight and length were not significantly affected by shell cleanliness and cleaning treatment. The study showed that washed eggs had a higher weight loss compared to intact and scraped eggs. Dirty eggs had a lower hatchability, a higher percentage of contamination and late mortality as well as a lower number of first grade chicks per incubation tray, compared to clean eggs. Cleaning treatments did not have a significantly positive effect on the incubation results of either clean or dirty eggs. Washing treatment had a particularly negative effect on dirty eggs as they had reduced hatchability and increased contamination. The absence of a positive effect of scraping and washing treatment on the incubation results makes justification of these cleaning treatments for floor eggs doubtful.

The aim of this paper is to present results achieved by adding dietary phytogenic additive (Biomin ® P.E.P. 125 poultry) on production and quality of table eggs in the early stages of laying period in commercial Hy Line Brown hens. The experiment was conducted from 16 to 28 weeks of hens age. During the experimental period the following parameters were determined every week : egg production, percentage of second grade eggs and egg weight. The examination of egg quality was conducted at 21, 24, 26 and 28 weeks of hens age. Based on the obtained results we can conclude that the addition of dietary phytogenic additive induced an increase in egg production and egg weight and reduced the percentage of second grade eggs. Significant effects of phytogenic additive on some egg quality parameters were not established.

The aim of this study was to examine the effects of treatment with a single injection of GnRH and PGF2a on estrous response, fertility and service period. A total of 120 lactating Simmental cows were divided into four groups of 30 cows each: group PGF2a 40 was treated on the 40 th day post partum with a single injection of 2 mL prostaglandin analogue (Estrumate), group PGF2a 50 was treated in the same way on the 50 th day, group GnRH was treated on the 40 th day post partum with a single injection of 2 mL GnRH analogue (Receptal), and the fourth group (control) was not hormonally treated. Fertility of cows was not significantly different (p>0.05). The difference in the estrous response and service-period between the control group and experimental groups was statistically significant (p<0.01).