Increasing temperature and CO2 concentrations can alter tritrophic interactions in ecosystems, bu... more Increasing temperature and CO2 concentrations can alter tritrophic interactions in ecosystems, but the impact of increasingly severe drought on such interactions is not well understood. We examined the response of a wheat-aphid-parasitoid system to variation in water-deficit stress levels. Our results showed that arid area clones of the aphid, Sitobion avenae (Fabricius), tended to have longer developmental times compared to semiarid and moist area clones, and the development of S. avenae clones tended to be slower with increasing levels of water-deficit. Body sizes of S. avenae clones from all areas decreased with increasing water-deficit levels, indicating their declining adaptation potential under drought. Compared to arid area clones, moist area clones of S. avenae had a higher frequency of backing under severe water stress only, but a higher frequency of kicking under well-watered conditions only, suggesting a water-deficit level dependent pattern of resistance against the para...
Increasing temperature and CO 2 concentrations can alter tritrophic interactions in ecosystems , ... more Increasing temperature and CO 2 concentrations can alter tritrophic interactions in ecosystems , but the impact of increasingly severe drought on such interactions is not well understood. We examined the response of a wheat-aphid-parasitoid system to variation in water-deficit stress levels. Our results showed that arid area clones of the aphid, Sitobion avenae (Fabricius), tended to have longer developmental times compared to semiarid and moist area clones, and the development of S. avenae clones tended to be slower with increasing levels of water-deficit. Body sizes of S. avenae clones from all areas decreased with increasing water-deficit levels, indicating their declining adaptation potential under drought. Compared to arid area clones, moist area clones of S. avenae had a higher frequency of backing under severe water stress only, but a higher frequency of kicking under well-watered conditions only, suggesting a water-deficit level dependent pattern of resistance against the parasitoid, Aphidius gifuensis (Ashmead). The number of S. avenae individuals attacked by the parasitoid in 10 min showed a tendency to decrease with increasing water-deficit levels. Clones of S. avenae tended to have lower parasitism rates under treatments with higher water-deficit levels. The development of the parasitoid tended to be slower under higher levels of water-deficit stress. Thus, the bottom-up effects of water-deficit stressed plants were negative on S. avenae. However, the top-down effects via parasitoids were compromised by water-deficit, which could favor the growth of aphid populations. Overall, the first trophic level under water-deficit stress was shown to have an indirect and negative impact on the third trophic level parasitoid, suggesting that parasitoids could be increasingly vulnerable in future warming scenarios.
The present study was performed to identify the effect of different milking methods and frequenci... more The present study was performed to identify the effect of different milking methods and frequencies on milk yield, composition and health of Holstein Friesian cattle at Government Dairy Farm (GDF) Quetta. Sixteen pure Holstein Friesian cattle breed lactating animals were selected according to their age, body weight and lactation period. They were divided into four groups i.e. A, B, C and D with four cows in each group. Research work was conducted on dry matter intake (DMIT), milking frequencies, milking practices (both hand and machine milking), animal behavior, milk composition (fats and solids not fats) and cost of milk production aspects in light of factual prevalent rates. Results on group mean values indicated that DMIT in groups A, B, C and D was 16.63±0.53 kg to 16.74±0.55 kg for all experimental animals, out of the total of 38 kgs feed/fodder, daily per cow. As a whole total dry matter intake depicted 25-26%. The effect of milking frequencies on milk yield was significant. In hand milking the mean values of milk yield in group A and B was 15.5 and 15.72 liters respectively; while machine milking twice 17.38 liters group C or thrice 17.74 liters group D were significantly different (P<0.05) as the machine milked cows thrice give comparatively high production. Percentage of milk fat composition in group averages recorded as 4.14±0.14. These values of hand milking in group B was 3.89±0.07. In group C the mean values were 3.98 ±0.06 and in group D these fat values were 3.95±0.16 respective. Results regarding mean values of milk solid not fats in group A, B, C and D were 9.72% ±0.17, 9.70%±0.05, 9.46%±0.11 and 9.46±0.08 respectively. These results show that practices and frequencies of milking did not have any significant effect on milk yield fats and / or SNF. Cost of milk production (based on cost of green fodder @ Rs. 150/-, Concentrate feed @ Rs 200/-, wheat straw Rs.25/-.With a highest milk production yield 17.74 liters milk fetched Rs. 106.4/-@ Rs. 60/-per liter.
Increasing temperature and CO2 concentrations can alter tritrophic interactions in ecosystems, bu... more Increasing temperature and CO2 concentrations can alter tritrophic interactions in ecosystems, but the impact of increasingly severe drought on such interactions is not well understood. We examined the response of a wheat-aphid-parasitoid system to variation in water-deficit stress levels. Our results showed that arid area clones of the aphid, Sitobion avenae (Fabricius), tended to have longer developmental times compared to semiarid and moist area clones, and the development of S. avenae clones tended to be slower with increasing levels of water-deficit. Body sizes of S. avenae clones from all areas decreased with increasing water-deficit levels, indicating their declining adaptation potential under drought. Compared to arid area clones, moist area clones of S. avenae had a higher frequency of backing under severe water stress only, but a higher frequency of kicking under well-watered conditions only, suggesting a water-deficit level dependent pattern of resistance against the para...
Increasing temperature and CO 2 concentrations can alter tritrophic interactions in ecosystems , ... more Increasing temperature and CO 2 concentrations can alter tritrophic interactions in ecosystems , but the impact of increasingly severe drought on such interactions is not well understood. We examined the response of a wheat-aphid-parasitoid system to variation in water-deficit stress levels. Our results showed that arid area clones of the aphid, Sitobion avenae (Fabricius), tended to have longer developmental times compared to semiarid and moist area clones, and the development of S. avenae clones tended to be slower with increasing levels of water-deficit. Body sizes of S. avenae clones from all areas decreased with increasing water-deficit levels, indicating their declining adaptation potential under drought. Compared to arid area clones, moist area clones of S. avenae had a higher frequency of backing under severe water stress only, but a higher frequency of kicking under well-watered conditions only, suggesting a water-deficit level dependent pattern of resistance against the parasitoid, Aphidius gifuensis (Ashmead). The number of S. avenae individuals attacked by the parasitoid in 10 min showed a tendency to decrease with increasing water-deficit levels. Clones of S. avenae tended to have lower parasitism rates under treatments with higher water-deficit levels. The development of the parasitoid tended to be slower under higher levels of water-deficit stress. Thus, the bottom-up effects of water-deficit stressed plants were negative on S. avenae. However, the top-down effects via parasitoids were compromised by water-deficit, which could favor the growth of aphid populations. Overall, the first trophic level under water-deficit stress was shown to have an indirect and negative impact on the third trophic level parasitoid, suggesting that parasitoids could be increasingly vulnerable in future warming scenarios.
The present study was performed to identify the effect of different milking methods and frequenci... more The present study was performed to identify the effect of different milking methods and frequencies on milk yield, composition and health of Holstein Friesian cattle at Government Dairy Farm (GDF) Quetta. Sixteen pure Holstein Friesian cattle breed lactating animals were selected according to their age, body weight and lactation period. They were divided into four groups i.e. A, B, C and D with four cows in each group. Research work was conducted on dry matter intake (DMIT), milking frequencies, milking practices (both hand and machine milking), animal behavior, milk composition (fats and solids not fats) and cost of milk production aspects in light of factual prevalent rates. Results on group mean values indicated that DMIT in groups A, B, C and D was 16.63±0.53 kg to 16.74±0.55 kg for all experimental animals, out of the total of 38 kgs feed/fodder, daily per cow. As a whole total dry matter intake depicted 25-26%. The effect of milking frequencies on milk yield was significant. In hand milking the mean values of milk yield in group A and B was 15.5 and 15.72 liters respectively; while machine milking twice 17.38 liters group C or thrice 17.74 liters group D were significantly different (P<0.05) as the machine milked cows thrice give comparatively high production. Percentage of milk fat composition in group averages recorded as 4.14±0.14. These values of hand milking in group B was 3.89±0.07. In group C the mean values were 3.98 ±0.06 and in group D these fat values were 3.95±0.16 respective. Results regarding mean values of milk solid not fats in group A, B, C and D were 9.72% ±0.17, 9.70%±0.05, 9.46%±0.11 and 9.46±0.08 respectively. These results show that practices and frequencies of milking did not have any significant effect on milk yield fats and / or SNF. Cost of milk production (based on cost of green fodder @ Rs. 150/-, Concentrate feed @ Rs 200/-, wheat straw Rs.25/-.With a highest milk production yield 17.74 liters milk fetched Rs. 106.4/-@ Rs. 60/-per liter.
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