نوع مقاله : مقاله پژوهشی
نویسندگان
1 بخش علوم دامی ، دانشکده کشاورزی، دانشگاه صنعتی اصفهان، اصفهان،ایران
2 بخش علوم دامی ، دانشکده کشاورزی، دانشگاه صنعتی اصفهان، اصفهان، ایران.
3 بخش علوم دامی، دانشکده کشاورزی، دانشگاه صنعتی اصفهان، اصفهان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The objective of this study was to assess the substitution of different levels of date palm leaves for conventional forages sources based on undigested forage neutral detergent fibers at 24 hours (24 uNDF) in feedlot lambs. Twenty-four male Afshari lambs (average age of 3 to 4 months and body weight 33±3 kg) were assigned to 3 experimental treatments: 1) Diet containing alfalfa hay and wheat straw with no date palm leaves, 2) 50% substitution of the forages with date palm leaves, and 3) 100% substitution of the forages with date palm leaves. The results showed that the NDF degradability at 24 and 288 h of ruminal incubation of date palm leaves was lower than that of wheat straw and alfalfa hay. Eating time, rumination time, and total chewing time were unaffected by the treatments. Feeding date palm leaves did not change DM digestibility, but fiber digestibility decreased linearly with increasing the level of date palm leaves. Moreover, rumen pH, ammonia nitrogen and blood metabolites were not affected by the treatments. The results showed that feed intake, average daily gain and final weight were similar among the treatments. However, feed conversion ratio tended to decrease with the increasing the level of date palm leaves in the diet. Overall, date palm leaves can be used as the only forage source in the diet of fattening lambs when conventional forage are deficient in dry area such as the south eastern regions of Iran
کلیدواژهها [English]
Extended Abstract
Introduction and Objectives
The major cost of livestock rearing, especially feedlot lambs, is related to feed. In dry areas and in the years of low rainfall, the supply of livestock feeds, in particular forage resources, is not only scarce, but also the provision of forage from other areas is limited due to the high cost of transportation and processing of forage feeds. Therefore, it is essential to find local alternative sources such as agricultural residues that could improve the economic rearing of animals. One of the agricultural residues in the south and southeast of Iran including Sistan and Baluchistan, Bandar Abbas, Bushehr and Kerman provinces are date palm branch. Currently, about 200 thousand hectares of lands in 11 provinces of the country are under date tree cultivation and development. Every year, some old palm leaves (12-15 fronds) are pruned from the trees under normal growth conditions. The palm branch consists of a hard petiole and a large number of leaflets which have low nutritional value because of high lignin content and low digestibility. Therefore, the feeding of date palm leaves, especially high-yielding animals, decreases feed intake and performance. Locally, the farm evidence indicates that if date palms leaves are finely chopped, then the animal will consume it well. Therefore, the objective of this study was to assess the substitution of different levels of date palm leaves for conventional forages sources (straw and alfalfa) based on undigested forage neutral detergent fibers within 24 hours (24fuNDF) on performance, digestibility and feeding behavior of feedlot lambs.
Material and Methods
Twenty-four male Afshari lambs (body weight 33±3 kg) were used in this study. Before the initiation of the experiment, all lambs were administered for enterotoxaemia vaccine and anthelmintic (ivermectin) and vitamin AD3E twice. After that, animals were assigned to 3 experimental treatments in a completely randomized design for a period of 60 days; The experimental treatments included different proportions of alfalfa hay and wheat straw to date palm leaves based on fuNDF24 as follow: 1) Diet containing 25% alfalfa hay and wheat straw with no date palm leaves (0% date palm leaves), 2) 50% substitution of the forages with date palm leaves (50% date palm leaves), and 3) 100% substitution of the forages with date palm leaves (100% date palm leaves). The diets were balanced based on fuNDF24 resulting in forage: concentrate ratio of 75: 25, 22.5: 77.5 and 19:81 for diets containing 0%, 50% and 100% date palm leaves, respectively. the level of energy, protein, neutral detergent fiber remained constant, but the amount of peNDF <8mm decreased and that of peNDF <1.18mm increased with increasing dietary date palm leaves. Alfalfa hay (theoretical length of cut 20 mm), wheat straw (theoretical length of cut 15 mm) and date palm leaves (theoretical length of cut 8 mm) were chopped using commercial forage grinder. The geometric mean particle size of date palm leaves was smaller than that of wheat straw and alfalfa hay (3.7 mm compared to 8.1 and 4.4 mm, respectively). Rumen degradability, feed intake, body weight, sorting index, chewing activity (eating and ruminating), blood metabolites, rumen pH and ammonia nitrogen were measured. The experimental data were analyzed using mixed procedure of SAS.
Results
The results showed that neutral detergent fiber digestibility at 24 and 288 h of ruminal incubation of date palm leaves (13.3%) was lower than that of wheat straw (25.1%) and alfalfa hay (33.4%). On the contrary, uNDF24 and uNDF288 (DM basis) of date palm leaves (86.7% and 68.1%, respectively) were lower compared to wheat straw (74.9% and 37.5%, respectively) or alfalfa hay (66.6% and 29.3%respectively). There was no difference across treatments for sorting index of long particles (19 and 8 mm). However, the sorting index was increased for short (1.18-8 mm) and fine (<1.18 mm) with increasing date palm leaves. Eating time (155 min/day) and rumination (269 min/day) and rates were unaffected by the treatments. Feeding date palm leaves did not change dry matter digestibility (59.4%), but decreased linearly fiber digestibility with the increase the level of date palm leaves (from 33.8% to 23.8%). Moreover, rumen pH (6.33), ammonia nitrogen (7.17 mg/100 ml) and blood metabolites were not affected by the treatments. Feed intake (2.16 kg/day), daily weight gain (293 g/day) and final weight (51.5 kg) were similar among the treatments. However, feed conversion ratio tended to decrease (7.93, 7.13 and 7.03 for diets substituted 0, 50 and 100% of forage with date palm leaves, respectively) and the economic efficiency was enhanced with the increasing the level of date palm leaves.
Conclusion
Overall, the use date palm leaves as forage source in high concentrate diet had no adverse effect on feed intake, performance, rumen fermentation or chewing activity and feeding behavior. Therefore, considering the reduced feed cost and the improvement of economic efficiency, it can be suggested to use high concentrate diets with date palm leaves without other forage for fattening lambs. This feeding strategy can potentially restore forage sources and sustain farming livelihoods under dry climate of the southern regions of the country.
This article contains all the data that were created or evaluated during the research.
The authors would like to sincerely thank the members of the Faculty of Animal Sciences, Isfahan University of Technology Research Council for the approval and support of this research.
The author declares no conflict of interest
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