List of Articles اکبر نیکخواه

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  1 - Optimal Forage Choices for Lactating Murciano-Granadina Dairy Goats: Feed Intake, Behavior Time Budget, Milk Production, and Blood Metabolites
  M.H. Khabbazan H. Amanlou D. Zahmatkesh E. Mahjoubi A. Nikkhah
  20.1001.1.2251628.2022.12.1.12.1
  It is important to optimize forage choices for improved milk production and goat health under intensive raising systems. Our hypothesis was that alfalfa hay (AH), corn silage (CS), and wheat straw (WS) can be utilized by lactating Murciano-Granadina goats towards effici More

  It is important to optimize forage choices for improved milk production and goat health under intensive raising systems. Our hypothesis was that alfalfa hay (AH), corn silage (CS), and wheat straw (WS) can be utilized by lactating Murciano-Granadina goats towards efficient milk production and that feed intake and efficiency and milk quantity and quality responses as well as metabolic parameters would differ among the forage sources. The objective was to determine effects of feeding different major forages on feed intake, behavior time budget, milk production and composition, and circulating blood metabolites in lactating Murciano-Granadina goats. Thirty lactating goats were used in a completely randomized design study with three treatments including diets containing 1) WS, 2) AH, or 3) CS at 40.3% of diet dry matter. Treatment diets were formulated to be isoenergetic (ME) and isonitrogenous (CP). Ten goats were assigned to each treatment. Forage source affected (P<0.01) dry matter intake (DMI), such that the highest intake was for CS (1904 g/d) and the lowest intake was for WS (1406 g/d) with AH being intermediate (1674 g/d). The yields of raw and fat-corrected milk, milk protein, lactose, and solids-nonfat were greater (P<0.01) for CS than for other two forages. Milk contents of fat, total solids, urea nitrogen, unsaturated fatty acids, polyunsaturated fatty acids, and blood concentrations of total proteins were greater (P<0.05) for AH than for other forages. Milk somatic cell counts tended to be lower (P<0.10) for CS than for AH and WS. Treatments did not affect (P>0.10) times spent standing, lying and ruminating, and blood concentrations of glucose, albumin, and non-esterified fatty acids. Total protein concentrations in serum were, however, greater (P<0.05) for AH than for CS and WS. In conclusion, different forage choices can be fed to lactating Murciano-Granadina goats with different aims; CS for increased milk yield, AH for improved milk fat content, and WS for lower feed cost. Changes in forage cost and availability, production systems and strategies, and consumers' demand will determine how to optimize forage choices for lactating goats. Manuscript profile
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  2 - Optimizing Starch Nutrition for Rhythmic Dairy Cattle: The Sustaining Economic and Environmental Challenges of Today's Industry
  A. Nikkhah
  20.1001.1.2251628.2021.11.2.1.5
  Starch makes up a considerable portion of dairy diets (up to >30%). Thus, starch utilization efficiency immensely affects rumen function, animal performance and health, farm economics, and environmental quality. It is crucial to take into account the ruminal digestio More

  Starch makes up a considerable portion of dairy diets (up to >30%). Thus, starch utilization efficiency immensely affects rumen function, animal performance and health, farm economics, and environmental quality. It is crucial to take into account the ruminal digestion rhythms of different cereals when formulating diets for optimal dry matter intake (DMI), milk production, and animal health. Optimizing the physical processing of cereal grains is required for maximal microbial protein yield and minimal sub-acute rumen acidosis (SARA). Physical processing of barley and corn grains, as the two most popular cereals in dairy diets, needs more contemplation towards synchronizing rhythms of starch and protein fermentation in the rumen. Optimizing the dietary inclusion rates of cereal grains and starch has been a key missing part in improving nutrient efficiency and gastrointestinal health and integrity. Global guidelines need to be developed to precisely address optimal dietary inclusion rates of different cereal grains. Setting such guidelines becomes more important when high-starch corn silage is major forage in the diet. Monitoring circadian rhythms of rumen fermentation when differently processed cereal grains are fed will allow developing feeding strategies that minimize the occurrence of SARA. The minimized SARA will enable decreasing nutrient loss across portal drained viscera (PDV) and splanchnic tissues. An innovative global philosophy is being developed to rely more on oil seeds and less on starchy grains in feeding dairy cows. To practically prevent SARA, physical processing can be partly effective, but essentially the dietary inclusion rate of differently processed cereal grains needs to be optimized. Lessons are to be learnt from human nutrition. Although metabolism differs between ruminants and non-ruminants, carbohydrates especially sugars and starch are under scrutiny and need to be limited in human diets to minimize risks from obesity and diabetes. Education, education and education is the final frontier for success in improving rumen and animal health as far as starch nutrition is concerned. For now, it is recommended to feed dairy cows no more than 25-28% starch (DM based). Future research will focus on establishing optimal dietary inclusion rates of differently processed barley and corn/sorghum grains for cows of different production levels and lactation stages. Rumen fermentation circadian rhythmicity and environmental considerations including decreased methane production and urinary and fecal nitrogen excretion will be discussed. Manuscript profile
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  3 - Physical Form of Calf Starter: Applied Metabolic and Performance Insights
  A. Nikkhah M. Alimirzaei
  20.1001.1.2251628.2023.13.2.1.9
  The objective of this review article was to evaluate and elaborate on dairy calves’ metabolic and growth responses to different physical forms of dry starter feed in relation to forage in the pre-weaning period. In addition, practical guidelines were discussed for More

  The objective of this review article was to evaluate and elaborate on dairy calves’ metabolic and growth responses to different physical forms of dry starter feed in relation to forage in the pre-weaning period. In addition, practical guidelines were discussed for on-farm uses. Apart from chemical composition, physical structure of solid feeds can influence nutrient intake and growth of young calves. Starter feed intake is essential for the timely development of a functional rumen and successful weaning transition with minimized weaning distresses. The calf starters produced commercially include pelleted, mashed, and texturized forms. Numerous studies have investigated the effects of physical form of starter and feed particle size on dairy calf performance. However, the results have been inconsistent. In addition, forage particle size in dairy calf diets has not been precisely determined and more investigations seem to be required. It is believed that alterations in the physicochemical properties of feed ingredients during processing influences rumen digestion that can partially explain the inconsistencies in research outcomes. Calf starter comprises large amounts of grains with different starch content and varying degradation dynamics, thereby differently affecting the rumen environment and calf growth. Grain type and processing method may interact with other starter ingredients such as forage and high-protein meals, making it difficult to decide which processing method or physical form would be optimal or preferred. Moreover, the first three weeks of calf life is thought to be more critical than the rest of the pre-weaning period, which requires distinct nutritional and management considerations. Encouraging calves to consume solid feed intake in the early ages may be a multi-advantage practice to ensure that calves eat more starter during the rest of the pre-weaning period. Accordingly, physical form of starter diet might affect solid feed intake differently during these two distinct pre-weaning periods. In conclusion, understanding the effects of feed processing on calf rumen physiology and metabolism may provide practical outlooks for optimal preparation of starter diets for calves at different stages of growth. Manuscript profile
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  4 - Physical Form of Concentrate for Lactating Murciano-Granadina Dairy Goats: Feed Intake and Sorting, Milk Production, and Blood Metabolites
  M.H. Khabbazan H. Amanlou D. Zahmatkesh E. Mahjoubi A. Nikkhah
  20.1001.1.2251628.2022.12.2.11.2
  Global demand for goat milk and its products is increasing. Goat producers are urged to improve feed efficiency and farm economics. Physical form of concentrate was hypothesized to affect lactating dairy goats’ responses in feed intake and sorting, milk production More

  Global demand for goat milk and its products is increasing. Goat producers are urged to improve feed efficiency and farm economics. Physical form of concentrate was hypothesized to affect lactating dairy goats’ responses in feed intake and sorting, milk production, and blood metabolites. The objective of this study was to determine effects of different physical forms of concentrate [mashed (M), pelleted (P), or textured (T)] on feed intake and sorting, milk production, and selected blood metabolites of lactating Murciano-Granadina dairy goats. Thirty Murciano-Granadina dairy goats in mid-lactation (87±6 days in milk; 2±0.04 kg/d milk yield) were used in a completely randomized design study and assigned to the three forms of concentrate (10 goats per treatment). Goats were fed the experimental diets as totally mixed rations (TMR). The data were analyzed using mixed models of SAS program. The dry matter intake (DMI) and yields of raw milk; fat-corrected milk; milk fat, protein, lactose, and solids not fat (SNF); and cheese as well as feed efficiency were improved (P<0.01) by feeding T instead of M and P. Feeding P vs. M improved milk production and feed efficiency (P<0.05). The milk percentages of fat, protein, lactose and blood concentrations of glucose, albumin, and non-esterified fatty acid (NEFA) were unaffected by treatments. Feed sorting occurred less for T than for the other physical forms of concentrate. Therefore, under the conditions of this experiment, feeding lactating Murciano-Granadina dairy goats TMR with textured concentrate compared to mashed and pelleted concentrates increased milk production and cheese yield estimates, and improved feed efficiency. Manuscript profile
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  5 - Effects of Freely Accessed Whey on Performance and Metabolism of Growing Murciano-Granadina Goats
  M. Yadegar Salehi A. Nikkhah M.H. Khabbazan B. Hajimohammadi Darabi S. Sadeghi B. Moshiri
  20.1001.1.2251628.2022.12.3.15.8
  The objective of the present study was to determine effects of freely accessed whey on feed intake and efficiency, growth performance, and various blood indicators of intermediary metabolism in growing Murciano-Granadina dairy goats. Thirty 5-month-old growing goats (16 More

  The objective of the present study was to determine effects of freely accessed whey on feed intake and efficiency, growth performance, and various blood indicators of intermediary metabolism in growing Murciano-Granadina dairy goats. Thirty 5-month-old growing goats (16±1 kg body weight; 15 males and 15 females) were randomly assigned to three treatments (10 goats per each treatment) in a completely randomized design study. The experimental treatments were provisions of 1) only freely accessed water or WA (without whey), 2) only freely accessed whey or WY (without water), and 3) freely accessed whey and water or WW (separately). The experiment lasted for 84 days including 14 days of adaptation and 70 days of sampling and data collection. A same total mixed ration was offered to all goats three times daily at 07:00, 14:00, and 21:00 h. Feed and liquid (whey and water) intakes were recorded daily and body weight (BW), body condition score (BCS), and rectal temperature (RT) were recorded biweekly. Blood was sampled at 0900 h on days 37, 60, and 84 for blood metabolites measurements. Data were analyzed by using the Mixed Model Procedures of SAS program. Results showed that BCS, RT, and daily feed and liquid intakes were not affected by treatments (P>0.05). However, average daily gain (ADG) and feed conversion ratio (FCR) were different among treatments (P<0.05), such that female goats fed WY had lower ADG and higher FCR than other female groups. Blood beta-hydroxy butyric acid concentrations were higher (P<0.05) in goats fed WY than in other goats. Blood insulin and non-esterified fatty acids concentration were lower (P<0.05) in goats on WW than in other goats. Blood total protein, albumin, and urea concentration were similar (P>0.05) among treatments. Findings confirmed that offering water and whey together (WW) had no undesirable impacts on goat growth performance. Thus, based on the results of the present study, freely accessed whey may be offered to growing goats alongside water. Also, male goats can effectively utilize WY (offering only whey without water) without any impacts on growth performance. Offering WY to growing goats increased blood glucose and different lipids and decreased some of the liver enzymes, which possess health and metabolic implications and warrant future investigations. Manuscript profile
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  6 - Crossbreeding Balouchi Sheep with Romanov: A Profitable Strategy to Improve Litter Size, Lamb Growth, and Carcass Characteristics
  A. Nikkhah M.H. Khabbazan A. Rezagholivand A. Rajaei S. Mokhtarzadeh H. Mousapour M. Moradi
  20.1001.1.2251628.2022.12.4.11.6
  Crossbreeding in sheep is strategically used to improve production and reproduction, especially when pastures have low quality. The objective of this study was to compare growth performance, birth and weaning body weights, and survivability between purebred Balouchi (n= More

  Crossbreeding in sheep is strategically used to improve production and reproduction, especially when pastures have low quality. The objective of this study was to compare growth performance, birth and weaning body weights, and survivability between purebred Balouchi (n=53) and crossbred Balouchi × Romanov (n=114) lambs. In addition, carcass characteristics (n=24) were determined. Balouchi ewes were inseminated with Romanov semen to produce crossbred lambs. All experimental lambs were weaned at 77 d of age and slaughtered at 10 months of age. Birth body weight of the purebred Balouchi lambs was significantly greater than that of the crossbred lambs (3.75 vs. 3.56 kg, P<0.01). However, weaning body weight (16.6 vs. 12.4 kg) and average daily gain from birth until weaning (152.2 vs. 126.0 g/d) and slaughter (125 vs. 95 g/d) were greater (P<0.05) for the crossbred lambs than for the purebred lambs. Slaughter body weight at 10-month age (36.9 vs. 36.1 kg) tended to be greater (P=0.08) for the crossbred lambs. Litter size was also increased by crossbreeding (1.13 vs. 1.00), but lamb survivability was not different between the two groups. The fat-tail-free carcass yield tended to increase with crossbreeding. Crossbreeding increased (P<0.05) the weights of testis (0.24 vs. 0.16 kg), liver (0.61 vs. 0.52 kg), heart (0.15 vs. 0.12, kg), and lung (0.47 vs. 0.40 kg), while it decreased the weights of skin (3.16 vs. 3.72 kg), fat-tail (0.30 vs. 1.29 kg), and total internal fats (1.08 vs. 2.06 kg). It is concluded that crossbreeding Balouchi ewes with Romanov’s semen resulted in improved litter size, weaning and slaughter body weights, average daily gains from birth until weaning and slaughter, and carcass characteristics without affecting lamb survivability. Therefore, crossbreeding can be a profitable strategy to increase lamb (meat) production in Balouchi sheep. Manuscript profile