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At least 19 recordsLinked to original sources
PubMed1992

High dietary taurine effects on feline tissue taurine concentrations and reproductive performance.

The reproductive performance and outcome of kittens was determined for female cats fed 0.05, 0.2 or 1% taurine. No adverse effects of high taurine diets were noted in the adults or offspring, and the reproductive performance was slightly better than that of females fed the normal (0.05% taurine) diet. Body weight at birth and brain weight at weaning were significantly greater in the very high taurine group than in the normal taurine group, although the greatest growth rate was achieved by the normal taurine group. The concentration of taurine in milk of lactating females was substantially higher in cats fed the higher taurine diets. Brain of adult cats was resistant to increases in brain taurine concentrations, as was brain of newborn cats. However, brain of juvenile cats responded to higher dietary taurine intake with increased taurine concentrations. These results indicate that the higher taurine content in cat foods recently introduced for prevention of feline dilated cardiomyopathy should have no adverse effects over a prolonged period on health and reproduction of cats.

Administration, Oral↗
PubMed1992

The effect of body condition, live weight, breed, age, calf performance, and calving date on reproductive performance of spring-calving beef cows.

Data from 321 spring-calving cows (mean calving date March 27) were used to assess the effects of body condition, live weight, cow age (from 4 to 13 yr), and breed (237 Hereford x Friesians and 84 Blue-Greys) and time of calving on the proportion of cows that became pregnant, the number of days from the start of mating to pregnancy, and calving interval. Mating started at turn-out to pasture in mid-May and lasted 9 to 10 wk. Body condition at calving and breed were the most significant animal factors affecting reproductive performance. Cows calving in higher body condition had shorter (P less than .001) calving intervals (11.2 d per unit of body condition at calving). Blue-Grey cows became pregnant in a higher proportion (90%) and calving interval was shorter (364 d) than in Hereford x Friesians (83%; 374 d). Body condition at the start of mating was less important and body condition at the end of mating had no effect. Live weight at calving and changes in live weight from calving to the start of mating and during the mating period had no significant effect. The proportion of cows becoming pregnant decreased significantly with age in Hereford x Friesian cows older than 7 yr. The variance in calving interval accounted for by calving date, body condition at calving, breed, and age was 42%.

Aging↗
PubMed1991

Effects of dietary fat on metabolic disorders and reproductive performance of dairy cattle.

Improved reproductive performance and reduced incidence of metabolic disorders have been postulated to be benefits of feeding supplemental fat to dairy cows. Increased plasma nonesterified fatty acid concentrations during fat supplementation may result from incomplete tissue uptake of fatty acids after lipoprotein lipase hydrolysis of very-low-density lipoprotein triglyceride; however, evidence suggests that net adipose tissue triglyceride hydrolysis may be increased during fat supplementation. Plasma 3-OH-butyrate concentrations remain relatively constant during fat supplementation but may have a tendency to be reduced if fat is supplemented to cows having relatively high basal plasma 3-OH-butyrate concentrations. Because plasma ketone levels usually increase when nonesterified fatty acid concentrations are elevated, it is hypothesized that potential antiketogenic effects of added fat are due to a glucose sparing effect. Supplemental fat does not seem to reduce hepatic lipid infiltration near the time of calving. Potential mechanisms by which supplemental fat may improve reproductive performance include stimulation of prostaglandin F2 a synthesis and secretion and enhanced utilization of blood cholesterol for progesterone synthesis. Days postpartum until first ovulation and luteal function of dairy cattle have been related to energy balance during the first 3 wk postpartum. Energy balance data for early lactation cows fed supplemental fat are not plentiful; however, slight but statistically nonsignificant increases have been observed when feeding fat. Cows fed supplemental fat that experience improved energy balance may begin to cycle sooner because of enhanced follicular growth and development. Applied studies examining the effects of supplemental fat on reproductive performance have provided inconsistent results.

Animals↗
PubMed1978

[Reproductive lifespan and reproductive performance in SPF C3H mice: the onset of reproductive life and production efficiency (author's transl)].

To improve the production system, the onset and the termination of reproductive life of C3Hf/HeMsNrs mice mated immediately after weaning and reared for 400 days of life, were studied. From weaning females mated with a full grown male (group A), the first litter was obtained at a mean age of 47 days, suggesting the first copulation at 26 days of age. The age of males at the first copulation was estimated to be at 44 days of age from the age giving the first litters in weanling males mated with weanling (group B) and full grown (group C) females. The sex ratio of litters delivered by young dams tended to be excess in males. The reproductive performance of dams in later life was not affected by the parturition in earlier age. The production efficiency with weaned youngs per pair during the first 200 days after mating was the highest in group A. It was found from these results that the C3H females attained their sexual maturity at 5 to 6 days after weaning, being available for breeding without any deletion in reproductive performance.

Age Factors↗
PubMed1992

Genetic influences on reproductive performance.

The potential for genetic improvement of reproductive performance in pigs is great. Improvement can be achieved by increased commercial use of F1 hybrid females produced by crossing lines with excellent reproductive performance and by selection within nucleus populations of these lines for improved reproduction as well a for growth and carcass characteristics. The value of incorporating reproductive traits in selection programs is critically dependent on the relative economic values of fat (or lean) and of extra pigs produced. There is widespread agreement that litter size is the first choice as both the selection objective and the criterion to improve reproductive performance, on economic, genetic, and ease of measurement grounds. Although there are few examples of successful response to selection for increased litter size in pigs (exceptions being the University of Nebraska selection experiment and results achieved by hyperprolific selection schemes), overall results do not suggest that selection for litter size is impossible, only that it is difficult with limited resources. Artificial insemination is being used increasingly by pig breeding companies to accelerate rates of genetic improvement and to improve dissemination. Combining data from genetically connected herds and analyzing with BLUP computer programs to make efficient use of information on relatives makes selection for litter size feasible while maintaining selection pressure for growth and carcass traits. Although selection for lifetime productivity is impractical today, the knowledge and data accumulated from successful breeding programs for litter size may help make it the selection objective of the future. Meanwhile, the search continues for useful indirect criteria for selection, from testis size to molecular markers, and scientists are working with highly prolific breeds of Chinese pigs to better understand the physiologic and genetic basis of large litter size.

Animals↗
PubMed1991

Effect of cobalt deficiency in the pregnant ewe on reproductive performance and lamb viability.

Reproductive performance and lamb viability in cobalt sufficient and subclinically deficient ewes, and from ewes experiencing repletion from and depletion into cobalt deficiency, were investigated in two experiments. The sheep were fed a cobalt deficient ration and supplementation was by oral dose according to treatment. The treatments had a significant effect (P less than 0.001) on ewe serum vitamin B12 and methylmalonic acid concentrations. There were no significant effects on ewe liveweight, condition score or conception rate. Cobalt deficient ewes produced fewer lambs and had more stillbirths and neonatal mortalities than cobalt sufficient controls. Lambs from deficient ewes were slower to start suckling (P less than 0.05), had reduced concentrations of serum immunoglobulin G and zinc sulphate turbidity levels (P less than 0.05), and had lower serum vitamin B12 and higher methylmalonic acid concentrations (P less than 0.05), than lambs from cobalt sufficient dams. Cobalt supplementation in either the first or second half of pregnancy only did not fully alleviate these adverse effects.

Animals↗
PubMed1992

Effects of expression of human or bovine growth hormone genes on sperm production and male reproductive performance in four lines of transgenic mice.

Reproductive performance was studied in transgenic males from lines expressing and transmitting four hybrid genes: mouse metallothionein-I/human growth hormone (GH) (MT/hGH), MT/hGH placental variant (MT/hGH.V), MT/bovine GH (MT/bGH) and phosphoenolpyruvate carboxykinase/bGH (PEPCK/bGH). Each male was exposed to three normal females for 1 week and to three different normal females for another week. Females were examined for vaginal plugs and necropsied on day 14 of pregnancy. Males were killed for analysis of organ weights, numbers of testicular spermatids, numbers of epididymal sperm and measurements of plasma glucose concentration. Fertility of MT/hGH and MT/hGH.V transgenic males was significantly lower than in normal males, primarily because most males failed to impregnate any females. In females that became pregnant, the numbers of corpora lutea, total fetuses and live fetuses did not differ from those in females mated to normal (nontransgenic) males. Fetal crown-rump length on day 14 of pregnancy did not differ between litters sired by normal or by transgenic males. Weights of testes and seminal vesicles were significantly greater in all four types of transgenic male, but daily sperm production per unit weight (g-1) of testis was not affected and epididymal sperm reserves were either normal or slightly higher than normal. Plasma glucose concentrations were significantly higher in PEPCK/bGH mice than in other mice. Average or individual reproductive performance of transgenic males from the various lines did not correlate with any of the parameters examined except for significantly heavier seminal vesicles in MT/hGH and MT/hGH.V males than in normal males; these transgenic males exhibited a high incidence of infertility. Since hGH and hGH.V, but not bGH, are lactogenic in rodents, it was concluded that chronic stimulation of GH and prolactin receptors by ectopically produced human GHs in transgenic mice compromises male fertility by an unknown mechanism. Reduced fertility of transgenic males with MT/hGH or MT/hGH.V hybrid genes is due to failure to inseminate or impregnate females rather than to reduced numbers of spermatozoa or gross changes in the male reproductive system.

Animals↗
PubMed1979

Reproductive performance of Iraqi buffaloes. I. Pattern of female reproduction.

In a buffalo herd at Amara Buffalo Breeding Station between October 1975 and October 1976 various features were investigated of the reproductive performance of heifers. The average age of the heifers was 22.01 at first estrus, 22.50 at ovulation, 26.05 at conception, and 38.8 months at calving. Estrus occurred at an average interval of 72.7 days after calving. Extended post-partum anestrus for more than 90 days was observed in 26.8% of the animals studied. The average length of the calving interval was calculated as 408 days. 67.3% of the calvings took palce between June and October.

Animals↗
PubMed1979

Reproductive performance of beef cattle in northwestern Queensland.

The reproductive performance of beef cattle in 5 herds mated all year round in north-west Queensland was examined from 1970 to 1973. Conception rates, conception patterns and branding rates were used to assess annual reproductive performance. The level of loss between the times of confirmed pregnancy and branding was defined. The mean annual conception rate was 83.1% with individual property means ranging from 75.4 to 90.9%. Conception rates for heifers, first calf cows and mature cows were 83.9%, 80.6% and 84.7% respectively. Conception patterns were influenced by seasonal conditions, 68.1% of conceptions occurring in the wet season, between December and May. In this region, conception patterns were highly correlated with rainfall during the previous month. Losses between the times of confirmed pregnancy and branding ranged from 5.9 to 27.7%. Body condition of animals varied and was dependent upon lactation, seasonal and parity effects.

Animals↗
PubMed1991

Light intensity effects on reproductive performance of turkey breeder hens.

Two trials were conducted to evaluate the reproductive performance of turkey hens to different light intensity during the lay period. In Trial 1 the hens were exposed to 16 h of light (L) and 8 h dark (D) per day (16L:8D) at 54, 108, or 216 lx and in Trial 2 a 2 x 2 factorial arrangement of treatments was used with main treatment factors being intensity level (54 versus 324 lx) and photoperiod (16L:8D versus 14L:10D). Data were collected for time to onset of lay, rate of lay, fertility, hatchability, and egg and poult weight in both trials, and feed intake in Trial 1. In both trials the light intensity treatments were similarly effective in the photoinduction of reproductive performance in Large White turkey hens. This occurred with daily photoperiods of both 14L:10D and 16L:8D in Trial 2 and there was no photoperiod by intensity interaction. There were no significant differences in feed intake or feed efficiency among the 54-, 108-, and 216-lx treatments of Trial 1. It may be concluded that reproductive performance of turkey hens in closed confinement is equivalent within an intensity range of 54 to 324 lx.

Animals↗
PubMedDate not supplied

The effects of melatonin and light treatment on the reproductive performance of yearling Suffolk rams.

The effects of melatonin and light treatments on the reproductive performance of yearling Suffolk rams was investigated. One group (group A, n = 5) remained in the local light environment (lat. 51 degrees 43'N). The other two groups (group B, n = 5; group C, n = 5) were given a priming period of long days [18 h light (L):6 h dark (D)] during 26 January-9 March. During 9 March-16 October, group B was exposed to short days (9L:15D) and group C was given melatonin implants (Regulin) at 5-weekly intervals. Testis diameter, sexual behaviour and semen quality were used to assess reproductive performance. The responses of groups B and C were similar and peak reproductive performance occurred in these groups significantly earlier than in group A. Peak performance was not maintained in groups B and C throughout the short day and melatonin treatment periods and this has been attributed to refractoriness. The response of group C clearly indicates that melatonin treatment may be considered as an alternative to photostimulation for the preparation of rams for out-of-season breeding.

Animals↗
PubMed1975

Observations on reproductive performance in the yearling mare.

Reproductive performance was studied in 137 yearling mares run with stallions in small groups for 3 months between June and August in 1968 to 1971 (four breeding seasons). Pregnancy diagnosis by repeated rectal palpation and qualitative tests for PMSG, showed that ninety-five mares conceived of which forty-four aborted spontaneously between Days 30 and 160 of gestation. Laboratory examination of twenty-one aborted fetuses failed to show any infectious agents. Serial quantitative and qualitative tests for PMSG in aborting animals gave results similar to those observed in mares with normal pregnancies. Plasma progestagen assays showed marked individual variations although the loss of the conceptus was always associated with a drop in progestagen level. The high incidence of early pregnancy loss in these pubertal mares may also be related to immaturity, inadequate nutrition and physical stress.

Abortion, Veterinary↗
PubMed1991

Reproductive performance following ectopic pregnancy.

The reproductive performance subsequent to operative removal of ectopic pregnancy was examined in 132 women. They represent 44.6% of 296 women admitted for ectopic pregnancy between 1981 and 1989. The follow-up period ranged from 6 months to 9 years, averaging 3.6 years. During the follow-up period, 69 (52.3%) pregnancies occurred. Among them, 60 (87%) were intrauterine and 9 (13% of the pregnant women) were repeated ectopic pregnancies. Full-term delivery was obtained in 73.9% of the pregnant patients. Forty of the 132 patients received conservative surgery and 92 patients received radical surgery for ectopic pregnancy. The operation method had no influence on subsequent fertility in women with an intact contralateral tube, who had significantly higher pregnancy (p less than 0.005) rate (3.8%) than women with an affected contralateral tube (39.5%, 47% and 41%, respectively). Compared with parous women (13.3%), the risk of repeated ectopic pregnancy was similar to nulliparous women (12.5%), but the nulliparous women had a slightly lower conception rate (40%) than parous women (54.8%). Unruptured ectopic pregnancies comprised 41.6% of our cases. There was no significant difference in fertility rate between ruptured and unruptured ectopic pregnancies in our study.

Fallopian Tubes↗
PubMed1992

Spermatogenesis and reproductive performance following human accidental exposure to bromine vapor.

The present study was undertaken to evaluate spermatogenesis and reproductive performance among 8 men and their spouses following accidental exposure to bromine vapor. Of the three cases with oligo-terato-asthenozoospermia (OTA), one had been diagnosed prior to and unrelated to the event. Mild OTA and unimpaired reproductive performance characterized the other two cases. Plasma levels of the follicle stimulating hormone and luteinizing hormone were normal in all men. One first-trimester abortion and one late abortion (due to chorioamnionitis) occurred among the 5 pregnancies conceived shortly after the accident. Results of the present study suggest a mild degree of spermatogenic suppression and impaired reproductive performance following paternal exposure to bromine vapor during the above described accident. However, due to the small size of the study cohort, a confidential cause-result linkage could not be established.

Accidents, Occupational↗
PubMed1976

A study of certain environmental factors and mineral chelation on the reproductive performance of young and yearling turkey hens.

The study presented was designed to determine the effects of laying cages and conventional litter floors, pen temperatures of 12.8 degrees, 21.1 degrees and 29.4 degrees C., and chelated (EDTA-Zn) vs. nonchelated trace mineral mixes on the reproductive performance of yearling force-molted and young Large White female turkeys. Reproductive performance, as measured by egg production, settable eggs, fertility and hatchability of fertile eggs, was not significantly different between young and yearling hens. Females fed a chelated trace mineral mix had a higher percentage of settable eggs, greater feed consumption and thicker egg shells. Females in laying cages laid at a higher rate, ate more feed, and weighed more than those on conventional floors. Significant differences were not observed between the two pen environments for hatchability of fertile eggs or egg weight. The percentages of settable eggs and of fertile eggs were lower when females were maintained in cages. A constant temperature of 29.4 degrees C. reduced egg production below that obtained from females maintained at 12.8 degrees and 21.1 degrees C. The high pen temperature also caused lower body and egg weights, more birds out of production and an increased incidence of molting. Feed consumption decreased with increasing pen temperatures. Fertility, hatchability, percentage of settable eggs and egg shell thickness were unaffected by the imposed temperature environments. Temperatures of 12.8 degrees and 21.1 degrees C. yielded comparable results for all reproductive parameters measured. Within the range of temperatures studied, results obtained suggest that optimum reproductive performance can be obtained with breeder turkeys when environmental temperatures are maintained between 12.8 degrees and 21.1 degrees C.

Animal Feed↗
PubMed1978

A health program for commercial dairy herds. 3. Changes in reproductive performance.

A health program service was implemented on 9 farms, for periods ranging up to 7 years. Reproductive performance was substantially improved, when performance indicators were compared with values for the herds prior to commencement of the service. On average, the mean calving to conception intervals for the herds were reduced by 24 days over their periods of participation in the program, from an initial value of 119 days. The intercalving interval was reduced by an average of 27 days. This improvement was associated with a reduction in the mean dry period length of 20 days, from an initial value of 117 days. There was a tendency for the lactation lengths to be reduced to an undesirable extent due to slow adaptation by management to the improvement in reproductive performance, but the problem was corrected late in the study. The improvement in performance was attributed to improved oestrus detection, correction of temporary nutritional deficiencies, and prompt treatment of genital tract disorders in individual animals. Results for a range of performance indicators related to reproductive function are reported in detail.

Abortion, Veterinary↗
PubMed1991

Use of a simulation model to evaluate the influence of reproductive performance and management decisions on net income in beef production.

A stochastic dynamic model of reproduction and a deterministic cow-herd economic simulation model were used to evaluate how management decisions and reproductive performance interact to influence net income in a cow-calf operation (1,000 cows) for 1 yr of production. The stochastic model was used to determine herd performance when length of breeding season (45, 70, or 120 d) interacted with three postpartum intervals of anestrus (48, 65, or 90 d) and three conception rates at first service (60, 70, or 80%). Short, moderate, and long postpartum intervals were used to reflect differences in reproductive performance. In addition, replacement heifers were bred beginning either 3 wk ahead of the cow herd or at the same time as the cow herd. Fifty-four simulations were generated. Inputs into the economic model were herd performance, livestock and feed prices, nonfeed costs, and feed requirements for 1 yr of production. Feed requirements were calculated separately for each postpartum interval to reflect three different body condition scores, thin, moderate, and good, to correspond with long, moderate, and short postpartum intervals. Net income was greatest with 70-d breeding seasons when the postpartum interval was short or moderate. When the postpartum interval was long, net income was greatest with 120-d breeding seasons because pregnancy rates, as a result of the long breeding season, were highest and feed costs were lowest for thin cows. Overall, net income was greatest when cows were managed to have postpartum intervals of moderate length. Breeding heifers 3 wk before the cows provided the most economic benefit with long postpartum intervals.

Age Factors↗