fattening calves

The shortage of feed, caused by the limitation and reduction of water resources, is the biggest challenge for the country's livestock industry. Every year, more than 20 million tons of by-products from the main agricultural production remain in the country, which are mainly used as animal feed. Agricultural by-products, which exceed the production of forage crops many times over, are valuable resources that can replace conventional feeds in animal nutrition. Due to their low protein content and low digestibility, they need to be processed. For almost a century, different processing methods have been used in many countries depending on the conditions and facilities, but unfortunately, the majority of these materials are still used raw and unprocessed as animal feed in the country, which is a waste of resources. Straw processing is carried out by various physical, chemical, and biological methods or a combination of these methods, with ammoniation being the most important chemical method. The use of ammonia gas for this purpose can facilitate and accelerate processing, especially with large quantities of by-products. This research was carried out to study the efficacy and economics of the method of ammonization of straw with ammonia gas and the use of the ammonia product in the diet of fattening calves.
Ammoniated wheat straw was prepared with ammonia gas at three weight percent of the dry matter of straw at 30% moisture by stacking method, and the chemical composition, digestibility, and gas production of the ammonia-containing product were determined. In the second phase, 30 Simmental crossbred fattening calves with an initial weight of 249.5±8.9 were divided into two control and experimental groups and for each group, considering three replicates of five calves for each group. Normal straw was used in the control group, and it was replaced by ammoniated straw in the experimental group. The duration of the trial was eight months, during which the weight gain of the calves was determined every 30 days, and the dry matter was consumed daily. Dry matter consumption, daily weight gain, feed conversion ratio, and the cost of weight gain of calves were determined and compared between the two groups.
The ammonia treatment of straw increased crude protein content in the ammoniated straw from 4.78% to 12.65%, and the amount of NDF and hemicellulose also decreased in ammoniated straw (from 71.33 to 66.80%, and from 30.75 to 26.25%, respectively), while the amount of ADF increased (from 38.7 to 41.20%). The ammonia treatment of straw increased the gas production per 24 hours from 25.71 mL to 38.06 mL and the estimated metabolizable energy from 5.69 to 6.8 MJ per kilogram of dry matter. The ammonia treatment improved the digestibility of dry matter (from 45.0 to 78.75%) and organic matter of straw (from 42.35 to 80.27%). Substituting normal straw for ammoniated straw in the diet of fattening calves increased daily dry matter consumption from 8.66 kg to 8.99 kg (P<0.01), daily weight gains from 1.33 kg to 1.48 kg, and average weight at the end of the fattening period from 423.98 kg to 440.67 kg (P<0.01), and improved feed conversion ratio from 6.43 to 6.01 (P<0.01). In addition, the use of ammoniated straw reduced the price of ration from 71230 Rials to 69210 Rials and the cost of feed for each kilogram of animal weight gain from 458008.9 Rials to 415952.1 Rials.
Ammoniation of straw with ammonia gas increased the metabolizable energy, crude protein, and digestibility of straw. The use of ammonia gas for this purpose increased the speed, ease, and efficiency of processing, making it suitable for processing large quantities of straw. The profitability of this method depends on the cost of the ammonia product, in particular the price of ammonia gas and its transportation costs. At the national level and from a macroeconomic perspective, this method increased the digestible nutrients of agricultural residues (metabolizable energy and crude protein), it is, in a sense, a type of food production by increasing productivity and without the consumption of water and other agricultural inputs. It provides more nutrients for livestock, which reduces dependence on traditional feed, reduces competition between humans and livestock for food, protects the environment, and makes production more sustainable.

Processing of agricultural by-products for animal feed can upgrade the supply of animal feed without increasing the current production and only by improving productivity via enhancing energy efficiency and maintaining it in the food supply chain, and at the same time, diminish the concerns of waste management, food security, resource constraints, and environmental protection. As a result, human and livestock competition for food make less and feed prices cut.

This experiment was performed to determine the optimal method of ammoniation of wheat straw with anhydrous ammonia (ammonia gas) including the effect of increasing the amount of moisture and the amount of gas used for ammoniation and investigating the effects of replacing ammoniated straw with straw in the diet of fattening calves in two stages. In the first stage, ammoniation of the wheat straw using four levels of moisture (0, 20, 25, and 30%) and four levels of ammonia gas (0, 2, 2.5, and 3%) was performed in a factorial experiment and the chemical composition and digestibility of the samples were determined and compared. In the second stage, in order to investigate the effects of using ammoniated straw in the diet of fattening calves, 24 Simmental fattening calves with an initial weight of 356 ± 15 were divided into control and experimental groups. In the experimental group, NH3-treated straw which was processed using 3% ammonia gas whith 30% moisture in straw, replaced untreated straw in the control group. Dry matter consumption and daily weight gain, feed conversion ratio, and weight gain cost of calves were studied for five months and compared between the two groups.

Ammoniation of straw did not cause significant changes in the amount of organic matter and ash. The percentage of straw crude protein as a result of ammoniation increased up to 2.7 times and with increasing ammonia level and moisture content, the amount of crude protein showed a tendency to increase. Ammoniation caused a significant difference in the amount of NDF, ADF, hemicellulose, and ADL in straw, and the digestibility of dry matter and organic matter was also improved. Daily dry matter intake increased in the experimental group (p<0.01) and the daily weight gain and mean weight at the end of the experiment period were significantly higher in the experimental group (p<0.01). The feed conversion ratio showed a significant improvement in the experimental group (p<0.01) and the use of ammoniated straw treated with 3% ammonia gas and 30% moisture reduced the ration price and feed cost per kilogram of livestock weight gain.

Treating wheat straw with anhydrous ammonia (ammonia gas) is a simple, fast, and effective way to process straw and increase its nutritional value and digestibility for livestock, and its economic efficiency depends on the availability and price of gas and the method used.

This study was conducted to determine the effects of adding spent wheat straw compost from Agaricus bisporus mushroom in fattening calves diet. Spent compost was provided from a mushroom production farm and the remaining particles were separated from the straw after mushroom cultivation. Spent straw compost was sun dried and chemical composition analyzed for DM, OM, CP, CF, NDF, ADF, Ca and P. Fifty male Holstein calves with initial average weight of 321± 18 kg were randomly divided into experimental and control groups. Diets were adjusted based on the average weight of the calves and NRC recommendation. Spent straw compost was used in the experimental group at 10% of the diet. The experimental period was 180 days. The animals were fed three times daily with total mixed ration offered ad libitum. Feed intake, body weight changes, feed conversion ratio and feed cost per kg bodyweight were determined and compared. Results showed that feeding spent straw compost did not have any significant effects on daily weight gain, feed intake and feed conversion ratio of feedlot calves. Average daily gain in the control and experimental groups were 1204 and 1150 g, respectively. Average daily feed intake was 9.8 and 10.1 in control and experimental group respectively and feed conversion ratio of control and experimental group were 8.2 and 8.8 respectively. The use of spent compost slightly increased the cost of the diet as well as feed prices per kg increase in live weight in the experimental group. According to the findings of the present study, compost straw can be include up to 10 percent of the TMR form diet of finishing calves, but its economic advantage is dependent on access and cost.

This study aims to investigate the technical efficiency of production factors in the industrial fattening calves’ farms in Markazi province with emphasis on risk management. For this purpose, technical efficiency was determined using Corrected Ordinary Least Squares (COLS) method and Timmer measure, and also relationship of studied variables were examined by statistical tests. Meanwhile, coefficient of variation measure was applied for risk measurement. The necessary data was completed through completion of questionnaire with direct interview from 102 farms in three capacity groups included small, medium and large from 7 townships of Markazi province, which were selected by appropriate stratified sampling method in the year 2012. The results showed that the mean technical efficiency for all studied farms was equal to 49/2 percent, which indicates that the farms have a moderate technical efficiency and they don’t optimally utilize production inputs. Khomein, Komijan and Zarand townships had the highest mean technical efficiency between all townships of the province, respectively. Meanwhile, there was 55 percent difference in technical efficiency between the highest and lowest technically efficient farms. The estimation of production function revealed that the highest production elasticity was belonged to labour, feed and active capacity inputs, respectively. The results also indicated that there was not significant relationship between active capacity of farms and technical efficiency (p>0.05). On the other hand, the study of coefficient of variation in price and live weight in the end of fattening indicated that the price risk was more as compared to production risk. Meanwhile, there was no significant relationship between livestock insurance and net income per head of fattening calves with technical efficiency, which are shown that the livestock insurance is not necessarily effective for risk management.

The aim of this study was to investigate the effect of urea treated baled wheat straw on fattening performance of male calves. The bales of wheat straw (about 10 kg each) were treated with urea solution to obtain 45% moisture and 4.5 % urea and were kept under plastic sheet for one month. Then the plastic was removed and samples of treated straw were taken for chemical analysis and in vitro studies. Bio-availability of the straws to rumen microbes was investigated using in vitro gas production and nylon bag techniques. Effect of treated wheat straw on fattening performance of male calves was assessed using 20 heads of Montbeliard male calves in 120 days of fattening period. Animals were divided into equal groups with 10 animals per each. The diet of both groups contained 70% concentrate, 20% wheat straw and 10% alfalfa but in treatment group wheat straw was substituted with urea treated wheat straw. The content of CP in both groups was 14.6% and deficiency of CP in control group was compensated by addition of urea. Animals were fed twice a day and total feed consumption was recorded daily. Animals were weighed every month after 14h of feed and water deprivation. The results showed that urea treatment significantly (p<0.05) increased CP from 2.7% to 6.8% and decreased NDF from 85 to 79 percent. Results of in vitro gas production showed that there was a significant difference (p<0.05) in volume of gas production between the untreated and the treated straws. Urea treatment significantly (p<0.05) increased the fermentation characteristics of b and c and metabolizable energy. Significant increase (p<0.05) was observed in potential rumen degradation and factor of b in the treated sample. Urea treatment did not affect average daily gain and voluntary feed intake but significantly (p<0.05) improved feed conversion ratio (from 8.14 to 7.51).