Mohammed A.F. Nasr

Impact of three THI levels on somatic cell count, milk yield and composition of multiparous Holstein cows in a subtropical region

In Egypt, cows milk represents 52.11% of the total milk production. Climatic condition is mainly expected to impact the welfare and productive performance of livestock animals. Thus, we aimed to explore the impact of temperature-humidity index (THI) on somatic cell count (SCC), milk production and composition on daily milk test records (33600) of Holstein cows under subtropical Egyptian conditions with different levels of THI. Our results revealed that daily milk yield and composition (fat%, protein %, yielded fat, yielded protein and the percentage of lactose) were higher in low THI (31.91kg, 3.91%, 3.22%, 418kg, 349kg and 4.20%, respectively) when compared with high THI. SCC significantly increased 36% from low to high THI. In addition to, it was increased with advanced parities 231.11% from 2nd to 7th parities. At high THI level, SCC was negatively correlated with total MY (r=-0.12P<0.05), 305 MY (r=-0.16P<0.05), protein % (r=-0.15P<0.01), fat% (r=-0.14P<0.01) and lactose % (r=-0.26P<0.01). The current study concluded that dairy cows performance was better in most of the investigated parameters at low THI than those in high THI. Thus, indicating a detrimental effect of THI on both welfare and economic return.

The impact of crossbreeding Egyptian and Italian buffalo on milk yield and composition under subtropical environmental conditions.

Buffalo are the second most valuable species in the world for milk production and their milk prices have been based on fat and protein composition. The aim of the paper was to compare the milk yield and composition of pure Egyptian buffalo (EB) and their crosses with the Italian buffalo and to investigate the impact of temperature humidity index (THI) on milk yield and composition under subtropical stressful conditions. 516 lactating buffalo were used (152 EB; 176 F1 crosses 50% EB and 50% Italian buffalo and 188 back cross (BC) 75% EB and 25% Italian buffalo). The results revealed that, milk yield (5·79 and 10·32%) and peak yield (6·36 and 7·67%) were significantly higher in F1 and BC than in EB, respectively. BC had 7·74 and 3·67% significantly higher daily yield when compared with EB and F1, respectively. EB were robust in the hot condition as the only reduction was in the peak of milk production from 15·02 in low THI to 13·72 kg in high THI, but fat and total solids%, were increased from 5·61 and 16·31 THI in low to 7·01 and 17·59 in high THI, respectively. BC was similar to some extent to EB as their milk was similar to EB under sever hot climate conditions (2331·92 and 2327·50 kg, respectively). A statistically significant reduction in the average daily milk yields was detected only in F1 from 10·33 to 8·38 kg in low and high THI level, respectively. The current study showed that BC produced a higher milk with higher daily average milk yield and peak yield with some evidence of robust under sever hot condition which were approximately similar to EB. Thus, it is recommended to encourage the producers to increase the number of BC animals in their farm for improving the milk production to fulfil the demand of Egyptian markets.

Growth performance, carcass characteristics, meat quality and muscle amino-acid profile of different rabbits breeds and their crosses

Meat production efficiency can be enhanced by crossbreeding to capture heterosis. This study aimed to investigate the impact of rabbit genotype on growth performance, carcass traits, meat quality and amino acids profile. A total of 504 weaned rabbits from nine genotypes of full factorial crossing of New Zealand White (NZW), Californian (CA) and Rex (RX) were used. Longissimus thoracis et lumborum muscles were assessed for meat quality and amino acids profile. There were no differences between groups at weaning and 6weeks, but by 10weeks differences were significant (P<0.001) and the numerically heaviest groups were CA×RX and RX×NZW (1970g, P<0.001) with to some extent better amino acids profile. In conclusion, RX growth performance was improved by crossing CA sire with RX dam and RX sire with NZW dam and to have dual purpose breed with better growth performance without hazard on carcass and meat quality. CA×RX and RX×NZW had the heaviest body weight at 10weeks of age and highest body weight gain during the whole finishing period.

Effects of divergent selection for growth on egg quality traits in Japanese quail

The experiment was designed to investigate the impact of selection for increased body mass on external and internal egg quality traits of Japanese quail. Three hundred and sixty Japanese quail, divergently selected over three generations for different body mass at 4 weeks of age, were used. Quail were homogeneously divided into three groups each consisting of 120 birds: high body mass (HBM), low body mass (LBM) and Control. ANOVA was used to detect the effect of selection on egg quality. In addition, correlation between external and internal egg quality traits was measured. Our results revealed that HBM quail laid heavier eggs (P = 0.03 compared with LBM but not significantly different with Control quail) with a higher external (shell thickness, shell weight, eggshell ratio and eggshell density, P = 0.0001) and internal egg quality score (albumen weight, P = 0.003; albumen ratio, P = 0.01; albumen height, yolk height, yolk index and Haugh unit, P = 0.0001) when compared with both the Control and LBM. The egg surface area and yolk diameter were significantly higher in HBM when compared with the LBM but not with the Control line. Egg weight was positively correlated with albumen weight (r = 0.54, P = 0.0001), albumen ratio (r = 0.14, P = 0.05), yolk height (r = 0.27, P = 0.0001), yolk weight (r = 0.23, P = 0.002), yolk diameter (r = 0.14, P = 0.05) and yolk index (r = 0.21, P = 0.005) but was negatively correlated with yolk ratio (r = –0.16, P = 0.03). Our results indicate that selection for higher body mass might result in heavier eggs and superior egg quality.

The effect of stillbirth on reproductive and productive performance of pure Egyptian buffaloes and their crosses with Italian buffaloes

High rates of stillbirth in buffaloes are not only emotionally and economically undesirable but also contrary to animal welfare practices. Thus, this study was aimed to investigate risk factors for stillbirth and analyze its effects on the productive and reproductive performance of pure Egyptian buffaloes (PE) and their crossing with the Italian buffaloes (F1 crosses 50%PE and 50%Italian buffaloes and Back cross (BC) 75%PE and 25%Italian buffaloes) under subtropical environmental conditions. Records of a total of 8388 (5169PE, 1494F1 and 1725BC) were used in this study with 1965 actual first parity records (489, 621 and 855, respectively). The incidence of stillbirth in the farms was 12.4% and 9.2% for primiparous and multiparous cows, respectively. It did not vary among seasons or due to gestation length, calf sex and conception after first insemination in BC buffaloes. BC buffaloes with stillbirths had shorter gestation length, first service post-partum and longer dry period (300.32, 33.67 and 207.05days, respectively) compared to those live births (311.28, 33.90 and 140.22days, respectively), implying that these animals could better adapt to the tough circumstances following stillbirth as reproductive indices were only slightly affected due to stillbirths. Contrarily, the productivity and reproductive performance of PE buffaloes were markedly decreased after stillbirth. Their milk yield, average daily milk yield and lactation length were decreased by 6.27, 10.29 and 6.36%, respectively after stillbirth, while days open, dry period and first service post-partum were increased after stillbirth by 14.28, 13.54 and 12.78%, respectively. The results from this study suggest that producers should be promoted to increase the BC animals in their farms with the intention of increasing milk production and ensure superior reproduction efficiencies with lower stillbirth incidence.

Growth performance, carcass traits, behaviour and welfare of New Zealand White rabbits housed in different enriched cages

The present study investigated the effect of gnawing sticks as environmental enhancers on the performance, carcass traits and behaviour of individually housed growing rabbits. Two batches of weaned New Zealand White (NZW) rabbits were used, each consisting of 135 animals. Rabbits were homogeneously classified into the following three groups, each consisting of 45 rabbits: rabbits housed individually in cages without enrichment (control), rabbits housed individually in cages enriched with wooden sticks from apple tree and rabbits housed individually in cages enriched with wooden sticks from willow tree. Rabbits reared in enriched cages with apple or willow sticks showed a significantly (P < 0.0001) better performance (live bodyweight at slaughter 2526 and 2591 g, total weight gain 1620 and 1683 g, average daily gain 21.04 and 21.87 g and daily feed intake 78.57 and 74.89 g respectively), and had a higher carcass weight (1648.39 and 1750.26 g respectively, P < 0.0001) than did the control group. Rabbits in apple-stick group had a higher daily feed intake (78.57 g, P < 0.0001) and lower carcass weight (1648.39 g, P < 0.0001) than did those in the willow-stick group. The cortisol concentration was significantly (P < 0.0001) lower in apple and willow groups (9.44 ± 0.02 and 9.35 ± 0.02 nmol/L respectively) than in the control group (17.24 ± 0.03 nmol/L). Moreover, cage enrichment with apple or willow sticks improved the duration of feeding (7.08 and 7.39 min/3 h respectively, P < 0.0001) and drinking (2.54 and 2.67 min/3 h respectively, P < 0.0001) time, and reduced abnormal behaviour (biting the bars of the cage 0.24 and 0.34 min/3 h respectively, P = 0.001) when compared with the control group. Overall, the current results indicated that cage enrichment (with wooden sticks from apple or willow trees for gnawing) increased the final bodyweight and some carcass traits, reduced abnormal behaviour and potentially improved rabbit welfare during intensive rabbit breeding.