مجله کاربردی علوم دامی ایران (Iranian Journal Of Applied Animal Science)
سال:1391 | دوره: | شماره: |تعداد مقالات:15

In pasture-based milk production systems, using available farm resources in order to reduce feeding costs, the composition and functional properties of dairy cows’ milk are of considerable importance to the dairy farmer, manufacturer and consumer. Basically, there are three options for altering the composition and/or functional properties of milk: 1) cow nutrition and grazing management, 2) cow genetics and 3) dairy manufacturing technologies. At the farm levels, manipulation of milk composition only occurs when it is perceived to be more profitable, normally; processing options are the option most considered. Nevertheless, opportunities exist for manipulation of milk composition on the farm to improve the human and physiological properties of milk and dairy products, such as enhanced concentrations of conjugated linoleic acid (CLA), or to improve its milk fatty acids (FA) composition for more efficient processing into a range of dairy products. This review considers the effect of dietary (pasture feeding, lipid feed supplements, seasonal and regional variations) and animal (breed, stage of lactation, parity and animal to animal) factors on milk FA composition of grazing dairy cows. Furthermore, it highlights the relevance that these factors, in the context of an integrative-view, might play on the sustainability of pasture-based milk production systems in humid areas in terms of milk differentiation and higher added value which profit would be directly reached for the milk producer on the farm.

Protein and energy are the two major components of feed that influence performance of the growing and fattening lambs. Provision of the quality of protein in the lamb’s diet does not only improve the animal performance but also ensures profitable animal production. Different vegetable protein sources are used to formulate the rations for growing and fattening lambs. These protein sources differ in amino acid profiles which results in varied responses of the animals. Protein source with a higher by-pass value have been re-ported to have more intense effects on N-balance, growth and muscle mass accretion than those which are lower in by-pass protein. Inclusion of protein sources with amino acid profiles matching closely to the amino acid needs of the growing lambs results in better growth performance and nitrogen utilization by the animal. Glucogenic amino acids present in some protein sources also improve the energy status of the animal by increasing gluconeogenesis. Presence of anti-nutritional factors may limit the inclusion of protein sources in the diet. Higher fiber contents like in sunflower meal adversely affect the animal performance by decreasing intake and digestibility. Canola meal has higher S contents that are available to the microbes at ruminal level to produce S containing amino acids. Furthermore, ruminal degradability of protein that is synchronized with carbohydrate digestion also results in better feed utilization and animal performance. So, a good protein source, regardless of its escape protein value, should have better amino acid and micronutrient profiles with safe levels of anti-nutritional factors.

The study was conducted to compare the effects of feedingAcacia auriculata (AA), Gmelina arborea (GA), Albizia lebbeck (AL) and Butryospermum parkii (BP) tree forages as a sole feed for Nigerian goats. Four goats (Yankasa) averaging one year and weighing 11.7±1.8 kg were used to measure the feed intake, di-gestibility and nitrogen balance. The leaves were offered ad libitum. Dry matter (DM) intakes were significantly different (P<0.05), with the highest on AL and GA (456.72 and 478.79 g/d respectively) and lowest on AA (155.01 g/d) with intermediate values for BP (207.65 g/d). Total intakes of N were significantly different among the browse plants (P<0.05). Significantly higher intake was observed on BP (125.41 g/d), while statistically similar intake was recorded on AL and GA and least on AA. The lower N intake of 31.54 g/d was observed in AA. The result of the nutrients digestibility showed a significant difference in the nu-trients digestibility (P<0.05). BP, GA and AL (80.56, 86.67 and 89.70 respectively) had significantly high digestibility, while AA had significantly lower DM digestibility (75.76). Also, the digestibility of organic matter (OM), crude protein (CP) and crude fiber (CF) followed similar pattern. Nitrogen balance showed significant difference (P<0.05) in fecal N output, AA had higher fecal N (16.76), followed by BP (12.42) and AL and GA had 9.95 and 7.70, respectively. Gmelina arborea, Albizia lebbeck and Butryospermum parkii have potential as protein supplement for Yankasa goats.

Data on 361 lambs of Mehraban (n=90), Ghezel (n=92), Ghezel × Mehraban (n=87), and Mehraban × Ghezel (n=92, sire breed listed first) were used to estimate individual Heterosis for lamb growth. The obtained results demonstrated that lambs of purebreds of Ghezel and Mehraban showed the highest and the lowest birth weight, respectively (P<0.05). Crossbred lambs of Mehraban × Ghezel showed significantly higher (P<0.05) average birth weight per ewe than Ghezel × Mehraban. Purebred Mehraban lambs showed the lowest total and average six month old weight per ewe (P<0.05) but the average and total six month old weight per ewe of Ghezel was not different than crossbreds groups of Ghezel × Mehraban and Mehraban × Ghezel lambs (P≥0.05). Individual heterosis for the average birth weight, total birth weight, average six month old weight and total six month old weight was estimated to be -0.37, -0.30, 0.22 and -1.03%, respectively (P≥0.05).

Genotypes of Iranian Zel sheep for Calpastatin (CAST) locus were determined by polymerase chain reac-tion-restriction fragment length polymorphism (PCR-RFLP) and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) methods and for Calpain (CAPN) locus by PCR-SSCP. Blood samples were collected from 200 purebred Zel sheep of Zel Breeding Station located in Golestan province in northeast of Iran. Extraction of genomic DNA was based on modified salting out method. The digestion of PCR products of CAST gene by Msp I and Nco I restriction enzymes revealed two alleles M and N, with frequencies 85.5 and 14.5%, respectively. Frequencies were 75, 21 and 4% for MM, MN and NN genotypes, respectively. Alternatively, using PCR-SSCP method, four genotypes including AA, AB, BB and AC with frequencies of 71, 21, 4 and 4%, respectively, were observed in this population. Analyzing CAPN gene by the PCR-SSCP method, revealed two different conformational patterns (AA and AB) with frequencies of 69 and 31% for AA and AB, respectively. Average heterozygosity for both loci was low (0.28 and 0.25% for CAST using PCR-SSCP and PCR-RFLP, and 0.26% for CAPN). Yearling weights (YW) were analyzed by a statistical model comprising PCR-SSCP and as a result CAPN genotypes had significant effect (P<0.01) on YW. A Chi-square test confirmed Hardy-Weinberg (H-W) equilibrium for the CAST locus using PCR-SSCP method but not for PRC-RFLP method and CAPN locus. Totally, the investigated herd had little genetic diversity and different factors disturb H-W equilibrium and PCR-RFLP and PCR-SSCP might be used successfully in these studies.

An experiment was conducted on eight weak and anaemic goats revealed pale conjunctivae, increased heart rate, rough hair coat, dullness and depression. The haematology showed significantly decreased haemoglobin (7.37±0.16 g %), packed cell volume (PCV) (23.37±0.56%), total erythrocyte count (TEC) (8.12±0.18 million/cumm), mean corpuscular haemoglobin (MCH) (9.10±0.30 pg) and mean corpuscular volume (MCV) (28.82±0.80 fl) in anaemic goats as compared to healthy goats. In anaemic goats, the serum level of total protein, albumin, albumin-globulin (A-G) ratio and blood glucose levels were significantly reduced. Biochemical analysis revealed decreased serum copper, cobalt and iron levels in anaemic goats. After haemato-biochemical analysis, anaemic goats were given a mineral preparation i.e., tablets COFECU plus at one tablet daily orally for 30 days. The anaemic goats gradually recovered by alleviating the anaemic syndrome in 30 days of treatment. The haemoglobin (Hb), packed cell volume (PCV), total erythrocyte count (TEC), mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV) parameters showed improvement after treatment but are not comparable with the values recorded for healthy control goats indicating some more duration for better recovery. No significant variations in neutrophils, lymphocytes, monocytes, eosinophils and basophils values were observed in anaemic goats before and after treatment. The biochemical parameters revealed decrease in total serum protein, albumin, albumin-globulin (A-G) ratio and glucose values in goats suffering from anaemia, which recovered satisfactorily as a result of treatment regimens given for 30 days. A significant improvement in serum copper, cobalt and iron levels were observed after treatment of 30 days but could not reach to the level of control. It can be concluded that tablet COFECU plus is quite effective with slow recovery rate in treating the nutritional anaemia in goats and suggest an increasein treatment period.

Six Red Sokoto (RS) and West African Dwarf (WAD) does, raised intensively in livestock farm of Michael Okpara University were evaluated for milk yield and composition in a ten-week study. The animals in their first parity were fed cut-and-carry forages in a cafeteria arrangement between 07: 00-08: 00 h daily and also were allowed access to concentrate supplementation by 14: 00 h. The forage consisted of a sword of Panicum maximum, Centrosema pubescens, Calapogonium mucunoides, Emilia sanchifolis, Tridax procumbens and Urenia lobata while the supplement was a 14.8% CP concentrate ration formulated from wheat, soya bean meal, maize offals, palm kernel cake. Drinking water was provided ad libitum. The does were hand milked daily from 6-8 am prior to feeding and yield determined for each group. Milk samples were bulked per animal per week and analyzed for total solids (TS), butterfat (BF), crude protein (CP), solids-not-fat (SNF) and total ash. Lactose was, however, determined daily from fresh milk samples and data obtained was analyzed using T-test. Results showed that lactose, CP and ash were not influenced (P>0.05) by species; however, butterfat, TS, SNF and milk yield differed significantly (P<0.05) between the small ruminant breeds. RS had relatively higher BF (4.81%) in milk than WAD goat (4.72%), but TS and SNF concentrations (%) were lower in the milk of RS (12.82, 8.22, respectively) than WAD (13.16, 8.59, respectively) goat. Macrominerals content of milk (calcium, potassium, magnesium, sodium and phosphorus) were also affected (P<0.05) by species. Calcium, magnesium and sodium concentrations (%) in milk were significantly higher (P<0.05) for RS (0.15, 0.11, 0.11, respectively) than WAD (0.12, 0.09, 0.09, respectively) goat; phosphorus and potassium levels in milk were, however, higher (P<0.05) in WAD (0.14, 0.11, respectively) than RS (0.13, 0.09, respectively) goat. Lactation performance for WAD and RS goats in the current investigation were relatively low when compared with existing records. Differences in yield and milk com-position within and between species in this study, relative to earlier reports, were attributed to genetic make-up, management and environmental factors.

The study was conducted to evaluate the effects of feeding varying levels ofFicus sycomorus leaf forages as protein supplements to a basal diet of urea treated maize stover. Four Yankasa goats averaging one year and weighing 11.7±1.8 kg were used to measure the feed intake, digestibility and nitrogen balance. The basal diet (urea treated maize stover) was supplemented with 0 (T1), 50 (T2), 100 (T3) or and 150 (T4) g of fresh F. sycomorus leaves. The intake of the basal diet was significantly (P<0.05) affected by supplementation with browse foliage. T3 had significantly P<0.05 higher maize stover intake. Significant (P<0.05) in-crease in total dry matter intake, was observed, with T4 being highest. Dry matter digestibility DMD was significantly (P<0.05) increased with supplementation. T3 and T4 were significantly higher and statistically similar (87.09 and 83.83), followed by T2 (75.82) and least T1 (71.82). Supplementation significantly (P<0.05) increased nitrogen retention, with an increase in the level of supplementation observed in this or-der 9.93, 15.46, 21.62, and 25.01 g/d for T1, T2, T3 and T4, respectively. Evaluation of Nitrogen retention as a percentage of intake followed a similar pattern. F. sycomorus has potential as a protein supplement and could be offered at 100g/day in growing goats fed urea treated low quality basal diets.

Semen from six adult male black Bengal goats (Capra hircus) was collected to compare the fresh and fro-zen thawed semen quality and investigate its relationship with the fertility. Each collected samples was divided into two parts: One part of semen was used as fresh and another part was filled into 0.50 ml straws, sealed, cooled (5°C) and equilibrated for freezing. In both cases, semen was diluted with commercial Tri-ladyl diluent (a Tris based diluter). The motility and morphology of fresh and frozen-thawed semen was subjectively evaluated by one operator. It was revealed that motility and sperm abnormality of the frozen semen differed significantly (P<0.05), but differed insignificantly in fresh semen between males. Besides these, fresh and frozen-thawed sperm motilities also differed significantly (P<0.01) between males which varied from 70.83±1.54 to 74.23±1.59% and 44.17±2.39 to 52.31±1.08%, respectively. A significantly (P<0.01) higher sperm abnormalities was observed in frozen-thawed semen (11.18±0.42 to 16.55±0.09%) than that of fresh semen (8.82±0.24 to 9.71±0.52%). Cervical inseminations were performed with fresh and frozen-thawed semen in 997 and 1004 female goats, respectively, both at Nucleus Breeding Flock (NBF) and four project areas. Fresh semen showed significantly (P<0.01) higher kidding rates (59.8%) than that with frozen-thawed semen (43.9%). The motilities of fresh and frozen-thawed semen were positively correlated (0.526 and 0.987; P<0.01), whereas the proportion of morphologically abnormal spermatozoa was negatively correlated (-0.530 and -0.776) with fertility of Black Bengal goats. Males with a higher motility and lower proportion of abnormal spermatozoa provided better fertility.

The effect of phosphorus supplementation to ammoniated rice straw was studied. Thein vitro experiment was carried out following the first stage of Tilley and Terry method. The treatments consisting of four diets were A=50% ammoniated rice straw+50% concentrate (control), B=A+0.2% phosphorus (P) supplement, C=A+0.4% phosphorus (P) supplement, and D=A+0.6% phosphorus (P) supplement of dry mat-ter. Completely randomized design was used as the experimental design with differences among treatment means were examined using Duncan’s multiple range test. Variables measured were total bacterial and cellulolytic bacterial population, cellulolytic enzyme activity, ammonia (NH3) and volatile fatty acid (VFA) concentrations, as fermentability indicators and synthesized microbial protein, as well as degradability indicators including dry matter (DM), organic matter (OM), neutral detergent fibre (NDF), acid detergent fibre (ADF) and cellulose. The results indicated that fermentability and degradability of diets consisting ammoniated rice straw with P supplementation were significantly higher than the control diet (P<0.05). It is showed that P supplementation is important for rumen fermentation and growth of rumen microbes. Overall supplementation of phosphorus at 0.4% of dry matter to ammoniated rice straw shown best results in terms of rumen fermentation, microbial protein synthesis and in vitro degradability.

The objective of this study was to compare the effectiveness of various combination activators of bovine oocyte following intracytoplasmic sperm injection (ICSI) in terms of cleavage and embryo development. Bovine ICSI oocytes were treated with a variation of treatments of combined or single activators as follows; 30 V for 15 x 2μsec of electrical pulse+10 μg/mL cycloheximide (CHX), 7% ethanol+CHX, 5 mM Cal-cium ionophore A23187 (Ca-I) +CHX, Ca-I+1.9 mM 6-dimethylaminopurine (6-DMAP), CHX alone, Ca-I alone. The highest cleavage (73.5%-79.7%), and blastocyst rates (28.0%-35.3%) were obtained in Ca-I+6-DMAP, ethanol+CHX and electrical stimuli+CHX groups. The treatment with CHX only or Ca-I only gave a significantly lower (P<0.05) yield of cleavagee rate and blastocyst than those treatments with Ca-I+6-DMAP, ethanol+CHX, electrical stimulation and Ca-I+CHX. In conclusion, these results show that post activation of ICSI oocytes with Ca-I+6-DMAP, ethanol+CHX, electrical pulse+CHX and Ca-I+CHX are more effective treatments for increasing blastocyst development than those CHX only or Ca-I only, however, activation with ethanol+CHX is recommended.

Heat stress (HS) often blamed for suboptimal reproductive efficiency and is a worldwide problem, which inflicts heavy economic losses reflected in limiting the breeding season of rabbits to be normally from Sep-tember to May in northern hemisphere and subtropical regions. The present experiment was conducted to study the effect of summer heat stress and the alleviating effect of some antioxidants on semen characteris-tics and the serum and seminal plasma oxidative/antioxidative status of New Zealand White (NZW) rabbit bucks. Forty-eight fertile NZW white bucks were randomly divided into six equal groups (n=8), first two groups served as control (summer heat stressed and winter) groups, the others, orally administrated ascorbic acid 40 mg/kg bw/d, zinc methionine 10 mg/kg bw/d, coenzyme Q10 10 mg/kg bw/d and L-carnitine 40 mg/kg bw/d. Blood and semen samples were collected once weekly among experimental period. Routine spermogram was performed. Lipid peroxidation, total antioxidant capacity and catalase activity in both serum and seminal plasma were assayed. The climatic data were continuously recorded among the experi-mental period and the weekly average temperature-humidity index (THI) was calculated. Summer HS adversely affected both qualitative and quantitative traits of spermogram but bucks remain within fertile limit. Thiobarbiric acid reactive substances (TBARS) showed a significant increase while total antioxidant capac-ity (TAC) and catalase showed significant decreases. Contrary to our expectation, selected antioxidants did not restore these parameters to their winter levels. It was concluded that zinc and L-carnitine were found to be the most beneficial antioxidants in the relief of spermogram of HS-induced effects. Serum and seminal plasma oxidative/antioxidant statuses followed an identical pattern in response to heat stress. Taking the current results into consideration, it can be stated that an adequate reproductive performance in NZW rabbit bucks can be achieved in summer and from the scientific point of view, it is not obligatory to stop breeding in summer months.

An experiment was performed to investigate the energy efficiency and effect of poultry house size on energy productivity in 3 different capacity management systems. Capacities of houses were 10000 (3 housings), 20000 (2 housings) and 28000 (1 housing) birds per production period and were assigned as HI, HII and HIII respectively. This experiment was conducted in a completely randomized design applying a nested pattern. Utilized energy in the form of fuel, electricity, feed, labour, wood shaving, chicks and utilized chemical as inputs and litter and broilers as outputs were measured in each production period. Result showed that inputs significantly decreased with increasing the size of poultry house from HI to HIII. A significant difference (P<0.01) in energy indexes was observed across the three capacities of housing investigated. Thus division input energy and cost in production of HIII exhiited better productivity than the other units in this study.

Feed restriction strategies are proven to be effective in increasing the growth performance and carcass parameters of broiler chickens. The objective of the present experiment was to evaluate the effects of feed removal for three hour time period on growth performance and carcass parameters of relatively older male broiler chickens. Twenty days old male broiler chickens (n=80) were allocated into 16 floor pens. Birds in eight pens were fedad libitum while those in other eight pens were fasted for 3 hours per day (13.00-16.00) during 21-42 d experimental period. There was a slight feed intake reduction (P<0.01) due to feed restriction during 21-25 d, but not thereafter. When feed was offered after three hours of deprivation, birds consumed significantly (P<0.01) higher amount of feed within first two hours, compared to the feed intake of ad libitum group during the same time period. Birds fed ad libitum were heavier (P<0.05) on day 42 but not on days 25, 30 and 35. Feed restriction significantly reduced the weight gain between 35-42 d (P<0.01) and the total weight gain (P<0.05) from day 21-42. Feed conversion ratio (FCR) between 30-42 d was significantly (P<0.05) lower under ad libitum feeding, and also overall FCR from 21-42 d was affected by the feeding regimes. Restricted feeding increased the total giblet weight (liver+heart+gizzard) (P<0.10), the carcass weight (P<0.01) and dressing percentage (P<0.05) while reduced (P<0.01) the length of the small intestine relative to carcass weight. Restricted feeding tended to reduce (P<0.10) the percentage of abdominal fat. The results conclude that feed restriction for three hours per day from days 21-42 increased dressing percentage while reducing abdominal fat content of matured male broiler chicken.

The aims of the present study were to propose a polymerase chain reaction-restriction fragment length polymorphism PCR-RFLP genotyping method for the AY_376689: c.773C>T single nucleotide polymorphism SNP of the equinePRKAG3 gene, related to muscle performance, as well as to characterize this SNP and a second polymorphism, AAWR_02017454: g.121684T>C of the SPATA1 gene, related to male fertility, in Mangalarga horses, in order to provide a basis for future studies investigating the association between markers and traits of interest in this breed. For this, 151 Mangalarga horses of both sexes, representatives of the population of the State of Sao Paulo, Brazil, were used. Polymerase chain reaction-restriction fragment length polymorphism PCR-RFLP was found to be adequate for the genotyping of the AY_376689: c.773C>T single nucleotide polymorphism SNP of the PRKAG3 gene. However, this polymorphism probably does not segregate in Mangalarga horses, a fact impairing association studies with muscle performance traits. The estimates of population genetic parameters obtained for the AAWR_02017454: g.121684T>C polymorphism of the equine SPATA1 gene demonstrated the possibility of association studies between this marker and traits related to male fertility.