Iranian Journal of Animal Science
Year:2009 | Volume:40 | Issue:2|Papers Count:13

Twenty-four Holstein male calves (BW=217±57kg) were employed to evaluate the effects of rapeseed oil supplementation on growth, carcass as well as on meat quality and fatty acid content of longissimus thoracis muscle in a completely randomized design. The calves were divided into three groups and allocated to three diets of: a corn/barley-based diet (C); a diet containing 2% (DM basis) rapeseed oil (LC); and one containing 4% (DM basis) rapeseed oil (HC). Feed offered was recorded daily, the calves were weighed monthly and slaughtered after 4 months of trial. The obtained data indicated that dry matter intake was greater for steers fed C diet than for those fed LC and HC (P<0.05), but feed efficiency was lower for steers fed C diet rather than LC and HC (P<0.05). There were no differences (P>0.05) observed in average daily gain, hot carcass weight, and in longissimus muscle area. No differences were observed (P>0.05) in carcass readings except for back fat in which calves fed the HC diet had more back fat as compared to those fed the C diet. There were significant differences observed in meat quality of longissimus thoracis muscle, i.e. the ether extract was significantly increased (P<0.05) while crude protein and moisture significantly reduced due to being fed LC and HC. The use of rapeseed oil had no effect on muscle ash content (P>0.05). Fatty acid composition was affected by treatments, Feeding LC and HC diets increased (P<0.05) the percentages of C18:0 and C18:1 while decreasing (P<0.05) the percentages of C14:0 and C16:1. There were no differences (P>0.05) observed in the percentages of C14:0, C17:0, C17:1, C18:2, and C18:3 of the treatments. Concluding from the economic aspects of the study, ause of 4 percent (DM basis) of rapeseed oil in the diet of growing male calves is recommendable.

A deterministic model was employed to simulate various progeny testing programs compatible with the conditions of Holstein dairy cattle population in Iran. In simulated programs, the selection intensity of bulls was increased by increasing the ratio of cow population in mate with young bulls. Selection accuracy in the programs was fixed because of the fixed progeny group. Economic efficiency (the ratio of return to cost) increased with a decline in the increase in the number of young bulls reaching to its maximum value of 6.07 by 29 young bulls. Genetic gain per generation and return of progeny testing programs increased by increase in the number of young bulls, until their maximum values reached. The maximum genetic gain values were 430.7683 Kg, and 21924417479 Rials, with 29 and 99 young bulls, respectively. The cost of program increased linearly with a value of 51984332 Rials per bull. As a consequence, the program with maximum genetic gain per generation or return would not necessarily maximize the economic efficiency. Sensitivity of economic efficiency and number of young bulls of optimized programs were investigated through a 20% fluctuation in economic parameters. As a result, economic efficiency of optimized program had the most sensitivity at 20% increase in discount rate and as well the economic value of milk production, and number of young bulls in the optimized program showed the most sensitivity to the 20% increase in discount rate. No change in the number of young bulls in the optimized program was observed through an increase of 20% in bull price, bull survival rate, semen storage costs, price of culled sires and economic value of milk production.

Adjusted milk yield for 305 days and two milking times along with actual first lactation records of 187138 Holstein cows were used to find out the effect of record adjustment on variance components estimation and on genetic evaluation. Records had been gathered by the Animal Breeding Center of Iran during years 1991 to 2006. The pedigree file included 288032 animals. A single animal model with Average Information Restricted Maximum Likelihood (AIREML) was employed for data analysis. Milk yield heritability was estimated as 0.24 and 0.23 for adjusted and actual records, respectively. The rank correlations of 0.977, 0.975, and 0.987 were estimated for all, female, and male animals respectively based on the estimated breeding values of adjusted and non-adjusted records. The rank correlations among the 100, 200, 1000, and 2000 top animals were 0.500, 0.377, 0.491, and 0.529 respectively. In general, it could be concluded that adjustment of records tends to incline the breeding value of animals toward the population mean, leading to selection of animals of average breeding value.

Linear Programming is a helpful and applied method for diet formulation based on minimum cost, but the minimum cost does not always mean maximum profit. This study was carried out to introduce a new diet formulation method based upon maximum profit to be replaced for minimum cost method. A total of 400 one-day-old broiler chicks (Ross 308) were employed in the study. All broilers were fed similar diets in the starter period. The experimental diet contained five nutrient density levels, but with nutrient to energy ratio being kept constant. Weight gain (P<0.01) and feed consumption (P<0.01) were significantly affected by the experimental diet. Software was designed in a way able to formulate diets based on maximum profit in a dynamic manner, and as well to predict the performance during the growth period. The predicting with this method showed that by decrease of broiler price in slaughterhouse or increase in cost of ingredients (except corn), diets of low nutritional value get more economical and if broiler price in slaughterhouses increase or ingredients' cost (except corn) decrease, high nutritional value diets yeild the greatest economical productivity. The results of this study indicate that diet formulation based on maximum profit method by using nonlinear programming could be effectively used in broiler diet formulations.

The effects of Monesin and propylene glycol on feed intake, milk production, and composition as well as some blood metabolites of 16 primiparous and multiparous Holstein lactating cows (60±30 Days In Milk (DIM), milk production of 33±3 Kg/day) were evaluated. Cows were experimentally in a arranged in a randomized complete block design of: 4 feeding treatments, and 2 blocks of either primiparous or multiparous. They were fed a balanced total mixed ration of 60% concentrate and 40% forages (with or without additives). Cows in group I were fed Total Ixed Ration (TMR) with no additives (control). Cows in group II were fed TMR with 335 mg/head/day Monensin. Cows in group III were fed TMR with 400 ml/head/day of propylene glycol, and finally cows in group IV were fed TMR with 335 mg/head/day of monensin and 400 ml/head/day of propylene glycol. Daily milk yield, milk composition and some blood metabolites were recorded. Data were analyzed using mixed models for repeated measurements. The experimental treatments did not affect either feed intake or milk composition, but propylene glycol caused significant increase in cows' milk yield (P<0.05). Monensin along with propylene glycol significantly increased concentrations of plasma glucose and insulin (P<0.05). Plasma triglyceride was lower in monensin with propylene glycol treated¬ cows (P<0.05). This treatment had not significantly affected the concentration of plasma calcium and phosphorus (P>0.05). Based upon the results of the present study propylene glycol can improve milk production of cows in their early lactation stage and monensin together with propylene glycol improves the concentration of glucose and insulin, in the plasma.

An experiment was conducted to evaluate the effect of withdrawing vitamin and/or trace mineral premixes from grower and finisher diets of broilers. A 2×4 factorial arrangement of treatments, consisting of four diets and two-removal times (from 28 to 49, and from 35 to 49 days of age) was utilized. The four diets consisted of control, supplemented with vitamin (VIT) and Trace Minerals (TM) (T1); TM with no VIT supplements (T2); VIT but no TM supplements (T3); neither VIT nor TM supplements (T4). Average Weight Gain (WG) and Feed Intake (FI) were not affected by treatments of 28 to 35 days of age (P>0.05). Feed intake for T2 was lower (P>0.05) than for T1 in the 35 to 42 days of age removal time. There were no significant (P>0.05) differences observed between T1 and other treatments for this trait. Feed intakes for T1 and T3 were greater (P>0.05) than those for the other treatments during the last week of age. Feed efficiency (FE) was greater (P<0.05) for T4 than for T3 during the removal time of 35 to 42 days of age, but differences were not significant (P>0.05) in comparison with the other treatments. No significant (P>0.05) differences were observed among T1, T2, and T3 for feed efficiency. During the second days of age period weight gain for T2 and T4 were lower (P>0.05) than those for T1 and T3 during the last two weeks of age. FI for T3 was greater (P>0.05) than that for the other treatments during the last week of age, but no significant (P>0.05) differences were observed between T1 and T4. FI for T1 was greater (P<0.05) than for T3 during this period. FE for T3 was lower (P<0.05) than those for the other treatments during the last two weeks of age while greater (P<0.05) than for T4, but no significant (P>0.05) differences were observed among T1, T2 and T3. Carcass characteristics, mortality and incidence of leg disorders were not affected by treatments in this experiment (P>0.05).

This experiment was conducted to determine the effects of different molting programs on performance of W-36 Hy-line laying hens. The experiment was based on a completely randomized design. The experimental treatments were: restricted feeding method (on-off), California method with 4-d feed removal period (CAL-4), California method with 10-d feed removal period (CAL-10), north Carolina method with 14-d feed removal period (NC-1), north Carolina method with modified diet in resting period (NC-2), full fed (FF) method based on high com molt diet, Recommended Method by breeding management guide (RM). Early egg production was significantly different among such long term feed removal methods as (CAL-10), (NC-1), (NC-2) and other treats (P<0.05). Different molting procedures had no effect on feed conversion ratio (FCR) in the production period. Body weight reduction was significantly different between (FF), (CAL-4) treats and such long-term methods as (NC-1), (NC-2) (P<0.05). Shell thickness, egg persistency, haugh unit, and relative egg shell weight were determined in pre-experiment as well as in 5 and 10 weeks past the second production and there was no difference observed among these parameters although increased with molt in all groups. The results indicated that induced molting is an effective way to recovery in both quality and rate of egg production and it was concluded that the Full Fed (FF) program in addition to being suitable and simple was the optimum method for recovery of production, along with the needed animal welfare.

The objective of this study was to determine the effect of some environmental factors on the parameters and characteristics of the lactation curve in Iranian Buffalo ecotypes. The data consisted of 53222 test-day records in various stages of lactation and different parities recorded from 743 herds by Iranian Animal Breeding Center (ABC) during 1992-2005. The parameters and characteristics studied were milk production at the beginning of lactation (a); slope of the lactation curve up to the peak of milk production (b); slope after the peak of milk production (c); peak time; peak yield and persistency. Average milk yield, a, b, c, peak time; peak yield and persistency were 2340.8, 8.6, 0.6, 0.2, 3.2, 9.3, and 2.8 respectively. The effect of herd and year were significant on all parameters and characteristics of lactation curve (P<0.01). Season exerted a significant effect on milk yield, a, c, peak time and persistency (P<0.01). The effect of lactation period was significant on milk yield, a, c, peak yield (P<0.01) and b, persistency (P<0.05). Lactation period had no significant effect on peak time (P>0.05). Calving age had significant effects only on c, persistency (P<0.01) and b (P<0.05).

To estimate the genetic parameters for production and reproduction traits in Holstein cows, information from 15 herds recorded by Animal Breeding Center of Iran during 1980–2004, were employed. Estimations were made using restricted maximum likelihood method under an animal model ranging DF-REML and MATVEC software. Estimates of heritabilities for yield traits were moderate and ranged from 0.15 (fat yield) to 0.26 (milk yield). Heritabilities for fertility traits were low, and varied between 0.04 (interval from calving to first service) to 0.07 (gestation period length). Genetic correlations between yield traits were form -0.5 (milk yield and protein percentage) to 0.81 (milk yield along with fat yield). Most genetic correlations between fertility traits were close to zero. Genetic correlation estimates among yield traits and fertility traits varied from -0.51 (open days and protein yield) to 0.96 (protein yield and calving interval). Due to antagonistic genetic correlations between fertility traits and production traits, both these traits need to be taken into account in a selection program.

The aim of the present study was to evaluate the effects of sun-drying, ensiling and addition of Polyethylene Glycol (PEG) on deactivation of tannins in the Pistachio By-products Hull (PBH). The chemical composition, protein quality and phenolic compounds of fresh pistachio by-products hull, sun-dried and ensiled for either 30 or 60 days were assessed. Organic Matter Digestibility (OMD) and metabolizable energy (ME), either with or without PEG addition were assessed. Moreover, protein quality as according to CNCPS was determined. Following ensiling Water Soluble Carbohydrates (WSC), NDFom, ADFom and protein fractions B3 and C decreased (P<0.05), while the content of protein fractions A and B1 were increased (P<0.05). The concentrations of NDFom, ADFom, lignin (sa), NDIN and ADIN in dried PBH were increased (P<0.05), although, the content of WSC and protein fraction B2 decreased (P<0.05). Ensiling for 60 days caused decrease in the condensed tannins, hydrolysable tannins and protein precipitable phenolics (P<0.05). Adding PEG to fresh, sun-dried and ensiled PBH, however, increased the ME and OMD (P<0.05). In conclusion, adding PEG to fresh, sun-dried and ensilaged PBH increased (P<0.05) ME and OMD demonstrating the positive influence of PEG, not evident in either mere sun-drying or mere ensiling, on inactivation of tannins in PBH.