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PubMed1989

Effects of prostaglandin on the reproductive performance of dairy cows.

A single injection of a synthetic analogue of prostaglandin F2 alpha (fenprostalene; Syntex) on the day of calving or between days 14 and 21 after calving did not affect the calving to first service interval, the number of services per conception or the conception rate of dairy cows. In a second trial, cows calved more than 45 days were injected once weekly with prostaglandin F2 alpha (dinoprost; Upjohn) or fenprostalene until served at the first detected oestrus. The calving to first service interval and the conception rate were not affected. Following injection of either prostaglandin, the spread in the pattern of onset of oestrus and the range in the proportion of cows (75 to 98 per cent) seen in oestrus within seven days were similar. This variation in the time of onset of oestrus after the administration of prostaglandin precludes limiting oestrus detection to four or five days per week, and is a major limitation to the use of prostaglandins in breeding programmes in dairy cows.

Animals↗

PubMed2001

Concentrations of ketones in milk in early lactation, and reproductive performance of dairy cows.

Samples of blood and milk were taken from clinically ketotic cows at 12-hour intervals before and after treatment The concentration of beta-hydroxybutyrate was determined in plasma and milk, and the concentration of acetone was determined in milk. Measurement of milk acetone had the optimal combination of sensitivity, specificity and positive predictive value to identify ketotic cows and was subsequently used in a comparison of the fertility of ketotic and normal cows. Two samples of milk were taken approximately two weeks apart, between 12 and 60 days after calving, from 410 cows on three farms and the concentration of acetone in the milk was measured. Thirty cows with milk acetone concentrations of at least 0.4 mmol/litre were compared with paired control cows with milk acetone concentrations less than 0.3 mmol/litre. The ketotic cows had a significantly longer calving-to-conception interval and a significantly higher culling rate due to a failure to conceive (P<0.05).

3-Hydroxybutyric Acid↗

PubMed1987

Experimental liver cirrhosis does not influence reproductive performance of female rats and development of hepatic biotransformation in their offspring.

Experimental hepatic cirrhosis was produced in virgin female Wistar rats by thioacetamide (TAA) administration with the drinking water from the 4th up to the 6th month of life. Mating occurred 31 +/- 3 d after cessation of TAA treatment. At the time the body mass of cirrhotic rats was not different from that of untreated controls. Body mass gain during pregnancy, length of gestation, litter size and body mass of the newborns were not influenced by experimental cirrhosis. Lactation seems to be slightly decreased in TAA-dams in the first 5 postnatal days, reflected by lower growth rates of TAA- and control-pups nursed by TAA- in comparison to control-dams. Somatic development (body mass) and hepatic biotransformation (ethylmorphine N-demethylation and ethoxycoumarin O-deethylation) were not different in the TAA- and control-offspring up to adulthood. Liver mass was enhanced in TAA-offspring at birth, but not any longer in 10-d-old and older rats.

Animals↗

PubMed1993

Productivity of Boran cattle and their Friesian crosses at Abernossa Ranch, Rift Valley of Ethiopia. I. Reproductive performance and pre-weaning mortality.

Data collected on number of services per conception (NSC), age at first calving (AFC), calving interval and calf pre-weaning mortality rate of Boran cattle and their Friesian crosses were evaluated. The NSC was 1.81, 1.61 and 1.69 for Boran, F1 Boran-Friesian and three-quarter Friesian heifers respectively. The AFC varied from 31.5 months in the F1 crosses to 46.8 months in the Boran heifers artificially inseminated with Friesian semen. The mean calving intervals were 465, 552, 525 and 487 days for Boran cows naturally mated to Boran and Friesian bulls, Boran and F1 cows artificially inseminated with Friesian semen respectively. The preweaning calf mortality rate was 3.4% and was significantly influenced by parity, sex and interaction of breed with year of birth. Year as well as season had in general significant effects on the traits considered. However, the variation between mating or breeding groups was also large and it was in favour of the F1 crosses.

Age Factors↗

PubMed1985

Reproductive performance of chimeric mice produced from genetic lines that differ in litter size.

A population of chimeras was made by aggregating 8- and 16-cell embryos from two mouse strains: a randomly bred line (C) and a selected line characterized by large litters (JU), with litter sizes of 7.7 and 13.5, respectively. The two genotypes were developmentally "balanced", as judged by the high frequency (90%) of chimeras with an intermediate or high degree of coat-color chimerism, a chimeric sex ratio of 2.2:1 males:females, and a high percentage of chimeras (31% of males, 71% of females) with germ cells of both strains. Litter size characteristics, including ovulation rate, implantation rate, rates of pre- and postimplantation embryo survival and number born were studied in the female chimeras and compared with the performance of both parent lines and to the genetic cross of the two lines. Values for JU females exceeded those for C females for all parameters studied except postimplantation embryo survival, which was the same for both lines in second litters and was lower for JU's third litters. For most traits, means for genetic crossbreds and chimeras were similar, regardless of whether the means were at or above the midparent average. In contrast, for ovulation rate and body weight, genetic crossbreds and chimeras clearly differed, with chimeric females being similar to the JU line and genetic crossbred females exhibiting additive inheritance. Because of phenotypic differences between experimental chimeras and crossbreds produced from the same two lines, chimeras may provide a useful model for studying the physiologic basis for expression of genetic differences in quantitative traits.

Animals↗

PubMed1976

Relationship of biotin to reproductive performance of Leghorn-type hens.

Five floor pens with 14 Leghorn-type breeder hens each, in their 4th month of production, and 2 males per pen were fed a practical-type breeder diet composed largely of soybean meal and milo supplemented with unidentified hatchability factor sources and adequate levels of vitamins and minerals. Five additional pens were fed an identical ration supplemented with biotin at a level of 550 mcg./kg. of diet. Treatment was for a period of 7 months. A 3% improvement in production was obtained by biotin (550 mcg./kg.) supplementation, which was found to be highly significant (P less than or equal to .005) by chi-square analysis. A slight improvement was noted for feed efficiency. Biotin supplementation had no effect on egg size or adult livability. Fertility and hatchability were both significantly improved by biotin supplementation. Fertility and hatchability differences were found to be highly significant by chi-square analyses. Increased hatchability was due to a decreased number of early dead, late dead, and pipped embryos that failed to hatch.

Animals↗

PubMed1985

Reproductive performance, pre-weaning growth rate and pre-weaning lamb mortality of Djallonké sheep in Ghana.

Production records for a flock of Djallonké sheep kept in the forest belt of Ghana were analysed to determine the effects of some environmental factors on the performance of the breed. The period under study covered April 1969 to November 1979. The mean ages at first conception and first lambing and the mean lambing interval were 498, 638 and 264 days respectively. The overall twinning rate and prolificacy were 30.7 and 130.6% respectively. The season of birth and age of dam had significant (P less than 0.05) effects on prolificacy and twinning rate. The birth weights of the lambs were affected significantly (P less than 0.05) by age of dam, type of birth, sex and season of birth with the mean birth weight being 1.77 kg. Weaning weight (mean of 8.36 kg) and pre-weaning growth rate (mean of 0.076 kg/day) were affected significantly (P less than 0.05) by types of birth. Type of birth significantly (P less than 0.05) affected pre-weaning mortality of lambs (overall mean of 20.95%).

Animals↗

PubMed1989

A farming systems study of abortion in dairy cattle on the Atherton Tableland. I. Reproductive performance.

Herd health records from 1983 to 1985 were analysed for a sample of 19 dairy farms on the Atherton Tableland in tropical north Queensland. Abortion and first service conception rates were calculated for each farm for each year. The association between abortion rate and stage of gestation at pregnancy diagnosis was investigated as well as the association between abortion rate and lactation status. There was a significant linear increase in abortion rate over the 3-year period, during which the mean rate was 7.3 +/- 2.1% (range 4.5% to 10.9%). There was also a significant variation in first conception rates during the same period, when the mean first service conception rate was 51.8% +/- 6.6% (range 42.4% to 65.8%). A significantly higher abortion rate was recorded in first lactation cows. Of 178 abortions in all lactation groups (1984), 20.3% were repeat abortions by the same cows. Of 163 abortions, a majority (80.4%) occurred during months 3 to 7 of gestation. No significant association was found between the timing of pregnancy diagnosis and occurrence of abortion.

Abortion, Veterinary↗

PubMed1977

Biotin-supplementation of diets; the incidence of foot lesions, and the reproductive performance of sows.

The effect of biotin supplementation of diets for breeding sows was investigated in a herd where the sows exhibited symptoms resembling those of experimentally induced biotin deficiency. Twenty sows received diets supplemented with 250 mcg D-biotin per kg in pregnancy and 150 mcg D-biotin per kg in lactation. Over a six month period the supplemented sows showed a 28 per cent reduction in the number of foot lesions recorded. Twenty-two control sows showed no reduction in foot lesions. Sows on the supplemented diets produced more piglets at birth than controls, but the differences were not significant. However, second parity supplemented sows did produce significantly more live pigs than controls (1-64 +/- 0-77, P less than 0-05). The weaning to remating interval was significantly reduced from 15-31 +/- 2-85 days in the controls to 6-23 +/- 2-85 days in the supplemented sows (P less than 0-05) and the percentage of sows exhibiting oestrus within seven days of weaning was increased from 56 per cent to 89 per cent.

Animals↗

PubMedDate not supplied

Long-term effects of an experimental infection with Trypanosoma congolense on reproductive performance of trypanotolerant Djallonké ewes and west African dwarf does.

Ten West African Dwarf (WAD) does and 12 Djallonké ewes were artificially infected with a West African strain of Trypanosoma congolense and observed over two years. The infected animals showed a chronic anaemia together with a persistent parasitaemia but very low mortality and increase in body weights was not significantly different from the control. In the infected sheep significant differences were found in offspring production at three and five months due to a higher mortality among the lambs. The infected goats had more abortions and stillbirths and period to first kidding, total number of parturitions, production at birth, one, three and five months were significantly different from the controls. A productivity index was calculated and revealed that a chronic T congolense infection significantly decreases the productivity of WAD goats during two years whereas in Djallonké sheep, the loss in productivity is recovered after one year. Although both species are regarded as trypanotolerant, the Djallonké sheep show a better tolerance to a chronic T congolense infection that the WAD goats.

Abortion, Veterinary↗

PubMedDate not supplied

Effects of atrazine on reproductive performance in the rat.

The effects of subacute exposure to atrazine on body weight, ovarian cycling, conception rate and the size of litters in Fischer strain rats were studied. An atrazine dose of 120 mg kg-1 body wt given p.o. daily for 7 days to both female and male rats caused statistically significant loss of body weight in both sexes during the period of treatment. After the cessation of treatment the body weight of female rats remained below control body weights at least for 2 weeks. In male rats the difference in body weights narrowed with time and reached control level 5 days after the last dose. Atrazine caused a significant increase in the relative weights of pituitary and prostate. Atrazine also transiently prolonged the oestrous cycle, characterized by extended vaginal dioestrus. As a result of disturbed ovarian cycling, the rate of successful mating decreased in the first week after treatment when both sexes were exposed or exposed females were mated with an unexposed male. No similar effect was observed when only the males were exposed. The size of litters did not differ significantly between experimental groups.

Animals↗

PubMed1996

Effect of intraruminal monensin capsules on reproductive performance and milk production of dairy cows fed pasture.

Cows from three herds calving in spring that were fed on pasture were paired by herd, production index, predicted calving date, and age. One cow from each pair was allocated randomly to the treatment group and received a controlled-release capsule of monensin 1 mo prior to the start of AI. A random sample of 20 matched pairs of cows was selected within each herd to monitor BW and metabolic parameters. Treated cows produced more fat, protein, and liters of milk per day during the 2nd mo of monensin activity and produced a greater total milk volume than did control cows. Treated cows gained less BW during the 1st mo after treatment. No significant differences were identified in submission rates, overall pregnancy rates, or pregnancy rate to first or second AI. Blood urea nitrogen was elevated in the treatment group as a main effect, and NEFA were elevated in the 2nd and 3rd mo after treatment. There was no significant effect on blood concentrations of glucose, albumin, or BHBA.

3-Hydroxybutyric Acid↗

PubMed2002

Effects of porcine follicle-stimulating hormone on the reproductive performance of female zebra finches (Taeniopygia guttata).

It has been suggested that follicle-stimulating hormone (FSH) may play a role in egg size/number trade-offs in oviparous vertebrates. We tested this hypothesis in an avian species by administering porcine FSH (pFSH) to intact, captive female zebra finches (Taeniopygia guttata) during egg formation. We predicted that (1) pFSH would increase the number of ovarian follicles recruited into rapid yolk development and so increase clutch size, (2) an increase in clutch size would lead to a reduction in egg size, and (3) doses of pFSH that were not sufficient to increase clutch size would increase yolk deposition and so increase egg mass. Although a range of pFSH doses decreased egg mass by ca. 10% in three separate experiments, the reduction in egg mass occurred in the absence of an increase in the number of eggs laid. Porcine FSH decreased mean clutch size significantly in one experiment and reduced median clutch size significantly in the other two experiments. The results of this study did not support the hypothesis that FSH mediates a trade-off between egg size and clutch size in birds.

Animals↗

PubMed1992

The effects of dietary protein level on the reproductive performance of bobwhite hens.

Two experiments were conducted to evaluate the protein requirement of adult bobwhite quail. Flight-type quail were used in one experiment and meat-type quail in the other. Corn and soybean meal diets containing 12, 15, 18, 21, and 24% protein were fed. Increasing the protein level of the diet from 12 to 15% significantly increased egg production with the flight-type bird. However, only a nonsignificant increase in egg production was obtained with the meat-type birds when the protein level was increased to 15%. Higher levels of protein did not result in further increases in egg production in either strain. Increasing the protein from 12 to 18% (flight) or 21% (meat) resulted in increased egg weight. Egg mass of flight-type hens receiving 18 and 21% protein was significantly greater than egg mass from hens receiving 12 and 15% protein. Hatch of fertile eggs, hatch of total eggs, chick weight, or weight of adult birds were not affected by protein level. Feeding the 12% protein diet resulted in significantly reduced fertility in the flight-type birds but not in the meat-type birds.

Animal Feed↗

PubMed2006

Prospects for improving reproductive performance through genetic selection.

Prospects for improving female fertility in dairy cattle using genetic selection are reviewed. Today's high producing cows have shorter estrous cycles, fewer standing events, shorter duration of estrus, and more frequent multiple ovulations. Although high milk production is often implicated as the cause of impaired fertility, the impact of inadequate body condition appears to be greater, as the latter has a significant impact on probability of conception, rate of embryonic loss, and proportion of anestrous animals. Genetic improvement of female fertility can be achieved by indirect selection for longevity or body condition score, or by direct selection for traits such as daughter pregnancy rate. Most leading dairy countries have implemented genetic evaluation systems for female fertility in the past decade, but refinement of these systems to account for hormonal synchronization, differences in the voluntary waiting period, exposure to natural service bulls, and other confounding factors is warranted. Recent work has focused on the development of data collection and genetic evaluation systems that will allow selection of bulls that have daughters that are resistant to common health disorders, including mastitis, lameness, ketosis, displaced abomasum, and metritis. Such systems will allow selection of animals that can remain healthy and fertile while producing large quantities of milk.

Animals↗

PubMed1984

Etiologic factors and subsequent reproductive performance in 195 couples with a prior history of habitual abortion.

A diagnostic screening program was applied to 195 couples with a prior history of habitual abortion (i.e., three or more consecutive abortions). Abnormalities were identified in 110 (56%) of the couples. Such identification was significantly more frequent in couples with primary habitual abortion than in couples with secondary habitual abortion (p less than 0.001) and also more frequent in couples with second-trimester abortions than in those with first-trimester abortions (p approximately equal to 0.01). The abnormalities most commonly observed were anomalies of the uterine body (15%), endometrial infections (15%), and cervical incompetence (13%). Hormonal dysfunctions were detected in 5%, and there were chromosomal aberrations in 3% of the couples. The women in the group showing abnormalities were offered surgical or medical treatment, and 80% of those who subsequently conceived carried their pregnancies to term. Among the couples with no abnormal findings, women receiving specific antenatal counseling and psychological support had a pregnancy success rate of 86%, as compared to a success rate of 33% observed in women who were given no specific antenatal care (p less than 0.001).

Abortion, Habitual↗

PubMed1993

Reproductive performance of thoroughbred mares on six commercial stud farms.

The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the first served oestrous cycle (77.8%) than in mares that needed two served oestrous cycles to become pregnant (65.4%). Of all diagnosed pregnancies, 19.5% were not completed. Pregnancy loss was lower (P < 0.05) in maiden (12.4%) than in barren (19.7%) or foaling (20.9%) mares. Twins were diagnosed in 7.8% of all pregnancies. If one conceptus was lost without external interference, 84.1% of pregnancies went to term. If one conceptus was manually crushed, 55.9% of pregnancies were maintained. If prostaglandin was used to terminate twin pregnancies, 60% of mares so treated produced foals the following year.

Age Factors↗

PubMed1986

Restricted feeding and reproductive performance of individually caged broiler breeder males.

Two experiments were conducted, one in the summer and another in the fall, involving 95 Hubbard broiler breeder males per experiment. Breeder males were randomly placed in individual cages at 26 (Trial 2) or 30 (Trial 1) weeks of age and provided with five levels of feed intake. The Hubbard White Mountain male Management Guide recommendation (154 g/bird/day) was designated as the control level (100%). Other levels were 115, 85, 70, and 55% of the control level. The effects of feed intake on body weight, semen volume, percent semen-packed cell volume, luteinizing hormone (LH), and testes weight were determined. Body weights were significantly decreased as feed intake was decreased. Dietary restriction levels of 115, 100, 85, and 70% had no significant effects on semen volume or semen-packed cell volume. Dietary restriction of 55% resulted in reduced semen volume, semen-packed cell volume (except in Trial 1), and testes weight. Dietary restriction had no significant effect on LH. A calculated metabolizable energy (ME) value of 346 kcal of ME/bird/day, which lies between the 85 and 70%-fed groups, should be adequate for normal body weight maintenance with the Hubbard broiler breeder male grown in individual cages.

Animals↗