مجله پژوهش در نشخوار کنندگان
سال دوم شماره 4 (زمستان 1393)

An experiment was carried out to evaluate how dietary rumen degradable and rumen undegradable protein level may alter nitrogen efficiency and urea transporter-B expression in growing Baluchi male lambs. Three Baluchi male lambs (30±2 kg BW) were used in a change over design and given 1 of 3 isonitrogenous supplements: 1) high ruminally degradable protein (RDP/RUP 80:20), 2) medium ruminally degradable protein (RDP/RUP 75:25) and 3) low ruminally degradable protein (RDP/RUP 70:30). Treatments had significant effect on Soluble Fraction (P<0.05), Degradable Fraction (P<0.05), Degradation Rate (P<0.05) and Effective Degradability (P<0.05). A significant difference was observed for DM (P<0.05), CP (P<0.05) and NDF (P<0.05) digestibility. The maximum value of NH3-N (P<0.05) and BUN (P<0.05) concentration was measured in HRDP diet followed by MRDP and LRDP diets. Fecal N excretion of LRDP (g/d) (P<0.05) diet was significantly higher than diets MRDP and HRDP. Urinary N excretion of HRDP diet (g/d) (P<0.05) was significantly higher than other diets. A significant difference was observed for ruminal urea transporter-B mRNA expression (P<0.05). In conclusion, this study show that dietary changes in rumen degradable and rumen undegradable protein produce significant changes in urea transporter-B expression within the ovine rumen. Our findings suggest that the dietary regulation of urea transporters plays a major role in altering urea entry into the gastrointestinal tract.

In this study we produced and evaluate solid state fish oil supplements using spray drying and ca-salt formation. In the case of microencapsulation, two different types of wall materials (with different levels of fish oil were used. Nutrient content and fatty acid profiles, covering properties of different wall systems and protein and carbohydrate fractions according to CNCPS were addressed. Also, series of in vitro studies were carried out to determine potential of spray dry microencapsulation on ruminal biohydrogenation and gastrointestinal release of fish oil in comparison with ca-salts. Maillard wall materials provided more oxidative protection and encapsulation efficiency than non-maillard ones (p<0.05). Protein and carbohydrate fractions were different between maillard and non-maillard walled microcapsules (p<0.05). Highest biohydrogenation in all of the incubation times was belong to unprotected oil and free fatty acids, after that, lowest and highest biohydrogenation after 48 hours of incubation was seen with maillard and non-maillard encapsulated fish oil, respectively and ca-salts had intermediated behavior (p<0.05). Oil content in microcapsules affected fatty acid profile and biohydrogenation extent in all of the incubation times (p<0.05). Ruminal and post ruminal oil release from maillard and non-maillard microcapsules was statistically different (p<0.05). Although protecting from ruminal Biohydrogenation, incomplete oil release from microcapsules despite of high rumen protection, particularly in the case of maillard wall materials, warrants further in vivo studies.

This research was conducted to evaluate the effects of different levels of fenugreek seeds or extract on some in vitro rumen fermentation and gas production characteristics. Samples of a total mixed ration (TMR) without any additive (control treatment), 4 diets with different levels of fenugreek seeds (2, 4, 6 and 8 percent of dry matter) and 4 diets containing different levels of fenugreek extract (0.5, 1, 1.5 and 2 percent) were incubated with rumen fluid. Gas production (GP) of feed samples were measured at hours 2, 4, 6, 8, 12, 24, 48, 72 and 96 of incubation and gas production parameters, digestibility of organic matter, short chain fatty acids (SCFA) production and metabolizable energy of the samples were estimated. Final pH and ammonia-N concentration of incubation fluids were measured at the end of incubation. Addition of fenugreek seeds had significantly increased cumulative GP and GP potential and constant rate (P<0.05). Means of SCFA were not significantly different among treatments, but rations containing fenugreek seeds had higher organic matter digestibility and metabolizable energy compared to control (P<0.05). Addition of fenugreek seeds at levels above 4 percent significantly increased pH (P<0.05), but the ammonia-N concentrations showed no significant trend in response to increasing levels of fenugreek seeds. Increasing levels of fenugreek extract up to 1 percent increased levels of cumulative GP, potential of GP, digestibility of organic matter and SCFA production and metabolizable energy significantly (P<0.05), but higher levels of it had no more effect on these parameters. Constant rate of GP was significantly higher when 1.5 percent fenugreek extract was added and increasing levels of it had increasing effect on lag time (P<0.05). Addition of 0.5 percent fenugreek extract significantly increased pH (P<0.05). Based on results of this experiment it can be concluded that the inclusion of 2 to 4 percent of fenugreek seeds or 0.5 to 1 percent of fenugreek seed extract can improve rumen fermentation characteristics, digestibility of organic matter and SCFA production.

This trial was performed to determine the effects of different levels and physical forms of corn and wheat grains in the starter diet on performance, some of serum metabolits, fecal score, diarrhea and digestibility of acid detergent fiber (ADF) and starch in Holstein dairy calves. Fourty eight calves (40.1±3.0 kg) were randomly assigned to four different treatments consisting of control (corn grain milled), the ratio of 50:50 whole grain corn and wheat, the ratio of 50:50 milled grain corn and wheat, and whole grain corn. After birth, all calves were fed enough amounts of colostrum for the first 3 days and then recieved 4 kg of milk in entire trial. Starter consumption was measured daily and body weight was recorded at day of birth, weeks 3 and 6 and at the weaning time. Results showed that starter intake and average daily gain were highest in calves fed starter containing whole grain corn and wheat and were the lowest in calves fed starter including corn grain milled (P<0.01). Overall, different treatments had no significant effects on feed efficiency measured at different stages. Although, there was tended to significant (P=0.06) in the entire period. Blood glucose and BHBA were the highest and lowest respectively, in calves fed whole grain corn and wheat. Furthermore, this group had greater ruminal pH compared to the other groups (P<0.01). There was no differences in fecal score and days having diarrhea between groups. Apparent digestibility of starch and ADF were significantly higher in calves fed a blend of corn and wheat grain compared to their fed alone corn. It was concluded that using a mixture of whole grain corn and wheat in starter diet could be a proper alternative to fine ground corn in Iranian dairy calf rearing systems.

The effect of feeding roasted- or extruded soybean and their equal combination instead of soybean meal on feed intake, milk yield and milk composition, meal pattern and chewing behavior was evaluated using four multiparous (DIM = 113 ± 14) and four primiparous (DIM = 96 ± 20) Holstein dairy cows. Cows were used in a replicate 4 × 4 Latin square design with 21-d periods. Experimental diets were: 1) diet containing soybean meal (13.88% of dietary DM); 2) diet containing roasted soybean (15.22% of dietary DM); 3) diet containing extruded soybean (15.55% of dietary DM); and 4) diet containing equal blend (7.69% of dietary DM) of roasted- and extruded soybean. Feed intake, sorting index, meal pattern, and chewing behavior were measurement using standard procedures. Milk yield and milk composition, dry matter intake, meal size and inter-meal interval were not influenced by experimental diets. Although both meal length and total eating time tended (P=0.06) to be increased for primiparous vs. multiparous cows, eating rate (P=0.06) and dry matter intake (P=0.01) were greater for multiparous cows. Experimental diets had no effect on sorting index. Number of rumination bouts and total rumination time were greater for primiparous vs. multiparous cows. Results indicated that milk yield, dry matter intake, feeding pattern, and chewing activity were not influenced by feeding processed soybean instead of soybean meal.

The aim of this study was to determine effects of dietary high-linoleate seed (soybean) and high-oleate seed (canola) on blood metabolites and growth parameters of lambs fed diets containing different levels of energy and protein. Thirty male Afshari lambs were used to evaluate the effects of two dietary energy and protein levels (2.3 Mcal/kg metabolisable energy (ME), 14% crude protein (CP) and 2.7 Mcal/kg ME, 16.4% CP) and different levels of each oil seed (no seed, 5% soybean, 10% soybean, 5% canola, 10% canola) on blood metabolites and growth parameters. Lambs were randomly allotted to 10 dietary treatments as a 2×5 factorial arrangement. Diets were fed ad libitum for 84 days, after 14 days of adaptation. Feed intake was recorded daily and weight gain and blood metabolites were determined once each 14 and 28 days, respectively. The results showed that increasing dietary contents of CP and ME increased feed intake, growth rate, protein efficiency ratio and improved feed conversion ratio. Using 5% soybean seed in the high energy and protein diet resulted in a higher feed intake, gain and final weight (P<0.05). Serum glucose, cholesterol and low density lipoproteins were not altered, but serum high density lipoprotein was higher and albumin, triglycerides and very low density lipoprotein were lower in the lambs fed with oilseeds rich in unsaturated fatty acids (P<0.05). Finally, it was seen that supplementation of 5% soybean seed in high density diet had a positive effect on performance of growing lambs.

This experiment was conducted to study the fatty acid profile of subcutaneous adipose and fat-tail of two fat-tailed lamb breeds, Sanjabi and Mehraban. All lambs were born from oestrus-synchronized ewes lambs were raised and finished under identical feeding conditions. Twelve 3-month age male lambs (6/each breed) were used. The mean initial body weights were 23.33±0.48 in Sanjabi and 26.10± 2.14 kg in Mehraban. The animals were housed individually. All animals were weighed and slaughtered at the end of a 90 days fattening period. After slaughter subcutaneous adipose samples were rapidly dissected, between the 8th and 9th rib from the right side of the carcass. Samples from fat-tails were also taken at the same time. The samples were stored at -20 °C for fatty acid analysis. Total n-6polyunsaturated fatty acid content of subcutaneous adipose (P<0.05) and conjugated linoleic acid (cis-9 trans-11) (P=0.05) were higher in Sanjabi compared to Mehraban lambs. Linoleic and α-linolenic acid of subcutaneous adipose were also significantly (P<0.05) higher in the Sanjabi lambs. There were no significant differences in unsaturated fatty acids to saturated fatty acids ratio and n-6 to n-3 ratio (n-6:n-3) (P>0.05) between two breeds. The level of C17:1, C14:1 and C17:0, C15:0 of fat tail were significantly higher in Sanjabi compared to those in Mehraban breed. The current study showed that adipose tissue from Sanjabi lambs had higher proportion of total poly unsaturated fatty acids and conjugated linoleic acid while, fatty acid profile of fat tail was similar in two breed.

In this study, inbreeding coefficients and effect of inbreeding depression on growth traits were estimated using pedigree and body weight records of Karakul sheep kept (over a period of 24 years (1984-2008)) at the breeding station in Sarakhs, Razavi Khorasan, Iran. Inbreeding coefficients for all animals were estimated using Van Raden algorithm due to low pedigree completeness index. Inbreeding depressions on growth traits were estimated as the regression of body weight in different age, average daily gains in pre-weaning and post-weaning on animal and dam’s estimated inbreeding coefficients as co-variables. The mean of inbreeding for all animals, females and males were 1.59, 1.64 and 1.54 percent, respectively. Inbreeding depression per 1 percent increasing of individual inbreeding for birth, 3,6,9 and 12 month weight and average daily gains in pre-weaning and post-weaning was -0.005, -0.039, -0.117, -0.168, -0.17,-0.0004 and -0.0005 Kg, respectively. Inbreeding depression per 1 percent increasing of dam inbreeding for these traits was 0, -0.050, -0.014,-0.042, -0.055, -0.0006 and 0 kg, respectively. Estimated inbreeding coefficients for this breed showed high degree of close mating in this herd and due to the significant effect of inbreeding on some growth traits it is suggested that this breeding station should use a breeding plan to avoid mating of close relative animals and will use from assortative and compensatory mating.

In this study, a method based on using image processing and artificial neural network is introduced to determine curl type and pelt size of new born lambs in Zandi sheep. The data was collected from luxury pelt collection belong to the Zandi sheep breeding center Khojir, Tehran, Iran. Primarily, curl type and dimensions were determined by experienced appraisers for some pelts. Then, some digital images were captured from different curl types on the pelts and from different pelt dimensions. The features related to curl type determination and pelt size estimation were extracted from digital images using image processing tools (IPT) of MATLAB software. Two different Artificial Neural Networks were designed for classification of curl types and estimation of pelt size, independently. To classifying the curl types, a neural network was trained with the accuracy of 100%, and in the test phase it could classify the 7 curl types with the accuracy of near 95%. The accuracy of pelt size estimation was near 99% for the second tested neural network. There was a significant correlation (97.15%) between true and ANN estimated pelt sizes. The results indicated that there is a potential of using artificial intelligence as a replacement for the human sense, to determine pelt quality in the new born lambs of pelt sheep.

The purpose of this study was to evaluate the energy consumption and greenhouse gas emissions of dairy farms in Guilan province. Data were collectedthrough questionnaires and interviews with managers of 44 dairy units. The relationship between energy inputs and milk yield for each head was studied through using Cobb-Douglas model. Data analysis revealed that a high portion of total energy consumption was allocated to the two inputs including animal feed and fossil fuels with a share of 82% and 13% respectively. Total energy inputs, productivity, specific energy and energy efficiency were calculated as 52592.81 MJ head-1, 0.25 LiterMJ-1, 7.40 MJ Liter -1 and 0.47 respectively. Regression coefficients indicated that the impact of energy inputs including human labor, fossil fuels and animal feed on the produced milk yield for each head were positive and the impact of energy inputs of electricity and agricultural machinery were negative. The results of the sensitivity analysis showed that an increase of 1 MJ in energy inputs of animal feed, fossil fuel and human labor will lead to an additional increase in milk yield for one head by 3.80, 0.084 and 0.096 liter, respectively, and an increase of 1 MJ in energy inputs of electricity and machinery, will lead to a decrease of 0.64 and 3.60 liter, respectively. Total greenhouse gas emissions of Guilan dairy farms were calculated as 1132.61 CO2eq head-1. Two inputs of diesel fuel and electricity with a share of 84% and 15% respectively had the highest share of greenhouse gas emissions.