فهرست مطالب نادر پاپی

This study was aimed to evaluate the effects of supplementary feeding on productive and reproductive performance of Zel sheep breed, in mating, late pregnancy and lactating periods. For this purpose, 120 ewe Zel, 2-5 years old, average body weight of 33.8 ± 4.78 kg that had reproductive, were selected from the Zel flock of National research station of Gavdashat Mazandaran province and divided to two same group. The treatments contained; The first group (control); the ewes fed with basal diet + 100 gr concentrates in late pregnancy and the first two months of lactating, The second group (Experimental group); the ewes fed with basal diet + 200, 300 and 400 gr concentrates in mating, late pregnancy and the first two months of lactating periods, respectively. Each group was divided to two subgroups of 30 heads, and then entrance to a pen with a ram for 40 days. The results showed that, apparent fertility, prolificacy, ewe reproductive performance, and ewe productive performance of control and experimental groups, were 85% and 90%, 111.8% and 114.8%, 95% and 103.3%, and 91.7% and 107.7%, respectively. The live body weight of ewe after parturition, was not significant between control and experimental groups. The lamb’s birth weight of experimental group (3.4 kg) was significantly higher than control group (3.0 kg, (p<0.05), but the weaning weight of lambs (13.5 and 14.7 kg, in control and experimental group respectively), did not affected by supplementary feed. In general, using supplementary dietary in concentrate form, in mating, late pregnancy, and lactating periods, improves the reproduction performance, and ewe production performance, and economical efficiency of sheep breeding units.

Compensatory growth is actually a physiological process in which the animal's potential, after a period of dietary restriction, can be exploited to increase growth and growth efficiency during the free feeding period (Hornick et al 2000). Compensatory growth is widely used today in various countries. Another specific management approach (short-term strategies) in lamb fattening is appropriate weight at the beginning of fattening (Santos Silva et al 2002). The benefits of applying a compensatory growth mechanism during the breeding period can be improved feed efficiency during the compensatory growth period (Abouhif et al 2013 and Sami et al 2016), reduced feed cost throughout the breeding period, also improved weight gain during the breeding period (Clark et al 2007; Abuhif et a l 2015) and reduced energy maintenance needs (Kamalzadeh et al 2009; Shadnosh et al 2011). Considering the feedlot of 320,000 fattening lambs in Lorestan province per year and the possibility of using feed restriction to promote the use of compensatory growth in lamb fattening, the project was carried out aims to investigate the possibility of process changing the growth rate, fattening and physical and chemical composition of carcass lambs Lori breed by short-term strategies of feed restriction.This study was conducted to investigate the effect of different weight start of feed restriction on growth performance and carcass lambs traits Lori breed lambs.

Fifty four male Lori lambs with a mean live weight of 26 kg were selected for the experiment. Treatments were consisted of 6 feed restriction treatments (60,80%) and ad libitum(fattening diet without restriction) for two weights (30 and 35 kg). At the beginning of expriment, 54 experimental lambs were fed the same diet.After a 14 day pre-feed restriction period, a group of 27 individuals that had reached an average weight of 30 kg were separated from the rest and subjected to feed restraint treatments. The remaining 27 lambs were fed the former diet for 35 days until reaching a weight of 35 kg. Upon reaching this group, an average of 35 kg dietary restriction was applied.The feed restriction period for both groups was 30 and 35 kg for 35 days. Then the 30 kg group for 49 days and the 35 kg group for 28 days until the end of the fattening period were re-fed the control diet (fattening ration without restriction and ad libitum). At the end of experiment, daily weight gain, final weight, feed conversion ratio, feed efficiency and feed intake were calculated and then three lambs were slathered from each treatment. Carcass characteristics were calculated with the cost of production per kg of weight gain, carcass and lean meat. Analysis were done by repeated measurements basis on a completely randomized design with a mixed model procedure. Comparison of mean treatments was performed by Tukey test. The statistical model was as follows:Yijk= μ + Ti+ Dk + Aij+ (T*D)ik + εijk.

The results of Table 2 showed that the effect of the experimental diets had no significant effect on all the traits of lambs weighing 30 and 35 kg over the pre-feed restriction period. Results showed that there were significant difference between the final weight of lambs at the end of feed restriction period (P<0.05). At the end of the re-feeding, no significant differences were observed among the control treatment (30 and 35kg) with 60 and 80% feed restriction groups. In the present study, at the beginning of the re-feeding period in the respective treatments, the daily weight gain in the feed restriction treatments was significantly higher than the control groups at 30 and 35 kg. There were significant difference among intake dry matter of lambs at the end of feed restriction period (P<0.05). At the end of compensatory growth, there was observed no significant difference between control and restriction groups. During the re-feeding period, feed conversion ratio was lower in feed restriction treatments compared to control treatment (30 and 35 kg). Compensated feeding reduced FCR in lambs with prior feed restriction compared to control. The results showed that feed efficiency and feed intake needed to maintain live weight are affected by the animal feeding program. Results of physical composition of carcass during re-feeding showed that the average of most carcass traits in the control treatment (30 and 35kg) and 80% of feed restriction treatment for 30kg lambs had no significant difference and were higher than other groups. Also in the compensatory growth experiment, there was no significant difference between the number of empty body weight, hot carcass and cold carcass weight sa well as dressing percentage due to no difference in the final live weight between the 30 and 35 kg control groups with 80% feed intake. Another study in other ruminants was consistent with feed restriction and compensatory growth.Meanwhile, the fat tail weight and percentage and total carcass fat were higher in the control treatment (30 and 35kg) than in all control groups. The results showed that the percentage of carcass lean meat in the compensatory groups was higher than the control treatments. This study showed that lambs with 80% feed restriction for 30kg lambs due to higher weight gain and FCR were more favorable in terms of fattening condition than control lambs who consumed feed during whole period. Also, this treatment was the total carcass fat percentage lower and lean meat higher and ultimately, the production costs per kg carcass and lean meat were lower than other treatments.

This study was conducted to register and introduce the biometric indicators of the Zel sheep on some flock of stockbreeder who were inhabit Mazandaran villages. The live weight, body biometric, milk and its composition, and fleece of 200 ewes and 20 rams was recorded during one year randomly. Based on results of ewe biometric traits, these values were recorded; live weight 33.8±4.78 kg, chest circumference 82.6±7.01 cm, body length 41.4±3.76 cm, body height 63.8±4.69 cm, and tail 24.5±4.02 cm. the values of milk daily quantity, fat, protein, and lactose were 700±170.3, 4.3±1.56, 4.9±0.59, and 4.7±0.49 respectively. The recorded traits of ewe fleece weight, staple, diameter and efficiency were; 1700±0.30 gr, 10±2.33 cm, 34.7±2.68 mic, and 64.2±5.78 percent. The lambs birth weight, weaning weight, and daily gain weight to weaning for male and female mean, were 2.9 kg, 13.100 kg, and 130 gr respectively. The live weight, chest circumference, body length, body height, and tail length of Rams were 6505 kg, 88, 50.5, 65.4 and 22 cm respectively.

The present study aimed to determine the proper weaning age of Zel lambs. For this purpose, ninety male and female lambs (average live body weight =2.57±0.41 kg) selected and were divided into three groups (each group = 30). The experimental treatments were; 1. weaning at an average age of 60 days, 2. 75 days, or 3. 90 days. The lambs were introduced to fattening program and were fed with iso-energetics and iso-nitrogenous diets until 6 months of age. The dam’s ewe of all groups enters to mating program two months after parturition and ewe lambing data contain dam’s weight, lamb’s mortality, litter size, lamb’s birth weight, and sex were recorded. Results showed that dry matter intake (DMI) and feed conversion ratio (FCR) did not affect by weaning age of lambs. The lambs that weaned at 60 days old, had higher average daily gain (ADG) at fattening period, then lambs were weaned at 75 and 90 days old, significantly. The parturition rate, prolificacy rate, lambing rate, and litter size of groups weaned at 60, 75, and 90 days of age were 88, 81, and 85; 119, 118, and 117; 104, 96, and 100; and 19, 18, and 17% respectively, and did not observed significant between the treatments. It concluded that Zel lambs weaned at 60 days old, could increase growth performance compared to elder lambs, and improves the reproductive performance of ewe.

The present study was undertaken to investigate the effects of dietary substitution of corn silage on dry matter intake, production and reproductive performance, and nutrient digestibility of Mahabadi lactating goats. In this case, a total of twenty pregnant female goats with 2-5 years old were selected and attributed into two groups of ten goats regarding to age, weight and the numbers of calving. The experiment was done based on completely randomized design. Experimental treatments consisted of diet control and dietary substitution of forage part with corn silage at 20 percentage of dry matter. The ratios of concentrate to forage in diet were 45 to 55 and 57 to 43 in pregnancy and lactation periods, respectively. Results showed that dietary inclusion of corn silage had no significant effects (P>0.05) on body weight and metabolic body weight alterations in pregnancy and lactation periods. Feeding corn silage didn't affect (P>0.05) daily and metabolic feed intake in both pregnancy and lactation times, colostrum and daily milk production, reproductive parameters of goats, and kids weight. Feeding silage corn silage in diet led to significant increases (P<0.05) in organic, organic in dry matter, and crude protein digestibility and tended (P=0.09) to increase in neutral detergent fiber digestibility. In general, results indicated that dietary inclusion of corn silage not only had no adverse effects on reproductive performance of pregnant goats, but also it could improve nutrient digestibility of Mahabadi lactating goats.

This study was conducted to investigate the effect of canola seed (raw and roasted) and diet concentrate levels on growth performance and quantitative and qualitative characteristics of carcass of Lori male lambs. A total of 54 male 30±0.86kg lambs were selected for the experiment. Treatments consisted of two levels of canola seed (raw and roasted) and three levels of concentrate (60, 70 and 80%). The experiment was conducted as factorial with completely randomized design (2 × 3) with three replicates (each replicate containing 3 lambs). The effect of canola seed (raw and roasted) and diet concentrate level on weight gain and feed conversion ratio were significant (P<0.05). The most daily gain and the bet feed conversion ratio were 230g and 5.52 in lambs fed with roasted canola seed and 70% concentrate, respectively.  The canola seed (raw and roasted) and diet concentrate had a significant effect on lean meat percentage, total carcass fat percentage and cold and hot carcass percentage (P<0.05). The highest carcass yield, cold carcass weight, carcass and meat percentage were related to lamb fed with roasted canola seed and 70% concentrate (P<0.05). The production cost per kg of live weight, cost per kg of carcass and lean meat in lambs fed roasted canola seed and 70% concentrate were lower than other treatments. The results showed that the qualitative characteristics including pH, chemical composition and color of meat were not affected by diets.  The results of this study showed that the treatment of roasted canola seeds and 70% concentrate was superior to other treatments due to higher performance characteristics and better carcass traits.

Compensatory growth is the overweight that is achieved by providing the animal with access to adequate food after a period of nutritional restriction. Therefore, a livestock that is affected by a period of feed restriction after re-feeding, especially at the beginning of this period, has less maintenance requirements compared to a livestock that has not been affected by the feed restriction period. Considering the feedlot of 320,000 fattening lambs in Lorestan province per year and the possibility of using feed restriction to promote the use of compensatory growth in lamb fattening, the project was carried out aims to investigate the possibility of process changing the growth rate, fattening and physical and chemical composition of carcass lambs Lori breed by short-term strategies of feed restriction.

Twenty male Lori lambs with a mean live weight of 30±1.45 kg were selected for the experiment. The four experimental diets included 1) the control group (fattening diet without restriction and ad libitum); 2) 80% ad libitum group 3) 70% ad libitum group 4) 60% ad libitum group. At the end of experiment, daily weight gain, final weight, feed conversion ratio, feed efficiency and feed intake were calculated and then three lambs were slathered from each treatment. Carcass characteristics were calculated with the cost of production per kg of weight gain, carcass and lean meat. Percentage of dry matter, ash, crude fat and crude protein were determined for meat chemical composition. Performance data, carcass traits and chemical composition of carcass were completely randomized design with four replications (each replication including six lambs and three for carcass traits and carcass chemical composition) by analysis of covariance means of mixed model procedure. Comparison of mean treatments was performed by Tukey test.

Results showed that there were significant difference between the final weight of lambs at the end of feed restriction period (p < 0.05). At the end of the re-feeding, no significant differences were observed among the control treatment with 70% and 80% feed restriction groups (P>0.05). There were significant difference among intake dry matter of lambs at the end of feed restriction period (p < 0.05). At the end of compensatory growth, no significant difference was observed between control and restraint groups. During the re-feeding period, feed conversion ratio was lower in feed restraint treatments compared to control treatment. Feed efficiency was similar to feed conversion during feed restriction and re-feeding period in the experimental groups. Results of physical composition of carcass during re-feeding showed that the average of most carcass traits in control and 80% of feed restriction treatments had no significant difference and were higher than 70 and 60% of feed restriction. Meanwhile, the fat tail weight and percentage and total carcass fat were higher in the control group than in all control groups. The results showed that the percentage of cold carcass lean meat in the compensatory groups was higher than the control treatment. Percentage of carcass chemicals in feed restriction period showed that dry matter, percentage of crude protein and fat in control treatment were higher than feed restriction treatments and there were significant difference among treatments (P <0.05). The percentage of crude protein in the re-feeding period was higher than the control group.

This study showed that lambs with 80% restriction of feed due to higher weight gain, feed conversion ratio were more favorable in terms of fattening condition than control lambs who consumed feed during whole period. Also, this treatment was the total carcass fat percentage lower and lean meat higher and ultimately, the production costs per kg carcass and lean meat were lower than other treatments.