Composition of meat in La Belle and White Plymouth Rock chickens, slaughtered at different age

Т. Popova*, E. Petkov, M. Ignatova

Institute of Animal Science, 2232 Kostinbrod, Bulgaria
(Manuscript received 16 May 2015; accepted for publication 8 June 2016)

Abstract. An experiment with two lines of chickens – synthetic line La Belle and White Plymouth Rock was carried out in the Institute of Animal Science, Kostinbrod to assess the meat quality in regards to chemical composition and the fatty acid profile at the age of 9 and 18 weeks. The age affected the lipid content which decreased significantly in breast (p<0.05) and thighs (p<0.01) in the older chickens of both lines. The content of protein and moisture in breast differed between the lines (p<0.05), showing higher protein and lower moisture in White Plymouth Rock chickens, while in the thigh muscles the line and age significantly interacted (P<0.001) in regards to these traits. Interactions between the two factors (p<0.01) was observed for the ash content in the breast, whereas in the thighs it tended to decrease with the age in both lines. The fatty acid composition of the meat was influenced mainly by the age of the chickens. The total content of the saturated fatty acids was increased in the thighs of the older birds (p<0.01), while the proportion of the monounsaturated fatty acids was decreased in the breast (p<0.01) and thighs (p<0.001) with advancing age of the chickens. The opposite was observed for the content of the polyunsaturated fatty acids in the breast, which increased at higher age of slaughter (p<0.001). In thigh meat, the changes of the polyunsaturated fatty acids induced by age followed the same pattern, however significant interaction with the line was observed (p<0.05). The cholesterol content in the breast differed significantly between the two lines (p<0.05) and reduced with age (p<0.001). In the thighs considerable decrease (p<0.001) of the cholesterol was observed in La Belle birds.

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Effect of herd and number of lactation on milking temperament score in Black-and-White cows

Abstract. The study comprises 143 Black-and-White cows from three cattle farms with free cubicle rearing (one) and tied rearing (two). The number of cows by farms is as follows: farm 1 – 69 cows, farm 2 – 34 cows and farm 3 – 40 cows. All cows in lactation from Ist to VIIth at the time of evaluation have been included, respectively in Ist lactation – 40 cows, in IInd – 28 and in IIIrd and further lactation – 75 cows. To assess the temperament a 5-point scale has been used, respectively 1 – very nervous and 5 – very calm cows. Recording the milking temperament has been done once during lactation and all cows currently in lactation on the three farms have been assessed. Primiparous up to the 30th day after calving have not been included in the assessment. Statistically significant effect of the farm on the milking temperament score has not been reported. In the three studied farms relatively high, above 80% share of calm cows has been reported – scores from 3 to 5. The highest is the relative share of nervous animals (scores 1 and 2) of farm 2 – 17.6%, and the lowest – of farm 3 – 12.5%. Statistically significant effect of the number of lactation on the milking temperament score has been reported. The highest is the percentage of nervous animals – 22.5% in cows at first lactation and, respectively, the lowest is the share of the calm ones – 77.5%. With cows after Ist lactation the percentage of nervous cows is half less and it remains almost unchanged in later lactations. The highest is the LS-mean score for the temperament of cows in IIIrd and further lactations – 4.15, followed by those in IInd. The lowest is the LS-mean score for temperament of cows in first lactation – 3.82.

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Effect of age upon the reproductive performance of Japanese quails

The present study was carried out to monitor the reproductive traits of Japanese quail breeds reared in Bulgaria. The quail breeds kept at the Poultry Breeding Section at Trakia University: Pharaoh and Manchurian Golden, were used. Breeder flocks consisted of 8 female and 3 male birds. The eggs from each
breed were collected for three consecutive days in the middle of every production month. The incubation was performed under standard conditions in a smallscale
industrial incubator (Victoria-560). For the entire experimental period, 3902 Pharaoh and 3617 Manchurian Golden quail eggs were incubated. The
average percentage of hatched vital quails during the 7-month experimental period was 75.70% in the Pharaoh and 75.97% in the Manchurian Golden breed.
The incubation waste in both breeds consisted mainly of infertile eggs and late embryonic deaths – 18.66% and 18.52% of incubated Pharaoh and Manchurian
Golden eggs, respectively. During the first production month, the hatchability of incubated eggs was statistically significantly lower (P<0.001 in Pharaoh and
P<0.01 in Manchurian Golden quails) mostly due to the late embryonic deaths.

Effect of age upon the reproductive performance of Japanese quails

А. Genchev