taher yalchi

Crude protein is a key element in regulating the diet of ruminants and is considered one of the most expensive nutrients needed by livestock. Feeding management plays an important role in the elimination of nitrogen in the production environment and the emission of greenhouse gases in animal husbandry systems (Avathar et al 2021). When there is excessive discharge of nitrogen in the environment, it causes the ecological balance in surface waters to be disrupted and the groundwater to be polluted (Dijkstra et al 2011). Excretion of these compounds in the environment will increase with fermentation, digestion and inefficient metabolism, and the increase in inefficiency in the rumen is caused by the complex and competitive metabolic pathways in the rumen microbial population. Therefore, increasing efficiency in the use of nutrients, especially nitrogen, to minimize their excretion from the animal's body should be considered. Various methods can be implemented in an animal husbandry unit to improve the use of nitrogen in ruminants. One of these solutions is to reduce the crude protein in the diet, but it has been reported that this method can have a negative effect on animal production (Chibisa and Motswangwa 2013). Another solution is nutrient synchronization or synchronizing the fermentation rate of dietary protein and energy sources, which has led to limited success (Yelchi et al 2020). Another solution is to create oscillating in the concentration of crude protein in the diet and feed it intermittently at intervals of one to three days, and previous reports show that this method has improved nitrogen retention and its utilization in the body compared to eating constant amounts of crude protein daily in sheep and cattle (Rach et al., 2021). This study was conducted in order to investigate the effect of constant and intermittent feeding of dietary crude protein on ruminal parameters and microbial protein synthesis in sheep.

Three diets were adjusted with 12, 14 and 16% crude protein but with the same metabolizable energy and protein. 8 male sheep were used in metabolic cages in a 4x4 Latin square design (four treatments with 2 squares and 8 replications). The first treatment received a diet with a crude protein level of 14% constantly. The second, third and fourth treatments received diets with 12 and 16% crude protein at intervals of 24, 48 and 72 hours, respectively. Nitrogen balance and retention, rumen and blood parameters, volatile fatty acids and microbial protein synthesis were measured.

The lowest total excreted nitrogen (via urine and feces) was observed in the treatment with 48-hour raw protein consumption interval (P=0.031). The retained nitrogen showed a significant increase in this treatment as compared to the constant crude protein feeding treatment (P=0.045). It has been reported that the increase in nitrogen retention in ruminants that received diets with oscillating crude protein levels is due to increased urea recycling in the rumen (Cole, 1999). It seems that the transfer of urea from the blood to the rumen during the consumption of diets with low crude protein level (times 24, 48 and 72 hours) in oscillating diets increased and it compensates for the shortage of nitrogen in the rumen. In this condition, nitrogen excretion through urine also decreases and the efficiency of nitrogen use increases. The highest rumen liquid ammonia nitrogen was observed in the treatment with 48-hour crude protein consumption interval, but the pH and concentration of volatile fatty acids did not show any significant difference among the experimental treatments. Comparing the treatment of constant crude protein feeding (14%) with the treatments with intermittent consumption of crude protein (12 and 16%) in terms of the concentration of volatile fatty acids in the rumen fluid of the experimental sheep, including acetate, propionate and butyrate, as well as total volatile fatty acids, there is not a significant difference. The same ratio of concentrate to fodder and the similarity of the feed ingredients in the diets can be a reason for the lack of significance between the experimental treatments, which is in line with the results of previous researches (Khattab and Abdulwahid, 2018). A significant difference was observed between the experimental treatments in terms of allantoin, total purine bases excreted, as well as nitrogen and microbial protein production, and the treatment with oscillating consumption of raw protein at a time interval of 48 hours had the highest amount. Albumin and total blood protein measured between the experimental treatments showed no significant difference, but blood urea nitrogen was the highest in the treatment with 48-hour crude protein consumption interval (P = 0.005). Microbial protein synthesis in the rumen is affected by many animal and dietary factors, including nitrogen amounts, nitrogen sources, carbohydrate and nitrogen degradation rates, type and amount of carbohydrates in the diet, dry matter consumption, stability of fermentation in the rumen, and synchronization between nitrogen and energy (Hall 2013). It seems that in diets that cause fluctuation in the entry of protein sources into the rumen, the recycling of nitrogen to the rumen is done more effectively through the blood vessels and the liver, which in addition to reducing the excretion of nitrogen from the body also increases the production of microbial protein, in other words, the efficiency of using feed nitrogen increases, which is evident in the results of this research.

The results showed that using the strategy of oscillating dietary crude protein concentration in sheep's diet improves nitrogen retention, rumen fermentation activities and microbial protein synthesis.

The aim of the current study was to improve the reproductive performance and birth weight of lambs using vitamin E and selenium (Ese) injection in estrus-synchronized Moghani ewes. In this research, a total of 200 Moghani ewes were divided into two groups in a completely randomized design. In the control group, only estrus synchronization was performed, but the second group was received two intramuscular injections of Ese (5 ml) on the days of sponging and sponge removal. Synchronization of estrus was done by inserting intravaginal sponges for 14 days followed by 400 IU eCG at sponge withdrawal. Two days after sponge withdrawal, ewes were joined with fertile rams. Twenty ewes from each group were selected randomly and their blood was sampled. The first and second blood samplings were done before inserting intravaginal sponges and three weeks after ram exposure, respectively. Then, some blood plasma metabolites were determined. After parturition, reproductive traits were calculated in each group. According to the results, lambing rate, fecundity rate, lamb production efficiency and twinning rate were higher in Ese group (88, 111, 126.1, 21.6 respectively) compared to control (73, 84, 112.3, 12.3 respectively). The birth weight of lambs did not significantly differ between the groups. Glucose and cholesterol concentration of blood were significantly higher in group receiving Ese three weeks after mating. In conclusion Ese injection improved the reproduction performance in Moghani ewes.

One of the environmental factors that lead to the reduction of poultry production is heat stress. Quince leaves are an agricultural waste that is a good source of flavonoid compounds and antioxidants. The purpose of this research is to investigate the effect of adding quince leaf in the diet on feed intake, weight gain, feed conversion ratio and blood parameters in broilers under heat stress conditions. This research was conducted using 160 broilers of Ross 308 strain with four treatments in four replications and each replication including 10 birds for 42 days in a completely randomized design. Quince leaf powder was added to the rations at four levels of zero (control), 1.5, 3 and 4.5%. In order to establish heat stress, the temperature of the hall was increased to 33 °C for 8 hours in the middle of the. Every week, the feed intake was measured and the chickens were weighed. In the second week of rearing, a significant increase (P=0.006) in feed intake was observed linearly with the increase in the level of quince leaf added to the feed rations, so that the highest amount of intake was in the treatment containing 4.5% quince leaf. In the third week, the highest weight gain was observed in the treatment with 1.5% quince leaf. In the fourth and fifth weeks, feed intake and feed conversion ratio did not differ significantly between treatments. In the sixth week, feed intake showed a significant decrease linearly (P=0.024) with the increase in the level of quince leaf added to the feed rations, but the feed conversion ratio linearly showed a significant improvement (P=0.017). In the entire rearing period, no significant difference was observed in terms of feed intake, weight gain and feed conversion ratio, although with the increase in the amount of quince leaf added to the feed rations, a relative improvement was seen in the feed conversion ratio, so that this ratio of 2.68 in the control treatment decreased to 2.44 in the treatment with 4.5% leaves. The use of quince leaf in the diets of broiler chickens under heat stress, especially in the early stages of growth, can increase feed intake, weight gain and improve feed conversion ratio, although no significant difference in terms of performance was observed in the entire rearing period, but a relative improvement was observed in the feed conversion ratio.

Crude protein is one of the most expensive components of feed and nutrients needed by animals. One of the ways to optimally use crude protein is to oscillating the level of crude protein in the diet and feeding it intermittently at intervals of one to several days. This study was conducted in order to investigate the effect of oscillating dietary protein concentration on growth performance and some rumen and blood parameters in fattening male lambs.

Three diets were adjusted with crude protein of 12, 14 and 16% and with the same metabolic energy. 36 male lambs with an average weight of 23.94±2.04 kg were used in four treatments in a completely randomized design. The first treatment received a diet with a crude protein level of 14%. The second to fourth treatments received diets with 12 and 16% crude protein at intervals of 24, 48 and 72 hours, respectively. Feed consumption, growth performance, feed conversion ratio, digestibility and some rumen and blood parameters were measured.

No significant difference was observed in terms of feed consumption and growth performance among the treatments, although the feed conversion ratio improved in the treatment with a 48-hour crude protein consumption interval and showed a tendency to be significant compared to the control treatment (p=0.063). The highest digestibility of organic matter was related to the treatment with 48-hour consumption interval, which shows a tendency to be significant compared to other treatments (p=0.091). No significant difference was observed between experimental treatments in terms of digestibility of dry matter, crude protein and neutral detergent fiber. The highest rumen ammonia nitrogen and blood urea nitrogen were in the treatment with 48-hour crude protein consumption interval (p<0.05).

The results of this research showed that the feed conversion ratio improves to some extent when using the method of creating oscillations the crude protein level of the ration and its intermittent feeding, but it had no effect on the growth performance of male lambs and feed digestibility, as well as rumen ammonia nitrogen and blood urea nitrogen increased. Therefore, it is recommended to use this strategy in feeding fattening male lambs.

Silymarin is the effective substance of thistle plant, which causes some physiological effects and improves nutritional behavior. This research was conducted to determine the central effects of silymarin on feeding behavior in broiler chickens and to find the mechanism of feed intake and to investigate its relationship with the serotonergic system.

In this research, 30 pieces of broiler chickens cannulated in the brain were used. In the first stage of the research (28 days old), silymarin was injected in the amount of 20 micrograms per kilogram of body weight. After injection, feed and water intake was measured in 30 to 180 minutes. In the second stage of the experiment (34 days), the relationship between silymarin and the serotonergic system was investigated. The treatments included 1- control, 2- methysergide, 3- ketanserin, 4- methysergide + silymarin, and 5- ketanserin + silymarin.

In the first stage, in 60 and 180 minutes, silimarin caused a significant decrease in feed intake (P<0.05). In the second stage, the central injection of the combination of silymarin with methysergide caused a significant decrease in feed consumption, while the central injection of the combination of silymarin with ketanserin had no significant effect on feed consumption. Central injection of silymarin had no effect on water intake in broilers.

The results showed that although central injection of silymarin decreased feed intake in broilers, it did not affect water consumption. Also, the central injection of the combination of silymarin with methysergide decreased feed intake in broilers.

 Before weaning, dairy calves are susceptible to many pathogens and nutritional problems. For several years antibiotics have been used to overcome these problems also to obtain economic benefits in terms of improved calves performance and reduced medication costs. However, the use of antibiotics in animal husbandry is in question because of antibiotic resistance of microorganisms. In an effort to replace antibiotics from animal feeds, many additives have been proposed. Probiotic, prebiotics and Organic and inorganic mineral salts are examples of these additives. Prebiotics are non-digestible carbohydrates which are not metabolized in the small intestine and fermented in large intestine. Mannan oligosaccharides and β-glucan are prebiotics which derived from saccharomyeces cereviciae cell wall and are able to block fimbriae of patho genic bacteria, and thus prevent their adhesion to the mucous epithelium. The administration of prebiotic to calves can decrease coliform population of large intestine and colon of calves. More recently, prebiotics have been shown to have immune-enhancing characteristics Also, Copper is a microelement that is present in many important processes in the body and plays a vital role. Copper deficiency in some parts of the world is a major problem in ruminants. For this reason, dietary supplements are commonly used to regulate the diet of calf to compensate for copper deficiency. Therefore, the purpose of this study was to investigate the effects of copper nanoxide and prebiotics on blood cell count and growth performance in Holstein suckling calves.

Twenty-eight Holstein calves with an average age of 1 to 8 days and an average weight of 39±1 kg were used in a factorial experiment as a completely randomized design with 4 treatments and 7 replications. Experimental treatments include: 1) Basal diet without additives, 2) Basic diet with 4 gr of prebiotic per day, 3) Basic diet with 15 ppm nanoparticles of copper per day, 4) Basic diet + 4 gr of prebiotic + 15 ppm nanoparticles of copper per day. The diet containing feed and milk was given two times a day i.e. in the morning (8:00 am) and evening (18:00 pm). Water was offered adlibitum. Whole blood samples were collected from jugular veins on d 60, approximately 3 h after the morning feeding. Samples were sent to the laboratory under refrigeration (4°C) till analyzed for WBC count, neutrophil, lymphocyte and monocyte concentration.Results and Discussion The results showed that the copper nanoxide, prebiotics and the interaction of copper nanoxide and prebiotics could not affect the final weight of suckling calves. The results showed that feed intake, daily weight gain and feed conversion ratio of suckling calves were not significantly affected by supplementation of prebiotic and copper nanoxide in the diet during the first, second month and experimental period. Also, Body length, Wither height and Heart girth of Holstein suckling calves were not affected by copper nanoparticles and prebiotics supplementation. Prebiotic, copper nanoxide and their interaction had no significant effect on white blood cells, red blood cells, hemoglobin and hematocrit. In contrast, copper nanoxide and prebiotics significantly increased the neutrophil percentage (P <0.05).

has shown that probiotic consumption had no significant effect on functional parameters of Baluch sheep including final weight, daily gain, feed intake and dietary intake. However the result of the other study suggests that prebiotic can be supplemented to the calves for better performance. In contrary to the results of the present study, other researchers have indicated that copper nanoparticles could improve growth performance and modulate intestinal microflora and intestinalmucosal morphology in weaned piglets. In the study addition of pro- prebiotic and symbiotic to the whole milk of dairy female calves increased average daily gain but dry matter intake and blood parameters related to immune system and cell-mediated immune response were not affected. However, when a combination of probiotic and prebiotic added to the milk a better improvement in average daily gain was observed. A study reported that haematological traits (WBC count, neutrophil, monocyte, lymphocyte and hemoglobin) were unaffected by prebiotic and synbiotic in weaned pigs. However, the other study showed that immune parameters such as lymphocytes, leukocyte and neutrophils tended to increase in supplementation of symbiotic.

In general, results of this experiment indicated that using prebiotics and copper nanoxide did not improve growth performance and blood cell count except neutrophil percentage.

This study was conducted to investigate the effect of oscillating dietary protein concentration on nitrogen balance and daily weight gain in fattening male lambs. Oscillating crude protein in the diet and feeding it intermittently at intervals of one to several days is one of the ways to use crude protein optimally. Three diets were adjusted with 14, 12 and 16% crude protein but with the same energy. 8 male lambs were used in metabolic cages in a 4x4 Latin square design (four treatments with 2 replications). The first treatment received a diet with a crude protein level of 14% constantly. The second to fourth treatments received diets with 12 and 16% crude protein at intervals of 24, 48 and 72 hours, respectively. Nitrogen balance, feed consumption, digestibility and some rumen and blood parameters were measured. No significant difference was observed in terms of nitrogen consumption and excretion through urine or feces among the treatments. The lowest total excreted nitrogen (urine and feces) was observed in the treatment with 48-hour consumption interval (P=0.031). The retained nitrogen showed a significant increase in this treatment compared to the treatment with constant feeding (P=0.055). The experimental treatments did not show any significant difference in terms of dry matter consumption and daily weight gain. The highest digestibility of dry matter was observed in the treatment with 48-hour consumption interval (P=0.027) but, digestibility of crude protein and neutral detergent fiber did not show a significant difference between the experimental treatments. The highest rumen ammonia nitrogen and blood urea nitrogen were in the treatment with 48-hour crude protein consumption interval (P<0.05). The data indicate that the use of oscillating dietary crude protein concentration strategy in the diet of growing male lambs improves nitrogen retention and digestibility of dry matter.

In order to investigate plant properties and forage value of lathyrus rotundifolius, this research was conducted in Namin rangeland. Persian everlasting pea is belong to legume family and it is a wild plant that grow at Heyran and Fandoghlo region. Based on local residents experience, they consider the forage of this plant as one of the best forage and collect it for livestock consumption. This plant is also doubly important with the biological stabilization of nitrogen, improving soil fertility, high leaf-to-stem ratio and high forage value. Due to the fact that farmers do not have enough forage, so recognizing local forage plants with high forage value and using them can play an important role in providing forage and production sustainability.

Sampling was performed to evaluation of forage properties at three growth stage including before flowering, flowering and after flowering stages. The study area is located at latitude 38.40 degrees east and longitude 48.55 degrees north (cold and humid climate). The average annual rainfall in the region is 369 mm and the average annual temperature in the region is 9.63 ° C. The area soil is brown and relatively acidic. Traits such as plant height, vegetative growth period, flowering time and ripening time were evaluated. Chemical compositions of the collected samples include dry matter, organic matter, total carbohydrates, neutral detergent insoluble fibers, acid detergent insoluble fibers, cellulose, hemicellulose, lignin, crude protein, crude fat (ether extract), crude ash, Nitrogen and minerals such as iron, copper, zinc, manganese, phosphorus, potassium were also measured.

Results showed that the highest amount of organic matter, crude protein, crude fat, nitrogen, phosphorus and copper were obtained in the early flowering stage. The quality of forage in the post-flowering stage (early seedling) was significantly reduced. And the amounts of insoluble fibers, cellulose, hemicellulose and lignin increased. The percent of organic matter decreased with increasing age of the plant, so that its amount decreased from 94.4% at the beginning of flowering to 91.8% at the beginning of seeding. The amount of total carbohydrates at the beginning of flowering was 65.7%, which increased with the age of the plant, so that its amount reached 78.6% in the early stages of seeding. Insoluble fibers in neutral and acidic detergents also increased with increasing plant age and the lowest amount was observed in early flowering and the highest amount was observed in early seeding stage. The amount of lignin also increased significantly with increasing plant age, so that its amount was 7.3% in early flowering and 12.1% in early seeding stage. The trend of changes in crude protein and crude fat in forage composition was similar and decreased with increasing plant age. Crude fat decreased with increasing plant age. So that its amount decreased from 5.2% at the beginning of flowering to 2.5% at the beginning of seeding stage, but the amount of raw ash increased with the age of the plant and its amount increased from 5.6% at the beginning of flowering to 8.2% increased in early in seeding stage.

The decrease in forage fat can be attributed to the re-transfer (remobilization) of assimilates to the seeds and the increase in ash percentage can be attributed to the accumulation of elements in the shoots. Therefore, with the increase of crude ash, the percentage of dry matter, total carbohydrates, insoluble fibers, cellulose, hemicellulose, lignin, manganese, and zinc increased. Results showed that wild lathyrus is desirable as forage crop and it can be used as desirable forage crop.

Using horticultural and agricultural products such as almond hull is a useful way to compensate for feedstuff shortages and reduce environmental pollution. This study was conducted to investigate the effect of slow-release non-protein nitrogen replacement (Nitrosa) with urea in diets containing almond hulls on microbial protein production and nitrogen balance in sheep in order to provide an inexpensive non-forage fiber source with easily accessible nitrogen.

Materail and Methods:

This study was performed using four adult sheep weighing 49.33 ± 4.59 which were kept in metabolic cages were assigned in a 4×4 Latin square design in four 19-days periods. Feed intake and daily excretion of feces and urine were measured. Four rations were tested with the same raw protein and energy content, which contained 36% of the total crude protein content of non-protein nitrogen supplements. Only urea was used in the first treatment. In the second treatment, 24% of the crude protein required by urea and 12% by Nitrosa were provided. In the third treatment of urea and Nitrosa, respectively, 12 and 24%, and in the fourth treatment, Nitrosa was used only to provide 36% of the total crude protein needed in four periods. Each period included 14 days of habit and 5 days of measurements.

Allantoin showed a significant difference between treatments under the influence of experimental diets. So that treatment 3 had a significant difference with treatment 1 and 2, but did not differ with treatment 4. Also, treatment 2 had a significant difference with treatment 4 (p<0.05). Xanthine and hypoxanthine were not affected by diets (p>0.05). Uric acid, total purine derivatives excreted and all purine derivatives absorbed microbial nitrogen production, and microbial protein production under experimental diets showed a significant difference between treatments (p<0.05). The dry matter digestibility, crude protein, crude fat, and organic matter were not affected by the experimental syringes and there was no significant difference between the treatments (p>0.05). The digestibility of insoluble fiber in neutral detergent under the influence of experimental diets showed a significant difference between treatments (p<0.05). Treatment 4 had significant differences with treatment 1 and 3 and there was no difference between treatment 4 and 2.

Based on the results Using Nitrosa in diets containing almond hull as a low-cost non-forage fiber source also low-protein can be useful in improving the digestibility of fiber.

In the livestock industry around the world, most decisions are about increasing profitability per head, which is not an independent process and is affected by the interactions of biological functions such as (production, reproduction and health) and prices that are changed by policy. Replacement and breeding affect profitability (Nasre Esfahani, 2018). Issues such as feed price fluctuations and the lack of coherent policies to support the dairy industry in the country have made the profession one of the most risky jobs in the economy. When a producer wants to make the decision to remove or replace a cow, it is best to compare the future benefits and expected benefits of keeping a cow or replacing an animal with another. The most important objective of a livestock unit is to maximize the profit of the herd, one of the issues affecting this profit is the criteria and rate of elimination (Rogers et al,1988). If culling and replacement are not optimal, the cows are removed sooner or later than the optimal deadline, the profitability of the herd decreases. The need to determine the optimal time to remove cows requires simultaneous consideration of several biological and economic variables (De Vries,2006). The removal decision must be based on the anticipated future earnings of the cow. The longer the livestock has a livelihood in the herd, the more profit the livestock earns. The decision to properly, optimally and reasonably eliminate livestock is made by comparing the present value of the future cash flow of the cow present in the herd to the present value of the future cash flow of its replacement heifers, ultimately occupying the most valuable animal in the present (Groenendall et al,2005). The application of dynamic programming in the animal sciences is more on animal substitution issues. The optimal policy at each stage represents the best decision from that stage to the final stage. This method calculates an expected value for each of the situations that can be faced and the decision maker selects the best decision based on the expected value based on the situations ahead. Several dynamic programming models for optimal replacement decision making in dairy herds have been proposed by (De Vries,2004) and (Van Arendonk,1985). (Cardoso et al,1999) reported optimizing replacement and inoculation policies in dairy cows by calculating monthly income, costs and probability of elimination.

In this study, using raw data collected from industrial dairy farms of Ardabil between 2015 and 2018, the biological parameters of the herd, such as the shape of the lactation curve, the risk of forced removal and the possibility of pregnancy in different lactation periods and Different months after calving were estimated. The financial information of the herd was also obtained in the form of an economic questionnaire from the studied units. It was further developed by incorporating biological parameters and financial information into a bio economic model in Dairy Vip software. The feature of this software is that it simulates the livestock over time and also calculates the performance of the herd based on breeding and replacement decisions with the goal of maximizing profitability. Milk production was evaluated using daily milk production records and fitting the incomplete gamma curve (Wood). Dairy Vip software defined average daily milk production levels in the herd by entering lactation data (raw milk quantity, incremental milk slope to peak production and milk slope decrease until peak production). Mean milk yield of 305 days at first to third lactation and peak lactation was reported in Table 1.The mean 21-day inoculation rate and cattle breeding rate were 49.3% and 37%, respectively. By default Dairy Vip software, a maximum livestock can be in the herd 24 months after calving. The risk of fetal loss from the second to the eighth month was 6.24, 4.16, 2.08, 1.11, 0.45, 0.19, and 0.19 percent, respectively. A Dynamic programming model was developed to determine the optimal replacement policy for cows in dairy farms and in economic conditions in Ardabil province. The objective function investigated in this study was to maximize the present value of net income from current cows and alternative heifers. Markov chain simulation was used to estimate the expected statistics under optimal policy.

The implications of the decision policies for optimum and non-optimum removal using Dairy Vip software are presented in Table 3. With the implementation of optimal policies, the overall annual removal rate increased from 30.11% to 43.8%. However, the forced removal rate fell by 2.3%. Pregnancy rate increased from 18/15 to 18.2% and increased by 2.89%. Based on the above results, it can be inferred that the economic importance of increasing the pregnancy rate is more urgent in herds with poorer reproductive performance. Also, the non-optimal catch rate dropped from 33.9% to 37%, indicating an increased likelihood of livestock being pregnant in different months. The 21-day inoculation rate ranged from 47.6 to 49.3%, indicating appropriate cow inoculation. By reducing the days of gestation in dairy cows can increase milk production, which in this study reduced the optimal days of gestation from 139 days to 132 days, which resulted in a significant 7-day decrease in milk production and finally annual. Open days are the interval from birth to the next gestation period, from 167 days to 161 days. With the decline in pregnancy, the rate of pregnancy increased. Calving distance also decreased from 13.6 to 13.3, which was reduced to 0.3 per month, which in turn increased annual milk production. As shown in Table 3, the optimal daily milk yields were increased from 41.4 to 44.2 by the optimal policies, which increased the daily milk yield by 3 kg per cow. And the annual yield of milk increased from 12548 to 13483 kg per cow. Reducing the average days of lactation increased the daily and annual production of productive cows by 3 and 935 kg, respectively.

Decisions to optimize voluntary removal and estimation of livestock value by computer simulation in Dairy VIP software enable improved economic returns. This improvement is due to the decrease in average lactation days in the herd resulting in increased milk production, cattle sales and calf production. Although the implementation of optimal policies is associated with increased livestock removal and replacement costs and increased feed costs, however, the increased revenue from implementing these policies could well offset the increased costs. In general, it can be concluded that increasing milk production in medium-sized cows is the most important factor in increasing economic profit. The results of this study showed that low-yielding animals showed their least future benefit in early lactation, indicating that they should be eliminated sooner.

[1] The nutrient synchrony is synchronization of ruminal fermentation rate of energy and nitrogen which is a method to increasing microbial protein synthesis, improving nitrogen efficiency, decreasing urinary nitrogen excretion and improving animal performance. Microbial protein production is important for ruminants. Current concepts of ruminant nutrition focus on optimizing ruminal microbial protein synthesis. Microbial yield in rumen depends largely on the supply of carbohydrates and nitrogen in the rumen. Balancing the rate of supply of nitrogen and energy yielding substrates to rumen microbes has been proposed in order to maximize the capture of rumen degradable protein and to optimize microbial growth rate and its efficiency. A more efficient capture of rumen degradable protein would reduce the requirement for expensive undegradable protein sources and also reduce the excretion of urinary nitrogen which case to environmental pollution and economical losses. Synchronization index expressed as the ratio between the hourly degradability of nitrogen with organic matter or carbohydrates in the rumen where the highest value for the synchrony index is 1.0. This research was done to evaluate the effect of synchronizing the rate of carbohydrate and crude protein ruminal fermentation on ruminal fermentation products, microbial protein synthesis, and nitrogen balance and blood parameters in sheep which were fed with similar components or structure high concentrate diets.

Chemical compositions and degradability parameters of crude protein and carbohydrate for alfalfa hay, wheat straw, barley grain, corn grain, sugar beet pulp, wheat bran and soybean meal were determined. Three diets were formulated for feedlot male lambs with same energy and metabolizable protein but containing different synchrony index 0.64, 0.78 and 0.92 which calculated by using degradation parameters of carbohydrate and crude protein of feeds from the diet. The effects of synchrony index of diets by 6 rumen-fistulated sheep with an average weight of 30.17±1.17 kg in metabolic cages were assigned in a duplicate 3×3 Latin square design (2×3 animals; 3 periods). Samplings were done in 3 periods (each period containing 14 days for adaptation and 5 days for sampling). Rumen fluid was collected for 5 consecutive days in the end of each period and ruminal fermentation parameters containing pH, NH3-N and volatile fatty acids were determined. Urine of sheep was collected end of each period for 5 days and microbial protein synthesis was estimated by measuring purine bases also nitrogen balance was calculated from the values of nitrogen consumption and excretion. Bleeding (19th trial day) were done from sheep and blood parameters such as glucose, albumin and blood urea nitrogen were determined.

There was no significant difference in ruminal pH among diets during fasting conditions or before feeding. Also there was no significant difference in ruminal pH between treatments at 3 or 6 hours after feed intake. With increasing synchrony index, ruminal NH3-N concentrate reduced especially at 1.5 and 3 hours after feed intake. Total volatile fatty acids highest at 3 hours after feed intake for diet had highest synchrony index. With increasing synchrony index, total volatile fatty acids concentration increased almost by 20 percent. Also the propionate concentrates increased not only before feeding but also at 3 hours after feeding. Total volatile fatty acids and propionate concentration showed a linear trend between diets at 3 hours after feeding. Purine bases such as allantoin, uric acid, xanthine and hypoxanthine, total purine derivatives excreted or absorbed also microbial protein synthesis not affected by experimental diets. With increasing synchrony index, total excreted nitrogen reduced but nitrogen retained and its efficiency increased. Blood parameters such as glucose, albumin and blood urea nitrogen not affected by treatments.

with increasing synchrony index of the diets, microbial protein synthesis did not increase but total volatile fatty acids concentration and retained nitrogen increased whereas ruminal NH3-N concentration and total excreted nitrogen decreased. However, increasing nutrient synchrony index in high concentrated diets did not show the expected desirable results such as increasing microbial protein synthesis however did not also show undesirable results such as animal health. Due to the beneficial effects as increasing in fermentation and decreasing nitrogen excretion or environmental pollution using the high synchrony index diets can be useful for feed formulation or providing the perfect mix of feed items to meet nutritional requirements of sheep.

The purpose of this study was to investigate the effect of processed alfalfa silage with acetic acid and Ecosyl on feed intake, microbial protein synthesis and blood parameters in four Moghani male sheep (90±2 kg BW) using a changeover design consisting of four 14-day periods. The experimental treatments were 1) alfalfa silage without additive as control, 2) alfalfa silage treated with Ecosyl, 3) alfalfa silage treated with 5% acetic acid, and 4) alfalfa silage treated with acetic acid and Ecosyl. The results showed that feed intake was not affected by treatments. The amounts of excreted purine derivatives were 12.29, 7.02, 12.03 and 8.64 g/d for alfalfa silage (control), alfalfa silage treated with acetic acid or Ecosyl and their combination. Also, the adsorbed purine derivatives values were 13.46, 7.19, 13.14 and 9.12 g/d for control, alfalfa silage treated with acetic acid or Ecosyl and their combination. Untreated alfalfa silage, treated with either acetic acid, Ecosyl or their combination resulted in 9.79, 5.23, 9.56 and 6.63 g/d of microbial protein synthesis, respectively. The excreted purine and adsorbed purine derivatives and microbial protein synthesis were reduced in alfalfa silage treated with acetic acid and Ecosyl and their combination (P<0.05). There were no significant differences in blood metabolites among the treatments, except for cholesterol values. Alfalfa silage treated with acetic acid alone did not change the nutritional values; however, alfalfa silage treated with acetic acid and Ecosyl improved the nutritional parameters in sheep.

This study was conducted to determine solubility and acid production of some feedstuffs in various fermentation conditions. The solubility was determined at a temperature of 39°C for 24 h and the potential of acid production (PAP) was measured by adding calcium carbonate to filtered fermentation medium. Fermentation of feedstuffs was performed in special gas production syringes both natural and induced acidosis conditions. Total feedstuffs had 316.1 g kg-1 and 11.72 mg Ca g-1 for DM solubility and PAP, respectively. The best regression model to estimate PAP was made by non-fibrous carbohydrates (NFC) for all feedstuffs (R2 = 0.91) and by soluble OM in DM for both high NFC and high crude protein groups (R2 = 0.83). In natural fermentation condition there was high correlation (r = -0.91) between pH and gas production. The rice hull and wheat straw had the highest and the sugar cane molasses and citrus pulp had the lowest pH in 6h natural fermentation condition. The rice hull, wheat straw, alfalfa hay, corn silage and sugar beet pulp were more resistant than others in induced acidosis. The results showed that solubility and NFC content can be used in models that estimate PAP of feedstuffs. Also determination of fermentation characteristics of some common and by-products or lesserknown feedstuffs in terms of acid and gas production in a short time is possible by presented screening methods.