نشریه علوم دامی (پژوهش و سازندگی)
پیاپی 145 (زمستان 1403)

This study aimed to investigate the effects of human resource training on improving production index of broiler farms in Ardabil province. Initially, out of 418 active broiler farms, the status of 50 farms was examined at the provincial level. The production units were divided into the following groups based on production index and using cluster analysis: group 1 (production index equivalent to 250), group 2 (production index less than 250 and greater than 200), group 3 (production index less than 275 and greater than 250), group 4 (production index less than 300 and greater than 275), and group 5 (production index greater than 300). Subsequently, these groups were trained in both face-to-face and non-face-to-face formats during the production period. In this process, factors affecting production index were also evaluated, and existing issues were examined in each trained farm. Finally, the obtained data were compared with the current conditions using paired t-test. The results of this study indicated that in groups with production index less than 250, training significantly increased feed conversion ratio by 7% and production index by 14% (p<0.05). However, in the group with a production index above 300, a less significant impact was observed on slaughter weight and production index (p<0.05). Overall, human resource training had a greater effectiveness in improving production index in low-performing units.

This research was designed to compare the effect of processing corn silage, and barley and corn grains on feed intake, digestibility and rumen parameters in sheep. Eight Kermani lambs were used with average weight of 53.2±4.1 kg. The experiment was carried out as 2×2 factorial design in the form of a Latin square design in four periods of 21 days. A part of chopped corn forage was processed. Silages were prepared from processed and unprocessed forage in nylon bags. The experimental diets were 1. Diet with 30% processed silage with barley grain, 2 .Diet with 30% processed silage with corn grain, 3. Diet with unprocessed silage with Barley grain and 4. Diet with unprocessed silage with corn grain. Physical processing of corn forage increased the pH of silage, but the sensory evaluation score decreased (P=0.01). The dry matter (DM) intake was higher in diets containing processed silage (1.96 vs 1.82 kg, P<0.04). The digestibility of organic matter (OM) was higher in the corn grain diet and the diet with processed silage. The feed intake and the rumen pH levels were lower in processed silage diets and ammonia nitrogen concentration was lower in the processed silage with barley grain diet (P<0.05) eight hours after feeding. The time of feed intake and rumination were higher in unprocessed silage diets. In general, the processing of corn forage increased the DM intake and increased the OM and protein digestibility in sheep. The effect of grain types on animal responses was less than processing levels.

This study was conducted with the aim of investigating the use of different levels of wheat distillers dried grains with solubles (WDDGS) in feed with or without enzymes on performance, intestinal morphology and ileal digestibility of broiler chickens. For this purpose, 300 pieces of one-day-old male and female broilers of Ross 308 strain with an average one-day weight of 42 grams were used. This design was implemented as a factorial 3x2 in the form of a completely randomized design with 6 treatments and 5 replications. The experimental diets included three levels of WDDGS (0, 10 and 20%) with and without enzyme (125g per ton). The results showed that the use of 20% WDDGS reduced the feed consumption of the final period and the average of the entire period compared to the control treatment (P<0.05). The use of 10 and 20% WDDGS in the diet of broilers decreased the digestibility of dry matter compared to the treatment without WDDGS. Also, the 20% level of WDDGS reduced protein digestibility compared to the 10% level. The use of enzyme also increased protein digestibility significantly (P<0.05). Also, broiler chickens fed with a diet containing 20% WDDGS had lower hair height and greater crypt depth than the treatment without WDDGS, but the use of enzyme caused hair height. Finally, it can be concluded that the use of 10% level of WDDGS does not have a negative effect on performance.

This research was conducted with the aim of comparing two types of hormones produced internally and externally and the conventional method in the region in order to improve reproductive performance. In this study, 75 adult ewes were classified based on weight and age then were divided into three groups: control treatment-Conventional system, Second and third treatment from 25th March until 6th June, non-breeding season mating with ovulation simulation was performed with using progesterone treatment (CIDR) and injection of 400-IU eCG and progesterone treatment (CIDR) and injection of 500-IU hCG respectively. Data on parturition date, the number and weight of borned and weaned lambs were recorded. Pregnancy rate, prolificacy rate, litter size, fecundity rate, borned lamb crop and weaned lamb crop and viability rate were calculated. Data analysis was performed with using SAS software. The results showed that synchronization and stimulation of ovulation in two experimental treatments in terms of parturition rate, pregnancy rate, fecundity rate, weaning rate, Borned lamb crop and weaned lamb crop had better performance compared to the control group. (p<0.05). Net income from the two treatment groups was higher during one and a half years compared to the control group. Also, there was no significant difference between the two types of internal and international hormones in terms of performance (p<0.05). According to the results, It was found that hCG hormone can be used as a suitable substitute for eCG hormone in implementing reproductive management method to lambing concentration within a certain period of year

This study was carried out to investigate the effect of different levels of probiotics and barley on egg quality and quantity, microbial population, intestinal morphology, immune response, and some blood parameters of Japanese laying quails. The experiment was conducted as a factorial 2x2 in the using 200 pieces of Japanese laying quail from the age of 45 days with 4 treatments, 5 repetitions, and 10 birds per repetition for 8 weeks. The experimental rations included two levels of barley (zero and 10%) and two levels of probiotics (zero and 150 g/ton). The addition of probiotics increased the amount of Haugh units and albumin percentage of quail eggs, and the addition of barley increased the amount of Haugh units . Quails fed with barley and probiotics showed higher egg weight and percentage of production, respectively . The height of the intestinal villi was lower at the level of 10% barley .The height and amount of the Lactobacillus population were higher and the crypt depth and Escherichia coli population was lower in the ileum of quails supplemented with probiotics . Based on the results of this research, adding probiotics to diets containing barley improved the percentage of egg production, HDL, and the number of Lactobacillus bacteria, and reduced serum cholesterol, the number of Escherichia coli bacteria, and the depth of intestinal ileum crypt. It can be suggested that supplementing 10% barley along with 150 grams of probiotics per ton of feed has beneficial effects on the performance of laying quails.

In this study, the effect of adding a mixture of medicinal plants to the diet of lactating ewes on growth performance and antioxidant properties of suckling female lambs was investigated. Twenty-four lactating Roman ewes at first lambing along with 24 female lambs of three to five days old weighing 3.17 ± 0.15 kg were kept in individual pens for 65 days in a completely randomized design. Experimental groups of ewes included: 1-control (basal diet), 2-basal diet + 15g of herbal powder including 60% cumin, 30% coriander and 10% peppermint, 3-basal diet + 15g of herbal powder including 45% cumin, 45% coriander and 10% peppermint and 4-basal diet + 15g of herbal powder including 30% cumin, 60% coriander and 10% peppermint. Lambs were weighed every two weeks and, blood was taken from the lamb's jugular vein at the end of experiment. The final weight (21.64 vs. 16.89 kg) and ADG (276.67 vs. 211 g) of lambs in second treatment were higher (P<0.05) than the control. The RDW in the second and third treatments was lower than that of control. The blood total antioxidant capacity of lambs in the second treatment was higher (P<0.05) than control (0.09 vs. 0.04 mmol/l). Incorporation a mixture of cumin, coriander and peppermint in proportions of 60, 30 and 10%, respectively, to the diet of lactating ewes improved the ADG and blood total antioxidant capacity of female suckling lambs, and no adverse effects were observed on hematology and blood parameters

In the present study, a total of 336 one-day-old broiler chickens (Ross 308 strain) were used in a completely randomized design with four treatments to evaluate the effects of barley rootlets (BR) as a feedstuff in broiler nutrition. Dietary treatments consisted of a control group based on corn and soybean meal, along with three additional treatments, similar to the control but including 1.5, 3.0, and 4.5% BR. Feeding diets containing BR impaired broiler growth performance as reflected in poor feed conversion ratio and body weight gain. Inclusion of BR at 4.5% significantly increased digesta viscosity in jejunum and reduced the villus height to crypt depth ratio with concomitant increase in the moisture content of the litter. In conclusion, the use of BR can be limited up to 1.5% and the levels above that impair broiler response. Poor growth performance resulting from BR was associated with reduced feed consumption, increased viscosity of intestinal contents, and reduced villus height to crypt depth ratio. Levels of BR above 4.5% caused poor litter quality as indicated by higher moisture content in the litter.

This study aimed to determine the effect of adding different levels of pistachio peeling residues (PPR) on chemical composition, in vitro fermentation characteristics, and gas production components of total mixed ration silage (TMRS). The rations were prepared by mixing 60% fodder material (alfalfa, straw, and corn silage) and 40% concentrate based on dry matter (DM) with four levels of PPR (0%, 5%, 10%, and 15%) and ensiled in two-liter containers for evaluation and sampling at three times interval (30, 45, and 60 days). Silage characteristics, chemical composition, fermentability (by gas test), NH3-N concentration, lactic acid, and ME of the samples were measured. Data was statistically analyzed using of a completely randomized experiment for each period of time. Results showed that using of 15% PPR in TMRS decreased DM, OM, NDF, ADF, NH3-N, and lactic acid content significantly (P<0.05). However, pH, ash, EE, and ME were increased by adding different levels of PPR in TMRS (P<0.05). Additionally, TMRS without PPR had the highest sensory evaluation compared to other silages (P<0.05). Gas production and in vitro apparent DM digestibility decrease in 45 days after ensiling by adding PPR to TMRS (P<0.05). Based on the results, it is possible to use up to 10% of the PPR in TMRS.

In this study thity-two new-born Holstein male and female calves (3-d-old) were randomly assigned to one of four treatments: 1) feeding whole milk (HM) in 2 times/d (2×; HM-2×), 2) feeding HM in 3 times/d (3×; HM-3×), 3) feeding waste milk (WM) in 2× (WM-2×); and 4) feeding WM in 3× (WM-3×). The lowest starter dry matter (DM) intake (pre-weaning and entire period), total DM intake and the highest average daily gain (ADG; post-weaning and entire period) and feed efficiency (FE) were was observed in WM-3× calves compared to other groups (P<0.05). Calves in WM-3× group had the highest hip height (weaning and the end of experiment), body weight (BW; the end of experiment) and body length (weaning and the end of experiment) compared to other groups (P<0.05). Based on the conditions of the present study, it can be concluded that feeding HM at 3× improved Holstein Dairy calves. Further researches are needed to evaluate these findings.

This research aimed to assess the effect of feeding Salicornia bigelovii fodder on the growth and carcass performance of fattening lambs. The experiment was conducted using 63 male Afshari lambs in a completely randomized design with seven treatments and nine replications for 100 days. The treatments were diet without Salicornia (control) and diets containing levels of 45, 90, 135, 180, 225, and 270 g Salicornia, instead of alfalfa/kg DM. Compared to alfalfa, Salicornia contained lower amounts of protein, nitrate, and neutral detergent fiber (NDF), but higher content of ash, sodium, oxalate, and phenolic compounds. Feeding increasing levels of Salicornia caused a linear increase in daily water consumption (P<0.05). Daily intake of DM increased with increasing Salicornia levels (P=0.05), but consumption of organic matter (OM) and crude protein did not differ. Salicornia feeding had no significant effect on daily growth and feed conversion based on diet OM, but at levels of 135 g and more, it caused a decrease in feed conversion based on diet DM. Digestibility of DM (P=0.072) and ash (P=0.012) increased and NDF digestibility decreased (P=0.048) with increasing Salicornia consumption, but the digestibility of OM, crude protein and ether extract, and carcass yield did not change. Overall, feeding Salicornia up to 270 g/kg diet DM (with a forage-to-concentrate ratio of 40:60) increased the water consumption of animals, but it did not have a negative effect on the performance of fattening lambs, and it can be recommended to replace a portion of the diet forage in male Afshari sheep.

This study was conducted in order to investigate the effect of replacing soybean meal and cottonseed meal with mixed meal on performance, digestibility of nutrients, feed intake behavior, milk composition and blood parameters of Dalagh ewes. 21 lactating Dalagh ewes in week 6 of lactation (average body weight ± standard deviation = 38±2.6 kg) were randomly divided into 3 groups with 7 repetitions. The treatments were included: diet with soybean meal, diet with cottonseed meal and diet with mixed meal. The results showed that there is no significant difference between the experimental treatments in the final weight, daily weight gain and feed conversion rate of ewes. Dry matter intake and eating, rumination and chewing behavior increased in the treatment receiving mixed meal (P<0.05). In the treatment receiving mixed meal, a significant increase was observed in the amounts of daily milk production, non-fat solids and milk protein compared to the treatments receiving soybean meal and cottonseed meal (P<0.05). The digestibility of dry matter, organic matter and crude protein increased in the treatment receiving mixed meal (P<0.05), but the digestibility of NDF was not affected by the experimental treatments. No significant difference was observed in terms of glucose, cholesterol, triglyceride, total protein, albumin and globulin between different treatments, but the concentration of blood urea nitrogen in the treatments receiving soybean meal and cottonseed meal was higher than the treatment receiving mixed meal (P<0.05). According to results, mixed meal can be replaced with soybean meal and cottonseed meal in Dalagh ewe's diet.

Dietary protein plays an important role in ruminant nutrition, because in addition to providing amino acids, it’s a nitrogen source for microbial protein synthesis. Providing protein, especially for high-producing livestock, is one of the most important concerns of livestock farmers. Soybean meal has been used for a long time as an excellent source of CP for ruminants, but with the increase in its price, has challenge due to the limitation of production and direct consumption by humans. Due to the ability of ruminants to use NPN (urea), nitrogen unit density and its low price, it has been used as an alternative in ruminant diets. Urea is converted into ammonia in the rumen, on the other hand, fiber-digesting bacteria in the rumen need ammonia to growth. Hydrolysis of common urea is faster than the growth of microbes and the digestion of structural carbohydrates in the rumen, so it will reduce the efficiency of nitrogen use and even nitrogen poisoning in livestock. Slow-release urea (SRU) is a type of urea that slows release of nitrogen in the rumen. Substitution of SRU instead of common urea in the diet of ruminants that have a limit with protein sources can reduce the competition between humans and animals. Also, it will not have the dangers of common urea for livestock. This article review the effects of using SRU instead of common urea and plant protein sources in ruminants diet on feed intake, digestibility, fermentation parameters, growth and production, blood parameters and carcass characteristics.