ABSTRACT
Twenty four male lambs divided into four groups and were allocated to 90, 105, 120 and 135 days of fattening periods. At the end of each fattening period, lambs were slaughtered. The percentage of cold carcass on the basis of empty body weight in the mentioned periods were 57.0 +/- 0.94, 57.5 +/- 1.7, 59.9 +/- 3.3 and 62.2 +/- 4.4, respectively [p < 0.05]. Moreover, the average of subcutaneous and intramuscular fat percentages were 11.2 +/- 1.6, 13.4 +/- 3.2, 15.2 +/- 2.4 and 16.0 +/- 2.4, respectively [p < 0.05]. Average percentages of crude protein, ether extract, ash and moisture showed significant difference among experimental groups [p < 0.01]. Moreover, ratio of weight percentage for large and small intestine, blood, abdominal and kidney fat to empty body weight showed significant difference among groups. [p < 0.01]. Results show that net profit per kilogram live weight gain increases in longer fattening period. Increasing of fattening period cause carcass quality to be reduced. So, the reduction of feed efficiency and carcass quality is not in favor of the national benefits
Subject(s)
Animals , Male , Adipose Tissue , Sheep , Body Weight , EfficiencyABSTRACT
To study the possibility of reducing the carcass fat content through cross breeding of fat- tailed ewe [Zandi] with tailed sheep breed [Zel]. Completely randomized design. 65 Zandi ewes as well as 15 Zandi x Zel ewes and 6 Zandi rams. ANOVA followed by Duncan and chi2 and Man Whitney tests. In order to synchronize estrous, all ewes were treated for 13 days with controlled internal drug releasing device [CIDR] and eCG hormone. In lambing season, 23 pure F1 and backcross [R1] out of 61 lambs were fattend. The fattening period of Zandi pure and crossbred lambs were 90 days. The average daily gain [ADG] of pure F1 and R1 lambs were 165 [+/-11], 156[+/-11] and 162 [+/-11] grams, respectively. The proportion of lean meat [LM,] subcutaneous fat [SCF] and intramuscular fat [IMF] of R1 lambs were higher than the F1 and the values of the recent values were higher than the pure lambs [P<0.001]. The proportion of abdominal fat [ABF] in R1 and F1 lambs were higher and the bone percentage was lower than the pure lambs [P<0.005]. The fat tail proportion in R1, F1 and pure lambs were 3.6, 6.0 and 13.3, respectively. The proportion of body total fat [BTF] [i.e. fat tail+SCF+IMF+ABF] of R1 was higher than the F1 and pure lambs [P<0.005]. The percentages of carcass total fat [CTF] [i.e.fat tail +SCF+IMF] and the proportion of ether extract of R1 lambs were lower than the pure lambs [P<0.005]. Crud protein, moisture and ash of the debonded carcasses between pure and crossbred lambs had not significant difference. Results showed that in crossing Zandi ewes with Zel ram, the proportion of BTF had not decrease. Furthermore, in spite of lower fat tail proportion, fat deposition occurred in the other organs
ABSTRACT
Objective: to study the effect of CIDR on oestrous synchronization and comparison of twining percentage by using eCG and handing diet and their interaction
Design: completely randomized design
Statistical analysis: use of SPSS statistical program for parameter data and X2 and Man- Witny test for non- parameter data
Animals: a total of 69 ewes and 6 rams of Zandi breed
Procedure: sixty-nine Zandi ewes within 2-5 years old and weighting 47.9 [k5.6] Kg, were divided into 3 groups [group I fed in the pasture and two other groups were fed in their pens]. In order to synchronize oestrous cycle, all ewes [in 3 groups] were treated for 13 days with a controlled internal drug-releasing device [CIDR]. On the following day after removing CIDRs, ewes in groups 1 and 2 received an injection of 400 ILT eCG Two Zandi rams were then introduced to each group
Results: the results of the present study indicated that oestrus was induced within 36-48h post CIDR withdrawal in 100, 87 and 96 percentage of ewes in groups 1, 2 and 3 respectively and this differences were not significant. The percentage of parturition was 91, 83 and 87 in groups 1, 2 and 3 respectively and differences were not significant. The percentage of twining [based on ewes lambing] was significantly [P<0.05] lower in the group 3, comparing to groups 1 and 2 [29,37 and 15 in groups 1,2 and 3 respectively]. Male and single born lambs was heavier than female and twinborn lambs [4.2,4.2 and 3.7, 3.5 respectively], but differences were not significant. However, these differences within each group were significant [P<0.05]. The effect weight of dam on the born weight was also significant [P<0.05]
Conclusion: the result of this study indicated that using of synthetic hormone caused length period of pamuition decreased. Also difference of age and weight of lambs are lower. Besides cueing the synthetic hormones caused that percentage of twining increased