| Abstract |
This study was carried out at Animal Production Research Institute in participation with Animal Production Department Faculty Agriculture Banha University. The experimental work was conducted at privet farm during summer (from Jun. to Sept. 2008).
This trial aims to study the efficiency of new shades cover materials (shade-net and reed-mat) and new construction for shading, in subtropical areas, and comparing that new with ordinary materials physically and economically through reducing the costs of the shade's construction, which sometimes coasts about 45-50% from total housing costs. The experimental part was conducted on 100 growing cross breed male Friesian calves, aged about 9-10 months and weighted about 218 kg, assigned into 4 equal groups kept separately under loose semi shaded yards and fed ad-lib. at 7 am. (silage with ears, rice straw, and concentrates feed mixture).
The first group (G1) was used as a control group (kept under asbestos shade) for G2, G3 and G4. The second group (G2) was kept under reed shade. The third group (G3) was kept under shed-net. The last group (G4) was kept under asbestos shed + additives-NPN.
-The mean results could be summarized as follows: -
1-Thermoregulation responses:
Skin temperature (ST) and respiration rate (RR) decreased significantly by using reed (G2) and shade-net (G3) shades comparing with that of asbestos (G1). whereas, ST and RR slightly decreased significantly in G4 compared to G1 they were (31.71±.05,30.13±.05, 29.89±.0.05 and 31.34±0.5c°; and 58.52±.31, 53.95±.31, 53.54±.31 and 56.52±.31 r.pm) for G1, G2, G3 and G4, respectively.
-Also, ST and RR increased significantly through M2 (Jul.) and M3 (Aug.) than that of M1 (Jun.) and M4 (Sept.) according to the climatic changes. Both of ST and RR affected by daytime; reached their maximum at 2pm. then decreased significantly at 7pm. while reached their minimum at 7am.; At 7am., they decreased significantly (p<0.05) for both of G3 and G2 than those of G1 and G4; whereas, G1 was slightly higher significant than G4. At 2pm., the same trend was observed, also without significant differences between G2 and G3. At 7pm., both of ST and RR had the same trend, G2 and G3 decreased significantly than G1 and G4, also, G1 was slightly significantly higher than G4, with insignificant differences between G2 and G3 in RR only.
2- Hematological responses:
- Shade type did not affect on Hb%, globulin and alb/ glob ratio means. Whereas, shade type and additives-NPN enhanced TP, Alb. and TL in both of G3, G2 and G4 than G1which decreased significantly for all of them. Whereas, there were no significant difference between the three groups in TP, Alb. and TL, also there were no significant differences between G1 and G4.
-Experimental months had significant (p<0.05) effect on Hb%, whereas, M1 had the lowest value, and M4 had the highest one, whereas, M1 and M3 Hb% means had no significant differences between them. Each of TP, Alb., Glob. and TL gradually increased significantly through M2, M3 and M4 without significant differences between them comparing with M1.
3-Hormonal responses:
-Shading types did not improved T3 concentration comparing control group (G1). Whereas, there were insignificant differences between groups means which recorded 159.±10.5 189.8±10.5; 185.5±l0.5and 1625± 10.5, for G1, G2, G3 and G4, respectively.
-T3 decreased significantly (P<0.05) through M1, M2 and M3 significant differences between them compared with M4.(159.5±10.5; 144.5± 10.5; 174.9±10.5 vs. 218.8±10.5), for M1 ,M2 , M3 and M4, respectively.
4-Water consumption (WC):
-The water consumption (WC) did not affect with shade types, there was no significant differences between means; whereas, additives-NPN group (G4) affected significantly (P<0.05) on WC. It was found that, the lowest WC was obtained in G3 then G2 (33.85±.2l, 33.8±.21 L/d), respectively, than control (G1) and additives-NPN group (G4) groups which was (34.34±.21and 35.01±.21L/d.) respectively.
Water consumption (WC) gradually increased significantly, through experimental months from M1 (Jun.) to M4 (Sept.), by increasing the requirements of the animals. Whereas, the lowest value (26.15±.21L/d) was obtained in M1 and the highest one (39.22±.21 L/d) was obtained in M4.
5- Dry matter intake (DMI):
Dry matter intake affected significantly as a function of shade type applications; whereas, it increase significantly for both of G3 without difference between them; whereas, it decrease significantly for G1 and G4, without significant differences between them too.
-Months affected significantly on DMI, whereas, it increased gradually from M1 (Jun.) to M4 (Sept.) by increasing requirements of the animals.
6- Daily weight gain (DWG):
-Daily weight gain enhanced significantly (p<0.05) by shade type in G2 and G3 than in G1 and G4 with out significant differences between the lasts; they were (1.10±0.02 and1.16±0.02 vs. 0.97±0.02 and 1.00±0.02 kg/d, respectively) whereas, shade-net shading improved DWG more significantly than using reed shading by about 60g./day.
-Whereas, DWG was not affected significantly by month, but the highest gain observed in M4 and the lowest one obtained in M1.
7- Feed utilization (FU):
-Shading type improved significantly (p<0.05) FC and FE in G2 and G3 compared with G1 and G4. whereas, there were no significant differences between G1 and G4, also, between G2 and G3.
-Month affected significantly (p<0.001) on FC and FE whereas, it increased gradually from M1 (Jun.) to M4 (Sept.) by increasing the requirements of the animals and their daily weight gains.
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