Effect of genotype and some environmental factors on milk yield, milk composition, somatic cell counts, bacterial cell counts of local barki, damascus goats ans their crosses
Abstract: Desert Barki (B), Damascus (D) goats, F1 (crosses D.B) and the backcrosses {D X (D.B)} {B X (D.B)} were studied under semi-arid conditions of the coastal zone of the western desert of Egypt in 2002. Estimated overall mean of somatic cell count (SCC) of all genotypes in the present study of 5.36 x 105 SCC/ml milk was below the discriminating threshold values between healthy and infected udders given by PMO (1.0 x 106 SCC/ml). Least squares means ± standard errors of the studied traits in different levels of fixed effects during a complete lactation from morning and evening milking showed that the genotypes and order of lactation month had significant effects on log 10 SCC. Results did not show significant effect of parity of doe or type of kidding on SCC. Damascus goats produced higher daily milk yield, and protein% (0.329 ±0.02 kg and 3.7±0.06 %, respectively) than Barki goats in the morning. While all crossbreds were intermediate between them. Among crossbreds does, the F1 genotype DB produced the highest milk yield and protein% (0.306±0.2 kg and 3.5±1%, respectively). Differences between the genotype DB and the backcroses were not significant. The effect of genotypes on milk yield, fat %, protein % and lactose % were significant except for the effect on total solids % which was not significant. While in the evening the effect of genotypes was significant on daily milk yield and milk composition except for lactose % and total solids. Overall microbial quality of goat milk was high as indicated by the low standard plate count (SPC) value of 3 x l03 cfu ml-1. SCC had a positive relationship with SPC in the morning milking and a negative relationship with SPC in the evening. Barki milk contained high total viable bacteria for contagious pathogens except for Streptococcus Dysgalactia than all genotypes studied while the Damascus milk contained high total viable bacteria for environmental pathogens than all genotypes studied, while the crossbreds were intermediate between Damascus and Barki goats in these respects.
The SCC had a positive relationship (p<0.01) withfat %, protein % and total solids %, while it had a negative relationship (p<0.01) with DMY (kg) and lactose % in the morning and evening milkings. Daily milk yield had a negative relationship (p<0.01) with fat %, protein %, total solids % and lactose %in the morning and evening milkings.
Publication year 2006
Availability location معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
Availability number
Organization Name
City القاهرة
serial title 13th Conference of the Egyptian Society of Animal Production Cairo 10-11 December
Author(s) from ARC
Agris Categories Animal husbandry
AGROVOC
TERMS		 Environmental factors. Genotypes. Goats. Milk. Milk fat. Milk protein. Milk yield. Somatic cell count.
Publication Type Conference/Workshop
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