مجله کاربردی علوم دامی ایران (Iranian Journal Of Applied Animal Science)
سال:1390 | دوره: | شماره: |تعداد مقالات:10

Neonate ruminants possess little cell-wall and starch degrading enzyme activity. Importantly, early establishment of fibrolytic, amylolytic, and proteolytic capacities is influential for the early expansion of the reticulorumen epithelia. Such an early development in reticulorumen fermentation will enable a timely hepatic adaptation to volatile fatty acids assimilation. The early nutrient release in the reticulorumen can thus facilitate early weaning, reduce labor costs, save milk, and lessen health issues associated with late weaning. The principal objectives of this review are to delineate roles of exogenous, polysaccharidases (EP) in stimulating fermentation development of the reticulorumen in young ruminants, to discuss the literature on nutrient digestibility and calf performance response to dietary EPs, and to provide insights into future possibilities for using dietary EP for young ruminants. Evidence has been increasing that cow milk may reduce the risk of cancer development and cardiovascular diseases. Therefore, nutritional implications for humans of supplementing calf diets with EP and its potential for milk savings is also discussed. Dietary incentives leading to savings in milk would aid in meeting the rising human demands for well-distributed milk products. Applying EP to both pre- and post-weaning starters would need to be evaluated before EP could be commercially expected for young ruminants on a large scale. Any benefits of nutritional strategies to the animal industry must also consider their implications for human health. As such, dietary use of EP for young ruminants may be considered as an interface of animal nutrition, farm economics, and animal-human health.

The study of the potntial for using Leucaena leucocephala or Manihot esculenta for supplementing feeding of West African dwarf goats were carried out from November 2003 to January 2004 in the Experimental Farm of the University of Dschang. Twenty four West African dwarf goats, were divided in three groups of eight animals, each one 12 months old with average weight of 13.1±4.4 kg, were used in this study. The animals of the supplemented group received 500 g of Leucaena leucocephala (group 2) or 500 g of Manihot esculenta (group 3) per animal per day, whereas those of the control group (group 1) did not receive any supplement. The animals were weighed every 14 days for the evaluation of growth. The body condition score (BCS) was taken at the beginning and at the end of the study. A sample of 100 g of Leucaena leucocephala or Manihot esculenta leaves was taken for the chemical composition analysis. The supplements had a high percentage of crude proteins (26.1% DM and 28.1% DM respectively for Leucaena leucocephala and Manihot esculenta leaves) and organic matter (91.3% DM and 92.8% DM respectively for Leucaena leucocephala and Manihot esculenta leaves).The ash content was 8.7 and 7.3% DM for Leucaena leucocephala and Manihot esculenta leaves, respectively. At the end of the study, the average BCS (3.9±0.1 and 3.7±0.1 for animals of group 2 and group 3) and average weight (AW) of the supplemented goats (15.5±3.7 kg and 15.4±3.3 kg for animals of group 2 and group 3) was significantly higher (P<0.05) than that of the control group (BCS: 2.9±0.1; AW: 13.5±5.1 kg). The total weight gain was 0.7, 2.4 and 2.2 kg corresponding to a daily average weight gain of 8.3, 30.4 and 27.6 g/d respectively for the animals of group 1, 2 and 3. The Leucaena leucocephala or Manihot esculenta leaves significantly improved the growth of the West African dwarf goats in West Cameroon.

The effect of yeast culture (Saccharomyces cerevisiae) supplementation on laying hen diets was tested against flavomycin supplementation during 12 weeks, using 112 Brown Bovans laying hens, 52 week-old, divided into 7 equal groups fed on a basal diet containing 18.8% crude protein and 2810 kcal/kg ME (metabolizable energy) feed. Three groups were supplemented with 3 different levels of commercial yeast culture (1, 2 and 3 kg/ton) and 3 groups were supplemented with 3 different levels of flavomycin (50, 75 and 100 mg/ton). ncreased levels of yeast culture supplementation significantly decreased hen-day egg production (P<0.05). Flavomycin supplementation showed the same result with the exception of the group that received 75 mg/ton which showed significant (P<0.05) increase in hen-day egg production. Egg mass was significantly increased (P<0.05) for the group receiving 75 mg flavomycin and significantly decreased in the group receiving 3 kg yeast culture. Both yeast culture and flavomycin supplementation significantly lowered (P<0.05) feed intake as mg/hen/day. Feed conversion was improved significantly (P<0.05) by the addition of 2 kg yeast culture and 75 mg flavomycin per ton feed. The addition of 50 mg flavomycin improved yolk percentage significantly (P<0.05). The blood constituents showed no significant differences among treatments for TP, AL and GL (P>0.05) AST, ALT and Glu values showed an increasing trend, with the highest significant values (P<0.05) of AST and Glu for the supplementation level of 100 mg flavomycin.Higher level of flavomycin (100 mg/ton) had adverse effects on blood plasma biochemical profile, but had no significant effects on egg production (P>0.05).

The objective of this work was to determine the effect of sex, breed and birth season of calves on intensity of MLLT (m usculus longissimus lumborum et thoracis) area changes and development of the selected body parts in bulls and heifers of Blonde d´Aquitaine (BA) cattle during rearing period. Two generations of bulls (n=63) and heifers (n=68) of Blonde d´Aquitaine (n=61) and crossbreds C×BA (C-Czech Fleckvieh) (n=70) born from December 2004 to June 2006 were evaluated. MLLT area measurements and subjective evaluations of 3 basic body areas muscling (shoulder, back and rump) on live animals were performed at 120, 210 and 365 days of animal age. Statistically significant differences were determined in shoulder, back, and rump muscling in relation to animal sex in favor of bulls at 120 and 210 days of age (P<0.01 to P<0.001). Purebred animals achieved significantly higher muscling of rump at 120 days, and muscling of rump and back at 210 days (P<0.05 to P<0.001). Statistically significant differences were determined in animals muscling in relation to birth season (P<0.05 to P<0.001). Results indicate the best growth ability of purebred bulls born from the end of year to March. Breeders can use this fact as a recommendation for modification of breeding and mating system of beef cattle to achieve better encashment of slaughtered animals.

To measure an unbiased farm-specific efficiency of individual dairy farmers, a shadow-price profit frontier adjusted for market distortion was applied to a sample of 860 Iranian small intensive dairy farms surveyed in 2005-2006. This measure was then compared with that of unadjusted measure that assumes undistorted market. A multiple general linear model (GLM) technique was applied to the data to examine the multiple effects of pure-bred animals, and the used farm capacity on profit efficiency indices. The mean value of adjusted profit efficiency was 0.40, significantly different from the latter measure, i.e.0.72, revealing overstating efficiency by ignoring imperfect structure of market. The difference between the figures is attributed to an index of market efficiency that was estimated of 46% in average. The number of pure-bred animals in the herd was found to affect the profit efficiency indices. Regardless of their characteristics, all the farms can gain from correcting the distortion in milk market, where small and average-sized farms are domain farms in the country.

Rice bran (RB) is a major by-product, produced from the rice milling process. This study was conducted to evaluate the performance, egg quality, and blood biochemical parameters of 288 Hy-line laying hens fed diets with rice bran and commercial microbial phytase Natuphos® 5 000. The experiment was a 4×2 factorial one with four RB levels (0, 5, 10, and 15%) by two phytase levels (0 and 5000 FTU/kg diet). These diets were fed to experimental groups from 30 up to 42 week old. The results indicated that there were no significant phytase effects or rice bran levels, on hen-day egg production, feed intake, egg mass, yolk index, egg shell weight, egg shell thickness, haugh unit, specific gravity, and shell weight/surface area compared with control group. Inclusion of the RB or phytase in laying hens diets did not significantly influence biochemical parameters (cholesterol, triglyceride, uric acid, glucose, total protein and albumin), and cholesterol in yolk. The results suggested that supplementing 500 0 FTU/kg diet of phytase enzyme for layers resulted in no further improvement; it was also indicated that use of RB at a dietary level is beneficial to the laying hens industry, up to 15% in Iran. Moreover, since the price of RB was cheaper than other major ingredients, dietary inclusion of rice bran (RB) would be beneficial.

This experiment was conducted to evaluate the effects of different levels of nettle (Urtica dioica) a medicinal plant in starter and grower feeds on performance, carcass traits, blood biochemical and immunity parameters of broilers. A completely randomized design was used with 324 broilers (Ross-308) divided in nine treatments and three replicates (with 12 birds in each replicate) 1 to 42 days. The treatment groups consisted of: (1) control group with no nettle supplementation, in other treatments the level of nettle in starter and grower feeds were, (2) 0.75% in both starter and grower, (3) 0 in starter and 0.75% in grower, (4) 0.75% in starter and 0 in grower, (5) 1.5% in starter and 0.75% in grower, (6) 0.75% in starter and 1.5% in grower, (7) 0 in starter and 1.5% in grower, (8) 1.5% in starter and 0 in grower, and (9) 1.5% in both starter and grower. The results showed that the use of different levels of nettle in starter and grower feeds had significant effects on carcass traits of broilers (P<0.05). The highest percent of breast and thigh (35.04), (26.29) were observed in groups 9 and 3, the highest percent of gizzard (3.76) was observed in group 6 and finally the highest percentage of liver (3.63) was observed in group 7. The overall results showed that the use of 1.5% of nettle medicinal plant in starter and grower feeds without having any significant effects on performance and blood biochemical and immunity parameters, showed positive effects on carcass traits of broilers.

Three groups of 11 New Zealand White (NZW) rabbit does, each were reared from 12 weeks of age on iso-energetic diets containing 16, 14 or 12% crude protein (CP) were used to study influences on productive performance, digestibility, some carcass traits, haematological, biochemical and hormonal parameters of rabbit does. The results showed rabbits fed on 16% protein diet had heavier body weights (BW) and body weight gains (WG) than the other groups. Daily feed intake (DFI) decreased and daily protein intake (DPI) increased by increasing dietary CP level whilst the feed conversion ratio (FCR) slightly improved as dietary CP increased. Dressing percentage increased slightly with increasing dietary protein level, while, rabbits fed 12% protein diet had a lower carcass weights compared to others. Moreover, the assessment results of mated does clarified significant increase in average daily or total FI and FCR, but significant decrease in kindling (%) in group fed 14% CP and in fertility and prolificacy% in 12 and 14% CP groups assessment of reproductive parameters, low protein levels had an adverse effect on litter size and kidney and liver weights of kids, while bunny weight decreased in the group fed 14% CP. However, plasma biochemical analysis showed a decrease in blood urea nitrogen (BUN) levels and activity of alanine-aminotransferase (ALT) and increase in creatinine in both two CP levels while no significant change in the concentration of total protein (TP), albumin (A), globulin (G), A/G ratio, calcium (Ca), phosphorous (Ph), iron (Ir) and aspartate-aminotransferase (AST) activity among three experimental groups was recorded. Furthermore, hormonal assay revealed a decrease in insulin.

Eighteen primiparous rabbit does comprising of six per breed of New Zealand White (NZW), Chinchilla (CC) and Dutch Belted (DB). They were randomly allocated to three rebreeding interval groups of 7, 14 and 21 days postpartum. Three breeding males, one per breed were used giving a total of 21 rabbits. Significant (P<0.01) doe milk yield in week two (DMY WK2) was observed on rebreeding interval groups. Twenty one (21) day rebreeding group recorded highest (83.1±4.12 g) followed by seven day rebreeding group (72.4±2.30 g) while fourteen day group had the least (69.2±3.31 g). Doe milk yield variability (P<0.01) was evident on the third week with the 21 day rebreeding group had the highest (89.1±5.67 g) followed by fourteen day rebreeding group (77.4±4.56 g) while 7 day rebreeding group had the least (63.9±3.16 g). Doe milk yield in the fourth week also showed variability due to rebreeding groups. The 21 day rebreed group had the highest (61.1±3.57 g) next by 14 day rebreeding group (57.6±2.87 g) while 7 day group had the least (47.7±1.99 g). Significant doe milk yield week one (P<0.05) and week two (P<0.051) were observed to be affected by parity. In week one, parity 4 had the highest milk yield (79.8±5.03 g) followed by parity 5 (75.9±6.75 g) while parity 1 had the least (51.6±3.42 g). In the second week, milk yield was highest (84.9±8.30 g) in parity 5, followed by parity 4 (76.4±6.19 g) while parity 1 had the least (61.7±5.79 g). It was observed that milk yield of rabbits increase with increase in rebreeding interval as well as with increase in parity. Doe and litter parameters were observed better at increasing rebreeding interval among rabbit breeds.

To clarify fermentative alterations in the large intestine (hindgut) during grazing, fecal alcohol and volatile fatty acids (VFAs) concentrations were evaluated in 30 dairy heifers. The heifers were kept in pasture growing mixed grass herbage from spring (mid May) until October, and their rectal feces were collected periodically. Concentrations of ethanol, methanol and isopropanol were increased in runny feces at early stage of grazing, but gradually decreased thereafter, despite the fact that ethanol remained at a high level until early October. Fecal VFA concentration was barely influenced at early grazing stage; however, it showed marked decrease thereafter.Hindgut exposure of increased nutrients which escaped upper tract digestion might promote active alcoholic fermentation in the colon of the heifers, particularly during early grazing period when runny defecation happens frequently.