[Tóm tắt] Luận án Đánh giá khả năng thích ứng của giống cừu Phan Rang nuôi ở Thừa Thiên Huế

1. Conclusion Phan Rang sheep have existed and adapted to characteristic of dry – hot temperature, high average temperature and low humidity of Ninh Thuan over a hundred years. When Phan Rang sheep were raised in Thua Thien Hue’s conditions with generally particular weather cold -humid; cold- humid in Winter, hot- dry in Summer; Temperature and THI of Thua Thien Hue were lower than those of Ninh Thuan; Vice verse, Humidity of Thua Thien Hue was higher than that of Ninh Thuan; The following conclusions were reached initially: 1. Physiological indicators (rectal temperature, heart rate, skin temperature, red blood cell, hemoglobin, hematocrit and white blood cell) of sheep raised in Thua Thien Hue were no different compared to in Ninh Thuan; whereas, respiratory rate was higher (14.54 breaths/min), however, they were still within sheep’s generally physiological range. Temperature, humidity and THI correlated closely with respiratory frequency (R2: 0.73-0.82) and hemoglobin content (P<0.05). Sheep’s physiological parameters increased remarkably (P<0.05) in data of Temperature >29.50C, THI >28.5 and humidity <75%.

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tive performance; (ii) to determine the regression equations between temperature, relative humidity and temperature-humid index, to respiratory rates, hemoglobin concentrations and daily feed intakes; and therefore, the above findings have been provied further database on physiological indicators, and growth and reproductive performance of Phan Rang sheep kept in Thua Thien Hue province’s conditions. Thesis’s structure Besides the table of contents; list of tables, charts, pictures; reference; annexes; the thesis is composed of five major contents: (1) Introduction (pp. 1 – 4); (2) Literature review (pp. 5-52); (3) Materials and methods (pp. 53-67); (4) Results and discussion; and (5) Conclusions and recommendations. 30 CHAPTER 2. MATERIALS AND METHODS 2.1. Animals and feeds Animal: Experiment was done on Phan Rang sheep raised in Thua Thien Hue and those raised in Ninh Thuận. Feed: Natural grass, Elephant grass, Jackfruit foliage, Streblus foliage. 2.2. Locations Experiments were carried out from Feb 2009 to Dec 2012 at Hue University of Agriculture and Forestry; Center for Experiment and Research of Goat and Sheep in Ninh Thuan; Department of feed and animal products Analysis of National Institute of Animal Husbandary, and Department of Hematology and Blood Transfusion at hospital of Medicine and Pharmacy under Hue University.. 2.3. Experiments 2.3.1. Experiment 1 - Measuring temperature, humidity and THI in Thua Thien Hue and Ninh Thuan provinces 2.3.1.1. Measuring temperature and humidity Data on air temperature and humidity from 2007-2011 of Thua Thien Hue province were collected from Center for Hydro-Meteorological Forecasting of Mid-Central Vietnam and Statistics yearbook of Thua Thien Hue in 2012; of Ninh Thuan province collected from Station for Hydro-Meteorological Forecasting of Phan Rang, Ninh Thuan and Statistics yearbook of Ninh Thuan in 2012. Data on temperature, humidity of the pens in the experiments recorded with automatic Hygro-Thermometer (French) in 8 periods of time: 1.00; 4.00; 7.00; 10.00; 13.00; 16.00; 19.00 and 22.00h for all days of the months in 2 seasons: hot season (Jun-Aug/2009) and cold season (Dec/2009-Feb/2010). Hygro-Thermometer was put somewhere near the height of mature sheep, 0.8m from the ground, 0.6m from the pen floor. 2.3.1.2. Measuring Temperature-Humidity Index During these days of experiment for the thesis, THI was calculated in accordance with the formula of Marai et al. (2000): THI = T0C - {(0,31 - 0,31*RH/100)(T0C - 14,4) Of which: T0C: temperature (0C); RH: relative humidity (%) 2.3.1.3. Statistical analysis The collected data are managed on Microsoft Excel and statistically analysis on Minitab software version 15.10 (2010). The data are analyzed in form of descriptive statistics, the results of were presented as mean values (M) and standard error of the mean (SEM). 31 2.3.2. Experiment 2 – Determining the interactions between temperature, humidity and THI with some physiological parameters 2.3.2.1. Meaasuring physiological parameters Experiments were done on 24 Phan Rang sheep raised in Thua Thien Hue at the age groups of : 1, 3, 6, 9, 12 and 15 months, with 4 sheep in each group, together with 88 sheep raised in Ninh Thuan for of 3, 8, 17, 24, 20 and 16 sheep, respectively. Physiological parameters include respiratory rate (RR), heart rate (HR), skin temperature (ST) and rectal temperature (RT), which are monitored from each individual sheep. Monitoring is done three times a day at 7.00, 13.00 and 19.00h in two seasons: hot and cold. Physiological parameters of the sheep in the groups were defined everyday (two head /group was measured a day alternatively). At the above periods of time, measurements were done gradually on RR, HR, ST and RT. RR was recorded by counting the up and down peristalsis at the lumbar vertebrae on the left. HR was recorded by putting a stethoscope at the left chest of the sheep. RT was measured directly in the rectum and ST was measured close to the skin on the back for five minutes with a thermometer. 2.3.2.2. Measuring blood biochemical parameters Measurements were done on 24 Phan Rang sheep raised in Thua Thien Hue at the age groups of : 1, 3, 6, 9, 12 and 15 months, with 4 sheep in each group and 61 sheep raised in Ninh Thuan at the age of 4, 4, 6, 6, 5 months and 36 sheep, respectively. Blood was collected from all the sheep on the 27th day of Apr-Aug/2009 and Dec/2009-Feb/2010. Blood chemistry parameters: red blood cell count (RBC), white blood cell count (WBC), hemoglobin (Hb) and hematocrit (Hem) were defined with automatic cell counter SYSMEX KX 21 (Made in Japan). 2.3.2.3. Measuring temperature, humidity and THI During the measurement of sheep’s physiological parameters, data on T, RH, THI of the pens were also monitored to define the interactions between T, RH, THI and sheep’s physiological parameters. Methods to define T, RH, THI are presented in Exp. 1. 2.3.2.4. Statistical analysis Collected data were kept and managed under Microsoft Excel, dealing with descriptive statistics and analysis of variance (ANOVA) using the general linear model (GLM) of Minitab software version 15.10 (2010). The differences between mean were compared using Tukey method at credibility 32 of 95%. Non-linear regression was analized with the following quadratic equation: Y = ax2 + bx + c; Where: Y: physiological parameters; x: temperature, humidity or THI 2.3.3. Experiment 3 – Determining the interactions between temperature and THI with feed intake 2.3.3.1. Measuring daily feed intake Daily feed intake was carried out on 12 sheep raised in Thua Thien Hue at 3 age groups of 6, 9 and 12 months, with 4 sheep in each group, through 2 periods: during Apr. - Aug., 2009 and Nov., 2009 - Feb., 2010. Natural grass was used in the experiment and divided into 5 meals a day at: 7.00, 9.00, 13.00, 16.00 and 21.00h. The feed was estimated at 3% of LW (DM basis) and always available. The refused feed was recorded before the first meal of the next day. 2.3.3.2. Measuring temperature, humidity and THI of the pens On the monitoring days, sheep’s feed intake, T, RH and THI were kept records, calculating the average of each day to define the interactions between temperature, THI and feed intake. 2.3.3.3. Statistical analysis Collected data were kept and managed under Microsoft Excel and dealing with descriptive statistics and analysis of variance (ANOVA) under software Minitab version 15.10 (2010). Non-linear regression was analized with the following quadratic equation: Y = ax2 + bx + c, Where: Y: feed intake; x: temperature or THI. 2.3.4. Experiment 4 - Evaluating reproductive and growth performance 2.3.4.1. Growth performance and meat production Growth performance: In Thua Thien Hue, 24 sheep were used with the ages of 3, 6, 9, 12 and 15 months, with 4 sheep in each group, and 207 sheep in Ninh Thuan at the age of 3, 6, 9, 12 and 15 months for 57, 48, 43, 38 and 21 sheep, respectively; following the criteria on live weight, weight gain, measured lengths, and methods from standards of QCVN 01-71:2011 of Ministry of Agriculture and Rural development to calculate the sheep's growth speed (QCVN 01-71). Meat performance: 6 sheep of 9-month age (3 males, 3 females) were slaughtered following the standards of QCVN 01-71. 2.3.4.2. Reproductive performance Reproductive performance was monitored in 5 female sheep, 4 of them born in Thua Thien Hue and 1 old female in Ninh Thuan. All measurements were recorded according to the standards of QCVN 01-71. 33 2.3.4.3. Statistical analysis Collected data were kept and managed under Microsoft Excel and statistics was done on software Minitab version 15.10 (2010). The data are analysed in from of descriptive statistics, the results of study were presented as mean values (M) and standard error of the mean (SEM). 2.3.5. Experiment 5 – Evaluation of nutritive values of some local foliages 2.3.5.1. Experimental design Experiment was designed in Latin Square using 4 animals with 4 foliages and 4 periods. Each period lasted 20 days (15 first days in adaptation and 5 last days in collection). 2.3.5.2. Management Four sheep were housed individually in metabolism cages that allowed the separate collection of urine and feces, with racks for feed, racks for water. Drinking water was freely accessible. Elephant grass was chopped about 10 cm length prior to feeding, and foliage was separated from branch. All sheep were given feed for ad libitum every day, an estimation of 3% of LW (DM basis) and 5 meals were supplied a day at 7.00, 9.00, 13.00, 16.00 and 21.00h. 2.3.5.3. Samples and chemical analysis Feed intake was measured by recording daily the amount of feed offered and refused. In each collected sample period (5 days), sample of feed, faeces and urine were collected for later chemical analyses. Feed and fecal samples were analyzed dry matter (DM), organic matter (OM), total nitrogen (N) and total mineral (Ash) following AOAC (1990), the concentration of crude protein (CP) was calculated as N×6.25. Neutral detergent fibre (NDF) was determined as described by Van Soest et al. (1991). The gross energy of feeds and faeces were determined by bomb calorimetry (PAR 600, USA). Urine sample was analysed for total N according AOAC (1990). 2.3.5.4. Statistical analysis Data were analyzed by Minitab software version 15.10 (2010) using ANOVA method. The differences between means were compared using Tukey method at credibility of 95%. 34 CHAPTER 3. RESULTS AND DISCUSSION 3.1. Temperature, huminity and THI 3.1.1. Monthly temperature, humidity and THI in Thua Thien Hue and Ninh Thuan provinces The figure 3.1 shows the variations in average T, RH and THI over months in the period of 2007-2011 in Thua Thien Hue and Ninh Thuan. 15 17 19 21 23 25 27 29 31 1 2 3 4 5 6 7 8 9 10 11 12 Month T e m p e r a t u r e ( 0 C ) , T H I 65 70 75 80 85 90 95 H u m i d i t y ( % ) Temperature TT Hue THI TT Hue THI Ninh Thuan Temperature Ninh Thuan Humidity TT Hue Humidity Ninh Thuận Figure 3.1. Average monthly variations in temperature, the humidity and THI in Thua Thien Hue and Ninh Thuan (2007-2011) Figure 3.1 indicatsd that the average monthly environmental T, RH, THI in Thua Thien Hue and Ninh Thuan that had differences in absolute values and variable rule in each region. In both provinces, T and THI varied according to a general rule: trend to increasing from January and reached maximum in June, then reduced gradually to December. Average temperature in Thua Thien Hue was 2.80C lower than Ninh Thuan, but difference in average temperature of the hottest and coldest is bigger. Humidity in Thua Thien Hue was 9.3% higher than in Ninh Thuan and there was a remarkablely varied between the months of the year. Humidity in Hue changes according to the rule: decreasing remarkably from January to July, the increasinh from July to December; while the humidity in Ninh Thuan rose and fell between months. THI value in Ninh Thuan is high in around year (23.8-27.9); in which, there are 4 months (Nov.- Feb. of next year) THI of 23.8-25.2 and 8 months (March - October) THI of 25.8-27.9. Marai et al. (2000) reported that, THI ≥25.6 sheep experienced extreme severe heat stress. 35 With this result, sheep in Ninh Thuan always suffered thermal stress; in which the sheep was subjected to serious stress in 8 months of the year. This indicated that THI evaluation scale of Marai et al. (2000) might not be suitable for environmental conditions in Viet Nam. Hence, the experiments were conducted to evaluate sheep’s physiological reaction at the various levels of THI and determine THI limits in sheep. Analysis of details in section 3.2, 3.3. Overall, Thua Thien Hue has two distinct seasons; hot season (HS) from June to August with T of 28.1-29.00C, RH of 77.4-82.4% and THI is 27.3-28.0; cold season (CS) from December to February in next year with T of 19.1 to 20.90C, RH of 90.4-93.4% and THI of 19.0-20.7. 3.1.2. Temperature, humidity and THI in two experimental seasons 3.1.2.1. Temperature, humidity and THI of stall were measured in hours of days throughout experimental seasons Results of evaluation on variations of T, RH and THI at 8 periods of time of day in the hot and cold seasons showed in figure 3.2. 10 15 20 25 30 35 40 1 4 7 10 13 16 19 22 Hour T e m p e r a t u r e ( 0 C ) ; T H I 40 50 60 70 80 90 100 H u m i n i t y ( % ) Temperature (HS) THI (HS) Temperature (CS) THI (CS) Huminity (HS) Huminity (CS) Figure 3.2. Variations of temperature, huminity and THI of stall in hours in the hot and cold seasons in Thua Thien Hue The results of fig. 3.2 indicated the T and THI of stall in cold and hot seasons were on variable trend according to the general rule: they were minimum at 1 to 4a.m, and then they increased gradually and reached maximum at 13p.m, after that, then they drop tenderly to 22p.m. The humidity variation is constract with T and THI. Temperature amplitude in the cold season was more remarkable change than in the hot season. Therefore, in hot season, the temperature and THI rose highly at 7a.m to 19p.m, while the humidity fell dramatically that led to risks of 36 hot stress in sheep. In the cold season, the temperature and THI reduced outstandingly at 19p.m to 4a.m next day, humidity increased strongly at the same time, so that sheep would be subjected to cold stress. The above results showed that there was high relative humidity, which accounted for a large rate in the hot season and cold season in Thua Thien Hue. This was the significant distintc from Ninh Thuan. 3.2. Relationship between temperature, humidity, THI and physiological parameters 3.2.1. The physiological parameters Physiological parameters of Phan Rang sheep raised in Thua Thien Hue and Ninh Thuan are presented in Table 3.5. Table 3.5. Physiological parameters of Phan Rang sheep raised in Thua Thien Hue and Ninh Thuan Thua Thien Hue Ninh Thuan Criteria n M ± SEM n M ± SEM Rectal temperature (0C) 24 38.99 ± 0.02 88 39.27 ± 0.03 Respiratory rate (breaths/min)* 24 34.15 ± 0.53 88 19.61 ± 0.49 Heart rate (breaths/min) 24 66.94 ± 0.31 88 66.36 ± 0.29 Skin temperature (0C) 24 36.51 ± 0.04 88 35.39 ± 0.03 *Differences was statistically significant (P<0.05) Results in table 3.5 indicated that there were no significantly different on RT, HR, ST of sheep in Thua Thien Hue and Ninh Thuan (P>0.05), whereas, the RR frequency of sheep reared in Thua Thien Hue is significantly higher that in Ninh Thuan (P<0.05). The T and RH in Thua Thien Hue was always high, this was caused the restriction of sheep’s heat interchange through their skin so that it must be increased frequency of respiration for their heat abstraction. 3.2.2. Rectal temperature 3.2.2.1. Relationship between the temperature and rectal temperature Range limits from 17.5 to 33.50C, the relationship between the temperature of stall (x1, 0C) and sheep’s rectal temperature (Y1, 0C) expressed by the quadratic correlation equation as follows: Y1 = 0.0014x12 - 0.0305x1 + 38.76; R2 = 0.77; P = 0.001 Through calculation of increasing sheep’s rectal temperature at different temperature range of cage: ≤22.5; >22.5-26.3; >26.3-29.5 and >29.50C showed that there were significantly different in rectal temperature of sheep (P<0.05) (table 3.6). 37 Table 3.6. Effect of pen temperature on ractal temperature Rectal temperature (0C) Temperature (0C) Range M ± SEM ≤22.5 38.69 - 38.80 38.72a* ± 0.02 >22.5 - 26.3 38.80 - 38.90 38.85b ± 0.01 >26.3 - 29.5 38.99 - 39.04 39.02c ± 0.02 > 29.5 39.10 - 39.32 39.20d ± 0.02 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) Table 3.6 show that, in the range of 17.5-22.50C, sheep’s rectal temperature was relatively stable, with average of rectal temperature was 38.70C. When the temperature increased from >22.5-26.5; >26.5-29.50C, and >29.50C, sheep’s rectal temperature rose of 0.13; 0.17 và 0.180C, respectively. 3.2.2.2. Humidity and rectal temperature The humidity of stall in the range 56-93%, the correlation between humidity (x2, %) and sheep’s rectal temperature (Y2, 0C) as follows: Y2 = 0.0055x22 - 0.043x2 + 40.58; R2 = 0.64; P = 0.001 Humidity in the range of 59-75%, average of sheep’s mean rectal temperature was 39.210C; >75-90%: sheep’s rectal temperature droped 0.360C; >90%: sheep’s rectal temperature declined 0.480C, the differencies was statistically significant (P<0.05) (Table 3.7). Table 3.7. Effect of relative humidity on rectal temperature Rectal temperature (0C) Humidity (%) Range M ± SEM 59 - 75 39.1 - 39.3 39.21a* ± 0.02 >75 - 80 39.0 - 39.1 39.03b ± 0.03 >80 - 90 38.8 - 38.9 38.85c ± 0.03 >90 38.7 - 38.8 38.73d ± 0.03 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) 3.2.2.3. The correlation between THI and rectal temperature In the range of THI from 17.2 to 31.5, the correlation between THI (Y3) and rectal temperature (x3, 0C) was expressed by the quadratic correlation equation as follows: Y3 = 0.0025x32 - 0.0775x3 + 39.247; R2 = 0.64; P = 0.001 Monitoring rectal temperature changes according to the value of THI and evaluation scale of Marai et al., (2000) as follows (table 3.8). Table 3.8 show that there was significantly different in sheep’s rectal temperature when THI at the levels of ≤22.2; >22.2-25.6; >25.6-28.5 and >28.5 (P<0.05). In the range of THI >22.2-26.5, there was no significantly different in 38 sheep’s rectal temperature (P>0.05). This result indicated that it would be better to divide influence of THI on rectal temperature into 4 levels (≤22.2; >22.2-25.6; >25.6-28.5; >28.5) instead of 5 levels. Table 3.8. Effect of THI on rectal temperature Rectal temperature (0C) THI Range M ± SE ≤22.2 38.69 - 38.78 38.72a* ± 0.02 >22.2 - 23.3 38.80 - 38.85 38.82b ± 0.03 >23.3 - 25.6 38.85 - 38.94 38.90b ± 0.02 >25.6 - 28.5 38.91 - 39.01 39.01c ± 0.02 >28.5 39.09 - 39.30 39.20d ± 0.02 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) It was therefore, there were the correlation between temperature, humidity, THI and sheep’s rectal temperature. Rectal temperature of sheep trend to increase with increasing temperature and THI, humidity tended to reverse. Nevertheless, sheep’s rectal temperature were still in the normal range of physiological status. 3.2.3. Relationship between temperature, humidity, THI and respiratory rate 3.2.3.1. Temperature and respiratory rate In the range of temperature from 17.5 to 33.50C, relationship between temperatures (x4, 0C) and the respiratory rate (Y4, breaths/min) as follows: Y4 = 0.1888x42 - 6.3093x4 + 68.205; R2 = 0.81; P = 0.001 Differences of respiratory rate of sheep at 4 datums of temperature that was statistically significant (P<0.05) (table 3.9). Table 3.9. Effect of temperture on respiratory rate Respiratory rate (beat/min) Temperature (0C) Range M ± SEM ≤22.5 16.3 - 19.0 17.98a ± 1.74 >22.5 - 26.3 22.8 - 30.6 27.06b ± 1.62 >26.3 - 29.5 35.7 - 41.1 38.48c ± 2.05 >29.5 52.4 - 74.9 59.41d ± 1.62 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) 3.2.3.2. Humidity and respiratory rate The interaction between humidity (x5, %) and respiratory rate (Y5, breaths/min) following: Y5 = 0.0094x52 - 2.8963x5 + 206.92; R2 = 0.73; P = 0.001 When the humidity was >80%, the average of respiratory rate of sheep were 22.8 breaths/min; 75-80%: 44.66 breaths/min; <75%: 60.05 breaths/min (P<0.05) (table 3.10). 39 Table 3.10. Effect of humidity on respiratory rate Respiratory rate (breaths/min) Huminity (%) Range M ± SEM 59 - 75 56.4 - 64.1 60.05a ± 1.73 >75 - 80 38.1 - 41.6 44.66b ± 2.45 >80 - 90 26.4 - 28.5 26.77c ± 2.12 >90 17.8 - 20.0 18.88c ± 3.00 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) 3.2.3.3. THI and respiratory rate The correlation between THI (Y6) and respiratory rate (x6, breaths/min) as follows: Y6 = 0.3265x62 - 12.25x6 + 132.05; R2 = 0.82; P = 0.001 The changes of respiratory rate following the datum of THI based on evaluation scale of Marai et al., (2000) as follows (table 3.11). Table 3.11. Effect of THI on respiratory rate Respiratory rate (breaths/min) THI Range M ± SE ≤22.2 16.3 - 18.9 17.95a ± 1.26 >22.2 - 23.3 22.0 - 23.8 22.94ab ± 1.92 >23.3 - 25.6 25.9 - 30.0 28.28b ± 1.49 >25.6 - 28.5 30.6 - 41.7 37.36c ± 1.36 >28.5 49.4 - 65.5 58.74d ± 1.36 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) Table 3.11 showed that, respiratory rate of sheep had significantly difference among THI divided range by Marai et al., (2000) (P<0.05). However, with respiratory rate at the level of THI ≤22.2 and >22.2-23.3 there were no significantly different as well as in two next levels of THI were >22.2-23.3 and >23.3-25.6; Whereas, the clear difference between these levels and two remaining levels that were seen in the results of this study. Hence, dividing THI into 5 different levels that might be not suitable to climatic conditions of both the Central in particular and Vietnam in general. It can be seen through caculating that with THI of 17.5-22,2, average respiration rate were 17.95 breaths/min. When THI increased to >22.2- 28.5 breathing frequency increased of plus 19.4 breaths/min. Furthermore, with THI increased >28.5, respiratory rate climbed sharply, adding 40.8 breaths/min (table 3.11). The results above indicated that, T, RH and THI of stall influenced sheep’s respiratory rate. With low humidity and high environmental temperature, it was necessary for sheep to rise respiratory rate for their heat abstraction. 40 3.2.4. Relationship between the temperature, humidity, THI and heart rate 3.2.4.1. Temperature and heart rate Correlation between temperature (x7, 0C) and heart rate (Y7, breaths/min) as follows: Y7 = 0.0062x72 + 0.962x7 + 40.255; R2 = 0.70; P = 0.001 Variation of sheep’s heart rate were significantly defferent among 4 levels of temperature (P<0.05), the heart rate increased with increasing environmental temperature (table 3.12). Table 3.12. Effect of temperature on heart rate Heart rate (beat/min) Temperature (0C) Range M ± SEM ≤22.5 59.7 - 64.2 62.07a ± 0.49 >22.5 - 26.3 65.8 - 69.8 67.68b ± 0.47 >26.3 - 29.5 71.4 - 75.4 72.88c ± 0.74 >29.5 74.7 - 79.6 77.35d ± 0.52 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) 3.2.4.2. Humidity and heart rate The relationship between relative humidity of cage (x8, %) and heart rate (Y8, breaths/min) is expressed by the following equation: Y8 = -0.0065x82 + 0.4756x8 + 73.619; R2 = 0.61; P = 0.001 Table 3.13. Effect of relative humidity on heart rate Heart rate (beat/min) Huminity (%) Range M ± SEM 59 - 75 74.8 - 79.4 77.45a ± 0.68 >75 - 80 72.5 - 74.9 73.46b ± 0.98 >80 - 90 66.4 - 68.4 66.61c ± 0.81 > 90 60.8- 64.9 62.72c ± 0.97 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) The results in table 3.13 showed that, there was a remarkable sink a in heart rate with the level of humidity of 75-80, >80% (P<0.05). When humidity was high >80%, sheep's heart rate was of 62.7-64.65 breaths/min; less than 7-11 breaths/min and lower 11-15 breaths/min with humidity were >75-80% and 59-75%, respectively. This result that sheep were well adapted to the environment with low humidity. 3.2.4.3. THI and heart rate Interaction between THI of cage (x9) and sheep’s heart rate (Y9, breaths/min) was expressed by the following equation: Y9 = 0.0293x92 + 0.0129x9 + 50.049; R2 = 0.69; P = 0.001 The changes of heart rate in the datums of THI based on evaluation scale of Marai et al. (2000) as follows (table 3.14). 41 Table 3.14. Effect of THI on heart rate Heart rate (beat/min) THI Range M ± SE ≤ 22.2 59.60 - 64.70 61.75a ± 0.46 >22.2 - 23.3 65.73 - 66.70 66.08ab ± 0.70 >23.3 - 25.6 66.80 - 70.10 68.60b ± 0.49 >25.6 - 28.5 72.40 - 74.60 73.95c ± 0.54 >28.5 76.70 - 78.00 76.82d ± 0.49 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) Results of table 3.14 showed that sheep's heart rate had significantly differencrs when THI were ≤22.2; >22.2-25.6; >25.6-28.5 and >28.5 (P22.2-26.5, there were no significantly differencrs (P>0.05) in sheep's heart rate. This result indicated that, it was better to divide the influence of THI on sheep’s rectal temperature at 4 different levels (≤22.2; >22.2-25.6; >25.6-28.5; >28.5) instead of 5 levels The heart rate of the sheep had the volatility depends on temperature , humidity and THI. However, heart rate was less affected by T, RH and THI compared with rectal temperature and respiratory rate. When THI increased, heart rate and respiratory rate also rose, but the heart rate did not increase as much as the respiratory rate. 3.2.5. Relationship the temperature, humidity and THI with skin temperature 3.2.5.1. Temperature and skin temperature Correlation between temperature (x10, 0C) and skin temperature (Y10, 0C) expressed by the following equation: Y10 = 0.0216x102 - 0.9021x10 + 44.706; R2 = 0.84; P = 0.001 Temperature of stall were ≤22.5-26.3, there were no changes (P>0.05) in skin, the average of skin temperature were 35.470C. When temperature rose to 26.3-29.50C, skin temperature increased and added 0.640C; temperatures reached >29.5, skin temperature increased highly (add 2.270C), this discrepancy has statistical significance (P<0.05) (table 3.15). Table 3.15. Effect of temperature on skin temperature Skin temperature (0C) Temperature (0C) Range M ± SEM ≤22.5 35.3 - 35.4 35.32a ± 0.11 >22.5 - 26.3 35.4 - 35.9 35.63ab ± 0.11 >26.3 - 29.5 35.9 - 36.4 36.11c ± 0.15 >29.5 37.4 - 38.5 37.74d ± 0.11 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) 42 3.2.5.2. Relative humidity and skin temperature The regression equation between humidity (x11, %) and skin temperature (Y11, 0C) is: Y11 = 0.0014x112 - 0.3162x11 + 52.479; R2 = 0.69; P = 0.001 When the humidity was 59-75%, sheep's skin temperature was 37.950C. The humidity rose to >75-80%, sheep’s skin temperature reduced 1.250C; When the humidity were >80-90%, skin temperature of sheep decreased 2.310C (P<0.05). However, there were no significant differences were found in the levels of humidity >80-90% and >90% (P>0.05) (table 3.16). Table 3.16. Effect of humidity on skin temperature Skin temperature (0C) Huminity (%) Range M ± SEM 59 - 75 37.3 - 38.6 37.95a ± 0.17 >72.5 - 80 36.0 - 37.2 36.70b ± 0.25 >80 - 90 35.4 - 35.9 35.64c ± 0.21 > 90 35.3 - 35.4 35.35c ± 0.25 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) 3.2.5.3. THI and skin temperatures The regression equation between THI of (x12) and skin temperature (Y12, 0C) is: Y12 = 0.0309x2 - 1.2932x + 48.781; R2 = 0.82; P = 0.001 Skin temperature changes under data of THI based on evaluation scale of Marai and CS. (2000) as follows (table 3.17). Table 3.17. Effect of THI on skin temperature Skin temperature (0C) THI Range M ± SE ≤ 22.2 35.3 - 35.4 35.35a ± 0.07 >22.2 - 23.3 35.3 - 35.5 35.53a ± 0.10 >23.3 - 25.6 35.6 - 35.7 35.68a ± 0.09 >25.6 - 28.5 35.9 - 36.4 36.07b ± 0.81 >28.5 37.3 - 37.8 37.75c ± 0.09 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) The results in table 3.17 showed that skin temperature remained constant in the range of THI 0.05) and there were only statistically significant difference when THI>25.6. However, skin temperature in approximately of THI >25.6-28.5 were lower than those of THI>28.5 (P<0.05). Therefore, in order to determine influence of THI on skin temperature, it was possible to divide THI into 3 ranges were 25.6; 25.6- 28.5 and >28.5 instead of 4 once as proposal on rectal temperature. 43 3.2.6. Effect of seasons on blood physiological indicators 3.2.6.1. The blood physiological indicators Blood physiological indicators of Phan Rang sheep were presentec in table 3.18. Table 3.18. The blood physiological indicators of Phan Rang sheep Thua Thien Hue Ninh Thuan Specification n M ± SEM n M ± SEM Red blood cell count (106/mm3) 24 7.8 ± 0.11 61 7.52 ± 0.15 Hemoglobin valua (g%) 24 8.4 ± 0.15 61 8.93 ± 0.19 Hematocrit valua (%) 24 40.0 ± 1.71 61 42.01 ± 2.24 White blood cell count (103/mm3) 24 8.9 ± 0.23 61 8.85 ± 0.30 Results of table 3.18 indicated that, all parameters of blood (RBC, Hb, Hem, WBC) of sheep raised under temperature and humidity conditions in Thua Thien Hue were vibrational although these parameters were still within normal blood physiological limits of sheep breed and there was no significantly different compared to sheep raised in Ninh Thuan (P>0.05). 3.2.6.2. Effect of seasons on physiological indicators Effect of seasons on blood biochemical parameters was indicated in table 3.19. Table 3.19. Effect of seasons on blood physiological indicators Dry season Rainy season Indicators n M ± SEM n M ± SEM Red blood cell count (106/mm3) 20 6.80 ± 0.18 20 6.89 ± 0.16 Hemoglobin valua (g%) 20 6.94 ± 0.19 20 8.60 ± 0.16 Hematocrit valua (%) 20 38.29 ± 2.46 20 39.82 ± 2.46 White blood cell count (103/mm3) 20 8.06 ± 0.41 20 8.73 ± 0.35 *Statistically significant difference (P<0.05) The results of table 3.19 showed that, RBC, Hem, WBC were no significantly affected by seasons (P>0.05). Whereas, the number of hemoglobin were significantly between hot season and cold season (P<0.05). This difference could be due to low temperature and high humidity in cold season that enhanced metabolisms process, especially heat exchange capacity, wherefores Hemoglobin content rose. Therefore, based on initial physiological parameters, it could be seen sheep were adapted to new environmental condition in Thua Thien Hue. 3.3. Correlation between temperature and THI with feed intake 3.3.1. Temperature and feed intake In the range of temperature from 17.5 to 33.50C, the regression equation between feed intake (Y13, gDM/kgLW/day) with T (x13, 0C) as follows: 44 Y13 = -0.0874x132 + 3.0284x13 + 23.861; R2 = 0.81; P = 0.001 Table 3.20. Effect of temperature on feed intake Feed intake (gDM/LW/day) Temperature (0C) Range M ± SEM ≤22.5 47.6 - 51.0 49.3a ± 0.98 >22.5 - 26.3 42.7 - 47.4 45.2b ± 0.85 >26.3 - 29.5 36.8 - 42.9 40.1c ± 0.98 >29.5 26.4 - 36.1 37.7d ± 0.91 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) It could be seen from caculating; with temperature ≤22.50C feed intake was 49.3g DM/kgLW/day; with temperature >22.5-29.50C, feed intake decreased 9.2g DM/LW/day (drop of 18.7%) (P<0.05) (table 3.20). With temperature >29.5, for each additional 10C, sheep’s feed intake reduced 14.7g /DM/LW/day (compared with ≤22.50C). 3.3.2. THI and sheep’s feed intake Regression equation between THI (x14) and sheep’s feed intake (Y14, gDM/kgLW/day) was following: Y14 = -0.1461x142 + 5.594x14 - 4.1092; R2 = 0.81; P = 0.001 Table 3.21. Effect of THI on feed intake Feed intake (gDM/LW/day) THI Variation M ± SE ≤ 22.2 48.0 - 51.0 49.11a ± 0.75 > 22.2 - 23.3 46.1 - 47.7 46.78ab ± 1.15 > 23.3 - 25.6 43.6 - 47.6 45.15b ± 0.81 >25.6 - 28.5 39.3 - 42.6 41.09c ± 0.81 > 28.5 26.4 - 36.0 32.27d ± 0.81 * a,b,c,d Value within a column with different letters are significantly different (P<0.05) The data in table 3.21 show that feed intake was no significantly different when THI ≤22.2-23.3 (P>0.05) and they decreased gradually at the THI levels of which was higher. With THI>28.5 if THI rose one unit, feed intake would reduce average 16.2g DM/LW/day. 3.4. Reproductive and grow performance of Phan Rang sheep reared in Thua Thien Hue 3.4.1. Growth rate and meat production 3.4.1.1. Growth performance * Live weight: Results present in the table 3.22. Data in Table 3.22 indicate that LW of Phan Rang sheep raised in Thua Thien Hue was lower than that in Ninh Thuan. The previous studies concluded that environment played an important role in exhibiting the genetic potential, which was the factor impacted birth weight and growth performance of sheep (Akhtar et al., 2012; Singh et al., 2006). 45 Table 3.22. Live weight (kg) of Phan Rang sheep (kg) over age (months) Thua Thien Hue Ninh Thuan Ba Vi* Month age Parent n M ± SEM n M ± SEM M ± SEM Male 3 2.1 ± 0.23 - - 2.59 ± 0.7 At birth Female 2 2.3 ± 0.10 - - 2.27 ± 0.6 Male 2 11.5 ± 0.29 22 14.59 ± 0.3 12.48 ± 3.2 3 Female 4 11.7 ± 0.56 35 10.94 ± 0.3 11.36 ± 2.4 Male 6 16.9 ± 0.35 24 20.83 ± 0.4 17.47 ± 5.7 6 Female 8 15.3 ± 0.47 24 17.92 ± 0.3 16.99 ± 3.7 Male 8 19.5 ± 0.43 9 26.22 ± 0.4 24.19 ± 3.3 9 Female 9 18.2 ± 0.31 34 22.82 ± 0.4 21.64 ± 1.2 Male 10 22.3 ± 0.77 22 31.05 ± 0.4 29.09 ± 4.1 12 Female 11 21.6 ± 0.65 16 27.63 ± 0.6 24.63 ± 1.7 Male 10 26.1 ± 1.55 7 33.4 ± 0.5 33.3 ± 2.3 15 Female 12 24.0 ± 1.00 14 29.21 ± 0.5 26.1 ± 3.3 n: number of sheep; *source Đinh Van Binh et al., (2007) *Growth rate: Daily LW gains of sheep are presented in the table 3.23. Table 3.23. Daily weight gain and growth rate Items Parent 0-3 month 4-6 month 7-9 month 10-12 month Male 104.4 60.0 28.9 31.1 Absolute growth (g/head/day) Female 104.4 40.0 32.2 37.8 Male 138.2 38.0 14.3 13.4 Relativistic growth(%) Female 138.4 26.7 17.3 17.1 Table 3.23 indicated that, in the stage from at birth to the end of 3- months of age had the highest growth rate both in absolute growth and relativistic growth. Their growth speed gradually reduced with age and tended to stabilize over 12 months of age. *Size of sheep’s measurements Results from monitoring sheep’s withers height is presented in table 3.24. Table 3.24. Sheep’s withers height (cm) through months of age Thua Thien Hue Ninh Thuan Ba Vi* Month age Sex n M ± SEM n M ± SEM M ± SEM Male 2 49.0 ± 1.20 22 48.18 ± 0.98 53.6 ± 4.5 3 Female 4 46.0 ± 1.30 35 45.27 ± 0.86 51.5 ± 3.8 Male 6 56.8 ± 1.20 24 52.46 ± 0.82 55.3 ± 3.3 6 Female 8 53.1 ± 1.10 24 53.08 ± 1.08 54.3 ± 2.6 Male 8 61.3 ± 2.00 9 62.56 ± 1.38 57.5 ± 5.2 9 Female 9 58.3 ± 0.71 34 62.62 ± 0.86 56.8 ± 5.0 Male 10 66.5 ± 1.20 22 63.41 ± 1.59 61.1 ± 5.7 12 Female 9 65.3 ± 1.80 34 63.65 ± 0.90 61.7 ± 4.6 n: number of sheep; *reference numberic data from Dinh Van Binh et al., 2007 46 Table 3.24 shows that fin height of Phan Rang sheep raised in Thua Thien Hue has no difference between age groups compared to sheep raised in Ninh Thuan, except for differences in male sheep of 6 months of age and female sheep of 9 months of age. Results of monitoring chest girth of sheep is presented in table 3.25. Table 3.25. Chest girth (cm) of sheep through months of age Thua Thien Hue Ninh Thuan Ba Vi* Month age Sex N M ± SEM n M ± SEM M ± SEM Male 2 56.5 ± 0.87 22 58.68 ± 0.69 59.9 ± 3.2 3 Female 4 55.0 ± 1.30 35 54.49 ± 0.74 58.7 ± 2.6 Male 6 63.6 ± 0.98 24 64.5 ± 0.52 62.5 ± 2.4 6 Female 8 61.6 ± 0.48 24 61.79 ± 0.91 60.1 ± 2.7 Male 8 67.8 ± 1.50 9 71.44 ± 1.70 68.7 ± 6.6 9 Female 9 65.2 ± 1.50 34 70.0 ± 0.94 65.5 ± 4.7 Male 10 72.0 ± 1.50 22 77.23 ± 1.28 79.2 ± 3.9 12 Female 11 71.9 ± 1.60 16 70.0 ± 0.93 72.1 ± 4.2 n: number of sheep; *source of Đinh Van Binh et al., 2007 Results of table 3.25 show that, There were no differences between Phan Rang chest girth of sheep raised in Thua Thien Hue and sheep raised in Ninh Thuan among age group except for differences in female sheep of 9 months of age. Result of sheep’s scapulo-ischial length is presented in table 3.26. Table 3.26. Diagonal body length (cm) of sheep through months of age Thua Thien Hue Ninh Thuan Ba Vi* Month age Sex n M ± SEM n M ± SEM M ± SEM Male 2 49.5 ± 0.29 22 51.09 ± 1.35 57.2 ± 5.5 3 Female 4 48.0 ± 0.37 35 48.29 ± 0.93 55.5 ± 4.8 Male 6 54.8 ± 1.60 24 58.79 ± 0.91 59.7 ± 6.3 6 Female 8 54.4 ± 1.00 24 55.17 ± 1.07 58.6 ± 5.4 Male 8 63.8 ± 1.60 9 65.67 ± 1.19 62.4 ± 3.8 9 Female 9 62.7 ± 0.80 34 63.65 ± 0.90 61.7 ± 4.6 Male 10 67.8 ± 1.30 22 68.55 ± 1.28 65.8 ± 4.6 12 Female 11 67.4 ± 0.94 16 66.44 ± 1.20 64.1 ± 5.3 n: number of sheep; *source of Đinh Van Binh and CS., 2007 Results of table 3.26 show that, There were no differences between diagonal body length of Phan Rang sheep raised in Thua Thien Hue and in Ninh Thuan among groups except for differences in male sheep of 6 months of age. 47 3.4.1.2. Results from slaughter for surveyed target of sheep’s meat production Slaughter to determine body meat composition on 6 sheep (3 female, 3 male) at 9 months of age, average results were presented in table 3.27. Table 3.27. Carcass characteristics Thua Thien Hue Items Unit Male Female Ninh Thuan* Ba Vi * No head 3 3 4 6 Age month 9 9 9 9 Live weight kg 22.5 20 22.1 22.5 Carcass % 31.2 29.4 41.8 43.6 Meat % 26.6 27.8 30.2 32.05 Bone % 11.1 13.5 15.3 8.74 Blood % 2.8 2.2 4.1 3.1 Head % 8.0 9.7 6.88 7.07 Leg % 2.9 2.6 3.22 2.59 Skin, wool, tail % 11.2 10.3 - - Viscera % 11.4 10.7 - - Fat thickness cm 0.6 0.6 - - Loin muscle area cm2 6.4 5.9 - - *Sources: Đinh Van Binh et al., 2007. Table 3.27 showed that, carcass proportion and meat proportion of Phan Rang sheep raised in Thua Thien Hue was lower than those of sheep raised in Ninh Thuan or Ba Vi. In present study, carcass weight did not include skin and this might be a reason for lower proportion of carcass. On the other hand sheep had not reached the equivalent fatness due to rearing conditions and environment, and due to small number of sheep slaughtered (6 head) that might also have effect on the results. 3.4.2. Reproductive performance Results from monitoring in physiological and reproductive performnce of 4 lambs and 1 mother sheep, previously lambed once in Ninh Thuan then raised in Thua Thien Hue, were presented in table 3.28. Due to small number of sheep experimented, results of present study might be the intitial step just for reference and should be repeated in greater number. Table 3.28 showed that, age at first service, age at first insemination and age at first breeding of sheep raised in TT Hue were later compared to those raised in Ninh Thuan or Ba Vi. These might results from some impacts such as feeding method and sheep management. Weight at first in heat of Phan Rang sheep raised in TT Hue were heavier than those raised in Ninh Thuan and Ba Vi. Reason for this result 48 might be due to their age at first in heat was later, leading to heavier weight at first in heat. Table 3.28. Reproductive characteristics female sheep raised in ThuaThienHue Thua Thien Hue Items Unit n M ± SE Ninh Thuan* Ba Vì* Age at puberty Day 4 201.3 ± 2.84 185 181 Weight at puberty Kg 4 19.5 ± 0.87 16 17,0 Age at first mating Day 4 349.5 ± 20.8 305 295 Weight at first mating Kg 4 21.9 ± 1.83 22,5 23,1 Age at first breeding Day 4 501.5 ± 21.5 465 455 Weight at first breeding Kg 4 26 ± 1.41 27 27,8 Length of gestation Day 5 152 ± 1.14 150 146 Litter size Head 5 1 ± 0.00 1.33 1.36 *Reference sources of Đinh Van Binh et al., 2007. Gestation length, number of babies/farrow, birth weight of 5 sheeps raised in Thua Thien Hue were within the range of normal values of Phan Rang sheep and similar to those raised in Ninh Thuan, as well as those adaptively raised in Northern provinces. 3.5. Evaluation of nutritive values of some local foliage 3.5.1. Chemical composition and nutritive values Results of chemical composition of feeds were presented in table 3.29. Table 3.29. Chemical composition and nutritive values (M ± SD*) Feeds Items Natural grass Elephant grass Jackfruit foliage Streblus foliage DM (%) 20.5 ± 0.55 19.1 ± 0.90 32.5 ± 2.10 29.2 ± 3.07 OM (%DM) 87.9 ± 0.62 85.5 ± 1.31 91.3 ± 1.19 84.7 ± 2.73 CP (%DM) 10.4 ± 0.95 8.6 ± 0.61 13.5 ± 1.74 16.7 ± 2.32 NDF (%DM) 60.1 ± 2.34 61.8 ± 3.19 48.2 ± 2.90 39.4 ± 2.71 GE (kcal/kg DM) 3742±58.13 3609±24.58 4069±128.64 3549±119.70 Ash (% DM) 12.1 ± 0.62 14.5 ± 1.31 8.7 ± 1.19 15.3 ± 2.73 Data in Table 3.29 show that chemical composition and energy values of 4 kinds of feed in the experiment were fairly high. Notably, besides natural grass and elephant grass, kinds of familiar feeds, Jackfruit foliage and Streblus foliage were also popular feeds, with better chemical composition and nutrition, especially crude protein content, which might be the supplement feed for sheep, contribute to solve the shortage of feed. 3.5.2. Feed intake Daily feed intakes are shown in table 3.30. Table 3.30 show that feeds had significant impacts on sheep’s feed intake (P<0.05). Both kinds of grasses intake were higher by sheep 49 compared to Streblus foliage or Jackfruit foliage (P<0.05), while Jackfruit foliage and Streblus foliage intake were similar. However, the protein intake tended to be contrast. Protein intake in sheep fed Streblus foliage was more than the other feeds (P<0.05). Table 3.30. Daily feed intake Feed Items Natural grass Elephant grass Jackfruit foliage Streblus foliage SEM 1 P (kg/head/day) 0.53a 0.54a 0.40b 0.40b 0.013 0.000DM % LW 3.05ab 3.23a 2.46b 2.40b 0.161 0.007 OM (kg/head/day) 0.47a 0.46a 0.37b 0.33c 0.009 0.000 CP (kg/head/day) 0.056a 0.047b 0.055a 0.066c 0.002 0.004 NDF 0.32a 0.33a 0.19b 0.15c 0.005 0.000 GE (kcal/head/day) 2000a 1951a 1637b 1398c 34,23 0.000 a,b,c, Values in the same row with different exponent were difference (P<0.05) 3.5.3. Nutrient digestibility of feeds Digestibility of nutritients are presented in table 3.31. Table 3.31. Apparent digestibility of grasses and local foliages (%) Feeds Items Natural grass Elephant grass Jackfruit foliage Streblus foliage SEM 1 P DM 74.6a 76.6a 64.5ab 57.1b 3.63 0.03 OM 77.0a 78.9a 66.8b 65.9b 2.79 0.03 CP 76.7a 77.2a 49.6b 71.8a 2.47 0.00 NDF 74.7a 79.8a 52.5b 57.6b 3.93 0.01 GE 74.6a 77.4a 63.7b 60.2b 2.51 0.01 a,b,c, Values in the same row with different exponent were difference (P<0.05) Table 3.31 indicated that, digestibility of nutrition in sheep is significantly different among four kind of feeds (P<0.05). DM digestibility of Streblus foliage and Jackfruit foliage was similar (P>0.05), and lower than that of elephant grass or natural grass (P<0.05). OM digestibility of Elephant grass as well as from natural grass were higher compared to Streblus foliage and Jackfruit foliage (P<0.05), whereas, OM digestibility was similar between Streblus foliage and Jackfruit foliage or between elephant grass and natural grass (P>0.05). CP digestibility was similar between elephant grass, natural grass and Streblus foliage (P>0.05) and significantly higher compared to Jackfruit foliage (P<0.05). Digestibility of NDF and GE trended to be similar, however, elephant grass and natural grass were higher compared to Streblus foliage or Jackfruit foliage (P<0.05). 3.5.4. Digestible nutritients of tested feeds Based on calculation of results in tables 3.29 and 3.31, the digestible nutritients were presented in table 3.32. 50 Table 3.32. Digestible nutritients of the feeds Feeds Items Natural grass Elephant grass Jackfruit foliage Streblus foliage DM (g/kg fresh) 152.90 146.38 209.72 166.67 OM (g/kg DM) 676.89 674.94 609.68 558.59 CP (g/kg DM) 79.72 66.40 66.67 119.83 NDF (g/kg DM) 448.86 492.86 253.13 226.99 GE (kcal/kg DM) 2792.63 2793.53 2590.11 2138.12 a,b,Values in the same rows with different exponent were difference (P<0.05) Table 3.32 show that, there were differences in the nutrition digested by sheep over different kinds of feeds. Compared to natural grass and Elephant grass, DM and CP digested from Jackfruit foliage and Streblus foliage were higher, especially the protein digested from Streblus foliage (119,83 g/kg). Whereas, DM and CP intake were low (table 3.29), and digestibilyty of DM and CP were also low (table 3.31). 3.5.5. Nitrogen (N) balance Evaluation results of sheep’s nitrogen balance are shown in table 3.33. Table 3.33. Nitrogen balance Kinds of feed Item Natural grass Elephant grass Jackfruit foliage Streblus foliage SEM 1 P N intake (g) 8.92a 7.47b 8.72a 10.50c 0.330 0.00 N of faeces outgo (g) 2.08a 1.71a 4.39b 2.99c 0.245 0.00 Digestible N intake (g) 6.84ac 5.76a 4.33b 7.51c 0.330 0.00 N of urinary outgo (g) 1.11a 1.26a 0.84a 2.18b 0.200 0.01 N retention (g) 5.73ac 4.50abc 3.49b 5.33c 0.439 0.04 N retention (% of N intake (%) 63.8a 60.1a 40.0b 51.1ab 3.675 0.02 BV (%) 83,2 77,9 80,1 70,3 3,159 0,11 a,b,c,Values in the same rows with different exponent were difference (P<0.05) Table 3.33 showed that, N intake of sheep fed Streblus foliage was higher than that of sheep fed other feeds (P<0.05). N intake was lowest by sheep fed Elephant grass (P<0.05), whereas N intake by sheep fed natural grass and Jackfruit foliage were similar (P>0.05). Sources of roughages also had influence on the N retention in (P<0.05), N retention was the highest in sheep fed natural grass, next with Streblus foliage, Elephant grass and the lowest with Jackfruit foliage. Proportion of N retention as % of N intake was low in sheep fed Jackfruit foliage, whereas BV had no significant difference among four feed (P>0.05). BV values of feeds were in 70.3 to 83.2. 51 CONCLUSION AND RECOMMENDATIONS 1. Conclusion Phan Rang sheep have existed and adapted to characteristic of dry – hot temperature, high average temperature and low humidity of Ninh Thuan over a hundred years. When Phan Rang sheep were raised in Thua Thien Hue’s conditions with generally particular weather cold -humid; cold- humid in Winter, hot- dry in Summer; Temperature and THI of Thua Thien Hue were lower than those of Ninh Thuan; Vice verse, Humidity of Thua Thien Hue was higher than that of Ninh Thuan; The following conclusions were reached initially: 1. Physiological indicators (rectal temperature, heart rate, skin temperature, red blood cell, hemoglobin, hematocrit and white blood cell) of sheep raised in Thua Thien Hue were no different compared to in Ninh Thuan; whereas, respiratory rate was higher (14.54 breaths/min), however, they were still within sheep’s generally physiological range. Temperature, humidity and THI correlated closely with respiratory frequency (R2: 0.73-0.82) and hemoglobin content (P<0.05). Sheep’s physiological parameters increased remarkably (P<0.05) in data of Temperature >29.50C, THI >28.5 and humidity <75%. 2. Temperature and THI correlated closely (P<0.05) with sheep’s feed intake. With the temperature in the range of >29.5-32.50C, for each additional 10C sheep’s feed intake would decrease 14.7g DM/LW/day. When THI values were >28.5, for each additional 1 value sheep’s feed intake would decrease 16.2g DM/LW/day. 3. Most of growth performance of Phan Rang sheep raired in Thua Thien Hue were normal as well as sheep raised in other regions of the country; excluding mass and rate of carcass that were lower than sheep raised in Ninh Thuan . 4. Besides natural grass and Elephant grass, Jackfruit foliage and Streblus foliage were used potentially as sheep’ feed source in rearing of small householdes. It can be seen initially from above conclusions that Phan Rang is adaptability to humidity and tempereture environment of Thua Thien Hue. 2. Recommendations 1. Keep on studies on reproduction of Phan Rang sheep raised in Thua Thien Hue to find more obvious conclusion on adaptability in high humid environmental condition . 2. Study the influence of types of feed on meat quality and quality of sheep in humid hot condition in order to perfect sheep farming procedure in production system in Thua Thien Hue. 52 PUBLICATIONS RELATED TO THE STUDY 1. Bui Van Loi, Nguyen Xuan Ba, Nguyen Huu Van and Le Duc Ngoan (2013). Growth performance and physiological reproduction for sheep rearing in Thua Thien Hue province. Journal of Animal Husbandry Sciences and Technics. No. 8- 2013, pp: 65-74. 2. Bui Van Loi, Nguyen Xuan Ba, Nguyen Huu Van, Dinh Van Dung and Le Duc Ngoan (2012). The evaluation of nutritive value of certain types of forage for the sheep in Thua Thien Hue. Journal of Animal Husbandry Sciences and Technics. No. 10- 2012, pp: 63-68.

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