نوع مقاله : مقاله پژوهشی
نویسندگان
1 بخش تحقیقات علوم دامی مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان زنجان
2 گروه علوم دامی دانشکده کشاورزی دانشگاه زنجان
3 بخش تحقیقات تغذیه و فیزیولوژی مؤسسه تحقیقات علوم دامی کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی
4 بخش تحقیقات گیاهپزشکی مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان کرمانشاه، سازمان تحقیقات، آموزش و ترویج کشاورزی
5 گروه فیزیولوژی و فارماکولوژی دانشکده پزشکی دانشگاه علوم پزشکی زنجان
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Introduction: Lamb fatteners receive less benefit due to unawareness regarding the suitable methods of fattenering. As it is conventional in broiler breeding, the diet of pre-starter contains high levels of protein and energy, which is specified to freshly hatched chicks and it decreases the number of days between hatching and slaughter day every year. Therefore, the same method can be tested in newborn lambs, meaning that the lamb receives the whole mother's milk and the initial diet, which is referred to creep feeds. The creep feed contains at least 15 percent crude protein and breeding lambs immediately after birth, with receiving a diet either rich in metabolizable protein or low metabolizable protein with a lysine amino acid and a rumen-protected methionine. This may be substituted with the conventional method of feeding lamb via whole mother's milk, alfalfa and Rangeland forage and then, fed in an intensive system under Iranian conditions. The present research was designed and conducted to economically compare the conventional method with creep feeding method in Afshari lambs, and to investigate the possibility of shortening the time from birth to slaughter. Production of meat with high quality and quantity without increasing the number of livestock and gaining an appropriate profit in the short term is one of the main goals of the fattening industry. The cost of livestock feeds supply is about 65-70% of the costs of raising and maintaining. If these costs are reduced in a period of fattening, in addition to producing meat with a good quantity and quality, more income will be also earned by the livestock owner (Farzad 1996; Talebi and Edriss 1999; Mousavi et al. 2005, 2011). Improving human living standards, reducing physical activity and changing food habits have led to a reduction in tail fat consumption and a rise in demand for meat. Also, if low-fat and low-fat sheep are produced, improving the nutritional efficiency will increase the economic efficiency of fattening units (Talebi 1998), so that the livestock fed in the lower ages will have better food efficiency (Hasanpour 1965; Mousavi et al. 2005, 2011). Choosing the appropriate fattening method will reduce the starting age, longevity and cost of rearing lamb and leaving livestock out of the pasture, which will lead to a rapid return of payments and improvement of investment in the sheep industry, reduced overgrazing and preventing soil erosion and flood damage. Due to the advancement of ruminant nutrition science in recent years, it is possible to start fattenning at a young age. Then, the use of creeping rations is associated with a change in the composition of the diet, especially metabolizable protein; as a result, growth, daily weight gain, and feed efficiency are increased and carcass compositions may have more meat. The goal of this study was to select an appropriate Fattening system that would provide greater economic returns through a higher percentage of meat, less feed, and reduced lamb's longevity. Choosing the appropriate procedure of feedlot and deliver the lambs to slaughter weight in the possible shortest time reduces the cost of livestock and There was an additional livestock departure from the pasture.
Material and methods: 51 male lambs of Afshari were used in an unbalanced completely randomized design with 4 treatments included: treatment 1: Milk + alfalfa + pasture (conventional control without fattening as semi-intensive farming or CONT-UF ), treatment 2: Milk + alfalfa + pasture then get a fattening diet ( conventional control with fattening as semi-intensive farming or CONT-F ), treatment 3: milk + creep feeding ( included high protein metabolism as intensive farming or HMP), and treatment 4: milk + creep feeding (including low protein metabolism with lysine and methionine rumen protected as intensive farming or LMP +LMRP).
Results and discussion: The effect of creep feeding on average daily gain of lambs was significant (p=0.0001), (Table 2) Which was consistent with the results of others (Karim et al. 2001; Moriel and Arthington 2013; Yiakoulaki et al. 2007; Lardy and Maddock 2007). The reason for the increase in daily weight gain at an early age is due to the higher growth rate of the animal early in life, which is justified by growth curves that are consistent with the goal of experimenting with early onset of slaughter and slaughter at an early age. The low daily gain was due to the non-fattening control treatment, but it was fattened in the control treatment because fattening started at 5 months of age and the daily gain was lower at high ages. Reduced protein intake and amino acids intake and no effect on body weight changes were observed in creep diets, whereas in Abdelrahman and Hunaiti (2007), Purchas et al (1998) and Yousefian et al (2013) studies, weight gain was observed but in the experiment, Heydari et al (2014) reduced yield. Dry matter intake among the treatments was statistically significant and the highest rate was found in the fattening control (p=0.0001), (Table 2) Which is consistent with the results of other researchers (Eilami 1995; Eilami 2005; Kianzad 1993). The amount of dry matter consumed depends on the body weight of the animal as the age of the animal increases and consequently body weight increases feed intake in this experiment as slaughter age varies so the amount of consumption depends on the life of the animal and in creep treatments due to nutrient availability. As well as increased feed efficiency at an early age, the amount of dry matter consumed was low, whereas this was not the case for the control treatments because the dry matter consumed before the beginning of the feed was used to maintain low weight gain. FCR in the fattening and non-fattening controls increased significantly and recorded the highest amount in the fattened control (p=0.0001), (Table 2) This is in agreement with the results of other researchers (Eilami 1995; Eilami 2005; Kianzad 1993). The conversion factor is a function of the amount of feed consumed to increase body weight, which is an increase in the feed conversion ratio with increasing age of the animal due to the type of animal body stored so that as the age of the animal increases, the amount of fat stored in the protein increases and the cost of increasing each gram of fat tissue increases. Compared to the cost of increasing every gram of muscle tissue, this increases the conversion factor. Carcass effiency was reduced significantly in the non-fattening control (p=0.0001), (Table 3) While in the creep treatments, even at a young age, carcass yield had a higher number, indicating greater growth of organs, but no significant difference was observed between creep and fattening treatments. The greatest benefit was observed in LMP + LMRP treatment and loss was observed in CONT-F treatment (P = 0.0001), (Table 4) Since the fattened control treatment had a life span of 260 days and the other treatments reached the kill weight in the shortest time.
Conclusion: Baesd on the economic calculations, LMP+LMRP treatment was determined as a better method for finishing lambs.
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