Ahmed Askar - Academia.edu (original) (raw)

Papers by Ahmed Askar

Animal Biotechnology, Jan 17, 2023

Small Ruminant Research, 2011

Boer goat (BG), Spanish goat (SG), and Rambouillet sheep (RS) wethers, ≥2yr of age, were used in ... more Boer goat (BG), Spanish goat (SG), and Rambouillet sheep (RS) wethers, ≥2yr of age, were used in a crossover experiment with 28-day periods. Diets were ad libitum consumption of wheat straw alone (CON) or with a 90% soybean meal, 10% molasses supplement given at 0.22% BW (SBM). Initial BW was 35, 55, and 32kg for BG, RS, and SG, respectively. NDF digestibility was similar among animal types and between diets. BW change tended to be lowest for RS (−92, −158, and −107g/day for BG, RS, and SG, respectively; SE=22.6). ME intake was similar among animal types (244, 230, and 259kJ/kg BW0.75 for BG, RS, and SG, respectively; SE=16.6) and greater (P<0.05) for SBM vs. CON (320 vs. 168kJ/kg BW0.75). Total energy expenditure (EE) was greater (P<0.05) for RS than for BG (362, 415, and 402kJ/kg BW0.75 for BG, RS, and SG, respectively) and for SBM vs. CON (413 vs. 374kJ/kg BW0.75). EE by the portal-drained viscera (PDV) (1.34, 1.33, and 1.17MJ/day; SE=0.122) and liver (1.48, 1.44, and 1.32MJ/day; SE=0.133) was similar among animal types. Liver EE was greater (P<0.05) for SBM vs. CON (1.60 vs. 1.22MJ/day), but PDV EE was similar between diets. Net fluxes of ammonia N (AMN) and urea N (UN) across the PDV (AMN: 3.4, 2.4, and 3.2g/day (SE=0.69); UN: −5.2, −3.3, and −4.6g/day (SE=1.19)) and liver (AMN: −3.6, −3.2, and −4.3g/day (SE=0.78); UN: 7.6, 4.8, and 4.2g/day for BG, RS, and SG, respectively (SE=1.17)) were similar among animal types. In conclusion, the magnitude of any difference in N recycling among animal types was less than necessary to affect fiber digestibility. Nonetheless, some findings suggest a lesser ability of sheep to modify metabolic functions to cope with limited nutritional planes elicited by feeding crop residue-based diets, perhaps relating to metabolism by extra-splanchnic tissues.

Journal of Applied Animal Research, 2009

Sixteen Boer and 16 Spanish multiparous does were used to determine how stocking rate (SR), breed... more Sixteen Boer and 16 Spanish multiparous does were used to determine how stocking rate (SR), breed and stage of production influence energy expenditure and behavioral activities on pasture and to develop a simple method of predicting energy used for activity. The experiment began i n late spring at a n average of 24 d after kidding. Litter size was two and kids were Boer and Spanish. Two does of each breed resided in eight 0.5-ha grass I forb pastures. There were five periods, 56, 60, 63, 64 and 73 d in length, corresponding to mid-lactation, early post-weaning, the late dry period, early gestation and mid-gestation. During period 1 and the first part of period 2, two additional does with kids of each breed grazed in four High SR pastures, with other pastures designated as Low SR. Because of low available forage mass in period 3, grass hay was offered for ad libitum consumption in periods 3-5 and a concentrate supplement was provided in periods 4 and 5. Energy expenditure (EE) was estimated from heart rate (HR) on pasture and EErHR for each doe determined in a calorimetry system. A leg position /movement monitoring system and a GPS collar with position and movement sensors were used to estimate distance traveled and time spent grazing1 ea.ting, resting while lying, resting while standing and walking without grazing I eating. E E attributable to activity (EE,%), expressed as a percentage of the ME requirement for maintenance plus activity in confinement, was determined based on total EE, estimated milk production and doe BW and ADG. Forage

Most camels in the world are located in East African countries, where the arid climate limits liv... more Most camels in the world are located in East African countries, where the arid climate limits livestock alternatives, but camels, which can survive a week without water, are one of the most droughtresistant species. Consequently, pastoralists around the world, particularly in Africa, are shifting from cattle to camel and small ruminant production. In a changing climate scenario, camel, in particular, has a lot of promise for protecting poor and marginal farmers' socioeconomic standing as an alternative source of income. Despite its advantages over other domestic animals, the camel has received little attention, with the majority of attention being focused on cattle, sheep, and goats, among other things. Egypt has a significant deficit in red meat production and, is around 55% self-sufficient (543,000 tons), which is met by importing from abroad, primarily beef, up to 99% of all red meat imports, with a total of 21.5 billion pounds, posing a significant burden on the balance of payments. In this review, the activities of the National Campaign for the Promotion of Camel Productivity under the intensive production system to reduce the gap and enhance local red meat production are being explained, considering the harsh conditions brought on by climate change, drought, water scarcity, and environmental implications. In addition, the common camel diseases and rumen microbial populations and its classification are taking place in the review.

Small Ruminant Research, 2012

... A. Asmare a , R. Puchala a , K. Tesfai a , GD Detweiler a , LJ Dawson b , AR Askar a , T. Sah... more ... A. Asmare a , R. Puchala a , K. Tesfai a , GD Detweiler a , LJ Dawson b , AR Askar a , T. Sahlu a and AL Goetsch a ... consumption (AL; feed offered at 120% of intake on the preceding few days) of sorghum-sudangrass (Sorghum halpense) hay (4.3% ash, 7.8% CP, 76% NDF ...

Egyptian Journal of Nutrition and Feeds, 2019

hirty non-productive female Shami goats were employed in a 60-day experiment to study the effect ... more hirty non-productive female Shami goats were employed in a 60-day experiment to study the effect of grazing activity and supplementary feeding on energy expenditure (EE) and balance (EB). Goats were divided into three treatments, 10 per each. Animals were grazing a limited area of alfalfa with (GS) or without (G) a limited concentrate supplement, while animals in control treatment were in confinement (in-door, I) in which the same amount of supplement was given with alfalfa hay depending on their recommended requirements. The concentrate feed mixture, as supplementary feeding, was given to cover approximately 50% of the metabolisable energy used for maintenance requirements (ME m). Total EE was estimated by a heart rate (HR) monitor for 48h after individual calibration by oxygen consumption with a face mask open-circuit respiratory system. The internal marker technique was used to estimate the individual intake and digestibility for 6 animals per each treatment in which bags was used for total fecal collection. Animals in control group were consumed significantly less roughage (g/kg BW 0.75) in comparison with those in grazing treatments. Digestible energy was affected by grazing activity and supplementary feeding. Total EE was greater for grazing vs. indoor and reduced with supplementary feeding. As a result, the EB was positive and similar between animals in control (I) and GS groups, while a negative EB associated with body weight loss were observed when animals grazing without supplementation (G). In conclusion, grazing activity has a significant effect on the EE and consequently the ME m and supplementary feeding is essential to maintain grazing animals without deterioration.

Small Ruminant Research

Twenty-four one-year-old male Abu-duleik local sheep were used to evaluate the use of natural ran... more Twenty-four one-year-old male Abu-duleik local sheep were used to evaluate the use of natural rangelands under arid conditions. Dry and wet seasons were considered, each with twelve different animals divided into two treatments. Animals grazed the natural plants with (GS) or without (G) concentrate supplement. Esophageal fistulae were established in another eight two-year-old male to study the botanical composition of forages sheep consumed. Another sixteen one-year-old male were maintained in metabolic cages to determine the marker fecal recovery to be used in calculating feed intake and digestibility. The results of the grazing experiment revealed that average daily gain was −154 and 38 g/d in dry season, and 33 and 119 g/d in wet season, for G and GS, respectively. Forage intake was significantly (P < 0.05) higher in wet than in dry seasons (99.5 vs. 56.0 g DM/kg BW 0.75 /d, respectively) and that the supplementation did not significantly affect forage intake (75.2 vs. 80.3 g DM/kg BW 0.75 /d, for GS and G, respectively). A significant interaction (P < 0.01) between season and supplementation indicated that dry matter digestibility was similar between treatments in the wet season (73.4% vs. 71.0%, for GS and G, respectively) but greater for supplemented animals in the dry season (70.6% vs. 53.8%, respectively). Similar results were observed for organic matter and crude protein digestibilities. The supplementation did not affect the digestibility of neutral detergent fiber in the wet season but improved it in the dry season. A similar trend was observed for the acid detergent fiber digestibility. The results of the total digestible nutrients (TDN) and digestible crude protein (DCP) intake indicated that sheep can meet their energy and protein requirements by only grazing during the wet season, but their maintenance requirements were not met during the dry season. The plasma total protein concentration was higher (P < 0.05) in the wet than in the dry season and increased with supplementation. A similar trend was observed for the plasma urea, rumen ammonia and volatile fatty acids (VFAs) concentrations, which were significantly increased in the wet seasons compared to the dry season and were greater for supplemented animals. The opposite was observed for the plasma creatinine levels. Hence, it is concluded that the nutritive value of natural rangelands is higher in wet than in dry seasons and that the concentrate supplementation is essential to maintain animals during the dry season, providing the minimum level of ammonia and VFAs required for maintaining rumen microbial activity and fermentation for grazing sheep in arid region.

animal

The origin of post-ruminal purine bases (PB) was studied in 24 growing lambs that were given a pe... more The origin of post-ruminal purine bases (PB) was studied in 24 growing lambs that were given a pelleted concentrate plus barley straw (C) or whole barley grain plus protein supplement (WB). Six lambs from each treatment were slaughtered at 10 and 30 days post weaning after 15 N labelling of microbial nitrogen (N) and PB. Microbial contribution to digesta nonammonia N (NAN) and PB was lower (P < 0•01) when estimated from duodenal rather than abomasal samples (0•36 v. 0•52 (s.e.d. 0•021) for NAN and 0•47 v. 0•77 (s.e.d. 0•029) for PB) as a result of endogenous contamination. In comparison with 15 N, total PB/N led to higher estimates (P < 0•01) of microbial contribution to abomasal NAN in WB treatment (0•62 v. 0•46 s.e.d. 0•049). The difference was removed after correcting for microbial PB, while this effect was not observed with < the C diet, resulting in a marker by diet interaction (P < 0•05). Abomasal PB flow increased (P < 0•1) from 10 to 30 days after weaning mainly due to the higher proportion of microbial PB (0•70 v. 0•81 (s.e.d. 0•047)). Rumen apparent PB degradation did not differ between diets in older lambs, but it was proportionally 0•39 lower for WB treatment (P < 0•05) in younger lambs. When the microbial PB flow was estimated indirectly from labelled microbial N and the PB/N ratio of bacterial extracts the estimates were in agreement with those derived from PB-15 N in the WB treatment but resulted in unrealistic values in lambs on diet C. Results suggest that significant proportions of dietary PB can escape rumen degradation which may lead to overestimation of microbial contribution to abomasal NAN when the PB/N ratio is used as marker. The extent of the overestimation is affected by the lamb age and grain processing.

A total of 10 Barki sheep and 10 Baladi goats, were used in 4-month experiment to investigate the... more A total of 10 Barki sheep and 10 Baladi goats, were used in 4-month experiment to investigate the hypothesis that local sheep and goat can tolerate the feed shortage under semi-arid condition and there is a difference between sheep and goats in their ability to withstand this shortage and harsh condition. Animals were divided into two groups according to feeding level (50 and 100% of maintenance energy requirements). Changes in live body weight and some biweekly hematological and blood biochemical parameters were examined. Restricted feeding level negatively affected live body weight but the reduction in weight was not significant in comparison with the control diet. Both sheep and goats fed restricted diets showed a significant (P<0.05) decrease in Hemoglobin (Hb) and packed cell volume (PCV %). Similar reduction was shown in erythrocytes cell counts (RBCs) but it was only significant (P<0.05) in goats. Furthermore, animals fed the restricted feeding diets showed a significant decrease in white blood cells (WBCs) in both species but the reduction was much greater in goats than comparison sheep, 17.15 and 7.75%, respectively, in comparison with the control. Animals fed restricted diets show eel a significant decrease (P<0.05) in total protein, globulin, and triglyceride, and a non-significant increase in albumin, albumin/ globulin ratio, and total lipids in both species. While, glucose and cholesterol increased in sheep, both parameters decreased in goats. Alanine transferase (ALT), aspartate transferase (AST), and gamma glutamyl transferase (GGT) were increased in both species that received restricted diet. The increase in the three enzymes was significant in sheep, and only the GGT that was significant in goats. While alkaline phosphatase was significantly decreased in sheep, it was significantly increased in goats. In addition, restricted feeding resulted in a significant increase in blood urea, but significant decrease in creatinine concentration of both species. In conclusion, results revealed that both sheep and goats are adapted on the feed shortage and the tolerance of sheep to feed restriction is much higher than goats under semi-arid condition that is probably due to fat deposition in their tail.

Twenty four adult local desert non-pregnant and non-lactating females, 12 Barki desert sheep and ... more Twenty four adult local desert non-pregnant and non-lactating females, 12 Barki desert sheep and 12 Balady desert goats, were used to evaluate effects of long-term nutrient restriction on digestion and energy utilization. Animals were individually housed for a 3-month period and then moved to metabolic cages in two sets of 12 animals, three per treatment and species for each set. Six animals of each species were used as control and fed a concentrate mixture and alfalfa hay diet (50:50% as DM basis) at a level adequate for the metabolizable energy (ME) intake of maintenance (ME m , control). The other six animals were used as restricted diet and fed 50% of the previous amount relative to actual BW (restricted). Total Energy expenditure (EE) was estimated by heart rate (HR) monitor for 48-h period after its individual calibration by oxygen consumption with a face mask open-circuit respiratory system. Similar digestible energy was observed between animal species at control level (63.7 vs. 63.2%, SEM = 1.53), while a greater (P<0.01) digestibility was reported for sheep vs. goats at restricted feed intake level (60.8 vs. 50.9%, SEM = 1.53, respectively). Energy expenditure was greater (P<0.001) for control vs. restricted intake level (420 vs. 338 kJ/kg BW 0.75 /day, SEM = 10.2, respectively) and tended to be higher (P<0.10) for sheep vs. goats (394 vs. 364 kJ/kg BW 0.75 /day, SEM = 10.2, respectively). As a result, the energy balance was greater for control vs. restricted intake level (9.3 vs.-139.8 kJ/kg BW 0.75 /day, SEM = 8.27, respectively) and similar between both animal species (-62.4 vs.-68.0 kJ/kg BW 0.75 /day, SEM = 8.27, for sheep and goats, respectively). In conclusion, both desert Barki sheep and Balady goats are able to reduce their EE in order to improve their energy balance as a mechanism of adaptation when their ME intake is restricted below ME m requirements.

Twelve adult males of each Baladi goats and Barki sheep were divided, each, into four groups base... more Twelve adult males of each Baladi goats and Barki sheep were divided, each, into four groups based on body weight. Animals were fed a ration consisted of berseem hay (ad lib) and concentrate feed mixture (at the rate of 1.5% of body weight). Treatments were drinking sea water diluted with fresh water to contain 4.04g, 8.15g, and 12.33g total dissolved salts/100 ml (TDS l-1), for 2nd, 3rd and 4th treatments, respectively along with fresh water (0.42 g TDS l-1) as a control. Feed intake of both sheep and goats increased by increasing level of salinity, while species differences existed (P<0.05). Nutrient digestibility coefficients did not differ significantly due to salinity levels. Salinity levels effect appeared significant (P<0.05) on nitrogen utilization. Water intake increased in response to increasing salinity level till 8.15g TDS l-1, and then decreased at the higher level (12.33 g TDS l-1). Water intake response to load of elevated salt was higher in sheep than goats. Ne...

En un experimento factorial, con 2 réplicas de 6 corderos por sexo y tratamiento, un núcleo prote... more En un experimento factorial, con 2 réplicas de 6 corderos por sexo y tratamiento, un núcleo proteico con un 33% de proteína en la materia seca se ofreció incorporado al 25% en un gránulo integral de cebada junto con paja ad libitum (T) o con la cebada en grano a libre elección en comederos separados, bien sin paja (C) o con paja (CP). El consumo de paja disminuyó desde 50 a 33 ±3,0 g/d al suministrar la cebada en grano y él de núcleo representó el 44 y el 52 ±3,3% del concentrado en los tratamientos C y CP, sin que ello repercutiera en incrementos significativos de las ganancias de peso que fueron para los tratamientos C, CP y T de 357, 324 y 318 g/d en los machos y de 292, 283 y 294 ±11,4 g/d en las hembras, respectivamente. En un segundo experimento, con corderos machos, se compararon núcleos con contenidos proteicos del 43 (A) 35 (M) y 26% (B), formulados con cebada y soja, con el utilizado en el experimento anterior (N1). El consumo total de concentrado fue constante pero la pro...

Animal Biotechnology, Jan 17, 2023

Small Ruminant Research, 2011

Boer goat (BG), Spanish goat (SG), and Rambouillet sheep (RS) wethers, ≥2yr of age, were used in ... more Boer goat (BG), Spanish goat (SG), and Rambouillet sheep (RS) wethers, ≥2yr of age, were used in a crossover experiment with 28-day periods. Diets were ad libitum consumption of wheat straw alone (CON) or with a 90% soybean meal, 10% molasses supplement given at 0.22% BW (SBM). Initial BW was 35, 55, and 32kg for BG, RS, and SG, respectively. NDF digestibility was similar among animal types and between diets. BW change tended to be lowest for RS (−92, −158, and −107g/day for BG, RS, and SG, respectively; SE=22.6). ME intake was similar among animal types (244, 230, and 259kJ/kg BW0.75 for BG, RS, and SG, respectively; SE=16.6) and greater (P&lt;0.05) for SBM vs. CON (320 vs. 168kJ/kg BW0.75). Total energy expenditure (EE) was greater (P&lt;0.05) for RS than for BG (362, 415, and 402kJ/kg BW0.75 for BG, RS, and SG, respectively) and for SBM vs. CON (413 vs. 374kJ/kg BW0.75). EE by the portal-drained viscera (PDV) (1.34, 1.33, and 1.17MJ/day; SE=0.122) and liver (1.48, 1.44, and 1.32MJ/day; SE=0.133) was similar among animal types. Liver EE was greater (P&lt;0.05) for SBM vs. CON (1.60 vs. 1.22MJ/day), but PDV EE was similar between diets. Net fluxes of ammonia N (AMN) and urea N (UN) across the PDV (AMN: 3.4, 2.4, and 3.2g/day (SE=0.69); UN: −5.2, −3.3, and −4.6g/day (SE=1.19)) and liver (AMN: −3.6, −3.2, and −4.3g/day (SE=0.78); UN: 7.6, 4.8, and 4.2g/day for BG, RS, and SG, respectively (SE=1.17)) were similar among animal types. In conclusion, the magnitude of any difference in N recycling among animal types was less than necessary to affect fiber digestibility. Nonetheless, some findings suggest a lesser ability of sheep to modify metabolic functions to cope with limited nutritional planes elicited by feeding crop residue-based diets, perhaps relating to metabolism by extra-splanchnic tissues.

Journal of Applied Animal Research, 2009

Sixteen Boer and 16 Spanish multiparous does were used to determine how stocking rate (SR), breed... more Sixteen Boer and 16 Spanish multiparous does were used to determine how stocking rate (SR), breed and stage of production influence energy expenditure and behavioral activities on pasture and to develop a simple method of predicting energy used for activity. The experiment began i n late spring at a n average of 24 d after kidding. Litter size was two and kids were Boer and Spanish. Two does of each breed resided in eight 0.5-ha grass I forb pastures. There were five periods, 56, 60, 63, 64 and 73 d in length, corresponding to mid-lactation, early post-weaning, the late dry period, early gestation and mid-gestation. During period 1 and the first part of period 2, two additional does with kids of each breed grazed in four High SR pastures, with other pastures designated as Low SR. Because of low available forage mass in period 3, grass hay was offered for ad libitum consumption in periods 3-5 and a concentrate supplement was provided in periods 4 and 5. Energy expenditure (EE) was estimated from heart rate (HR) on pasture and EErHR for each doe determined in a calorimetry system. A leg position /movement monitoring system and a GPS collar with position and movement sensors were used to estimate distance traveled and time spent grazing1 ea.ting, resting while lying, resting while standing and walking without grazing I eating. E E attributable to activity (EE,%), expressed as a percentage of the ME requirement for maintenance plus activity in confinement, was determined based on total EE, estimated milk production and doe BW and ADG. Forage

Most camels in the world are located in East African countries, where the arid climate limits liv... more Most camels in the world are located in East African countries, where the arid climate limits livestock alternatives, but camels, which can survive a week without water, are one of the most droughtresistant species. Consequently, pastoralists around the world, particularly in Africa, are shifting from cattle to camel and small ruminant production. In a changing climate scenario, camel, in particular, has a lot of promise for protecting poor and marginal farmers' socioeconomic standing as an alternative source of income. Despite its advantages over other domestic animals, the camel has received little attention, with the majority of attention being focused on cattle, sheep, and goats, among other things. Egypt has a significant deficit in red meat production and, is around 55% self-sufficient (543,000 tons), which is met by importing from abroad, primarily beef, up to 99% of all red meat imports, with a total of 21.5 billion pounds, posing a significant burden on the balance of payments. In this review, the activities of the National Campaign for the Promotion of Camel Productivity under the intensive production system to reduce the gap and enhance local red meat production are being explained, considering the harsh conditions brought on by climate change, drought, water scarcity, and environmental implications. In addition, the common camel diseases and rumen microbial populations and its classification are taking place in the review.

Small Ruminant Research, 2012

... A. Asmare a , R. Puchala a , K. Tesfai a , GD Detweiler a , LJ Dawson b , AR Askar a , T. Sah... more ... A. Asmare a , R. Puchala a , K. Tesfai a , GD Detweiler a , LJ Dawson b , AR Askar a , T. Sahlu a and AL Goetsch a ... consumption (AL; feed offered at 120% of intake on the preceding few days) of sorghum-sudangrass (Sorghum halpense) hay (4.3% ash, 7.8% CP, 76% NDF ...

Egyptian Journal of Nutrition and Feeds, 2019

hirty non-productive female Shami goats were employed in a 60-day experiment to study the effect ... more hirty non-productive female Shami goats were employed in a 60-day experiment to study the effect of grazing activity and supplementary feeding on energy expenditure (EE) and balance (EB). Goats were divided into three treatments, 10 per each. Animals were grazing a limited area of alfalfa with (GS) or without (G) a limited concentrate supplement, while animals in control treatment were in confinement (in-door, I) in which the same amount of supplement was given with alfalfa hay depending on their recommended requirements. The concentrate feed mixture, as supplementary feeding, was given to cover approximately 50% of the metabolisable energy used for maintenance requirements (ME m). Total EE was estimated by a heart rate (HR) monitor for 48h after individual calibration by oxygen consumption with a face mask open-circuit respiratory system. The internal marker technique was used to estimate the individual intake and digestibility for 6 animals per each treatment in which bags was used for total fecal collection. Animals in control group were consumed significantly less roughage (g/kg BW 0.75) in comparison with those in grazing treatments. Digestible energy was affected by grazing activity and supplementary feeding. Total EE was greater for grazing vs. indoor and reduced with supplementary feeding. As a result, the EB was positive and similar between animals in control (I) and GS groups, while a negative EB associated with body weight loss were observed when animals grazing without supplementation (G). In conclusion, grazing activity has a significant effect on the EE and consequently the ME m and supplementary feeding is essential to maintain grazing animals without deterioration.

Small Ruminant Research

Twenty-four one-year-old male Abu-duleik local sheep were used to evaluate the use of natural ran... more Twenty-four one-year-old male Abu-duleik local sheep were used to evaluate the use of natural rangelands under arid conditions. Dry and wet seasons were considered, each with twelve different animals divided into two treatments. Animals grazed the natural plants with (GS) or without (G) concentrate supplement. Esophageal fistulae were established in another eight two-year-old male to study the botanical composition of forages sheep consumed. Another sixteen one-year-old male were maintained in metabolic cages to determine the marker fecal recovery to be used in calculating feed intake and digestibility. The results of the grazing experiment revealed that average daily gain was −154 and 38 g/d in dry season, and 33 and 119 g/d in wet season, for G and GS, respectively. Forage intake was significantly (P < 0.05) higher in wet than in dry seasons (99.5 vs. 56.0 g DM/kg BW 0.75 /d, respectively) and that the supplementation did not significantly affect forage intake (75.2 vs. 80.3 g DM/kg BW 0.75 /d, for GS and G, respectively). A significant interaction (P < 0.01) between season and supplementation indicated that dry matter digestibility was similar between treatments in the wet season (73.4% vs. 71.0%, for GS and G, respectively) but greater for supplemented animals in the dry season (70.6% vs. 53.8%, respectively). Similar results were observed for organic matter and crude protein digestibilities. The supplementation did not affect the digestibility of neutral detergent fiber in the wet season but improved it in the dry season. A similar trend was observed for the acid detergent fiber digestibility. The results of the total digestible nutrients (TDN) and digestible crude protein (DCP) intake indicated that sheep can meet their energy and protein requirements by only grazing during the wet season, but their maintenance requirements were not met during the dry season. The plasma total protein concentration was higher (P < 0.05) in the wet than in the dry season and increased with supplementation. A similar trend was observed for the plasma urea, rumen ammonia and volatile fatty acids (VFAs) concentrations, which were significantly increased in the wet seasons compared to the dry season and were greater for supplemented animals. The opposite was observed for the plasma creatinine levels. Hence, it is concluded that the nutritive value of natural rangelands is higher in wet than in dry seasons and that the concentrate supplementation is essential to maintain animals during the dry season, providing the minimum level of ammonia and VFAs required for maintaining rumen microbial activity and fermentation for grazing sheep in arid region.

animal

The origin of post-ruminal purine bases (PB) was studied in 24 growing lambs that were given a pe... more The origin of post-ruminal purine bases (PB) was studied in 24 growing lambs that were given a pelleted concentrate plus barley straw (C) or whole barley grain plus protein supplement (WB). Six lambs from each treatment were slaughtered at 10 and 30 days post weaning after 15 N labelling of microbial nitrogen (N) and PB. Microbial contribution to digesta nonammonia N (NAN) and PB was lower (P < 0•01) when estimated from duodenal rather than abomasal samples (0•36 v. 0•52 (s.e.d. 0•021) for NAN and 0•47 v. 0•77 (s.e.d. 0•029) for PB) as a result of endogenous contamination. In comparison with 15 N, total PB/N led to higher estimates (P < 0•01) of microbial contribution to abomasal NAN in WB treatment (0•62 v. 0•46 s.e.d. 0•049). The difference was removed after correcting for microbial PB, while this effect was not observed with < the C diet, resulting in a marker by diet interaction (P < 0•05). Abomasal PB flow increased (P < 0•1) from 10 to 30 days after weaning mainly due to the higher proportion of microbial PB (0•70 v. 0•81 (s.e.d. 0•047)). Rumen apparent PB degradation did not differ between diets in older lambs, but it was proportionally 0•39 lower for WB treatment (P < 0•05) in younger lambs. When the microbial PB flow was estimated indirectly from labelled microbial N and the PB/N ratio of bacterial extracts the estimates were in agreement with those derived from PB-15 N in the WB treatment but resulted in unrealistic values in lambs on diet C. Results suggest that significant proportions of dietary PB can escape rumen degradation which may lead to overestimation of microbial contribution to abomasal NAN when the PB/N ratio is used as marker. The extent of the overestimation is affected by the lamb age and grain processing.

A total of 10 Barki sheep and 10 Baladi goats, were used in 4-month experiment to investigate the... more A total of 10 Barki sheep and 10 Baladi goats, were used in 4-month experiment to investigate the hypothesis that local sheep and goat can tolerate the feed shortage under semi-arid condition and there is a difference between sheep and goats in their ability to withstand this shortage and harsh condition. Animals were divided into two groups according to feeding level (50 and 100% of maintenance energy requirements). Changes in live body weight and some biweekly hematological and blood biochemical parameters were examined. Restricted feeding level negatively affected live body weight but the reduction in weight was not significant in comparison with the control diet. Both sheep and goats fed restricted diets showed a significant (P<0.05) decrease in Hemoglobin (Hb) and packed cell volume (PCV %). Similar reduction was shown in erythrocytes cell counts (RBCs) but it was only significant (P<0.05) in goats. Furthermore, animals fed the restricted feeding diets showed a significant decrease in white blood cells (WBCs) in both species but the reduction was much greater in goats than comparison sheep, 17.15 and 7.75%, respectively, in comparison with the control. Animals fed restricted diets show eel a significant decrease (P<0.05) in total protein, globulin, and triglyceride, and a non-significant increase in albumin, albumin/ globulin ratio, and total lipids in both species. While, glucose and cholesterol increased in sheep, both parameters decreased in goats. Alanine transferase (ALT), aspartate transferase (AST), and gamma glutamyl transferase (GGT) were increased in both species that received restricted diet. The increase in the three enzymes was significant in sheep, and only the GGT that was significant in goats. While alkaline phosphatase was significantly decreased in sheep, it was significantly increased in goats. In addition, restricted feeding resulted in a significant increase in blood urea, but significant decrease in creatinine concentration of both species. In conclusion, results revealed that both sheep and goats are adapted on the feed shortage and the tolerance of sheep to feed restriction is much higher than goats under semi-arid condition that is probably due to fat deposition in their tail.

Twenty four adult local desert non-pregnant and non-lactating females, 12 Barki desert sheep and ... more Twenty four adult local desert non-pregnant and non-lactating females, 12 Barki desert sheep and 12 Balady desert goats, were used to evaluate effects of long-term nutrient restriction on digestion and energy utilization. Animals were individually housed for a 3-month period and then moved to metabolic cages in two sets of 12 animals, three per treatment and species for each set. Six animals of each species were used as control and fed a concentrate mixture and alfalfa hay diet (50:50% as DM basis) at a level adequate for the metabolizable energy (ME) intake of maintenance (ME m , control). The other six animals were used as restricted diet and fed 50% of the previous amount relative to actual BW (restricted). Total Energy expenditure (EE) was estimated by heart rate (HR) monitor for 48-h period after its individual calibration by oxygen consumption with a face mask open-circuit respiratory system. Similar digestible energy was observed between animal species at control level (63.7 vs. 63.2%, SEM = 1.53), while a greater (P<0.01) digestibility was reported for sheep vs. goats at restricted feed intake level (60.8 vs. 50.9%, SEM = 1.53, respectively). Energy expenditure was greater (P<0.001) for control vs. restricted intake level (420 vs. 338 kJ/kg BW 0.75 /day, SEM = 10.2, respectively) and tended to be higher (P<0.10) for sheep vs. goats (394 vs. 364 kJ/kg BW 0.75 /day, SEM = 10.2, respectively). As a result, the energy balance was greater for control vs. restricted intake level (9.3 vs.-139.8 kJ/kg BW 0.75 /day, SEM = 8.27, respectively) and similar between both animal species (-62.4 vs.-68.0 kJ/kg BW 0.75 /day, SEM = 8.27, for sheep and goats, respectively). In conclusion, both desert Barki sheep and Balady goats are able to reduce their EE in order to improve their energy balance as a mechanism of adaptation when their ME intake is restricted below ME m requirements.

Twelve adult males of each Baladi goats and Barki sheep were divided, each, into four groups base... more Twelve adult males of each Baladi goats and Barki sheep were divided, each, into four groups based on body weight. Animals were fed a ration consisted of berseem hay (ad lib) and concentrate feed mixture (at the rate of 1.5% of body weight). Treatments were drinking sea water diluted with fresh water to contain 4.04g, 8.15g, and 12.33g total dissolved salts/100 ml (TDS l-1), for 2nd, 3rd and 4th treatments, respectively along with fresh water (0.42 g TDS l-1) as a control. Feed intake of both sheep and goats increased by increasing level of salinity, while species differences existed (P<0.05). Nutrient digestibility coefficients did not differ significantly due to salinity levels. Salinity levels effect appeared significant (P<0.05) on nitrogen utilization. Water intake increased in response to increasing salinity level till 8.15g TDS l-1, and then decreased at the higher level (12.33 g TDS l-1). Water intake response to load of elevated salt was higher in sheep than goats. Ne...

En un experimento factorial, con 2 réplicas de 6 corderos por sexo y tratamiento, un núcleo prote... more En un experimento factorial, con 2 réplicas de 6 corderos por sexo y tratamiento, un núcleo proteico con un 33% de proteína en la materia seca se ofreció incorporado al 25% en un gránulo integral de cebada junto con paja ad libitum (T) o con la cebada en grano a libre elección en comederos separados, bien sin paja (C) o con paja (CP). El consumo de paja disminuyó desde 50 a 33 ±3,0 g/d al suministrar la cebada en grano y él de núcleo representó el 44 y el 52 ±3,3% del concentrado en los tratamientos C y CP, sin que ello repercutiera en incrementos significativos de las ganancias de peso que fueron para los tratamientos C, CP y T de 357, 324 y 318 g/d en los machos y de 292, 283 y 294 ±11,4 g/d en las hembras, respectivamente. En un segundo experimento, con corderos machos, se compararon núcleos con contenidos proteicos del 43 (A) 35 (M) y 26% (B), formulados con cebada y soja, con el utilizado en el experimento anterior (N1). El consumo total de concentrado fue constante pero la pro...