Iranian Journal of Animal Science
Year:2018 | Volume:49 | Issue:1 |Papers Count:15

In this research the causal structure among calving traits of 29950 first-parity Holstein cattles of Iran including calving difficulty (CD), birth weight of calves (BW) and gestation length (GL) was revealed applying data collected by Iranian Animal Breeding in 131 herds from 1995 to 2004 by Inductive Causation (IC) searching algorithm. Significant structural coefficients were found for causal effects of BW on CD (0. 060± 0. 002) and of GL on CD (0. 007± 0. 002). Furthermore, the causal effect of GL on BW was significant (0. 219± 0. 005). Considering the revealed causal structure, standard and recursive multivariate models were compared applying deviance Information criterion (DIC) and predictive ability of models in terms of two measures including mean square of error and correlation between observed and predicted values. The obtained results revealed the causal effect of BW and GL on CD and the plausibility of recursive multivariate model over standard multivariate one. Therefore, considering the causal structure among calving traits is of crucial importance.

In present experiment fermantability of three halophyte species including: Atriplex leucoclada (AL), Suaeda fruticosa (SF) and Seidlitzia rosmarinus (SR) on individually or mixed forms as 0. 0, 33. 5 66. 5 and 100% with each other (9 diets), were evaluated in a compelet randomized design. These halophyte species were collected from southern rangelands of Khuzestan province during autumn and winter grazing season. The diets were different regarding the rate and amount of produced gas (P<0. 05). The AL produced lowest but diet containing 66. 5 SF+ 33. 5 SR (T8) had highest gas production compared with other diets (P<0. 05). Diet containing AL and SR respectively had the lowest and highest true OM digestibility, true fermentable OM, total volatile fatty acid, ME and maximum microbial mass production (P<0. 05). The fficiency of microbial mass production in AL was the highest and the lowest efficiency was for T8 diet. Concentration of rumen ammonia nitrogen with feeding all diets was higher than its threshold level, so they prepare enogh amount of ammonia nitrogen for max. microbial biomass production. Therefore, diets T5 and T8 were the best diets for provide the nutrients requirements of camels; but with the views of range improvement, combined diets are preferred than each of the three plants alone.

The aim of this study was to evaluate the effect of addition of three different permeable (Glycerol, Dimethyl formamide and Dimethyl acetamid) and two different non-permeable cryoprotectant (Trehalose and sucrose) to the extender on freezing capacity of Turkmen stallions’ sperm. Four healthy mature Turkmen stallions (8-10 years old) were used. Collected semen from stallions were processed and pooled after gel removal and before allocating to treatments [glycerol, dimethyl formamide and dimethyl acetamid (5 or 7 percent) and trehalose or sucrose (50 and 100 mM)]. The prepared treatments were frozen according to a standard method. After thawing viability and motility of all treatments were accessed. The results showed that the viability and motility of spermatozoa treated with extender containing 5 or 7 % dimethyl formamide (68. 6 ± 0. 93 and 63. 2 ± 2. 22 respectively) or dimethyl acetamid (68. 6 ± 1. 69 and 63. 6 ± 2. 76 respectively) were significantly higher than those which treated with 5 or 7 % glycerol (56. 8 ± 3. 06 and 55. 6 ± 1. 03 respectively) (P<0. 05). Also, results showed that the viability and motility of stallion spermatozoa were not influenced by the non-permeable cryoprotectants (P<0. 05). We concluded that dimethyl acetamid and dimethyl formamide can be proper alternatives for glycerol as a common stallion spermatozoa cryoprotectant and the sucrose and trehalose had no significant effect on the stallion sperm quality after freeze-thawing process.

The objective of this study was to compare the effect of five estrous synchronization protocols on ovulatory follicle diameter, progesterone concentration at AI and days 5 and 12 after AI and conception rate in Holstein cows during heat stress. Holstein cows (n=250) with more than 30 kg/d milk yield were randomly assigned to one of 5 experimental groups, 1) ovsynch (OV); 2) presynch-ovsynch (PO); 3) double ovsynch (DO); 4) G7G-ovsynch (G7G) and 5) PG7G-ovsynch (PG7G). Results showed that ovulatory follicle diameter was smaller in cows synchronized with OV protocol compared to other protocols (P˂ 0. 05). Progesterone concentration at days 5 and 12 post AI was lower in OV protocol compared to other protocols (P˂ 0. 05). Conception rates at days 32 and 62 post AI were lower in OV protocol compared to other protocols (P˂ 0. 05). There was no difference among other synchronization protocols (P <0. 05). In conclusion, results of present study showed that using presyhcnronization before initiation of Ovsynch can increase PR/AI of Holstein cows during heat stress.

In this research, cytoplasmic inheritance of yearling mohair weight (YMW) in Markhoz kids were studied by using Bayesian statistical method. Using records which gathered through 1992-2011 in Markhoz goat breeding research station in Sanandaj. GLM procedure of SAS statistical software was used to verify statistical significant of environmental factors on YMW and Gibbs1f90 software, based on animal model and Gibbs sampling, were used to estimate genetic parameters. Environmental factors such as year of birth, maternal age and sex as fixed effects, and animal age and body weight at recording time as covariates were considered in the model. Based on the results of this research, the minimum DIC was detected in Model 12. Which includes direct additive genetic effects, maternal additive genetic, maternal permanent environment and cytoplasmic genetic effects, taking into account the covariance between direct and maternal genetic effects. The ratios of direct additive genetic variance, maternal additive genetic, maternal permanent environment, cytoplasmic genetic on phenotypic variance were respectively 19. 27, 6. 6, 3. 03 and 1. 82 percent based on the selected model (model 12). In general, the results showed that selection based on direct genetic potential and partly on maternal genetic can improve the YMW. Due to the significant of cytoplasmic effects to enter the model on one hand and the low value of its variance on the other hand, it can be concluded that the role of Cytoplasmic inheritance as a correction factor is important, but it cannot be considered as selection criteria.

The aim of present experiment was to investigate the immunochemical characteristics as well as in vitro inhibitory effects of specific and nonspecific egg yolk antibody powder on Staphylococcus aureus growth, as one of the main pathogenic serotypes of Staphylococcus in human and animals. A total of 16 White Leghorn hens (Hy-Line W36) of forty weeks in age were immunized by killed sonicated vaccine after plotting the growth curve and incubating the bacteria until the end of exponential growth phase. This vaccine was prepared eggs were collected daily for 8 weeks, IgY was then isolated and lyophilized by Polson method. The immunochemical properties and growth inhibitory effects of specific and nonspecific sIgY were tested against Staphylococcus aureus. The results showed that the plasma and egg specific activity of IgY against Staphylococcus aureus markedly increased after the first immunization and remained on the highest titer throughout the experimental period (P<0. 01). Total IgY concentration and purity of specific IgY powder were 71% higher rather than the non-specific IgY powder (P<0. 05). The administration of specific IgY powder at 100 and 200 mg significantly (P<0. 05) reduced the bacterial counts during the incubation hours of 4 and 6. Compared to control group, using the highest level of specific IgY could significantly decrease 1. 20 log CFU/mL (P<0. 01). Therefore, the present findings indicated that Staphylococcus aureus accompanying with Freund’ s adjuvant (complete form in the first immunization and incomplete form in booster immunization) have a notable potential to produce high antibody levels for a long time period. In addition, Polson method is an effective way to obtain remarkable purity for IgY with high antibacterial efficiency and long term production.

Using SNP markers information and genomic evaluation approach, predicting the genetic merit of individuals without phenotypic records is now possible. However, using high-density panels for genomic evaluation of all individuals is not economically feasible. To achieve high genomic prediction accuracy with reasonable price, it is possible to genotype a proportion of animals with high-density panels and the rest of animals with low-density panels then impute them to high-density genotypes. In this study, the effect of three low-density panels (1k, 2k and 4k), genotype imputation to 10k panel and the relationship between reference and validation populations on the accuracy of genomic predictions and also the correlation between the estimated breeding values using panels with different densities in simulated data were assessed. The low density panels genotypes were actually consisting of 10, 20 and 40 percent of 10k markers selected randomly and FImpute was used for genotype imputation. As a general trend, by increasing the density of markers, the correlation between the estimated breeding values was increased using different panels. So, the accuracy of genomic predictions was similar using 4k and 10k genotypes. Moreover, imputing 4k to 10k genotypes, did not improve the accuracy of genomic prediction. However, the accuracy of estimated breeding values was increased after imputation from 1k or 2k to 10k. The accuracy of imputation was decreased when the reference and validation populations were more distant.

The aim of this study was to evaluate the effects of Pillaring bentonite nanostructure on growth performance, carcass components and blood parameters of broilers challenged by aflatoxin (AF). A total of 128 day-old Ross 308 broiler chicks in a completely randomized design were randomly allotted to 4 treatments, 4 replicates and 8 birds in each. The birds were reared for 35 days. Experimental groups consisted of: negative control (C), positive control (basal diet with aflatoxin) (AF) and two level 0. 25 and 0. 75 % of Pillared bentonite added to basal diet with aflatoxin B1 (positive control). The Pillaring process increased the concentration FeO (1. 99 to 8. 42%) and decreased concentration Na2O (2. 43 to 0. 43 %) in Pillared bentonite as compared to sodium bentonite. The aflatoxin increased feed conversion ratio and enzyme activity ALP and ALT as compared to control diet. Supplementation of 0. 25% Pillared bentonite to the infected diet of broilers increased the feed intake and body weight and decreased the concentration of ALT. Addition 0. 75% Pillared bentonite increased the concentration of ALT and ALP as compare to positive control. Therefore, the supplementation of Pillared bentonite nanostructure to broiler diets infected with aflatoxin improved the performance and reduced the liver enzyme activity. The results of present research showed that Aflatoxin may had no effect on body weight and feed intake of broilers and the levels of 0. 25 Pillared bentonite nanostructure has the best efficient on performance of broiler fed diets contained aflatoxin.

The objective of this study was to evaluate the effects of betaine supplementation (B-SUP) and vitamin B12 injection (VI-B12) during the transition period on serum metabolites in dairy cows. Thirty-two over conditioned multiparous Holstein cows assigned into 1 of 4 diets containing: CB (VI-B12), BC (50 g/day B-SUP), BB (VI-B12+ 50 g/day B-SUP) and control (CC) form 21 d before parturition (dbp) to 21 d postparturation (dpp). Blood sample was collected at-7, 2 and 42 dpp to determine serum metabolites of dairy cow and neonatal calves. The serum metabolites were not affected by experimental treatments (P>0. 05), except for glucose which was greater in BC and CB as compared to CC and CB treatments (P<0. 05). Among enzymatic indexes, a significant decrease was just showed in BB treatment as compared to CB treatment for GGT enzyme (p <0. 05). Also, serum metabolites in neonatal calves were not influenced by experimental treatments (P>0. 05). In conclusion, B-SUP and VI-B12 improved just glucose amount without any change in other blood parameters. Anyway, more researches can be give suitable results to us, particular if the protected form of the betaine is used.

The aim of this study was to investigate effect of dietary supplementation by high doses of α-tocopherol acetate breeder (20 weeks of age) were used in two groups, standard (n=30; body weight= 3. 109± 0. 169) and heavy (n=30; ± body weight= 3509± 0. 161) weight. Roosters were individually kept and randomly divided into 10 treatments (in a 2×5 factorial arrangements with six replicates in each group). The experimental treatments were fed a same diet supplemented with different levels of vitamin E (0, 100, 200, 300, 400 mg α-tocopherol acetate/kg diet) for 10 weeks. The heavy weight group received 30% excessive diet than standard group from beginning until the end of the experiment. After 5 weeks of adaptation period, roosters were fed by supplemented diet for 10 weeks. In the end of experiment roosters slaughtered and testicles removed from carcass for morphology and histology analysis. Results showed that vitamin E were significantly increased the size of testis, the number of seminiferous tubules in all treatment group compared to the control group (P ≤ 0. 05). As well as, in two body weight groups the weight of testis, left testis diameter, seminiferous tubules diameter, seminiferous epithelium thickness, number of leydig cell and blood vessels were highest in E400 group (P ≤ 0. 05). Finally, based on these results, it was concluded that high dose of vitamin E (400 mg/kg diet) improved testis morphology and histology parameters.

The interaction of fat supplementation (0 and 30 g/kg DM) and by-pass protein level (36 and 40% of dietary CP) was investigated on performance, skeletal measurements and blood metabolites of calf. Forty calves (aging 39 d) were used in a factorial design with four treatments. Experimental diets consisted of; 1) un-supplemented fat with low un-degradable protein (UF-LRUP), 2) supplemented fat with low un-degradable protein (SF-LRUP), 3) un-supplemented fat with high un-degradable protein (UF-HRUP), 4) supplemented fat with high un-degradable protein (SF-HRUP). The results show that supplementing fat in calves increased starter intake, gain as well as feed efficiency (P< 0. 01). No performance result was affected with fat-RUP interaction. Considering the growth parameters, fat supplementation improved body length as well as chest width. Greater RUP also increased hip height. The interactions of fat-RUP did affect chest width and wither height as well. However fat supplementation did not affect blood metabolites, greater RUP reduced both glucose and insulin concentrations. In conclusion, fat supplementation may be recommendable after 4 weeks of age in calves and the results would be more favorable if this supplementation would accompanied with greater RUP level.

Genomic selection using imputed genotypes can have an important role in increasing economic efficiency and the genetic improvement of the threshold traits. The objective of this study was to: investigate the accuracy of imputation and to evaluate its effect on area under receiver operating characteristic (AUROC) of threshold BayesA (TBA) and random forest (RF) algorithms for discrete traits with different genomic architectures. Genomic data were simulated to reflect variations in heritability (0. 30 and 0. 10), number of QTL (108 and 1080) and linkage disequilibrium (low and high) for 27 chromosomes. To simulate a condition close to reality, we randomly masked markers with 50% and 90% missing rate for each scenario; afterwards, missing genotypes were imputed and imputation accuracy was estimated. In the last step, to evaluate the AUROC of TBA and RF, original or imputed genotypes were used. The accuracy of imputation was improved with increasing level of LD and decreased missing rate. The total average of AUROC values were 0. 64 and 0. 66 when using RF and TBA, respectively. Comparing to original genotypes, using imputed genotypes with 50% and 90% missing rate decreased the average AUROC about 0. 013 and 0. 02 for RF and 0. 0018 and 0. 026 for TBA, respectively. Despite the higher AUROC of TBA at different scenarios, RF showed a better performance in large number QTL. Generally, genomic prediction based on imputed genotypes (5K) can be implemented to reduce of the cost of a genomic evaluation.

In this study, the effects of partial substitution of alfalfa hay (AH) with high fiber by-products (wheat straw: WS, beet pulp: BP) were evaluated on performance of high producing dairy cows. Eight high yielding cows (54± 2. 5 kg milk production) were used in a 4 × 4 Latin square design and fed 4 experimental diets. The 4 experimental diets contained constant level of corn silage (19. 2%) with different proportions of 1) 19. 2% alfalfa hay (CON), 2) 3. 8% AH, 5. 8% WS, 5. 8% BP (WS-BP), 3) 3. 8% AH, 8. 5% WS (WS) and 4) 3. 8% AH and 10. 2% treated WS (TWS). Diets were similar in of NEL, CP, and NDF contents but WS-BP and TWS diets had lower undigested NDF (uNDF) level. Results indicated replacement of AH with high fiber sources increased nutrient digestibilities (P < 0. 01). Moreover, cows received by-products substitutes showed greater dry matter intake than control cows (P<0. 01). Milk yield and milk composition did not differ across treatments. Therefore, this resulted in a tendency for improved milk production efficiency (P=0. 08) with feeding CON diet. Efficiency of 3. 5% FCM was similar among different diets. Feeding different by-products diets had no effect on ruminal pH, total VFA concentration, and chewing behavior, but tended to increase acetate: propionate ratio (P=0. 06). Substituting wheat straw with/without beet pulp for alfalfa hay resulted in improved DM and digestibility but reduced milk production efficiency in high-producing dairy cows.