Search

Milk is considered as the richest nutrition, being used by people. When drinking milk or water the radon gas will transfer from air to them rapidly. Since milk is majorly composed of water, probably radon existence in livestock consumable water could be the main cause of its presence in milk. Different portion of milk changed by radon gamma ray and consumption of radon included water or milk has its effects on the human body. For investigation the effect of radon in water or milk on human organs, this study has been done in two phases with MCNPX software. In the first phase, the dose rate of absorbed gamma ray by different portion of milk which is indoctrinated by 1 Bq/m3 of radon during a day is calculated. Moreover, the effects shown by milk and its components in radon gamma spectrum, which is demonstrator of milk absorption spectrum, are also surveyed. In the second phase as well, according to the human body phantom, the absorbed gamma dose caused by daily consumption of indoctrinated water or milk with 1 Bq/m3 radon is calculated. The production rate of free radicals in milk and its different components are derived according to escape data of MCNPX code.

The aim of this study was to evaluate the effect of postpartum mastitis between first calving and subsequent conception on production and reproduction performance as well as culling of Holstein cows. A data set of 9,183 first lactation cows was used. Results showed that the first cumulative 100 days' milk production and the milk yield standardized to 305 days were affected by the interval from calving to first mastitis (P0.05). Cows with one episode of mastitis produced more milk than those with repeated episodes of mastitis (P0.01). Increase in the number of mastitis episodes and also decrease in interval between first calving and mastitis increased services per conception (P0.001). Mastitis episode and the interval between calving and first mastitis had no apparent impact on the calving to conception interval (P0.05). Calving year, calving difficulty score, and cumulative first 60 days milk production had significant impacts on mastitis risk (P0.05). The interval from calving to the first incidence of mastitis decreased over the period studied (P0.001). Productive life tended to be decreased due to mastitis (P = 0.07). Survival analysis showed a significant difference between the lengths of productive life for cows with different intervals from calving to first mastitis (P0.01). The results demonstrated that clinical mastitis between first calving and conception reduced production and reproduction performance with an increase in chance of culling.

This study examined the effects of supplementation of fish oil and canola oil in the diet on milk yield, milk components and fatty acid composition of Holstein dairy cows in early lactation. Eight multiparous early lactation Holstein cows (42±12 DIM, 40±6 kg daily milk yield) were fed a total mixed ration supplemented with either 0% oil (Control), 2% fish oil (FO), 1% canola oil +1% fish oil (FOCO), or 2% canola oil (CO) according to a double 4×4 Latin square design. Each period lasted 3 wk; experimental analyses were restricted to the last week of each period. Supplemental oils were added to a basal diet which was formulated according to NRC (2001) and consisted of 20% alfalfa, 20% corn silage and 60% concentrate. Milk yield was similar between diets (p>0.05), but dry matter intake (DMI) was lower (p0.05). The proportion (g/100 g fatty acids) of short chain fatty acids (SCFA) decreased and polyunsaturated fatty acids (PUFA) increased (p0.05). The proportion of trans(t)-18:1 increased (p

The objective of this study was to evaluate the association of genetic differences in the bovine leptin gene and milk yield, reproduction, body condition score (BCS), and plasma glucose level in Iranian Holstein cows. In total, two hundred and thirty eight cows were used and genotyped for a restricted fragment length polymorphism at the leptin gene locus. Two genotypes, AA and AB, have been distinguished which have the frequencies of 0.89 and 0.11, respectively. The genotypes were distributed according to the Hardy - Weinberg equilibrium (Χ 2 = 0.733). During the first 12 wk of lactation, milk yield and composition, live weight, BCS and plasma glucose were measured in 50 cows. Data were analyzed based on a repeated measures ANOVA. During this period, milk yield and composition, live weight, BCS and plasma glucose level were similar among the genotypes. The first cumulative 60-d milk yield, 305-d milk yield, days to first breeding, days open and days from first breeding to conception using previous lactation records were also analyzed using Standard Least Square within mixed models. Fixed effects were year, season, parity and age at calving, and sire. For the reproductive traits the cumulative first 60-d milk yield was also added to the model. Animal was fitted as a random effect. A significant association was detected between the RFLP-AB genotype and 305-d milk yield (p

A study was conducted to isolate lactobacilli from the gastrointestinal (GI) tract of broiler chickens and to evaluate their application as a probiotic supplement. The GI contents of 12 broiler chickens from three different ages were collected and cultured on Man Rogosa and Sharp (MRS) agar. In order to determine bacterial species, different grown colonies were separated and subjected to the sequencing of the 16s ribosomal DNA fragment. An auto-aggregation test was performed for 39 isolated lactobacilli bacteria. Eight species were selected because of their convenient aggregation. In vitro tests including antibacterial activity, resistance to low pH, resistance to bile extract, ability to produce H2O2, cell surface hydrophobicity and adhesion activities on crop epithelial cells were performed for evaluating of probiotic potential for each strain. These tests were ranked according to their priority for probiotic strains. The total score obtained from different experiments is indicator of suitable strain. Under the in vitro conditions and with respects to the probiotic traits, Lactobacillus salivarius caeca4 and Lactobacillus crispatuscaeca10 were suggested as probiotic strain, and can be evaluated in an in vivo conditions of commercial birds. Key words: Lactobacilli, probiotic, gastrointestinal tract, chicken.

Twenty - nine Holstein cows were used to evaluate the effects of different dry period (DP) lengths on milk yield and composition, some blood metabolites, and complete blood count (CBC). Cows were assigned to one of 2 treatments: 1) 60-d dry period, 2) 35-d DP. Milk yield, from calving to 60 days, was not different for cows on the treatments (p =0.130). Cows in the 35-d DP produced more milk protein and SNF compare with cows in treatment 1 (p ≤ 0.05). Serum glucose, non-esterified fatty acids (NEFA), beta hydroxyl butyrate acid (BHBA), blood urea nitrogen (BUN), urea, and glutamic oxaloacetic transaminase (GOT) were all similar among the treatments. Body condition score (BCS), body weight (BW), complete blood count (CBC) and health problems were similar between the treatments. The results of this study demonstrated we can reduce the dry period length to 35 days with no problems., {"references":["J. B.Andersen, T. G. Madsen, T. Larsen, K. L. Ingvartsen, and M. O.\nNielsen. The effects of dry period versus continuous lactation on\nmetabolic status and performance in periparturient cows. J. Dairy\nSci. 88:3530-3541. 2005.","E. L.Annen, R. J. Collier, M. A. McGuire, J. L. Vicini, J. M. Ballam,\nand M. J. Lormore. Effect of modified dry period lengths and bovine\nsomatotropin on yield and composition of milk from dairy cows. J.\nDairy Sci. 87:3746-3761. 2004.","K. C. Bachman. Milk production of dairy cows treated with estrogen\nat the onset of a short dry period. J. Dairy Sci. 85:797-803. 2002.","K. C. Bachman and M. L. Schairer. Invited review: Bovine studies\non optimal lengths of dry periods. J. Dairy Sci. 86:3027-3037. 2003.","A. V. Capuco, R. M. Akers, and J. J. Smith. Mammary growth in\nHolstein cows during the dry period: Quantification of nucleic acids\nand histology. J. Dairy Sci. 80:477-487. 1997.","C. E. Coppock, R. W. Everett, R. P. Natzke, and H. R. Ainslie. Effect\nof dry period length on Holstein milk production and selected\ndisorders at parturition. J. Dairy Sci. 57:712-718. 1974.","M. A. De Feu, A. C. O. Evans, p. Lonergan, and S. t. Butler. The\neffect of dry period duration and dietary energy density on milk\nproduction, bioenergetic status, and postpartum ovarian function in\nHolstein-Friesian dairy cows. J. Dairy Sci. 92: 6011-6022. 2009.","J. K. Drackley. Biology of dairy cows during the transition period:\nThe final frontier. J. Dairy Sci. 82:2259-2273. 1999.","A. J. Edmonson, I. J. Lean, L. D. Weaver, T. Farver, and G. Webster.\nA body condition scoring chart for Holstein Dairy Cows. J. Dairy\nSci. 72:68-78. 1989.\n[10] E. Farries and S. Hoheisel. The influence of reduced dry periods on\nsome performance and metabolism traits in dairy cows. J. Dairy Sci.\n72(Suppl.1):565. (Abstr.) 1989.\n[11] D. A. Funk, A. E. Freeman, and P. J. Berger. Effects of previous days\nopen, previous days dry and present days open on lactation yield. J.\nDairy Sci. 70:2366-2373. 1987.\n[12] R. R. Grummer. Strategies to improve fertility of high yielding dairy\nfarms: Management of the dry period. Theriogenology 68s: s281-\ns288. 2007.\n[13] R. R. Grummer and R. R. Rastani. Why reevaluate dry period length?\nJ. Dairy Sci. 87(E-Suppl.):E77-E85. 2004.\n[14] M. S. Gulay, M. J. Hayen, H. H. Head, C. J. Wilcox, and K. C.\nBachman. Milk production from Holstein half udders after\nconcurrent thirty- and seventy-day dry periods. J.Dairy. Sci. 88:\n3953_3962. 2005.\n[15] M. S. Gulay, M. J. Hayen, K. C. Bachman, T. Belloso, M. Liboni,\nand H. H. Head. Milk production and feed intake of Holstein cows\ngiven short (30-d) or normal (60-d) dry periods. J. Dairy Sci.\n86:2030-2038. 2003.\n[16] R. N. Heitmann and J. M. Fernandez. Autoregulation of Alimentary\nand Hepatic Ketogenesis in Sheep. J. Dairy Sci. 69:1270-1281. 1986.\n[17] K. L. Ingvartsen and J. B. Andersen. Integration of metabolism and\nintake regulation: A review focusing on periparturient animals. J.\nDairy Sci. 83:1573-1597. 2000.\n[18] J. W. Klein and T. E. Woodward. Influence of length of dry period\nupon the quantity of milk produced in the subsequent lactation. J.\nDairy Sci. 26:705-713. 1943.\n[19] E. Lotan and J. H. Adler. Observations on the effect of shortening the\ndry period on milk yield, body weight, and circulating glucose and\nFFA levels in dairy cows. Tijdsch. Diergeneeskd. 101:77-82. 1976.\n[20] T. G. Madsen, M. O. Nielsen, J. B. Andersen, and K. L. Ingvartsen.\nContinuous lactation in dairy cows: Effect on milk production and\nmammary nutrient supply and extraction J. Dairy Sci. 91:1791-1801.\n2008.\n[21] D. Mashek, K. L. Ingvartsen, J. B. Andersen, M. Vestergaard, and T.\nLarsen. Effects of a four-day hyperinsulinemic-euglycemic clamp in\nearly and mid-lactation dairy cows on plasma concentrations of\nmetabolites, hormones, and binding proteins. Domest. Anim.\nEndocrinol. 21:169-185. 2001.\n[22] A. Pezeshki, J. Mehrzad, G. R. Ghorbani, H. R. Rahmani, R. J.\nCollier, and C. Burvenich. Effect of short dry periods on\nperformance and metabolic status in Holstein dairy cows. J. Dairy\nSci. 90:5531-5541. 2007.\n[23] R. R. Rastani, R. R.Grummer, S. J. Bertics.A. Gumen, M.C.\nWiltbank, D. G. Mashek, and M. C. Rich. Effects of varying dry\nperiod length and prepartum diet on metabolic profiles and lactation\nof periparturient dairy cattle. J. Dairy Sci. 86(Suppl. 1):154. (Abstr.)\n2003.\n[24] R. R. Rastani, , R. R. Grummer, S. J. Bertics, A. Gumen, M. C.\nWiltbank, D. G. Mashek, and M. C. Schwab. Reducing dry period\nlength to simplify feeding transition cows: Milk production, energy\nbalance, and metabolic profiles. J. Dairy Sci. 88:1004-1014. 2005.\n[25] B. Remond, J. Kerouanton, and V. Brocard. The effect of reducing or\nomitting the dry period on the performance of dairy cows. Prod.\nAnim. 10:301-315. 1997.\n[26] SAS Institute. User-s Guide: Statistics. Version 8 ed. SAS Institute,\nCary, NC. 1999.\n[27] H. Seifi, M. Gorji-Dooz, M. Mohri, B. Dalir-Naghadeh, and N.\nFarzaneh. Variations of energy-related biochemical metabolites\nduring transition period in dairy cows. Comp. Clin. Pathol. 16:253-\n258. 2007.\n[28] L. R. Schaeffer and C. R. Henderson. Effects of days dry and days\nopen on Holstein milk production. J. Dairy Sci. 55:107-112. 1972.\n[29] M. L. Schairer. Estrogen treatments for the initiation of dry off in\ndairy cows. M.S. Thesis. Univ. Florida, Gainesville. 2001.\n[30] A. Smith, , J. V. Wheelock, and F. H. Dodd. Effect of milking\nthroughout pregnancy on milk secretion in the succeeding lactation.\nJ. Dairy Res. 34:145-150. 1967.\n[31] J. T. Sorensen and C. Enevoldsen. Effect of dry period length on\nmilk production in subsequent lactation. J. Dairy Sci. 74:1277-1283.\n1991.\n[32] E. W. Swanson. Comparing continuous milking with sixty-day dry\nperiods in successive lactations. J. Dairy Sci. 48:1205-1209. 1965.\n[33] R. D. Watters, , J. N. Guenther, A. E. Brickner, R. R. Rastani, P. M.\nCrump, P. W. Clark, and R. R. Grummer. Effects of Dry Period\nLength on Milk Production and Health of Dairy Cattle. J. Dairy Sci.\n91:2595-2603. 2008.\n[34] J. W. Wilton, E. B. Burnside, and J. C. Rennie. The effects of days\ndry and days open on the milk and butterfat production of Holstein-\nFriesian cattle. Can. J. Anim. Sci. 47:85-90. 1967.\n[35] D. A. Whitaker, W. J. Goodger, M. Garcia, B. Perera, and F.\nWittwer. Use of metabolic profiles in dairy cattle in tropical and\nsubtropical countries on smallholder dairy farms. Prev. Vet. Med.\n38:119-131. 1999."]}

Several studies have indicated that reducing the length of the dry period to less than 60 days had a more detrimental effect between the first and second lactation than between later lactations (Annen et al., 2004). Other studies demonstrated that a dry period less than 40 days reduces milk yield in the subsequent lactation (Sørensen and Enevoldsen., 1991). Several experiments designed to examine the effects of reducing the days dry to approximately 4 weeks have shown no difference in milk production and/or fat corrected milk in the subsequent lactation (Gulay et al., 2003). The aim of the present experiment was to determine the effect of days dry (from 10 to 90 days, 10 days interval) on subsequent milk production and fertility of high producing Iranian Holstein cows.

Grains are often substituted for forage in ruminant diets to increase feed intake, diet fermentability, and animal growth rate. However, greater dietary starch concentration can lead to digestive disorders, such as ruminal acidosis and reduce performance (Owens et al., 1998). Adding non-forage fibre source, such as sugar beet pulp (SBP), to low-forage diets might reduce the negative effects of increased starch fermentation without increasing the filling effect of the diet to the same extent as forage fibre. So, substituting SBP for barley grain in a diet with moderately low forage content should alter ruminal fermentation and might increase mean or minimum ruminal pH. Thus, the objective of this study was to evaluate the effect of the substitution of barley grain with SBP on ruminal pH and ammonia nitrogen (NH3-N) concentration in Holstein steers.

Recently, there has been an interest in shortening the non-income-producing dry period (DP). Retrospective analysis of farm data and planned experiments both indicate about a 5 to 6% loss in milk yield during the subsequent lactation when the DP is reduced by approximately 30 d (Rastani et al., 2005). Additional milk produced during the extra 30 d of lactation can compensate for some of the loss in the subsequent lactation. There are, however, some advantages to reducing the dry period length, including increased income from milk in the current lactation, simplified management of dry cows through movement toward a one-group nutritional strategy, decreased metabolic disorders, and reduced strain on dry cow facilities. The aim of this study was to determine the effects of dry period length on milk production and composition in early lactating Holstein cows.

For profitable production of milk, a nonlactating or dry period is established between lactations of dairy cow. There has been substantial recent interest in shortening dry periods. Physiological studies show that the changes the udder goes through to prepare for the next lactation take about three weeks, and yet current advice is that the most appropriate dry period for a modern dairy cow is 45 to 60 days. More recent studies show good reason to question that advice, and suggest dry periods of 30 to 35 days have no detrimental effect on production, but information relating the effects of dry period to subsequent reproductive performance of lactating cows is sparse (Grummer, 2007). Also, the effect of this management change on follicular dynamic has not been adequately evaluated. Therefore, the objective of the present study was to determine the effects of dry period length on follicular dynamics in early lactating Holstein cows.

Sugar beet pulp (SBP) is fed to ruminants as a non-forage fibre source (NFFS) ingredient. Early work by Ronning and Bath (1962) demonstrated that SBP was similar in feeding value to barley grain for lactating dairy cattle, supporting classification of beet pulp as an energy concentrate. Sugar beet pulp contains approximately 40% neutral detergent fibre (NDF) and is unique in its high concentration of neutral detergent soluble fiber, especially pectic substances (~25% of dry matter (DM)). However, the effects of SBP when substituted with different feed sources in ration are variable that depend on chemical composition, types and physical characteristics. The time which cows spent eating and ruminating (total chewing time) is a measure of the physically effective fibre value of a feed. The objective of the present experiment was to evaluate the effect of substitution of barley grain with SBP as a NFFS on chewing activity of Holstein steers.

Revenue from dairy farms is directly dependent upon reproductive efficiency because it affects milk production and the number of calves born (Thurmond et al., 1990). Pregnancy loss can have devastating effects on economical success in dairy farms. Normal annual abortion risks have been cited to be 3–5%, once cows are beyond 42 days of pregnancy (Hovingh, 2002), or similarly an observable 2–5% in most dairies (Kirk, 2003). Although, there is little or no indication that milk production is a risk factor for increased pregnancy losses in dairy cattle (Santos et al., 2004), there is little information on the effect of pregnancy losses on subsequent milk production. The aim of this study was to evaluate the impact of different calving classes including eutocia, dystocia, stillbirth and abortion in the first calving on subsequent milk production in Iranian Holstein dairy cows.

Microbial inoculants are applied to forage at the time of ensiling to accelerate the decline of pH during the initial stage of silage fermentation, to preserve plant carbohydrates through homofermentation, and to preserve plant protein by decreasing proteolysis and deamination. Thus, inoculated silages are expected to improve animal performance. Whole crop barley has a low buffering capacity and abundant fermentable carbohydrates and is considered relatively easy to ensile. Results of previous experiments indicated that lactic acid bacteria-based inoculants have the potential to improve the ensilage of whole crop barley (Kung and Ranjit, 2001). The objective of the present study was to determine the chemical composition and in situ dry matter degradability of whole crop barley silage treated with one of two different types of inoculants (Lactobacillus plantarum or mixed with Pediococcus pentosaceus plus propionbacter freudenreichii as provide 1×105 CFU of lactic acid producing bacteria plus 1×104 CFU propionbacterium per g of DM).

There are too many physiological and nutritional factors which can influence lactation performance of early lactation Holstein dairy cows. Supplemental fat sources are utilized in rations for dairy cows as a common method to increase the energy density of the diet, especially in early lactation (Juchem et al., 2007). The fat sources also have a positive effect on milk fatty acid profile. Canola seed which contains 40% fat is an excellent source of dietary fat high in unsaturated fatty acids and protein for dairy animals. Canola oil contains 51% oleic, 25% linoleic, and 14% linolenic acids. Fish oil contains relatively high concentrations fatty acids of the n-3 family. It seems that feeding a blend of different oils will have more positive productive response than individual usage of them. The aim of this study was to evaluate the effect of feeding diets containing fish oil and canola oil starting from transition period on milk production and composition of early lactating Holstein cows.

Cow longevity is highly related to dairy farm profit. Cows are culled for a variety of reasons. The predominant reasons for culling are reproduction (i.e., failure to conceive), health, and low production (Bascom and Young, 1998). Half of the herd removals occur involuntarily and prematurely because of health disorders (Beaudeau et al., 2000). The decision to cull is a complex one. Farmers may consider many individual (such as age, stage of lactation, milk production, health status, and reproductive performance) and economic (such as milk price, the price of culled cows, and the price and availability of replacement heifers) factors when deciding to cull a cow. On the other hand, the risk of culling is not consistent across all stages of lactation. Cows experience the highest risk shortly after calving (Fetrow et al., 2006). Survival analysis allows for a more appropriate management of censored data and time-dependent covariates. Analyses of the reason and timing of culling is needed to predict herd performance. The objective of this study was to study the reasons and timing of cows leaving herd in two large Holstein dairy farms in Iran.

In ruminants, as much as 50% of the dietary crude protein can be converted to ammonia by ruminal microorganisms. A part of ammonia can be utilized as a bacterial nitrogen source; however, rates of ammonia production often exceed rates of ammonia utilization. Peptides are intermediates in the conversion of ingested protein to ammonia in the rumen and their accumulation depends upon the nature of diet (Mesgaran & Parker, 1995). The objective of the present experiment was to investigate the effect of diets differing in concentrate: lucerne hay ratios on the ruminal pH, ammonia-nitrogen concentration and ruminal peptide nitrogen concentration in Holstein steers.

Reproduction and milk production are the principal factors that are influencing dairy farm profitability. The dairy industry in Iran has changed dramatically in the last decade. The shift toward more productive cows and larger herds in Iran is associated with a decrease reproductive efficiency (Heravi Moussavi et al., 2004). Increased knowledge about the principal causes of reduced fertility is essential. The root cause of the declining fertility is probably a combination of a variety of physiological and management factors that have an additive effect on reproductive efficiency. Dairy cattle are inseminated and pregnancy is established while dairy cows are lactating. Based on the analyses of large datasets, there is clearly an antagonistic relationship between milk production and reproduction in dairy cattle (Lucy, 2001). It was shown that the hazard ratio for cumulative first 60-day milk yield and conception in high producer cows was 8 percent less than the others and also high milk yield was a risk factor for several reproductive disorders (Grohn and Rajala-Schultz, 2000). The objective of this study was to evaluate the effect of first 60-day cumulative milk yield on days open in Iranian Holstein dairy cows.

Forage quality is a key factor in dairy cattle nutrition. High moisture forages are so susceptible to loss their nutrients during ensiling. Canola is one of the oilseed plants that belong to Brassica species. Canola forage has high level of moisture in its tissues and must be wilted to 60 -65% moisture before ensiling. On the other hand, molasses and urea as two silage additives can be effective in improvement and preservation of canola forage quality. Molasses is commonly used to provide readily available energy for lactic acid fermentation. Addition of molasses can increase dry matter content of silage that related to relatively high dry matter content of molasses (Baytok and Aksu, 2005). Meanwhile, silage protein content can be increased and proteolysis decreased with the addition of urea. Application of urea to harvested forage before ensiling can restrict the fermentation processes and release ammonia to potentially enhance nutritive value of the ensiled crop and reduce deterioration during storage. The main objective of this study was to evaluate effects of different levels of urea and molasses on chemical composition and in vitro DM digestibility of whole crop canola silage.