Soraya Rafiee; Ali Sadeghi-Sefidmazgi; Seyed Reza Miraei Ashtiani; Hasan Mehrabani Yeganeh
Abstract
Objective: Linear type traits are recorded for some reasons in dairy cattle. Cows might reach to a high length of productive life and milk yield based on their ideal scores of type traits. In the dairy industry, type traits have indirect economic values due to genetic correlation with production, reproduction, ...
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Objective: Linear type traits are recorded for some reasons in dairy cattle. Cows might reach to a high length of productive life and milk yield based on their ideal scores of type traits. In the dairy industry, type traits have indirect economic values due to genetic correlation with production, reproduction, clinical mastitis and length of productive life. The main object of our study was to identify type traits that have high enough genetic correlation with length of productive life, clinical mastitis and somatic cell score. Therefore, we conducted a meta-analysis as a statistical tool, on studies investigating the correlation between length of productive life, incidence of clinical mastitis, and somatic cell score with type traits in Holstein dairy cows.
Material and methods: A comprehensive search of the literature was conducted using the key words “genetic correlation”, “type traits”, “length of productive life”, “clinical mastitis”, “somatic cell score” , “Holstein cow” in Google Scholar search engine. Out of the 103 potentially relevant papers found, 75 studies were excluded from the analysis, because these studies did not contain appropriate data. Finally, from the search results, we prepared three real data sets in relation to genetic correlation of linear type traits with length of productive life (6 studies), clinical mastitis (8 studies), and somatic cell score (17 studies) in Holstein cows. These studies involved the total of 263065, 4716267 and 922090 animals, corresponded to length of productive life, clinical mastitis and somatic cell score, respectively. Analyses were performed using “metafor” procedure in R software package. Due to the differences in estimation methods and sample sizes in different studies, a random model was used to perform the meta-analysis and to estimate key statistics such as effect size, 95% confidence interval and measure of heterogeneity (.
Results and discussion: The obtained results from meta-analysis showed that the type traits with higher genetic correlations with length of productive life were central ligament 0.19 and udder depth 0.14. Furthermore, somatic cell score was more genetically correlated with body condition score (-0.31) and udder depth (-0.25). The largest genetic correlation of clinical mastitis estimated was with udder depth (-0.28) and teat length (-0.23). Test of heterogeneity (statistics) indicated that there was significant heterogeneity (variance among studies) at the highest level (more than 99%). Results of this study might indirectly be applicable for estimation of type traits’ economic values of Holstein cow’s selection indices.
Conclusion: Meta-analysis of genetic correlation between length of productive life, somatic cell score and clinical mastitis with linear type traits clarified that central ligament, udder depth, body condition score and chest width could be used as indicator traits in Holstein cows breeding programs. Results suggest that central ligament and udder depth as main mammary system traits potentially might be taking into account to constract indices for selection in dairy breeding programs. Cows can produce higher amount of milk and spend higher productive period when they have achieved to ideal scores of type traits.
Jaber Khani; Ali Assadi-Alamouti; Mojtaba Yari; Elias Soltani
Abstract
Objective: Climate change has intensified research efforts toward replacing alternative forages for traditional sources used in the diets of ruminants. In Iran, water scarcity has severely limited alfalfa cultivation during the past decade, despite that it has been traditionally fed as a main portion ...
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Objective: Climate change has intensified research efforts toward replacing alternative forages for traditional sources used in the diets of ruminants. In Iran, water scarcity has severely limited alfalfa cultivation during the past decade, despite that it has been traditionally fed as a main portion of cattle diets. The aims of this study were to evaluate the agricultural performance, botanical characteristics, and chemical and nutritional value of two varieties of fodder vetch (Common vetch (Vicia sativa) and hairy vetch (Vicia villosa)) and one variety of fodder pea (Pisum arvense) as compared to alfalfa hay (Medicago sativa).
Method: The experiment was carried out in 2020, as a completely randomized design, with each of the four legume crops cultivated on one hectare as the experimental treatments. The seeding rate was 60 kg/ ha and the soil type was loamy-clay.
Results: The results indicated that both fresh and dry forage yields from hairy vetch were significantly higher than those of the other forages (p<0.05). Additionally, hairy vetch exhibited the highest physical productivity (crop yield per unit water) and economic productivity (benefit per unit water), while alfalfa had the lowest values for the latter parameters (p<0.05). Alfalfa and fodder pea contained the highest quantities of organic matter (89.6% and 89.5% of dry matter, respectively), followed by hairy and common vetch (86.6% and 85.4% of dry matter, respectively). Common vetch fodder contained 27.2% crude protein, while alfalfa contained 17.9%. Fodder peas and hairy vetch contained 22.1% and 22.7% crude protein, respectively. The highest neutral detergent fiber content was found in hairy vetch and alfalfa (41.1% and 41.2%, respectively), whereas the lowest was observed in common vetch fodder at 36.6% of dry matter. Alfalfa had lower soluble protein content (fraction A) but higher contents of protein fractions B2, B3, and C, compared to fodder peas and fodder vetch varieties. Nutritional parameters estimated from equations developed for forages showed that common vetch had superior feed consumption potential, digestible dry matter, total digestible nutrients, relative forage quality, net energy for lactation, and relative feed quality across treatments (p<0.05).
Conclusions: Favorable nutritional characteristics of the experimental forages combined with agronomic yield parameters, and water utilization efficiency led to the conclusion that the legume crops studied in this experiment were potentially comparable to alfalfa for ruminant diets. In vivo studies are needed to further explore the performance effects of these legumes and their optimal inclusion levels as forage substitutes for alfalfa.
Behzad Khorrami; Seyed Alireza Vakili
Abstract
Objective: Cattle are the major reservoirs of the pathogenic bacteria Escherichia coli O157:H7, and approximately 30% of feedlot cattle shed E. coli O157:H7. Feedlot calves are fed high concentrate diets in order to increase feed efficiency. It has been reported that populations of E. coli O157:H7 were ...
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Objective: Cattle are the major reservoirs of the pathogenic bacteria Escherichia coli O157:H7, and approximately 30% of feedlot cattle shed E. coli O157:H7. Feedlot calves are fed high concentrate diets in order to increase feed efficiency. It has been reported that populations of E. coli O157:H7 were higher in grain-fed than in forage-fed cattle, and when cattle were abruptly switched from a high concentrate diet to an all-forage diet, total E. coli populations declined 1000-fold. Therefore, strategies that decrease E. coli O157:H7 prior to slaughter will reduce human exposures to this virulent pathogen. However, a dietary switch to forage in feedlot calves is not advocated due to feasibility, weight loss and other logistical issues, other feedstuffs rich in phenolics such as essential oils (EO) could be a more feasible alternative strategy to reduce E. coli O157:H7 populations. Data available indicate a strong bactericidal activity of EO against pathogenic bacteria such as E. coli O157:H7. Among the EO, thyme (THY) and cinnamon (CIN) oil have attracted considerable attention in several literatures due to their potential antibacterial activity against ruminal microbes. The aim of the present research was to evaluate the effects of THY and CIN on E. coli O157:H7 population in the rumen and feces of feedlot calves fed high-concentrate diets.
Method: Twenty-four growing Holstein calves (214±16 kg initial BW) were used in a completely randomized design and received their respective dietary treatments for 45 d. Treatments were: 1-control (no additive), 2-THY (5 g/d/calf), 3-CIN (5 g/d/calf) and 4- forage (sudden switch from grain diet to forage diet in the last ten days of experiment; as positive control for relative abundance of E. coli O157:H7 in the rumen and feces). Calves were fed ad libitum diets consisting of 15% forage and 85% concentrate. Ruminal and fecal samples were collected from calves at the end of the experiment. Quantitative detection of E. coli O157:H7 in samples were done using specific primers and real-time PCR method.
Results: The average dry matter intake (DMI) and daily weight gain (ADG) of feedlot calves from day 36 to day 70 of the experiment was not affected by the experimental treatments. However, DMI and ADG decreased, and feed conversion ratio increased in calves fed forage treatment from day 71 to 80 (P<0.05). Supplementation of THY or CIN decreased the relative abundances of E. coli strain O157:H7 (rbfE) in rumen contents (P<0.05), while they did not affect strain O157:H7 (iudA). But forage treatment decreased the population of both strains of E. coli O157:H7 in the rumen fluid of feedlot calves compared to the control treatment (P<0.05). The experimental treatments also reduced the relative abundances of both strains of E. coli O157:H7 in the rumen and feces of feedlot calves compared to the control treatment (P<0.05).
Conclusion: The results showed that the use of thyme and cinnamon essential oil in feedlot calves diet can be a more suitable way compared to nutritional methods such as abruptly switched from a high grain diet to an all-forage diet to reduce the population of pathogenic bacteria Escherichia coli O157:H7 in the rumen and reduction of its shedding in feces.
Maghsad Sahneh; Abdolhakim Toghdory; Taghi Ghoorchi; mohammad asadi
Abstract
Objective: The nutritional value of corn industrial products is very important and it is one of the valuable sources of organic materials for industrial usage. Starch, animal feed, sugar syrup and oil are extracted from corn in starch factories. Residues from food industries are among the industrial ...
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Objective: The nutritional value of corn industrial products is very important and it is one of the valuable sources of organic materials for industrial usage. Starch, animal feed, sugar syrup and oil are extracted from corn in starch factories. Residues from food industries are among the industrial wastes that can be consumed by animals. In extracting starch and preparing glucose from corn, some by-products are obtained which are suitable for animal feeding. Among these products, the corn steep liquor is more taken into consideration. Corn steep liquor, which is produced during the wet milling process of corn kernels to extract corn starch and oil, is a relatively cheap, tasty and easily available product for animals and it has potential to be used as a feedstuff in ruminants due to its proper energy and protein content and low fiber concentration. Corn liquor, is a viscous liquid with a light to dark brown color which has a smell similar to silage and acidic pH, 3.86, which can be used in animal feed. Material and Methods: This study was conducted to evaluate the effect of corn steep liquor replaced for soybean meal on feed intake and ruminal fermentation of lactating Dalagh ewes. Twenty one ewes with parity 3 (average weight of 36±3.7 kg) were used in 3 treatments and 7 repetitions in the form of a completely randomized design. The treatments included: 1) control, 2) diet containing 4 percent of corn steep liquor of DM and 3) diet containing 8 percent of corn steep liquor of DM.
Results and Discussion: The results showed that dry matter intake increased with the increase of dietary corn steep liquor level (P≥0.05). There was no significant difference in rumen pH and protozoa population. Rumen ammonia nitrogen concentration increased with the increase of corn steep liquor level in the diet (P≥0.05). There was no significant difference in the concentration of butyrate, isovalerate, valerate and the ratio of acetate to propionate in the rumen among the experimental treatments. However, with the increase in the dietary level of corn steep liquor, the concentrations of propionate increased and the concentration of acetate and total volatile fatty acids decreased in the rumen (P≥0.05). Blood cholesterol concentration was not significantly different between different treatments; but total protein, urea nitrogen, triglyceride and blood glucose concentrations increased with increasing the level of corn steep liquor in the diet (P≥0.05).
Conclusion: According to the results, it can be recommended to add corn steep liquor to animal rations up to the level of 200 grams per kilogram of dry matter consumed.
Reza Naseri Harsini; Farokh Kafilzadeh; Mojtaba Haghighat
Abstract
Objective: Castration is one of the management activities practiced worldwide in order to reduce aggressive behaviour, sexual activity and to facilitate management ease. Numerous studies have been conducted comparing production efficiencies and carcass traits of intact and castrated beef cattle and sheep. ...
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Objective: Castration is one of the management activities practiced worldwide in order to reduce aggressive behaviour, sexual activity and to facilitate management ease. Numerous studies have been conducted comparing production efficiencies and carcass traits of intact and castrated beef cattle and sheep. It has been agreed generally that castration causes less growth efficiency and produces carcasses with higher fat contents which results in increased proportion of saturated fatty acids. However, effects of castration on mentioned parameters in goats has been less investigated, despite the fact that goats genetically deposit less fat in their muscles with a more favorable fatty acid composition compared with other ruminants. Therefore, this research was conducted to evaluate the effects of castration on growth performance and carcass and meat quality attributes in Markhoz kids.
Method: Sixteen male Morkhoz kids (13.2±1.6 kg live body weight, 3 months old) were used to evaluate the effects of castration on growth performance, carcass and meat quality attributes and fatty acid composition of longissimus thoracis and semimembranosus muscles based on a completely randomized design with 2 treatments and 8 replicates. Kids were castrated using ring castration in the respective treatment one week before the beginning of the experimental period. During 119 days of feeding experimental diet (formulated to meet NRC recommendations for small ruminants), growth performance of kids were recorded individually. Then, all kids were slaughtered and enough samples of each muscle were collected from the left side of each carcass, vacuum-packed and frozen at −20°C until subsequent determination of meat quality attributes including shear force, cooking loss, colour, proximate composition and fatty acids profile. The value of pH24, percentages of drip loss and water holding capacity were determined immediately on the day after slaughtering.
Results: Morkhoz kids castration decreased average daily feed intake and daily weight gain and increased feed conversion ratio significantly (P<0.05). However, cold carcass percentage, back fat thickness and rib eye area were not affected by castration. Fat percentage of longissimus thoracis and semimembranosus muscles increased significantly in response to castration (P<0.05), but crude protein content of muscles was similar in intact and castrated kids. Meat quality attributes of mentioned muscles, including pH24, drip loss, water holding capacity and shear force were not affected by castration; however, cooking loss percentage in longissimus thoracis muscle decreased significantly by castration (P<0.05). L* and b* indexes of meat colour showed similar values in both muscles of intact and castrated groups, but the value of a* index was significantly lower in muscles of castrated kids (P<0.05). Castration had no significant effect on fatty acid composition of intramuscular fat in the longissimus thoracis muscle and only minor effects on the fatty acid composition of semimembranosus muscle were observed, including significant reduction in C14:1 cis and C18:3 cis3 fatty acids percentages (P<0.05).
Conclusion: Results showed that Morkhoz kids castration, in addition to diminution of growth performance and feed efficiency, increase fat content of muscles which is not a desirable change with respect to consumers’ health.
Alireza Valizadeh; Ali Khatibjoo; Hassan Shirzadi; Mahdi Soltani
Abstract
Objective: Recently, the inclusion of phytogenic feed additives in poultry for the purpose of supplementing gut health and positively impacting performance has received a great deal of attention and concern. Thyme is used in poultry nutrition in the form of herbal feed additive as it is known that its ...
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Objective: Recently, the inclusion of phytogenic feed additives in poultry for the purpose of supplementing gut health and positively impacting performance has received a great deal of attention and concern. Thyme is used in poultry nutrition in the form of herbal feed additive as it is known that its contents, such as thymol and carvacrol, have a positive impact on broiler performance and feed utilization, which in turn results in enhanced economic profits. This improvement in performance can be attributed to activation of the digestive system structure and function which causes an enhanced absorption and metabolism of the nutrient supplement and its ability to alter the gut microbiota. Formulating diets based on ideal protein concept aim to reduce total N-excretions and ammonia emissionswhile meeting the nutritional needs of the animals. Poultry needs a specific quantity and balance of essential amino acids and nitrogen (for synthesis non-essential amino acids, NEAA) rather than crude protein. Chickens fed the standard levels of dietary protein can synthesize NEAA from excess essential amino acids. However, when low-protein diets are used, less EAA is available for NEAA synthesis. Reducing dietary protein in broiler feed is not a new subject. However, it is revealed that only few trials covered an entire production cycle with several feeding phases while majority of experiments focused on one phase only. Thyme improve protein afficiency
Method: in this experiment, the effect two levels of Zataria multifolra (0 and 0.5 %) and two protein levels (100 (CP100) and 95 (CP95) % of Ross-308 broiler chickens’ requirement) on growth performance, physiological responses and meat quality were studied. In a completely randomized design with 2×2 factorial arrangement, 280 Ross-308 broiler chickens (one-d-old, mixed sexes) were allocated to 4 treatments, 5 replicates and 14 birds in each replicate. Growth performance, immune response, blood metabolites, blood cell count, meat quality and jejunum morphometry were considered.
Results: Feed intake, BW and FCR of finisher and total period of production, carcass parameters except abdominal fat percentage were not affected by thyme poweder, protein levels or their interaction (P > 0.05) while inclusion of thyme powder on CP100 diet improved BW and BWG of broiler chickens during starter and grower periods (P<0.05). Inclusion of thyme powder on CP95 diet decreased serum cholesterol and LDL-cholesterol and increased HDL concentration. Feeding CP95 diet contatining 0.5 thyme poweder led to increase total protein concentration and decreased liver enzymes activity (P < 0.05). Also, feeding CP95 diet containing thyme powder decreased heterophile but increased lymphocyte count (P<0.05). Dietary treatments had no significant effects on humoral immune response, relative weight of lymphoid organs, breast and thigh meat pH and color, and jejunum morphometry.
Conclusions: In conclusion, apart from addition of thyme powder, 5 percent protein dilution in this experiment had no negative effects on growth performance, immune response and meat quality of broiler chickens and it maybe suggestible for broiler chickens.
Hossein Mohammadi; amir hossein khaltabadi farahani
Abstract
Objective: Over the last decade, interest in detection of genes or genomic regions that are targeted by selection has been growing. Identifying signatures of selection can provide valuable insights about the genes or genomic regions that are or have been under selection pressure, which in turn leads ...
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Objective: Over the last decade, interest in detection of genes or genomic regions that are targeted by selection has been growing. Identifying signatures of selection can provide valuable insights about the genes or genomic regions that are or have been under selection pressure, which in turn leads to a better understanding of genotype-phenotype relationships. The aim of this study was to identify candidate genes and genomic region related to litter size trait in Murcia-Granadina goats using the selective sweep methods.
Material and Methods: In this study, data from 643 Murcia-Granadina goat genotyped using Caprine 50 K BeadChip were used. Quality control measures were performed in Plink by setting animal call rate of 0.90, SNP call rate of 0.90 and SNPs with minor allele frequencies (MAF) lower than 0.01. To identify the signatures of selection, two statistical methods of FST and hapFLK were used. Candidate genes were identified by SNPs located at 1% upper range of FST and hapFLK. Finally, GeneCards and UniProtKB databases were also used to interpret the function of the obtained genes.
Results and Discussion: Using FST approach, we identified nine genomic regions on chromosomes 4, 5, 6, 8, 12, 13, 14, 15, and 22 chromosomes. The identified candidate genes associated with litter size trait in these genomic regions included KMT2E, CAMK2D, CTNNAL, DACH1, DNMT3B, STK3. Some of the genes located in identified regions under selection were associated with the oocyte growth, development and differentiation of ovarian follicles, fertility and growth and development of granulosa cells, which can be directly and indirectly related to the trait of the litter size. Also, survey on extracted QTLs was shown that these QTLs in cow orthologous associated sperm count and calf size. The results of hapFLK statistics in this research led to the identification of four genomic regions on chromosomes 1, 2, 5, and 11. The identified candidate genes associated with the litter size trait in these genomic regions included EDA2R, KCNH7 and CNOT11. It was determined that they had different functions in folliculogenesis and spermatogenesis. Also, survey on extracted QTLs was shown in cow orthologous associated calving interval.
Conclusion: By the way, various genes that were founded within these regions can be considered as candidates under selection based on function. However, will be necessary to carry out more association and functional studies to demonstrate the implication of genes obtained from association analyses. Finally, the results of our research can be used to understand the genetic mechanism controlling litter size trait.
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