Milk is synthesized by mammary epithelial cells of lactating mammals. The synthetic capacity of the mammary gland depends largely on the number and efficiency of functional mammary epithelial cells. Structural develop...Milk is synthesized by mammary epithelial cells of lactating mammals. The synthetic capacity of the mammary gland depends largely on the number and efficiency of functional mammary epithelial cells. Structural development of the mammary gland occurs during fetal growth, prepubertal and post-pubertal periods, pregnancy, and lactation under the control of various hormones （particularly estrogen, growth hormone, insulin-like growth factor-I, progesterone, placental lactogen, and prolactin） in a species- and stage-dependent manner. Milk is essential for the growth, development, and health of neonates. Amino acids （AA）, present in both free and peptide-bound forms, are the most abundant organic nutrients in the milk of farm animals. Uptake of AA from the arterial blood of the lactating dam is the ultimate source of proteins （primarily 13-casein and a-lactalbumin） and bioactive nitrogenous metabolites in milk. Results of recent studies indicate extensive catabolism of branched-chain AA （leucine, isoleucine and valine） and arginine to synthesize glutamate, glutamine, alanine, aspartate, asparagine, proline, and polyamines. The formation of polypeptides from AA is regulated not only by hormones （e.g., prolactin, insulin and glucocorticoids） and the rate of blood flow across the lactating mammary gland, but also by concentrations of AA, lipids, glucose, vitamins and minerals in the maternal plasma, as well as the activation of the mechanistic （mammalian） target rapamycin signaling by certain AA （e.g., arginine, branched-chain AA, and glutamine）. Knowledge of AA utilization （including metabolism） by mammary epithelial cells will enhance our fundamental understanding of lactation biology and has important implications for improving the efficiency of livestock production worldwide.展开更多
Many advances in genetic selection, nutrition, housing and disease control have been incorporated into modern pork production since the 1950s resulting in highly prolific females and practices and technologies, which ...Many advances in genetic selection, nutrition, housing and disease control have been incorporated into modern pork production since the 1950s resulting in highly prolific females and practices and technologies, which significantly increased efficiency of reproduction in the breeding herd. The objective of this manuscript is to review the literature and current industry practices employed for reproductive management. In particular the authors focus on assisted reproduction technologies and their application for enhanced productivity. Modern maternal line genotypes have lower appetites and exceptional lean growth potential compared to females of 20 yr ago. Thus, nutrient requirements and management techniques and technologies, which affect gilt development and sow longevity, require continuous updating. Failure to detect estrus accurately has the greatest impact on farrowing rate and litter size. Yet, even accurate estrus detection will not compensate for the variability in the interval between onset of estrus and actual time of ovulation. However, administration of GnRH analogs in weaned sows and in gilts after withdrawal of altrenogest do overcome this variability and thereby synchronize ovulation, which makes fixed-time AI practical. Seasonal infertility, mediated by temperature and photoperiod, is a persistent problem. Training workers in the art of stockmanship is of increasing importance as consumers become more interested in humane animal care. Altrenogest, is used to synchronize the estrous cycle of gilts, to prolong gestation for 2-3 d to synchronize farrowing and to postpone post-weaning estrus. P.G. 600~ is used for induction of estrus in pre-pubertal gilts and as a treatment to overcome seasonal anestrous. Sperm cell numbers/dose of semen is significantly less for post cervical AI than for cervical AI. Real-time ultrasonography is used to determine pregnancy during wk 3-5. PGF2a effectively induces farrowing when administered within two d of normal gestation length. Ovulation synchronization, single fix展开更多
This study was to assess the effect of fermented rapeseed meal(FRSM) in the diet of sows,taking into account the physiological period(pregnancy or lactation) and reproductive cycle(primiparous or multiparous sows),on ...This study was to assess the effect of fermented rapeseed meal(FRSM) in the diet of sows,taking into account the physiological period(pregnancy or lactation) and reproductive cycle(primiparous or multiparous sows),on production performance,nutrient digestibility,colostrum immunoglobulin content,and microbial flora in sows.The experimental material included 30 primiparous gilts and 30 multiparous sows after their second lactation.The animals in the control groups C_G(gilts) and Cs(sows)received a standard diet for pregnant or lactating sows,depending on the reproductive period.Experimental groups E_G and E_S comprised gilts and multiparous sows,respectively,receiving a diet with a 4%share of FRSM in place of soybean meal up to 100 d of gestation.In addition,from 100 d of gestation to7 d of lactation,the sows in experimental groups received a diet with a 9% share of FRSM,and then again a diet with a 4% share of FRSM until the end of lactation.The addition of 4% to 9% share of a FRSM component in feed significantly improves production parameters,mainly in primiparous gilts,leading to an increase in litter size and in litter weight at 28 d of age.It also helps to improve the digestibility of crude protein,fat,and crude fiber,and positively affects the gut microbiota of sows.Fermentation of rapeseed meal is an effective way to reduce anti-nutrients and to increase the level of lactic acid in the diet It also stimulates the immune system,which improves piglet health,reducing the severity of diarrhoea and mortality.展开更多
基金supported by Texas A&M Agri Life Research (H-8200)The Agriculture and Food Research Initiative Competitive Grant from the Animal Growth & Nutrient Utilization Program of the USDA National Institute of Food and Agriculture (2014-67015-21770)+4 种基金National Basic Research Program of China (2012CB126305)National Natural Science Foundation of China (31572412 and 31272450)the 111 Project (B16044)Natural Science Foundation of Hubei Province (2013CFA097 and 2013CFB325)Hubei Hundred Talent program
文摘Milk is synthesized by mammary epithelial cells of lactating mammals. The synthetic capacity of the mammary gland depends largely on the number and efficiency of functional mammary epithelial cells. Structural development of the mammary gland occurs during fetal growth, prepubertal and post-pubertal periods, pregnancy, and lactation under the control of various hormones （particularly estrogen, growth hormone, insulin-like growth factor-I, progesterone, placental lactogen, and prolactin） in a species- and stage-dependent manner. Milk is essential for the growth, development, and health of neonates. Amino acids （AA）, present in both free and peptide-bound forms, are the most abundant organic nutrients in the milk of farm animals. Uptake of AA from the arterial blood of the lactating dam is the ultimate source of proteins （primarily 13-casein and a-lactalbumin） and bioactive nitrogenous metabolites in milk. Results of recent studies indicate extensive catabolism of branched-chain AA （leucine, isoleucine and valine） and arginine to synthesize glutamate, glutamine, alanine, aspartate, asparagine, proline, and polyamines. The formation of polypeptides from AA is regulated not only by hormones （e.g., prolactin, insulin and glucocorticoids） and the rate of blood flow across the lactating mammary gland, but also by concentrations of AA, lipids, glucose, vitamins and minerals in the maternal plasma, as well as the activation of the mechanistic （mammalian） target rapamycin signaling by certain AA （e.g., arginine, branched-chain AA, and glutamine）. Knowledge of AA utilization （including metabolism） by mammary epithelial cells will enhance our fundamental understanding of lactation biology and has important implications for improving the efficiency of livestock production worldwide.
文摘Many advances in genetic selection, nutrition, housing and disease control have been incorporated into modern pork production since the 1950s resulting in highly prolific females and practices and technologies, which significantly increased efficiency of reproduction in the breeding herd. The objective of this manuscript is to review the literature and current industry practices employed for reproductive management. In particular the authors focus on assisted reproduction technologies and their application for enhanced productivity. Modern maternal line genotypes have lower appetites and exceptional lean growth potential compared to females of 20 yr ago. Thus, nutrient requirements and management techniques and technologies, which affect gilt development and sow longevity, require continuous updating. Failure to detect estrus accurately has the greatest impact on farrowing rate and litter size. Yet, even accurate estrus detection will not compensate for the variability in the interval between onset of estrus and actual time of ovulation. However, administration of GnRH analogs in weaned sows and in gilts after withdrawal of altrenogest do overcome this variability and thereby synchronize ovulation, which makes fixed-time AI practical. Seasonal infertility, mediated by temperature and photoperiod, is a persistent problem. Training workers in the art of stockmanship is of increasing importance as consumers become more interested in humane animal care. Altrenogest, is used to synchronize the estrous cycle of gilts, to prolong gestation for 2-3 d to synchronize farrowing and to postpone post-weaning estrus. P.G. 600~ is used for induction of estrus in pre-pubertal gilts and as a treatment to overcome seasonal anestrous. Sperm cell numbers/dose of semen is significantly less for post cervical AI than for cervical AI. Real-time ultrasonography is used to determine pregnancy during wk 3-5. PGF2a effectively induces farrowing when administered within two d of normal gestation length. Ovulation synchronization, single fix
文摘This study was to assess the effect of fermented rapeseed meal(FRSM) in the diet of sows,taking into account the physiological period(pregnancy or lactation) and reproductive cycle(primiparous or multiparous sows),on production performance,nutrient digestibility,colostrum immunoglobulin content,and microbial flora in sows.The experimental material included 30 primiparous gilts and 30 multiparous sows after their second lactation.The animals in the control groups C_G(gilts) and Cs(sows)received a standard diet for pregnant or lactating sows,depending on the reproductive period.Experimental groups E_G and E_S comprised gilts and multiparous sows,respectively,receiving a diet with a 4%share of FRSM in place of soybean meal up to 100 d of gestation.In addition,from 100 d of gestation to7 d of lactation,the sows in experimental groups received a diet with a 9% share of FRSM,and then again a diet with a 4% share of FRSM until the end of lactation.The addition of 4% to 9% share of a FRSM component in feed significantly improves production parameters,mainly in primiparous gilts,leading to an increase in litter size and in litter weight at 28 d of age.It also helps to improve the digestibility of crude protein,fat,and crude fiber,and positively affects the gut microbiota of sows.Fermentation of rapeseed meal is an effective way to reduce anti-nutrients and to increase the level of lactic acid in the diet It also stimulates the immune system,which improves piglet health,reducing the severity of diarrhoea and mortality.
