مجله پژوهش در نشخوار کنندگان
سال یازدهم شماره 1 (بهار 1402)

Lower critical temperature for a neonatal dairy calf ranges from 5 to 15°C. As the temperature drops below the calf's lower critical temperature, calf needs more dietary energy to maintain body temperature. If calves are fed the same amount of milk as under moderate environmental conditions, less energy will be available to support growth. In most small and medium holder Iranian farms, dairy calves are usually fed 4 L/d (equivalent to approximately 10% of birth weight) of liquid feed in fixed amounts until they are weaned on 60 d old. The aim of present experiment was to investigate the effect of milk replacer plane of nutrition (restricted vs. moderated; 4 vs. 6 L/d) on starter feed intake patterns, feeding behavior, and health in cold-stressed neonatal Holstein calves.

Twenty-four (n = 12 calf/treatment; 3 d old) newborn female Holstein calves (40.1 ± 0.84 kg; BW ± SE) were randomly assigned to receive either restricted (4 L/d; RPN) or moderated (6 L/d; MPN) milk replacer (21% crude protein, 17% fat, and 43% lactose on a dry matter basis) plane of nutrition. Calves were reared outdoor in individual pens with a mean ambient temperature of 3°C during the experiment. Calves were fed milk replacer twice daily at 0800 and 1700 h in pens bedded with wheat straw. Milk replacer intake, starter feed intake, fecal score (on a 1–5 score system), and ambient temperature were measured daily. All calves were visually observed (every 5 min) to monitor the eating, ruminating, resting, standing, lying, drinking, and non-nutritive oral behaviors for a 8-h period (between 0900 and 1700 h) once per 3 successive d before weaning (d 50–52 of the trial) as well as once per 3 successive d after weaning (d 83–85 of the trial). Repeated-measures ANOVA was used to compare feed intake and feeding behaviors between treatment groups, and logistic regression model using a binomial distribution (PROC GLIMMIX) was used to assess the chance of diarrhea (≥3) and needs to medication before weaning. Poisson regression model (PROC GENMOD) was also used to test group differences in frequency and duration of diarrhea and days medicated before weaning.

Milk replacer dry matter intake and average daily gain were greater in MPN vs. RPN fed calves. Meal pattern including meal frequency (6.0 bouts/8-h), meal length (10.7 min), inter-meal interval (80.1 min), eating rate (14.5 g of starter feed/min), and meal size (154.5 g of starter feed/bout) and rumination pattern including the number of bouts (3.8 bouts/8-h), rumination duration (17.1 min), and interval between rumination bouts (129.2 min) were not affected by treatment groups. Time spent ruminating and time devoted to drinking were greater in MPN vs. RPN calves. Meal frequency, meal length, eating rate, meal size, rumination duration and time for standing were greater but inter-meal interval and time for lying were lower during the post- vs. pre-weaning period. Non-nutritive oral behaviors and diarrhea frequency were not affected by experimental treatments. Calves receiving RPN vs. MPN had lower chance of diarrhea and greater chance of medication. Days with diarrhea and medication days were shorter in RPN vs. MPN fed calves.

Feeding MPN increased average daily gain in cold stressed calves. The lack of significant different in starter intake between experimental treatments was probably due to the lack of difference in the number and size of the meals. Although the calves fed MPN experienced higher chance of diarrhea with longer duration, but the incidence of diarrhea was not affected by the level of milk replacer feeding.

As respects Food processing may increase livestock performance. Today some methods of grain processing have been considered. On the other hand, lack of animal feed, especially with the development of industrial methods of animal husbandry waste in many parts of the world, has led farmers and researchers to think about identifying and using agricultural and livestock waste and new food sources for animal nutrition, including poultry manure. And urea is mentioned in the diet of ruminants. Due to the fact that no research has been done on the effect of barley grain processing methods and non-protein nitrogen sources in the diet on growth performance, nutrient digestibility and carcass characteristics in of Afshari breeding fattening lambs, the present study was conducted.

This experiment was conducted in a completely randomized design with seven treatments including a control treatment containing whole barley grain (without milling) and without urea and chicken manure, treatments 2, 3 and 4 respectively containing processing method of milling, filling and pelleting with a certain level of urea. (1%) And treatments 5, 6 and 7 containing processing methods of milling, filling and pelleting with a certain level of poultry manure (12%) were performed on Afshari breeding fattening lambs. Each treatment consisted of 5 fattening lambs at the age of 3 months 24±1 which were kept individually in separate cages for 14 days of acclimatization period and 84 days of fattening period. Dry matter, ash, crude fiber, crude fat and crude protein were determined using the method (AOAC, 2000), Neutral detergent fiber and Acid detergent fiber based on the method of Van Soest et al (1991). At the end of the rearing period, three heads from each treatment were randomly sacrificed and hot carcass weight and cold carcass weight and its components were measured.

The number of daily feed intakes, daily weight gain and feed conversion ratio were significantly different between experimental treatments. The apparent digestibility of dry matter and organic matter were significantly different, and the control treatment (whole barley grain without urea and poultry manure) had the highest apparent digestibility. Digestibility in non-fibrous carbohydrates was significantly different, so that treatment 5 (processing method of milling with poultry manure) had the highest apparent digestibility. Experimental treatments were significant on thigh weight, neck weight, tail weight, ventricular fat weight, carcass length and half-carcass length.

The results showed that barley grain processing methods with non-protein nitrogen sources had a significant effect on daily weight gain, dry matter consumption, feed conversion ratio, some organs of fattening lambs, digestibility of dry matter, and organic matter compared to the control group. In general, it is possible to use barley grain processing with urea (1%) and poultry manure (12%) in the diet of fattening lambs without harmful effects on production parameters and fattening performance.

Myostatin gene is an inhibitor of skeletal muscle developmentmutations in its coding regionpromotesmuscle growth in some breeds, mutation of the myostatin gene has a significant effect on the increase of the body weight and carcass traits. This study was aimed to investigate the polymorphisms in exon 3 of the myostatin gene and evaluate investigation of body weights and carcass traits measured by ultrasound in Kurdi sheep.

In this study, back fat thickness and loin muscel area traits were measured by ultrasound instrument. Blood samples were collected randomly from 139 Kurdi sheep and following DNA extraction, a 388 bp fragment from exon 3 of myostatin gene was amplified. For genotyping of myostatin gene, PCR-SSCP, PCR-RFLP, and direct sequencing techniques were used. To determine the fixed effects of gender, birth type and birth year on the studied traits, GLM procdure of SAS software was used. Least square means comparison of different fixed effects subclasses was carried out by Tukey-Kramer test at 5% probability level. To measure the relationships between tarits, pearson correlation was used.

In PCR-RFLP technique, after enzymatic digestion of all samples, only one genotype was observed and this locus was monomorphic. PCR-SSCP analysis showed two band patterns A and B, which were very similar in shape. Therefore, to determine the actual genotype, some samples with different band patterns were evaluated by direct sequencing technique. The results showed that there is no polymorphism among samples. The mean ultrasonic fat thickness and loin muscle area in this study were 0.46 cm and 7.78 cm2, respectively, with an average body weight of 43.42 kg at the time of ultrasonography. The correlation between the two ultrasound carcass traits (UBF and UMA) was positive (r=0.84, P<0.0001). The lowest correlation coefficient of carcass fat thickness and ocular muscle area with the studied traits were 0.02 and 0.3, for birth weight and weaning traits, respectively. The highest correlation coefficient of the studied traits with carcass fat thickness and loin muscle area were 0.82 and 0.87 for body weight at the time of ultrasonography and middle tail width, respectively (P=0.001).

In this study, using PCR-SSCP, PCR-RFLP and direct sequencing, only one genotype was detected in the myostatin gene. Considering that various studies have introduced the mutated allele of the myostatin gene as an effective allele on the double muscling for breeding and improving the quality and quantity of meat, the studied herd did not have the allele. Considering the relatively suitable diversity observed in the studied traits, especially the carcass traits measured by ultrasound, there will be a possiblity to improve the traits through selection.

One of the destructive effects of climate change is the reduction of precipitation and global warming which is leading to shortage of water resources. Therefore, it seems necessary to introduce water-resistant plants that are resistant to heat and drought (as sources of new forage plants). In this regard, the cultivation of dehydrated and drought-resistant forage (such as new cultivars of amaranth) was on the agenda. There is little information about the silage formation and nutritional value of forage of new Amaranth cultivars (in hot and humid Golestan province). The aim of this study was to determine the characteristics of silage, fermentability, digestibility, energy and metabolizable forage protein of three new cultivars of amaranth cultivated in Golestan province.

Forage of three new Amaranth cultivars including Laura, Sim and Kharkovsky. They were grown on a research farm Arqi-mahaleh in Golestan province and harvested at the time of flowering. These forages were chopped into pieces of two to four centimeters and mixed with a weight ratio of five percent molasses and five percent wheat straw. They were stored in silage in 10kg buckets. After 45 days (in the laboratory of the Animal Science Research Institute), the silos were reopened. Sensory evaluation and silage properties of experimental treatments, were measured. Then chemical compounds including dry matter (field and silage), crude protein, crude ash, crude fat, soluble sugar, were analyzed. Gas production test (by Menke and Steingass method) using ruminal leachate of three cows (by ruminal fistulation) and at different fermentation times including 2, 4, 6, 8, 12, 24, 48, 72, 96 hours were done. Digestibility, determination of energy and metabolizable protein (in a completely randomized design with six treatments in three replications) was performed. In final, metabolizable energy and protein as well as daily dietary intake of experimental treatments, were obtained.

Dry matter, crude protein, crude fat, crude ash, neutral detergent fiber, water soluble carbohydrate and non-fiberous carbohydrates in forage silage of Laura cultivar were 23.0, 18.8, 0.97, 21.2, 30.5, 2.5 and 28.6 percent, respectively In Laura forage silage, total sensory evaluation, flag point, ammonia nitrogen (mg), acetic acid (mg), lactic acid (mg), propionic acid were 15.8, 7.78, 4.4, 18.4, 0.45 And 1.15 respectively. Gas production in silos of Laura, Sim and Kharkovsky cultivars (during 24 hours of rumen fermentation per 200 mg) were 45.3, 43.9 and 42.1 ml, respectively. Dry matter and organic matter digestibility in forage silage of Laura cultivar were 66.5 and 70.2 percent, respectively. The amounts of digestible energy, metabolizable energy, net energy and digestibility (dry matter, organic matter and organic matter in dry matter) of fodder and silage of Laura cultivar were higher than the other two cultivars. Relative forage value, relative nutritional quality and feed ratio (g / day / kg body weight during maintenance) in amaranthus silage (Laura cultivar) were 122.3, 108.0 and 43.8, respectively.

Laura forage silage has better silage characteristics and crude protein, gas production, higher digestibility, higher protein and metabolizable energy, as well as relative forage value, relative feed quality and better-feed intake. This silage had a better quality for ruminant nutrition than other silage experimental treatments.

Suckling calves are exposed to different stressors such as birth, pathological factors and environmental factor stress which cause increase of reactive oxygen species (ROS) production and oxidative stress. Trace minerals are a part of some antioxidative enzymes which are necessary for health maintenance. Trace mineral amount of colostrum and milk is not optimal and usage of trace mineral supplements are necessary for suckling calves. Therefore, the aim of this study was evaluation of adding a mixed supplement of trace minerals including copper, iron, zinc and manganese on growth performance, biochemical, enzymatic, antioxidant, hormonal and hematological parameters.

A total of 20 day-old male and female suckling Holstein calves were randomly divided in to two equal groups (ten calves per group) based on initial body weight (40±5 Kg) and until weaning (day 63) they were kept in individual pens. the control group calves were fed with milk and starter diet including whey protein as trace mineral career and treatment group were fed with milk including 15 part per million (ppm) iron sulfate (FeSo4), 6 ppm zinc sulfate (ZnSo4), 6 ppm manganese sulfate (MnSo4) and 1.5 ppm copper sulfate (CuSo4) supplements and basal starter diet including 100 ppm FeSo4, 40 ppm ZnSo4, 40 ppm MnSo4 and 10 ppm Cuso4 supplement until weaning on day 63. During entire experimental period calves accessed starter diet and water ad libitum. Feed intake was calculated daily and calves were weighed weekly to calculate feed conversion ratio (FCR) and average daily gain. Blood samples were collected on days 0, 21, 42 and 63 to determine plasma trace mineral levels and biochemical, enzymatic, hormonal, antioxidant and hematological parameters.

The results indicated that growth performance, catalase and superoxide dismutase activity, total antioxidant capacity, and thyroxine (T4) concentration were not affected by trace mineral supplement. Although, plasma zinc concentration and high density lipoprotein concentration were recorded higher in animals received supplemented trace minerals (P<0/05), low density lipoproteins concentration was lower in the calves fed with trace mineral supplement (P<0/05). In addition to the parameters listed above, alkaline phosphatase concentration, red blood cells count, hemoglobin and hematocrit and triiodothyronine (T3) concentrations were significantly increased in the calves received trace minerals supplement (P<0/05).

Totally, supplemental trace minerals could not improve growth performance and enzymatic antioxidant activity of suckling Holstein calves; however, some biochemical, hormonal and enzymatic parameters related to inflammation, ossification, and cellular basal metabolism were improved in suckling calves.

About 70% of the cost of livestock breeding is related to feed, so the preparation of balanced diet with inexpensive ingredients can play an important role in the profitability of production in breeding. One of the cheapest sources of feed for ruminant animals is the agricultural by-products that are not consumed by humans. Canola Straw is one of the major agricultural by products in Golestan province whose digestibility is low because of containing high amounts of lignocellulosic materials. Processing lignosellulotic feeds with alkaline components can improve their digestibility throw breaking cellulos-lignine bonds. This research was conducted to investigate the effect of canola straw processing with urea on feed digestibility and weight gain performance and some blood parameters of fattening lambs.

For this purpose, 18 5-month-old male lambs of the Dalaqh breed (30-35 kg body weight) were randomly assigned to three nutritional treatments. The control treatment was a fattening diet with a ratio of forage (alfalfa and straw in equal proportions) to concentrate 64:36. In the second treatment, 50% of wheat straw was replaced with untreated canola straw and in the third treatment with urea treated canola straw. After a two-week habituation period with the same ration and initial weighing, experimental rations were fed to the lambs and continued until the end of the 70-day fattening period. During this period, the lambs were weighed every 14 days. At the end of the period, the lambs were weighed and blood sampled. Blood samples were analyzed to determine the serum urea nitrogen, glucose and total protein concentrations. In order to determine the feed intake and digestibility, during two weeks, the remaining feed and feces samples of each animal were collected daily, and the amount of acid insoluble ash was used as an internal marker to calculate the digestibility of experimental feeds.

The average daily feed intake of lambs fed with a diet containing processed canola straw (925.00 gr.day-1) was significantly (P<0.05) higher than lambs fed with diet containing wheat straw or unprocessed canola straw (respectively 887.32 and 850.00 gr.day-1). Also average daily gain of lambs in treated canola straw group was significantly higher than untreated canola straw group (respectively 178.09 vs. 141.53, P<0.05), but feed treatments had no significant effect on feed conversion rate of lambs. Processing with urea significantly (P<0.05) increased the digestibility of dry matter, NDF and ADF (respectively 61.30, 71.11 and 35.30 %) compared to unprocessed canola straw (respectively 55.45, 66.42 and 27.96%) and control (respectively 58.80, 68.82 and 28.76 %). Processing canola straw with urea significantly (P<0.05) increased crud protein digestibility of diet compared to control (60.32 vs. 54.04 %). The levels of serum urea in treated canola straw treatment was significantly higher than untreated canola straw and wheat straw treatments (respectively 17.82, 15.50, 14.82 mg/dl, P<0.05), but the average serum glucose, total protein, total cholesterol and triglyceride levels were not significantly different among the treatments.

The results of this research showed that canola straw processing with urea can improve its nutritional value and nutrient digestibility, feed intake and weight gain performance of lambs.

Studies has been shown that the replacement of % 30 rice straw with alfalfa hay had no adverse effect on lamb grow performance also it had been shown on the goat and cow performance. The use of rice straw decreases the ration prices also it reduces environmental pollution.The goal of this study was to indicate the effect of replacing rice straw with wheat straw on the fattening lamb performance, rumen fermentation, protozoa population and some blood parameters.

In this research, the effect of replacing rice straw with wheat straw on the fattening lamb feeding has been investigated. The 28 male lambs, with an average weight of 30kg, have been divided into four groups of eight animals. The sample lambs in four groups have different accesses to rice straw and wheat straw as follows: the control group has access to 70% concentrate with 30% wheat straw; the second group has access to 70% concentrate with 30% rice straw; the third group has access to 70% concentrate with 30% straw (including 15% rice straw and 15% wheat straw); and the fourth group has access to 70% concentrate and rice straw enriched with urea. The feedstuffs characteristics, weight gain, feed digestibility, rumen fermentation, and blood parameters of lambs during the fatting season have been measured.

The results show that replacement of different levels of rice straw has no negative effect on the final weight, daily weight gain, feed conversion coefficient, dry matter intake, and economic coefficient of fattening lambs; Besides, this replacement has led to a significant increase in ruminal gas (digestibility) in squirrel lambs. Dry matter percentage, raw fat, protein, and ration consumed NDF of squirrel lambs did not affect by replacement of different levels of rice straw. However, the addition of 30% of refined straw has led to a considerable reduction in digestibility of the raw protein ration of squirrel lambs. The overall protein of lambs’ blood who received the ration consisted of 30% rice straw, 15% rice straw+15% wheat straw, and 30% wheat straw was enhanced. However, no change was observed in blood urea nitrogen, cholesterol, triglyceride, and glucose blood. The small intestinal histomorphometry parameters were improved by the addition of different levels of rice straw. The lambs receiving ration including 15% rice straw+15% wheat straw and 30% refined wheat straw, have higher Dasytricha, Entodiniinae, Diplodiniinae, and Ophrioscolecinae populations than the lambs receiving the control ration. Also, adding different levels of rice straw to lambs’ ration has led to a significant increase in total rumen Protozoa.

The overall results indicate that the rice straw can be utilized in fattening lambs’ ration without affecting the livestock.

In Iran, corn silage is an important part of ruminant forage. Mechanical processing of corn forage can improve the properties of corn silage. In this process, chopped fodder is processed using toothed rollers. In this way, it is increased the digestibility of starch and cell wall. Barley starch has a fast ruminal fermentation, and while increasing the production of microbial protein, it can cause an increase in the incidence of digestive abnormalities in ruminants. Neutral detergent fiber (NDF) of sugar beet pulp are very digestible. This study was conducted in order to investigate the effect of two processing levels of corn silage and barley grain and sugar beet pulp on silage quality, feed intake, digestibility of nutrients, rumen parameters and feed intake behavior of Kermani sheep.

In this research, four 2-year-old Kermani lambs with an average weight of 42 ± 2.8 kg were used in a 2x2 factorial experiment in the form of a Latin square design in four periods of 21 days. The experimental diets were: 1)processed corn silage + concentrate with barley seeds, 2)processed corn silage + concentrate with sugar beet pulp, 3)unprocessed corn silage + concentrate with barley seeds, 4)unprocessed corn silage + concentrate with sugar beet pulp. The daily feed was distributed in two equal portions on 8/00 and 18/00. Research data were stored in Excel software and statistically analyzed with SAS software.

Silage processing decreased the percentage of dry matter (DM) and NDF, increased NH3-N, pH (4.42 and 4.04, respectively, P=0.02) and sensory evaluation (15 and 18, respectively, P=0.02) score of silage. Feed intake was higher in the processed silage diets and the diet with barley grain. The digestibility of organic matter (OM) and NDF was higher in the diet containing sugar beet pulp. Ruminal NH3-N (mg/dL) (21.17 and 22.81, respectively, P=0.02) was higher in diets containing processed silage at two and eight hours after feeding, and it was lower in diets containing sugar beet pulp at 6 hours after feeding. The pH of the rumen fluid in the diet containing sugar beet pulp with processed silage was significantly higher than in other experimental diets at eight hours after feeding (P=0.01, 6.92),. The population of rumen protozoa was higher in the unprocessed silage and barley grain diets. Feed intake time was higher in unprocessed silage diets. However, the most rumination time was related to sheep fed processed silage diets. The highest chewing time was in barley seeds diets.

Although corn fodder processing caused a decrease in the sensory evaluation score in the processed silages, it caused an increase in DM intake and OM intake in diets containing this type of silage. The effect of processing silage on animal responses were greater than the effect of barley grain or sugar beet pulp on these responses. It is recommended to process corn fodder with dry matter of about 30 percent.