فهرست مطالب

Livestock Science and Technology - Volume:7 Issue:1, 2019
  • Volume:7 Issue:1, 2019
  • تاریخ انتشار: 1398/07/22
  • تعداد عناوین: 7
|
  • I. Sadr Arhami, G. R. Ghorbani, Sh. Kargar*, A. Sadeghi, Sefidmazgi, M. Hoseini Ghaffari, M. Caroprese Pages 1-10

    The objective of this study was to compare the effects of soybean (SB) meal (SBM) with increased rumen undegradable protein as roasted SB (RSB), extruded SB (ESB) or their equal blend (RSB + ESB) on production performance, nutrient digestibility, N-utilization efficiency, and blood metabolites in mid-lactation dairy cows. Eight lactating Holstein cows (BW = 534 ± 52 and DIM = 104 ± 5; mean ± SD) were used in a replicated 4 × 4 Latin square design with four 28-d periods receiving 4 diets: (1) 13.88% of diet dry matter (DM) as SBM; (2) 15.22% of diet DM as RSB, (3) 15.55% of diet DM as ESB, and (4) 7.69% RSB plus 7.69% ESB (RSB + ESB). Each experimental period consisted of a 14-d diet adaptation followed by 14-d data collection. Dry matter intake, actual milk and 3.5% fat-corrected milk yield were not affected by the diet. Average milk fat and protein percentages (3.42 and 3.11%) and yields (1.28 and 1.17 kg/d), respectively, were not different among the diets. Plasma urea N concentration was similar across SB products but decreased compared with SBM. Feeding processed SB reduced NH3</sub>-N concentration in the rumen (14.0 vs. 17.2 mg/dL; processed SB vs. SBM), indicating lower ruminal degradation of processed SB protein, and thereby improved N-utilization. Based on our results, RSB and ESB and their equal blend had a similar effect on productivity and N-utilization efficiency in mid-lactation Holstein cows.

    Keywords: dairy cow, soybean meal, roasted –, extruded soybean, nitrogen efficiency
  • F. Rezaii*, J. Bayat kohsar Pages 11-19

    Two experiments were conducted to evaluate the effects of microwaving, autoclaving (moist heating), and roasting (dry heating) on gas production parameters and in situ</em> rumen degradability of soybean meal (SBM). SBM was treated by roasting at 140℃ for 30 and 60 min, and at 160℃ for 30 and 60 min, autoclaving at 121℃ for 20 min, and microwaving for 2, 4, and 6 min. A gas production trial was performed using rumen fluid collected from fistulated sheep. Cumulative gas production was recorded at 2, 4, 6, 8, 12, 24, 36, 48, 72, and 96 h after incubation. The organic matter digestibility (OMD), metabolizable energy (ME), net energy (NE), and short-chain fatty acid (SCFA) in gas production trial were calculated after 24 h incubation. For in situ</em> technique, three fistulated sheep of the Dalaq breed (with an average weight of 54 ± 1 kg) were housed in individual cages and fed at the level of maintenance. Samples of the processed and unprocessed SBM were ground to pass through a 3 mm screen, and 5 g of each sample were transferred into nylon bags. The results showed that treatments had a significant effect on gas production potential (P<0.05). With increasing the heating duration, gas production potential increased in roasted treatments. Processing methods significantly reduced gas production (P<0.05). The lowest volume of gas production was recorded for the autoclave treatment. Processing with Micro-6 and moist heating (autoclave) resulted in a significant decrease in organic matter digestibility (OMD) compared to dry heating (roasting). Micro-6 treatment significantly (P<0.05) decreased the concentration of SCFA compared to other treatments. The results of in situ</em> experiments showed that processing of SBM significantly reduced the rate of dry matter and protein degradation (P<0.05). Processed SBM had a lower rapid degradable fraction (a) and higher slowly degradable fraction (b) compared to the control treatment. In conclusion, the methods of heating (autoclaving, dry heating, and microwaving) of SBM decreased the gas production and gas production rate and ruminal protein degradability.

    Keywords: soybean meal, heat process, microwave, degradability
  • M. Takallozadeh *, M. Bashtani, H. Farhangfar Pages 21-31

    A total of 21 dairy goats in mid lactation were randomly assigned to three experimental diets in a completely randomized design. The diets contained 0, 3, or 6% WAS, and consisted of 45% forage and 55% concentrates. Milk fat and the ratio of milk fat to milk protein were significantly lower in goats fed diets containing 6% WAS (P≤0.01). Digestibility of crude fat was higher, and that of neutral (NDF) and acid (ADF) detergent fiber was lower in the goats fed diets containing WAS (P≤0.05). Milk fatty acids C14: 1 and C18: 1 and C16: 1, C18: 2, CLA and C18: 3 were significantly higher in animals which received diets containing WAS. Total mono unsaturated fatty acid (MUFA) content, poly unsaturated FA (PUFA), and PUFA/saturated FA (SFA) ratio were significantly higher in the goats fed diet containing 6% WAS (27.04%, 3.94% and 0.05, respectively). Desaturation index for C16: 1 was significantly higher in WAS goats (P≤0.01). Concentration of plasma HDL in goats (38.14-39.28 mg/dL) was higher WAS goats (P≤0.05). In conclusion, supplementation of WAS to dairy goats at a level of 3 and 6% was an effective means of increasing concentrations of unsaturated FA, especially oleic, linoleic, CLA, linolenic, and PUFA in milk fat, and plasma HDL.

    Keywords: unsaturated fatty acid, desaturation index, dairy goat, digestibility, milk fat
  • A. Shokrinejad Gerdin, A. Akhlaghi *, M. J. Zamiri, Z. khaksar, F. Saemi Pages 33-37

    Published data on 4-week-long administration of extra thyroxine (T4</sub>) in broiler breeder hens to alleviate the cold-induced ascites in their offspring suggested that long-term maternal hyperthyroidism would affect the gastrointestinal tract morphology. Broiler breeder hens (n=70) were reared in individual cages and allotted to control and hyperthyroid groups (five replicates of seven hens each). Thyroxine, dissolved in water, was orally administered to the hyperthyroid group (0.3 mg T4</sub>/bird/day) for 100 days and the control group received an equal volume of drinking water. At the end of the experiment (64 week of age), two birds per replicate (20 hens in total) were selected for histological evaluation of the gastrointestinal tract. Thyroxine treatment resulted in an increase in plasma concentration of T4</sub>; however, triiodothyronine (T3</sub>) level was not affected. The results of this study showed that long-term administration of T4</sub> had no adverse effects on the gastrointestinal morphology in broiler breeder hens; therefore, long-term maternal T4</sub> administration may be recommended as a treatment to reduce the ascites incidence in the progeny. However, further studies are needed to confirm this recommendation as a preventative treatment in reducing the ascites incidence.

    Keywords: ascites, gastrointestinal morphology, thyroxine
  • M. Khodaei Motlagh *, M. Zhandi, M. Kazemi Bonchenari, M. H. Moradi, A. Mohamadi Pages 39-44

    Fifteen fertile rams (live weight 55.9 ± 1.21 kg, and 2.5-3 years old) were randomly allotted to three diets consisting of 0 (Control), 12.5 (PBP-12.5), and 25 % (PBP-25.5) pistachio by-products (PBP) in dry matter. Sperm motility parameters were detrimentally affected in animals feeding on PBP-25% diet (P<0.05). Sperm concentration of C17-1, C22-6-n-3, C18-2-Cis and C22-6 n-3 fatty acids decreased but that of C18-0 and C18-1-Cis fatty acids increased at the highest level of dietary PBP. The results indicated that 12.5% PBP in dry matter, as a cheap by-product, may be included in the ram diet for extended periods without any discernible detrimental effects on sperm characteristics. However, fertility trials need to be performed to substantiate this conclusion.

    Keywords: Farahani ram, pistachio by-product, sperm parameters
  • Sh. Barjasteh, G. R. Dashab *, M. Rokouei, M. M. Shariati, M. Vafaye Valeh Pages 45-53

    Genotype imputation from low-density to high-density (SNP) chips is an important step before applying genomic selection, because denser chips can provide more reliable genomic predictions. In the current research, the accuracy of genotype imputation from low and moderate-density panels (5K and 50K) to high-density panels in the purebred and crossbred populations was assessed. The simulated populations included two purebred populations (lines A and B) and two crossbred populations (cross and backcross). Three scenarios were assessed for selecting the subset of the references that used to impute un-genotyped loci of animals in the validation set, where: 1) high relationship with validation set, 2) randomly, and 3) high inbreeding selecting. Imputing the individuals of validation set 5K and 50K to marker density 777K using the various combinations of reference set was performed by FImpute software. The imputation accuracies were calculated using two methods including Pearson correlation coefficient (PCC) and concordance rate (CR). The results showed that imputation accuracy in the purebred populations lines A and B was higher than the cross and backcross populations. When the reference set has been selected based on high relationships, the genotype accuracy in lines A and B was the highest, and there was less difference between imputation from 5K and 50K density to 777K compared to the other subset selection methods. In the crossbred population with imputation from 50K to 777K, the imputation accuracy was the highest in the state of the randomly selected of the reference population (0.98 and 0.97 for PCC and CR, respectively). In the backcross population, the imputation accuracy was the lowest when the reference set selected according to the high inbreeding, which it could be resulting from the lower homozygosis in these populations.

    Keywords: genotype imputation, single nucleotide polymorphism, accuracy
  • Y. Naderi* Pages 55-62

    Body weight (BW) records (n=11,659) of 4961 Kurdi sheep from 215 sires and 2085 dams were used to estimate the additive genetic, direct and maternal permanent environmental effects on growth from 1 to 300 days of age. The data were collected from 1993 to 2015 at a breeding station in North Khorasan province; Iran. Genetic parameters for growth traits were estimated using random regression test-day models. The residual variances were modeled by a step function with various classes. The model 16 with a polynomial of 3 order for fixed effect, 6 order for direct genetic effect, 6 order for direct permanent environmental and 6 order for maternal permanent environmental effects with the lowest Bayesian information criterion (BIC) was considered to be the best model. The direct heritability ranged from 0.01 at day 1 of age to 0.36 at 300 days of age. Genetic correlations ranged from 0.03 to 0.98 for body weight between different days of age. The small value of genetic correlation (0.03) among early (day 1) and late (300 days) weights showed that early weights were not under the same genetic control as weights at older ages. Genetic progress was realized and the estimated genetic parameters obtained could be used for further improvement of sheep and small ruminants.

    Keywords: Kurdi sheep, growth traits, genetic parameters, Legendre polynomials