Effect of evening primrose oil as food supplement on reproduction in the blue fox.

Addition of evening primrose oil (EPO) to a blue fox diet in the reproduction period was evaluated in an experiment with 2 groups, each of 12 male and 25 female blue foxes, regarding the effects on reproductive performance. The experiment was carried out as a field trial and the experimental period lasted from March 10 until the end of the mating season (males) or early July (females). During this period the control group was fed the standard diet of the farm and the experimental group was fed the same diet supplemented with 4.5 g EPO and 2.5 mg zinc sulphate per animal and day. An addition of 10 mg vitamin E per 500 mg EPO was made. The results were evaluated regarding male and female treatment effects. There was an increased rate of abortions in the EPO-group, but simultaneously a non-significant decrease in the frequency of barren females, resulting in a similar level of females without litters in both groups. A tendency for increased litter size in the EPO group was found, mainly as an effect of male treatment, which might indicate an effect on semen quality.     

Effects of High Dietary Levels of Fresh or Oxidised Fish Oil on Performance and Blood Parameters in Female Mink (Mustela vison) During the Winter,Reproduction, Lactation and Early Growth Periods

The effects of high dietary levels of fresh or moderately oxidised fish oil on performance and blood parameters in mink females were investigated during the winter, reproduction, and lactation periods. Furthermore, the effects of the diets on kit performance were investigated during the lactation and early growth periods. The investigation was carried out with a total of 292 females distributed in five experimental groups fed fresh fish oil stored frozen, fresh fish oil ensiled, oxidised fish oil stored frozen, oxidised fish oil ensiled, and soya oil, respectively. The females were weighed three times during the winter period, and the females and the kits were weighed at parturition and 2, 4, and 7 weeks post partum. Blood samples were collected from the females and the kits 6 and 8 weeks post partum, respectively. The results show that high dietary levels of fresh or moderately oxidised fish oil could be used for mink females during the winter and reproduction periods without any negative effects on performance, health and reproduction results. However, high levels of fish oil resulted in lower kit weights at weaning. These negative effects on kit growth were related to the dietary composition fed during the lactation and early growth periods and not to the diet used during the preceding winter and pregnancy periods. A high intake of polyunsaturated fatty acids resulted in a decreased number of blood platelets for both mink females and their kits.     

Effects of dietary protein level on nutrients digestibility and reproductive performance of female mink(Neovison vison)during gestation

The objective of this study was to determine whether nutrient digestibility and reproductive performance of pregnant mink(Neovison vison) were affected by different dietary protein levels. One hundred and twenty female mink were randomly assigned to four groups, receiving diets of fresh material with different protein levels. The dietary protein levels,expressed as percentage of dry matter(DM),were 32,36, 40 and 44% respectively. These values corresponded to average 320, 360, 400 and 440 g protein/kg DM, respectively. Results were as follows. All of crude protein digestibility, nitrogen(N) intake, N retention increased along with dietary protein level increasing. Low protein level(32%) significantly reduced the above indicators(P 0.05). DM digestibility and ether extract digestibility were not affected by dietary protein level. Results of mated females, barren females, kids per litter, live born kids per mated female, birth survival rate, and birth weight showed that mink achieved optimal reproductive performance when dietary protein level was 36%. In conclusion, dietary protein was anticipated to significantly influence some nutrients' utilization. Adopting the appropriate dietary protein level allow better reproduction performance. The most preferable reproductive performance was achieved when diet contained 275.5 g digestible protein per kg DM for female mink in gestation.     

Conception rates in farm mink (Neovison vison) in relation to first mating date,age and color variety

The aim of the study was to analyze the effects of the first mating date, age and color variety on the conception rates in farm mink. We analyzed female mink reproductive performance in 492 Sapphire and 463 Standard Black females over 3 or 4 years. The analysis included the number of inefficient matings, the interval between the first inefficient mating and the efficient mating (copulation) and the conception rates. The results show a significant effect of female's age and color variety on the conception rates. The youngest, yearling females of either color needed a higher number of matings per conception, as compared to older, 2‐ and 3‐year‐old females. Black females demonstrated a higher number of inefficient matings (1.066), as compared with Sapphires (0.730). Yearling females were most often mated from 1 to 10 March, and older females from 11 to 20 March. Older females achieved better conception rates than the yearlings. Dates between 11 and 25 March proved to be the optimum for the first mating, since the highest conception rates were observed if the females had mated during this period.     

Effects of equine chorionic gonadotropin on reproductive performance in anestrous mink.

The incidence of anestrous mink during the normal breeding season has been reported to be as high as 5%. We sought to induce estrus in these mink by using various doses of equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG). Seventy-five female mink maintained under standard ranch conditions failed to demonstrate estrus during the annual breeding season in March. These anestrous mink were randomly assigned to treatment groups. Treatments were given on March 16 and again on March 18. On these 2 d, mink were treated with equal doses of saline, 25, 50, or 100 IU of eCG, or 50 IU of eCG on March 16 and 50 of IU of eCG + 100 IU of hCG on March 18. Females were paired with males beginning on March 22. None of the saline-treated mink mated. In contrast, reproductive performance of the anestrous mink was significantly improved by treatment with eCG. This included proportion of mink breeding (47 to 100%), proportion giving birth (33 to 80%), and average litter size (2.6 to 4.0 kits per whelping female). Reproductive efficiency improved with increasing doses of eCG and was not further improved by addition of hCG. These results demonstrate that eCG has a potential application for treating anestrous mink during the breeding season.     

Response of animals to dietary gramine. II. Effects of feeding high-gramine yellow lupin seeds on reproductive performance of rats and on selected hematological and biochemical parameters in offspring.

Two groups of 26 male and 26 female rats at the initial age 30 +/- 2 days were fed during 31 weeks on diets containing 20 percent of yellow lupin seeds having low (LG) or high (HG) gramine content. The animals were mated twice within nutritional groups, 1 male: 1 female, and their main reproductive parameters were recorded. In both reproductive cycles body weight of females at mating, after parturition and after 21-days lactation was lower in HG than in LG group. Fertility rate and body weight of neonates were not affected by the diet while number of neonates per litter tended to be lower by 0.7 and 0.8 pups in HG than in LG group. Body weight of weaners was also substantially smaller in dams fed on HG than LG diet. Relative weight of spleen but not of liver, kidney and heart was significantly greater in HG females. Four weeks old males and females issued from the first litters born to LG and HG animals (ten males and ten females per treatment) were fed individually on respective diets during 3 weeks. Feed intake and growth rate did not differ between the treatments. In males relative weight of liver and testicles was greater, while hematocrit and red blood count were lower in HG than in LG group. In females organ weights did not differ. Activity of liver enzymes determined in males was not affected by the diet. It may be concluded that high-gramine lupin affects negatively lactational performance, probably via lower feed intake, but it does not induce apparent teratogenic effects in the progeny.     

One-generation reproduction toxicity study of Dithane M-45 (mancozeb) and lead acetate

The reproductive toxicity of lead acetate and of a fungicide formulation (Dithane M-45) containing 80% mancozeb was studied on rats. Lead acetate was applied in the feed in the following dose groups: control, 1,000, 5,000 and 10,000 mg/kg of diet. The three treatment groups received, in addition to the above doses of lead acetate, 4,500 mg/kg Dithane M-45 in the diet. The method was based on the OECD Guideline for Testing of Chemicals No. 415 (1981). Clinical symptoms and mortality were not found in the parent generation. The body weight of female animals decreased significantly before the pregnancy period. This tendency was also seen in males after the combination treatment. At the two high dose levels a remarkable body weight increase was seen in the female animals during the lactation period. As a result of treatment, decreased body weight of offspring was measured during the lactation period. No gross pathological changes were seen. Histological examination showed general tubulonephrosis in the experimental animals. It can be established that the administration of Dithane M-45 did not enhance the reproductive toxicity of lead acetate.     

舍饲滩羊母羊日粮营养水平对其繁殖性能的影响

旨在探讨日粮营养水平对舍饲滩羊母羊繁殖性能的影响。选取舍饲滩羊母羊作为试验对象,测定其在不同繁殖期的体重变化;同时,以轮牧滩羊母羊作为对照,测定并比较二者在不同繁殖期血清中的氮含量和激素含量,计算并比较二者在试验期间的主要繁殖性能指标。结果表明,舍饲羊妊娠前期和妊娠后期日增重分别为40.56 g和19.33 g,哺乳期体重日减轻53.17 g;舍饲羊在整个繁殖期的血清TP含量均高于轮牧羊,而轮牧羊在整个繁殖期的血清SUN含量均高于舍饲羊;舍饲羊在空怀期、妊娠后期和哺乳期血清中的E2含量高于轮牧羊,轮牧羊在妊娠后期和哺乳期的血清LH含量高于舍饲羊;试验期间,舍饲羊的繁殖成活率高于轮牧羊,且舍饲羊一年产两胎的母羊比例高于轮牧羊。改善日粮能量和蛋白质供给水平,能够有效提高滩羊母羊的繁殖率。     

组合添加剂对水貂繁殖性能的影响

为研究组合添加剂对水貂精子活力、配种率、平均窝产仔数、断奶成活率、断奶平均体重等繁殖性能的影响。选择种母貂36只、公貂6只,随机分为对照组和试验组,每组3只公貂,18只母貂,母貂设2个重复。对照组貂饲喂基础日粮,试验组在基础日粮基础中添加组合添加剂3 g/(d·只)。试验期120 d,试验期内,测定精子活力、配种率、平均窝产仔数、断奶成活率、断奶平均体重。结果显示,组合添加剂对貂的繁殖性能具有明显的改善作用。与对照组相比,试验组公貂精子活力、母貂受胎率、平均窝产仔数、仔貂断奶成活率和45日龄断奶平均体重等繁殖性能指标分别提高了2.44%、3.93%、13.04%、2.49%、1.85%。     

The effects of pregnant mare serum gonadotropin on follicular development, mating and pregnancy in mink

Forty-four female ranch mink, maintained out-of-doors under standard conditions, were exposed to natural photoperiod supplemented with a period of artificial light from approximately 2300 hr to 0300 hr from early January to mid February. Breeding was initiated on March 1. After repeated attempts to breed the animals, it was determined that the likelihood of their breeding was very low, presumably due to the artificial and asynchronous long-day photoperiod. In an attempt to induce breeding, the mink were randomly assigned to one of four treatment groups: saline, 25 International Units (IU) PMSG, 37.5 IU PMSG and 50 IU PMSG. Significantly different (p<0.05) patterns of breeding success were observed following PMSG treatment. Approximately 90% of the 37.5 and 50 IU PMSG-treated females bred while only 30 to 50% of the females in the saline and 25 IU PMSG-treated groups bred. More importantly, there was a marked difference in successful pregnancies observed between the saline- and PMSG-treated animals. None of the saline-treated females bore offspring while 40% of the animals that were treated with PMSG gave birth, with litter size averaging between 4 and 5 kits per female. Histological evaluation of ovaries obtained from an additional 13 animals treated in a similar fashion demonstrated that PMSG treatment significantly increased the number of small follicles. These results demonstrate that the exogenous administration of PMSG has a potential application in increasing the reproductive efficiency of female mink with functional ovarian tissue yet rendered infertile due to other factors.     

Monitoring blood glucose levels in female mink during the reproductive cycle: 1. Prevention of hyperglycemia during the nursing period

Nursing sickness, the largest cause of death in female adult mink, is a metabolic disorder characterized by hyperglycemia. The impacts of body condition, dietary supplements, and reproductive status on the blood glucose concentration in female mink during the reproductive cycle were investigated. Mink dams on 3 farms were assigned to receive either herring oil (HerO) or chromium picolinate (CrPic) or to be in a control group, receiving only the basal diet, for 6 wk at the onset of lactation. Hyperglycemia was observed throughout the reproductive cycle. Significant differences in blood glucose levels were observed between farms, emphasizing the importance of herd genetics and of animal management and feeding practices in glycemic regulation. Female mink exhibiting hyperglycemia early in the reproductive cycle tended to remain hyperglycemic and to have poorer health and fewer kits. Glucose levels > 7 mmol/L can be considered critical in this regard. Supplementing the diet with CrPic reduced the blood glucose concentration. Results from this study suggest that a diet containing high-quality n-3 polyunsaturated fatty acids, high levels of carbohydrate, and CrPic supplementation may help the nursing mink dam maintain a normal blood glucose concentration during lactation.     

木瓜粉对新西兰白兔繁殖性能及泌乳性能的影响

选取前2胎产仔数相近、体况一致的新西兰白兔妊娠母兔48只,随机分成3组,探讨木瓜粉对母兔繁殖性能、泌乳量及血清激素等指标的影响。对照组饲喂基础日粮,试验Ⅰ、Ⅱ组分别在基础日粮中添加5％、10％木瓜粉。妊娠18天时试验开始至仔兔30日龄断奶时结束,为期42天。结果显示：与对照组相比．试验组仔兔初生窝重、21天窝重、断奶窝重显著提高（P〈0．05）,产仔数、活仔数、断奶数等差异不显著（P〉0．05）．两试验组间差异不显著（P〉0．05）;木瓜粉显著提高母兔7、14、21天的泌乳量（P〈0．05）,提高21天血清E2、PRL水平（P〈0．05）。结果表明添加木瓜粉可提高母兔的繁殖性能和泌乳性能。     

Lifetime reproductive and financial performance of female swine

OBJECTIVE: To evaluate reproductive and financial performance for commercial swine herds grouped on the basis of pattern of removal of female swine. DESIGN: Cohort study. SAMPLE POPULATION: 25 swine herds. PROCEDURES: Lifetime reproductive productivity was summarized as number of pigs weaned per herd day per mated female and as number of herd days per pig weaned per mated female. Factors associated with these 2 measures were determined by use of linear regression. Financial data from a commercial database were used to estimate maximum number of parities at removal associated with profitability. Sensitivity analysis was used to simulate how variations in daily maintenance cost and value per weaned pig would influence profitability. RESULTS: Mean number of pigs weaned per herd day per mated female was 0.054; mean number of herd days per pig weaned per mated female was 20.2. Both these measures were associated with proportion of nonproductive days during herd life, preweaning mortality rate per litter weaned, mean lifetime number of pigs born alive per litter weaned, and mean lifetime lactation duration. Maximum parity at time of removal associated with profitability ranged from 5 to 8. Daily maintenance costs per female had a greater impact on lifetime profitability than did value per weaned pig. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that lifetime reproductive and financial performance is optimized among swine herds that have higher proportions of high-parity females.     

乙基纤维素包被VC对SPF级豚鼠繁殖影响的初步研究

为评价乙基纤维素包被VC对SPF级豚鼠繁殖性能的影响,选取SPF级繁育适龄雄性豚鼠24只,雌性豚鼠72只,按性别随机分成对照组、试验组Ⅰ、试验组Ⅱ、试验组Ⅲ,每组24只,其中雄性6只,雌性18只。试验组Ⅰ、试验组Ⅱ、试验组Ⅲ豚鼠饲料中分别添加500、1 000、1 500 mg/kg的乙基纤维素包被VC,对照组饲料中添加1 800 mg/kg的单体VC。使母鼠完成2胎的生产,期间观察母鼠妊娠期情况、有无脱毛、流产情况和生产仔鼠的健康状况,计算各组母鼠受孕率、产仔率、仔鼠出生重、离乳率。结果表明,当乙基纤维素包被VC添加量为500 mg/kg时,可获得与添加单体VC一致的饲养效果;当乙基纤维素包被VC添加量为1 000 mg/kg时,SPF级豚鼠繁育指标达到最优,可满足繁殖状态下SPF级豚鼠对VC的需求;当乙基纤维素包被VC添加量为1 500 mg/kg时,SPF级豚鼠繁育指标并无显著变化。综上提示,饲料中添加乙基纤维素包被VC代替单体VC进行SPF级豚鼠饲养切实可行,且乙基纤维素包被VC最优添加量为1 000 mg/kg。     

Response to intensity of reproduction in mouse lines resistant or susceptible to fescue toxicosis

Our objective was to examine whether mouse lines divergently selected for response to fescue toxicosis differed in the impact of increasing reproductive intensity on growth, final weight or first and second parity reproduction. Resistant (R) and susceptible (S) females were never mated (NR), mated only once (low reproduction, LR), mated after their first litter was weaned (moderate reproduction, MR) or paired continuously with a male (high reproduction, HR), allowing concurrent pregnancy and lactation. Final weight was significantly higher in mated than in not mated females (31.6 ± 0.6, 35.9 ± 0.6, 36.8 ± 0.6 and 37.2 ± 0.5 g for NR, LR, MR and HR females respectively), but the effect of increasing reproductive intensity was similar in both lines. Neither genetic line, reproductive treatment (LR and MR versus HR) nor their interaction affected first parity traits of dams or pups. In second parity, S dams produced larger litters at birth and weaning and heavier litters at birth than R dams, and MR dams produced more pups and heavier litters than HR dams. As with first litters, however, line by reproductive treatment interactions were not significant or important. Concurrent pregnancy and lactation (the HR treatment) had a similar dampening impact on the expected increase in litter size between first and second parity of both lines. Thus, lines divergently selected for toxicosis response did not differ significantly in the impact of increasing reproductive intensity on dam or pup growth, reproductive output through two parities or mature size. This conclusion should not be generalized. Selection responses in livestock should be monitored to ensure that improvement in one trait does not lead to deterioration in others.     

Effects of Family Housing on Behaviour,Plasma Cortisol and Performance in Adult Female Mink (Mustela vison)

Various behavioural, physiological and production-related parameters were examined in 200 adult female pastel and pearl mink either family housed in three-room cages with no weaning or housed singly in one-room cages after normal weaning procedures. Scanning observations of behaviour and use of the cages were performed in the nursing period and several parameters related to reproduction were registered. The adult female mink were weighed when kits were 16 weeks old (September) and again at pelting time (November). Blood samples were collected from all adult female mink in September at which time the teat condition and fur damage were evaluated. After pelting, bite marks on the leather side of the skin were counted, fur damage was graded after severity and the fur size was measured. Some positive consequences of being family housed were revealed. The familyhoused adult female mink showed a lower level of stereotypes and a higher level of defensiveness and curiosity than the adult female mink in one-room cages during the nursing period. In September and November, family-housed adult females were heavier than singly housed adult females. However, most of the physiological or production-related parameters pointed in a negative direction for familyhoused adult female mink. Reproductive success was somewhat reduced, although not significantly. Plasma cortisol levels were elevated in September, indicating higher levels of stress in these females. They showed a generally poor teat condition in September, with a high proportion of swollen or bitten teats. A high proportion of these adult females showed fur damage in both September and November, and a high number of bite marks was found on the leather side of the skins of these females, indicating that family housing had a high cost for the adult female mink. In conclusion, there seem to be some benefits, at least on the behavioural level, in keeping adult female mink in three-room cages during the nursing period, but both physiological and production-related parameters indicated that the welfare of the adult female mink was threatened if she was continuously cohoused with her litter past the normal age of weaning.     

Incidence of nursing sickness and biochemical observations in lactating mink with and without dietary salt supplementation.

The impact of dietary sodium on the incidence of nursing sickness in mink dams and on the average litter biomass of 28 and 42 day old kits was studied. One group (n = 115 including 12 barren females) was given a standard feed mixture with a natural content of 0.53 g NaCl/MJ and another group (n = 115 including 8 barren females) was given the same feed mixture supplemented with NaCl to a final content of 1.00 g/MJ. The average dam weight at weaning was significantly lower (P < 0.001) and the incidence of nursing sickness during the last part of the lactation period 3 times higher in the nonsupplemented group. The average litter biomass at weaning did not differ between the 2 experimental groups. A number of biochemical markers of preclinical nursing sickness, e.g. plasma aldosterone and osmolality, Na+ and Cl concentrations in plasma and urine, were studied during the last part of the lactation period and at weaning in 20 dams of the nonsupplemented group, in 10 dams of the salt supplemented group and, for comparison, in 5 + 5 barren females on the day corresponding to day 34 after parturition in nursing mink. The nonsupplemented group had significantly lower concentrations of sodium and chloride in plasma and urine and a significantly higher concentration of plasma aldosterone as compared to the salt supplemented group. Distinct signs of relative salt deficiency and preclinical nursing sickness thus characterized the nonsupplemented group throughout this period, while more blurred hints of electrolyte imbalances were noticed in the sodium chloride supplemented group at weaning. A beneficial effect of salt supplementation on the incidence of nursing sickness was shown; however, it remains unclear whether salt deficiency can cause nursing sickness or whether salt acts as an appetite stimulant preventing inanition and the development of the disorder.     

Effects of Carbohydrate-free Diets on the Performance of Lactating Mink (Mustela vison) and the Growth Performance of Suckling Kits

The effects of carbohydrate-free diets on body weight changes, feed consumption, and plasma concentrations of nutrients, metabolites, and hormones in lactating mink and on growth performance in kits were investigated in a total of 108 litters during the lactation period of seven weeks. The litters were distributed in three experimental groups fed different ratios of metabolisable energy (ME) derived from protein and fat (61:38; 47:52; 33:66). The females and kits were weighed at parturition and 2, 3, 4, and 7 weeks after parturition. Blood samples were collected from females in the second, fourth, and sixth week of the lactation period. Carbohydrate-free diets fed to lactating mink can in principle support normal performance, health of the females, and growth performance of the kits. However, mink need a sufficient supply of available gluconeogenic precursors in the form of amino acids. In the present experiment, the diet with 33% of ME from protein contained insufficient amounts of gluconeogenic precursors for lactating mink, and three weeks post partum this group was excluded from the experiment. The differences in dietary protein level (61% and 47% of ME) and fat level (38% and 52% of ME) influenced the plasma concentrations of free fatty acids (FFA) and urea, but had minimal influence on plasma concentrations of other nutrients, metabolites, and hormones.     

羟甲基丁酸钙盐对妊娠后期-哺乳期母猪繁殖性能、乳成分及仔猪生长性能的影响

文章旨在评估日粮中添加羟甲基丁酸钙盐对妊娠后期到哺乳期母猪繁殖性能、乳成分及仔猪生长性能的影响.试验选择32头胎次接近的二元母猪,随机分为2组,每组4个重复,每个重复4头猪.对照组母猪在妊娠后期和哺乳期饲喂基础日粮,处理组母猪在妊娠和哺乳期饲喂基础日粮+8?mg/kg羟甲基丁酸钙,试验从分娩前6?d到仔猪21?d断奶....     

Effects of dietary star anise (Illicium verum Hook f) supplementation during gestation and lactation on the performance of lactating multiparous sows and nursing piglets

Thirty‐two sows were allocated to four treatments to evaluate the effect of dietary star anise (SA) supplementation during gestation and lactation on the lactational performance of sows. At 85 days of gestation, sows were randomly allotted to one of two diets supplemented with 0.5% SA or basal diet. After farrowing, sows were further allotted to one of two lactation diets supplemented with 0.5% SA or basal diet. On a weekly basis, body weight (BW) of sows and piglets was measured. Blood and milk samples were obtained from the sows and piglets. Number of days from weaning to estrus, milk yield and feed intake were also recorded. Weight gain of piglets from sows fed the SA‐supplemented diet during lactation was greater between days 7 and 14, days 14 and 21 and the overall experimental period compared with control groups. Supplementation of SA during lactation improved weaning weight of piglets, milk yield and average daily feed intake (ADFI) of sows. The SA diet increased concentrations of insulin‐like growth factor‐1 (IGF‐1) in ordinary milk and prolactin (PRL) in serum of sows. In conclusion, this study has indicated the beneficial effects of dietary SA addition in improving the lactation performance of sows.