General Commission for Scientific Agricultural Research-
Deir Ezzor Research Center
Aleppo University, Faculty of Agriculture
The effect of milking period length and balancing ration protein with Lysin and Methionine on meat production and quality of Awassi lambs was studied.
This research work was carried out at al-Shola Research Station to study the possibility of reducing milking period on mothers’ milk to 5 weeks instead of two months replacing milk with a mixture of plant forages. Also , the effect of balancing ration protein by adding lysine or methionine or both to the concentrated mixture raising percents of these amino acids up to that of sheep milk and then studying effect of these factors on growth, forage consumption rate and changing efficiency.
The effect of the previous factors on production and quality of meat was also studied. All the chemical analyses for the wide forage materials and for samples of meat, fat and liver were done at Aleppo university labs.
The results were statistically analyzed using SAS-6 program. The experiment was done on 60 lambs of Awassi, and all were taken from single bioth of one-day old, making five groups.
Five feeding treatments including: – first group (control) -weaned at the age of two months, whereas the rest groups were gradually weaned right from the fifth week, with giving a starter without supplements to the second group, adding lysine at 1.5 % to the third group, adding methionine at 0.7 % to the fourth group and adding lysine and methionine at 1.5 and 0.7 % respectively, to the fifth group.
Using the starter in feeding all the groups continued up to the end of the experiment, three sheep of 35-45 kg from each group were slain. Each slaughtered was weighed and cut into two parts (front, rear) with weighing the main parts, viz. (fatty tail, bones, fat, mutton), meat and bones percentages were calculated.
Also, the internal parts and the slaughtered muscles (semi -membrane, semi- string, thigh two – head , back long) studying characteristics of the back long muscle, as well.
Chemical analyses for samples of meat and fat (dry matter, fat, ash) were done. The ph in the meat samples was done, iodine number in the fat samples and percent of fat in the liver also carried out.
The results showed insignificant differences in forage consumption rate between the first and second groups, whereas adding amino acids led to increase the forage consumption rate by 7.7, 10.6 and 12.3 % when lysine, methionine and both were added, respectively.
Also, the results indicated that the control was superior to early weaned groups in increasing weight during the second month, but in the third the control group and the second one. However, the difference during the second month became insignificant at the end of the experiment. Adding lysine alone did not show any positive effect, but adding methionine showed an increase in forage consumption rate and improved growth rate. However, this effect did not appear until the third month of age up to the end of the experiment. On the other hand, adding lysin and methionine together led to increase forage consumption rate, growth rate and changing efficiency in the sheep.
The results showed insignificant differences in weight of the internal parts among the experiment groups, except belly fat and kidney fat were increased in unwanted places as result of early weaning, while adding the amino acid reduced this effect and adding both acids together avoided it. Also, the early weaning insignificantly increased the weight of belly in sheep in the same context.
It was found that adding lysine led to increase meat percentage and both acids increased it but at increase meat percentage and both acids increased it but at lower extent, while the early weaning had no effect on the meat percentage, but reduced bone percentage due to increasing weight of the bones as compared to rest of the groups. However, these differences were insignificant. It was also found that the early weaning increased fat accumulation in the slaughtered, whereas adding amin acids reduced fat percent and increased the mutton in the slaughtered. The early weaning and amino acids had no effect on the chemical composition of meat (dry matter, ash, fat) or on the meat ph. At the same time, the early weaning increased the fat percent in the liver, while adding amino acid reduced it with superiority to the rations with methionine. Also, the results indicated that the early weaning reduced the iodire number, while adding amino acids increased it i.e. improving quality of the fat. Regarding the characteristics of the back long muscle, it was found that the early weaning significantly reduced its weight and circum fernce but it significantly increased thickness of the fat layer above while adding amino acids increased weight and circumference of this muscle and reduced thickness of the fat layer above it.
Finally, weights of the slaughtered muscles were not affected by the early weaning or the amino acids, except the three-head muscle that the early weaning reduced its weight and the amino acids increased its weight.