SEARCH · PubMed Health

Results for “Reproductive performance”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources

PubMed2003

Effects of body condition score and score change on the reproductive performance of dairy cows: a meta-analysis.

A meta-analysis was conducted to evaluate the effects of body condition score (BCS) at parturition and at first AI, and of body condition change during the early lactation period on the variables pregnancy rate at first AI and number of days open in dairy cattle. Inclusion criteria for the publications were: comparison of at least two groups of animals of different categories of BCS or change (independent variables) and consideration of pregnancy rate at first AI or number of days open (dependent variables). Fifteen papers were selected and 23 excluded. Data corresponding to 7733 cows from 11 studies described in 10 papers were included in the analysis of pregnancy rate at first AI, and those derived from 4529 cows from 11 studies described in 10 papers were used to analyze effects on the number of days open. Analyses were stratified according to study design and milk production characteristics. We defined low, intermediate and high categories of BCS for values lower than 2.5, from 2.5 to 3.5, or higher than 3.5, respectively. The categories of body condition change were increase (gain in score), slight loss (0-0.5 point loss), moderate loss (0.6-1 point loss), and severe loss (over 1 unit loss). Intermediate body condition at parturition and at first AI, and a slight loss during the early lactation period were used as reference categories. The effects of body condition on the variable pregnancy rate at first AI were highly heterogeneous, while all the studies considering the number of days open presented homogeneous results. A clear association between body condition category and pregnancy rate at first AI was detected only when the effect of a low score at parturition was analyzed: pregnancy rate at first AI significantly decreased by about 10% in cows delivering in poor condition. Animals with a high BCS at parturition showed a significant reduction in the number of days open of 5.8 or 11.7 when compared with animals with an intermediate or low body condition, respectively. In animals in the high body condition category at first AI, the variable days open showed a significant drop of 11.9 or 24.1, compared to animals in the intermediate or low categories, respectively. A severe loss in score during early lactation was related to a significant (10.6) increase in the number of days open, while a slight or moderate body condition change, either loss or gain in score, was not significantly related to the variable days open. We found that the number of days open was a good indicator of the effects of BCS or change in score on reproductive performance in dairy cattle. The variable pregnancy rate at first AI, however, yielded heterogeneous results among studies.

Analysis of Variance↗

PubMed1994

Effect of dietary lipid supplementation on progesterone concentration and reproductive performance in suckled beef cows.

Using whole cottonseed as a lipid source, silage-based diets that were isocaloric and isonitrogenous yet varied in lipid level were fed to multiparous cows. In Experiment 1, 48 cows (n = 12 per treatment) were allotted to 1 of 4 treatments where diets were formulated to supply 3.9, 4.3, 5.3 and 6.3% of total lipid. In Experiment 2, 66 cows (n = 22 per treatment) were allotted to 1 of 3 treatments where diets were formulated to supply 3.1, 5.5 and 8.3% of total lipid. Length of the first ovarian cycle, length of the first normal estrous cycle, postpartum intervals to onset of ovarian luteal activity and to first estrus were not affected by diet (P>0.10) in either experiment. Mean progesterone (P(4)) concentrations for first normal estrous cycles were not different (P>0.10) in either experiment. Anestrous periods were divided into 3 phases for analyses: Phase I) parturition to onset of ovarian luteal activity, Phase II) first ovarian luteal activity and Phase III) first normal estrous cycle. No differences were observed in P(4) concentrations during any phase of the postpartum period. In conclusion, isocaloric and isonitrogenous diets with increasing levels of lipid had no effect on reproductive performance in suckled beef in these experiments.

Journal Article↗

PubMed2000

Induction of parturition with prostaglandin f2 alpha as a possible model to study impaired reproductive performance in the dairy cow.

Parturitions were induced in five cows, 2 weeks before term using prostaglandin (PG) F(2alpha). Two i.m. injections were performed with an interval of 24 h. All cows calved within 5 days (average 2.7 days) after the first injection of PGF(2alpha). Out of five cows, four had retained fetal membranes (RFM). Each animal was sampled for bacteriological examination using uterine biopsies twice a week during 42 days postpartum (PP). Jugular vein blood samples were withdrawn for PGF(2alpha)-metabolite and progesterone analyses five times per day during the first week PP and eight times per 24 h during the 2nd and 3rd weeks PP. From the 4th week, the sampling interval was reduced back to five times per day. From the 5th week PP, the sampling was reduced to two times per day and sampling was terminated after day 46 PP. Only morning samples were used for progesterone analyses. From day 10 PP, ultrasonography (US) was performed every 3rd day until day 39 PP for detection of ovarian activity and follicular dynamics. The highest incidence of bacteriological species was found during the first 3 weeks PP. After the 5th week of collection, all animals were free from bacteria. The species of bacteria found were Arcanobacterium (Actinomyces) pyogenes, Escherichia coli, alpha-hemolytic streptococcae and Pasteurella multocida. Immediately after parturition, very high levels of the PG-metabolite were seen in all animals, with a sharp decrease to line of significance around days 9-12 PP. Small increases above the line of significance were detected up to day 27 PP in cows with RFM, and after that time the levels were considered to be at baseline. Low levels of progesterone were seen in four animals during the whole experimental time. In one animal, an increase was seen on day 43 PP, which was maintained until the end of the experimental period on day 46 PP. Based on US, follicular waves were detected in all animals during the experimental period. In three animals, three non-ovulatory follicular waves were detected and in two animals, four non-ovulatory follicular waves were detected during 39 days of ultrasound sessions. Based on progesterone levels, only one animal was considered to have ovulated around day 40 PP. Results from the present study indicate that reproductive performance of cows after PG-induced parturitions differs from those of spontaneous cases of RFM. Differences regarding the resumption of ovarian activity were also observed between previous studies of dexamethasone-induced parturitions and the present study.

Actinomyces↗

PubMed1982

The effect of short term calf removal in combination with GnRH treatment and the effect of limited nursing on reproductive performance of postpartum suckled beef cows administered PGF2alpha for ovulation control.

Over a two year period, postpartum suckled Hereford and Angus Cows (n=213) were administered two injections of PGF2alpha (25 mg/injection) and divided into three groups. No additional treatments were administered to cows in Group I and calves were allowed to nurse their dams ad libitum. In Group II, calves were removed for 48 hours beginning on the third day following the initial PGF2alpha injection. These cows were given a subcutaneous injection of 250 microg GnRH dissolved in 2% carboxymethylcellulose midway through the 48 hour period. In Group III, calves were allowed to nurse their dams for only one hour per day for the first 7 days after the initial PGF2alpha injection. In year 1, PGF2alpha was administered 14 days apart whereas in year 2, PGF2alpha was administered 11 days apart. Cows were artificially inseminated at 72 and 96 hours after the second injection of PGF2alpha. In year 1, the numbers of cows that conceived to the timed inseminations were similar (P>.10) for the three groups. In year 2, a higher percentage of cows in groups II (P<.10) and III (P<.05) conceived to the timed inseminations than in group I. Other reproductive performance parameters were similar (P>.10) between groups for both years 1 and 2. In summary, limited nursing and short term calf removal in conjunction with GnRH treatment may improve the pregnancy rate in cows administered PGF2alpha for ovulation control.

Journal Article↗

PubMed1989

Postpartum reproductive performance in the multiparous mare fed to obesity.

Twenty multiparous Quarter Horse mares were assigned to one of two treatment groups at 40 to 75 d of pregnancy. Group 1 was the control group and the mares were fed to maintain a moderate degree of body fat (condition score 5.5 to 7). Group 2 was the obese group and the mares were fed to achieve (prepartum) and then maintain (post partum) an extremely high degree of body fat (condition score 9). Estrous intensity was evaluated using subjective teasing scores ranging from 0 (rejection) to 4 (maximum receptivity). Mares were artificially inseminated beginning with the second postpartum ovulatory cycle; the study was terminated after 63 d of pregnancy. Duration of estrus, maximum teasing score and the number of mares exhibiting overt estrus (teasing score > 2) did not differ between treatment groups during the first and second postpartum ovulatory cycles. The intervals from foaling to first cycle ovulation, foaling to second cycle ovulation, and first to second cycle ovulation were also similar between treatment groups. All mares in both treatment groups conceived and maintained pregnancy. The first cycle conception rate and the number of cycles per conception did not differ between treatment groups. A high degree of body fat produced by overfeeding during gestation did not adversely affect postpartum reproductive performance in the multiparous mare.

Journal Article↗

PubMed1996

Effects of tallow and escape protein on lactational and reproductive performance of dairy cows.

Experiments were performed to determine the effect of energy source and proportion of escape protein on lactational performance, body measurements, and reproductive activity. Sixty-eight lactating Holstein cows were assigned to one of four dietary treatments during wk 2 to 12 postpartum: 1) high fat (3% tallow), high escape protein (5% feather meal:blood meal, 85:15, DM basis); 2) high fat, low escape protein (0% feather meal:blood meal); 3) low fat (0% tallow), high escape protein; and 4) low fat, low escape protein. Diets were similar in energy and CP contents. Overall mean milk yield (32.9 kg/d) was not affected by diet, but efficiency of FCM yield was highest with high fat and high escape protein. Daily DMI and net energy balance were greater for cows fed the diet low in fat and low in escape protein, but days to first ovulation were not different among groups. Total cholesterol in plasma increased as DIM increased, and concentrations were greater for cows fed the high fat diets than for cows fed the low fat diets after 35 DIM. Concentrations of luteal phase progesterone and follicular phase estradiol tended to be greater for cows fed the high fat and low escape protein, but conception rate from first AI was greatest for cows fed the high fat and high escape protein. Supplemental tallow and escape protein did not consistently affect lactational performance but did improve efficiency of FCM yield and conception rate from first AI.

Animal Nutritional Physiological Phenomena↗

PubMed1989

Growth response, endocrine profiles and reproductive performance of fine-wool ewe lambs treated with ovine prolactin before breeding.

Twenty-four 6-mo-old ewe lambs received one of two ovine prolactin (oPRL) treatments 28 d before fall breeding. Beginning on the first day of treatment (Day 0), 12 lambs received a subcutaneous injection (12 ml) of a carrier vehicle (0 mg oPRL) on alternate days for 28 d while 12 lambs received injections containing 5 mg oPRL. On Days 0 and 28, jugular blood was collected from six lambs in each group before treatment and at 30-min intervals for 6 h thereafter. Neither feed intake, efficiency of gain nor animal weights differed (P > 0.20) between groups. One hour after treatment on Day 0, ewe lambs receiving 5 mg oPRL had greater (P < 0.10) serum PRL levels than did controls (121.9 and 61.5 +/- 24.7 ng/ml, respectively). Differences in serum PRL persisted throughout remaining sampling intervals on both Days 0 and 28. Serum samples obtained on alternate days during the 28-d treatment period revealed no differences (P > 0.20) in PRL concentrations between control (48.3 +/- 5.3 ng/ml) and oPRL-treated (55.7 +/- 5.3 ng/ml) ewes. Neither serum insulin nor growth hormone responded (P > 0.05) to exogenous oPRL on either Day 0 or 28. No difference (P > 0.30) in percentage of ewe lambs cycling during treatment or breeding was detected between groups. Subsequent lambing percentages were similar (P > 0.30), with 36.4% of control and 25.0% of oPRL-treated ewes producing offspring. Administering 5 mg oPRL on alternate days for 28 d before breeding did not enhance growth and(or) reproductive performance in virgin ewe lambs.

Journal Article↗

PubMed1993

The time required for the presence of bulls to alter the interval from parturition to resumption of ovarian activity and reproductive performance in first-calf suckled beef cows.

This experiment was designed to determine 1) if exposure of firstcalf suckled beef cows to mature bulls in the first 30 days, after 30 days, or continuously post partum reduces the postpartum anestrous period and 2) if exposure to bulls alters the first service pregnancy rate. Postpartum first-calf suckled crossbred (Angus x Hereford; Hereford x Angus) cows were randomly assigned to be 1) exposed continuously to mature, epididectomized bulls (BE; n = 18); 2) exposed to bulls for the first 30 days post partum (BE/NE; n = 17); 3) exposed to bulls after the first 30 days post partum (NE/BE; n = 16); or not exposed to bulls (NE; n = 18). Blood samples were collected weekly to be assayed for progesterone to determine resumption of ovarian cyclic activity. All the cows were bred for 21 days by AI while under their respective treatment regimens and were then exposed to fertile bulls for an additional 35 days. The postpartum interval to resumption of ovarian cyclic activity did not differ (P>0.10) among the 3 (BE, BE/NE, and NE/BE) treatment groups, but it was 15.4 d shorter (P<0.05) than for cows in the NE group. The overall pregnancy rates did not differ (P>0.10) among the treatment groups. The AI pregnancy rates for the BE/NE and NE/BE treatment groups were higher (P<0.05) than for the NE group. The AI pregnancy rates for the BE and NE treatment groups did not differ (P>0.10). The results showed that all three treatments (BE, BE/NE and NE/BE) similarly decrease the postpartum interval and that exposure to bulls may improve the reproductive performance of first-calf suckled beef cows.

Journal Article↗

PubMed2005

The effect of progesterone supplementation post mating and shearing of ewes in early pregnancy on the reproductive performance of ewes and birthweight of lambs.

AIM: To determine whether short-term progesterone supplementation post mating or shearing of ewes in early pregnancy affected either the proportion of ewes that lambed or that had multiple lambs, or the birthweight of lambs. METHODS: Romney ewes (n=457) were synchronised in oestrus using controlled internal drug-releasing (CIDR) devices containing progesterone, and mated to Romney rams over a 5-day period. The mid-point of mating (Day 0) occurred 2 days after the withdrawal of CIDR devices. Ewes mated (n=397) were randomly allocated to one of four treatment groups: shearing at Day 5, shearing at Day 30, no shearing, and no shearing plus progesterone supplementation using a CIDR device inserted on Day 3 for 6 days. During the period from Day 5 to Day 27, six harnessed Suffolk rams were placed with the ewes and matings recorded. At Day 48, all ewes that did not return to the Suffolk rams were scanned for pregnancy using ultrasound. At Day 140, single- and multiple-bearing ewes were set-stocked at 15.1 and 12.2 ewes/ha, respectively, and equivalent numbers of ewes from each treatment group were placed in each paddock. Blood samples from 10 unshorn and 10 progesterone-supplemented ewes were collected on Days 3, 6 and 9, and analysed for plasma progesterone concentrations. Lambs were identified to their dam and weighed within 12 h of birth, and again at 27 and 93 days after the mid-point of lambing. The ewes were weighed at regular intervals throughout the trial. RESULTS: Plasma progesterone concentrations of supplemented ewes were higher than those of unsupplemented ewes (3.28 vs 1.75 ng/ml) on Day 6 (p=0.02) but not on Day 9 (4.58 vs 4.63 ng/ml). Treatment of ewes had no effect on either the proportion of ewes which lambed to the synchronised mating period or that had multiple lambs. Lambs born to ewes shorn at Day 30 tended (p=0.09) to be heavier at birth (by 0.28 kg) than those born to unshorn ewes but this effect was not evident when data were corrected for length of gestation. Neither shearing at Day 5 nor progesterone supplementation had any effect on the birthweight of lambs, and the treatment of ewes had no effect on the survival rate of lambs to weaning. CONCLUSIONS: Progesterone supplementation for 6 days beginning 3 days post mating did not increase either the proportion of ewes that lambed or that had multiple lambs, or the birthweight of lambs. Shearing 5 days after mating had no significant effect on the reproductive performance of ewes and need not be avoided, but is unlikely to result in an increase in lamb birthweight. Shearing ewes at Day 30 may result in an increase in the birthweight of lambs but, ideally, ewes should be further advanced in pregnancy before shearing is undertaken.

Animal Husbandry↗

PubMedDate not supplied

Reproductive performance in women with uterus didelphys.

The reproductive history of 19 women with the diagnosis of uterus didelphys is reported. With this goal the patients were divided into two groups: A) composed of 15 patients who did not undergo any surgical correction of uterine anomaly; B) composed of 4 patients where metroplasty was performed. Diagnosis was made in 17 cases (85.9%) for reasons not related to the uterine anomaly, only in 2 cases did patients present with infertility complaints. Vaginal malformation was associated in 16 (85%) cases; in 11 cases longitudinal septum was present; whereas in 5 hemivagina atretica was found. Eleven group A patients had a total of 23 pregnancies of which 3 (13%) ended in spontaneous abortions, 2 (8.7%) were voluntarily interrupted, 3 ended in premature birth and 15 in term births, with 17 live babies for a live birth rate of 74%. If we consider that two pregnancies were voluntarily interrupted, we had 17 live babies out of 21 naturally evolved pregnancies, for a live birth rate of 81%. In group B 3 patients before treatment had 3 pregnancies all ending in spontaneous abortion. After treatment all had a live baby. Reproductive and gestational performances of women with uterus didelphys are preserved. In patients with infertility complaints, all associated causes must be ruled out before surgical correction. If these are present its correction must be attempted as first therapeutic step, and term pregnancy with live baby is the rule. Only if repeated abortions are not related to any other cause, can metroplasty, according to Bret-Palmer technique, be performed.

Abortion, Spontaneous↗

PubMed1987

Reproductive performance of women with unicornuate uterus.

The reproductive history of 19 women with a diagnosis of unicornuate uterus confirmed by laparoscopy or laparotomy is analyzed. The patients were followed for 2 to 10 years. One patient had a cavitary communicating rudimentary horn, four a cavitary noncommunicating rudimentary horn, seven a noncavitary rudimentary horn, and seven no rudimentary horn. Six of the patients presented with primary infertility. The other 13 women had a total of 29 pregnancies, 1 (3.4%) in a rudimentary horn determining rupture; abortions occurred in 17 (58.6%), premature labor in 3 (10.3%), and term births in 8 (27.6%), with a live birth rate of 38%. Of the 11 births, 6 (54.5%) were breech presentations, and 9 (81.8%) were cesarean sections. In five cases the rudimentary horn was removed, with associated salpingooophorectomy in three patients. Cervical cerclage was not performed in any of the patients.

Abortion, Spontaneous↗

PubMed2005

Seroprevalence of six reproductive pathogens in European wild boar (Sus scrofa) from Spain: the effect on wild boar female reproductive performance.

We studied the seroprevalence of six reproductive pathogens in Spanish hunter-harvested wild boar females. The sample was representative of the hunting harvest in the studied hunting estates. Mean antibody prevalences were: 60.6+/-0.06% for Aujeszky's disease virus (ADV), 56.6+/-0.09% for porcine parvovirus (PPV), 51.8+/-0.06% for porcine circovirus type 2 (PCV2), 29.7+/-0.09% for Brucella spp. and 36.3+/-0.1% for Toxoplasma gondii. We did not detect antibodies against porcine reproductive and respiratory syndrome virus (PRRSv). ADV seroprevalence was associated with PPV and PCV2 seroprevalence in Spanish wild boar females. Ovulation rate in the studied wild boar females was 4.41+/-0.16 (n=120), mean litter size was 3.91+/-0.16 (n=82) and the partial resorption index 0.92+/-0.17 (n=66). Ovulation rate and litter size were statistically associated with age. T. gondii seroprevalence was negatively related to ovulation rate and partial resorption index. Wild boars from managed fenced estates had antibodies against more pathogens than wild boars from open estates. Potential relations between management of wild boar populations and exposure of individuals to different reproductive pathogens are discussed.

Aging↗

PubMed1980

Impaired reproductive performance in DES-exposed women.

The reproductive history of 69 women with demonstrated diethylstilbestrol (DES)-related cervical-vaginal abnormalities is reviewed. All of the patients were sexually active non-contraceptive users who were studied over an 8-year period. Forty-six patients conceived, for an uncorrected fertility rate of 66.7%. Fourteen patients elected therapeutic abortion. The 32 remaining patients had 62 pregnancies which resulted in 26 living children, for a success rate of 41.9%. However, cervical cerclage was required for continuation of 8 of these successful pregnancies. The 36 pregnancy failures consisted of 19 first- and 11 second-trimester spontaneous abortions, 3 third-trimester losses due to permaturity, and 3 tubal pregnancies. Uterine abnormalities were found in all of the 25 patients who underwent hysterosalpingograms. Although other reproductive diseases unrelated to DES exposure in utero were also present in this select group of patients, it is probable that the high rate of infertility and pregnancy wastage is related to the uterine structural abnormalities encountered.

Abortion, Spontaneous↗

PubMed1988

Factors affecting broiler breeder performance. 7. Effect of varying levels of dietary protein on the development and reproductive performance of the dwarf broiler breeder.

Vedette dwarf broiler breeder female chicks were raised in floor pens and fed a standard starter ration. At 3 wk of age, 1,032 pullets were divided into four dietary treatment groups (258 bird/treatment). Birds were transferred into individual cages at 18 wk of age and at 21 wk of age assigned to one of four laying rations. Dietary treatments consisted of a 4 X 4 factorial design with four developer diets (12, 14, 16, and 18% protein) and four layer diets (12, 14, 16, and 18% protein). Body weight was determined at 6, 12, and 17 wk of age and thereafter at 4 wk intervals. Hen-day egg production was determined weekly from 21 to 58 wk of age. Specific gravity and egg weights were measured at 4-wk intervals on eggs collected over 4-day periods. Fertility and hatchability were measured at 32, 34, and 44 wk of age on the one-half of the birds in each treatment that had been artificially inseminated weekly with .05 mL of semen from Ross males. Embryonic mortality and chick weights of offspring were recorded when the breeder flock was 32 and 44 wk of age. Dietary treatment had a significant effect on body weight (P greater than .05) at Week 12, (12% and 14% vs. 16% and 18%) but by Week 17 differences were no longer significant. Significant differences in body and egg weights during the laying cycle were detected (P less than .05), with hens receiving the higher protein (16% and 18%) laying diets exhibiting heavier body and egg weights.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Reversibility of the effects of lead on the reproductive performance of female rats.

Potential reversibility of the reproductive effect of lead was studied in female albino rats after cessation of oral exposure to 7500 ppm lead as acetate in drinking water. Females mated and gave birth to their first offspring during 9 weeks of lead exposure. They then continued or discontinued exposure, were mated for the second time, and had their second offspring during a longer exposure (20 weeks) or after a period without lead. Food consumption, body weights, and fertility index were not altered irrespective of the exposure conditions. In the first and especially in the second offspring of exposed females, survival rates, litter sizes, and body weights of newborn and 11-day-old pups were decreased. Offspring born to dams in which exposure had been stopped were not different from controls. It was concluded that the adverse reproductive action of lead is reversible after withdrawal of the female from exposure.

Animals↗

PubMed1987

Genotype x environment interactions involving proportion of Brahman breeding and season of birth. II. Postweaning growth, sexual development and reproductive performance of heifers.

Postweaning growth, sexual development and reproductive traits were evaluated over a 3-yr period on 201 spring-born and 180 fall-born crossbred heifers with 0, 1/4 or 1/2 Brahman breeding. The proportion of Brahman breeding X season of birth interaction was significant for five traits (average daily gain weaning to yearling, yearling condition score, percentage of heifers detected in estrus, prebreeding condition score and percentage of heifers that became pregnant) and was not significant for six traits (yearling weight, hip height and conformation score, age and weight at puberty and prebreeding weight. Among spring-born heifers, 1/4 and 1/2 Brahman heifers outgained (P less than .05) 0 Brahman heifers from weaning to yearling by 50 and 66 g/d, respectively; among fall-born heifers, 1/4 and 1/2 Brahman heifers outgained (P less than .05) 0 Brahman heifers by 41 and 104 g/d, respectively. Yearling weight of 1/2 Brahman heifers was 13 and 10 kg heavier (P less than .05), respectively, than 0 and 1/4 Brahman heifers. Yearling hip height of 1/4 and 1/2 Brahman heifers were 1.9 and 5.7 cm taller (P less than .05), respectively, than 0 Brahman heifers. Weight prior to the start of the breeding season were similar among crossbred heifer groups and spring-born heifers were 66 kg heavier (P less than .05) than fall-born heifers. The percentage of heifers that became pregnant was similar among spring-born crossbred heifer groups, whereas among fall-born heifer groups 1/4 and 1/2 Brahman heifers were 25.2 and 49.4 percentage points lower (P less than .05), respectively, than 0 Brahman heifers.

Animals↗

PubMed2000

Effects of dietary lysine intake during lactation on blood metabolites, hormones, and reproductive performance in primiparous sows.

Effects of three dietary lysine (protein) concentrations during lactation on metabolic state, protein metabolism, reproductive hormones, and performance were investigated in 36 primiparous sows. Sows were assigned randomly to one of three diets containing .4% (low lysine, LL), 1.0% (medium lysine, ML), or 1.6% (high lysine, HL) total lysine from intact protein sources. All diets contained 2.1 Mcal NE/kg and exceeded the recommended requirements for all other nutrients. Actual lysine intakes over an 18-d lactation were 16, 36, and 56 g/d for sows fed LL, ML, and HL, respectively. Fractional breakdown rate of muscle was determined on d 4 and 15 of lactation by using a three-compartment kinetic model of 3-methylhistidine metabolism. Increasing lysine intake during lactation did not affect fractional breakdown rate of muscle on d 4 of lactation but decreased it on d 15 (P < .05). Sows fed LL had a reduced number of LH pulses on d 12 and 18 (P < .05) and reduced serum estradiol (E2) concentration on d 18 of lactation compared with sows fed ML and HL treatments. However, LH pulses and E2 concentrations were similar between ML and HL treatments (P > .35). Increasing lysine intake increased serum urea nitrogen (SUN) and postprandial insulin concentrations (P < .05) during lactation but had no effect on plasma glucose concentrations (P > .20). Sows fed HL had greater serum IGF-I on d 6 and 18 than sows fed ML (P < .05). Number of LH peaks was correlated with serum insulin concentration 25 min after feeding on d 6 and 18 (r = .31 to .41; P < .1) and pre- (r = .33 to .46) and postprandial (r = .30 to .58) SUN concentrations (P < .05) during different stages of lactation. Results indicate that, compared with medium lysine intake, low lysine intake increased muscle protein degradation and decreased concentrations of insulin, SUN, and estradiol and LH pulsatility. In contrast, high lysine (protein) intake increased SUN, insulin, and IGF-I, but did not increase secretion of estradiol and LH compared with medium lysine intake. Furthermore, nutritional impacts on reproduction may be mediated in part through associated effects on circulating insulin concentration.

Animals↗

PubMed1985

The effect of pen density during rearing on subsequent reproductive performance in gilts.

A study involving 109 crossbred gilts of Duroc and Landrace breeding that were reared in equal-sized pens with 8 or 16 pigs/pen was initiated to determine the effects of pen density during rearing on subsequent reproductive and maternal performance. Gilts in pens of eight were allowed 1.06 m2/animal from 30 to 65 kg and 1.25 m2/animal from 65 to 100 kg, whereas those in pens of 16 were allowed only one-half as much floor area per animal. Gilts raised in groups of eight farrowed 1.0 more pigs/litter (P less than .05), and .7 more pigs/litter born alive (P = .15), than gilts reared in groups of 16 pigs/pen. There were no pen-density differences in the number of corpora lutea at 30 d of gestation (P = .33) or in litter birth weight (P = .26). After adjusting by covariance for the number of live pigs at the beginning of the lactation period, gilts from the pen density of 16 had more pigs per litter alive (P less than .01) and heavier litter weights (P less than .05) at 21 d postpartum and higher piglet survival rates to 21 d (P less than .02) than gilts that were reared in the low pen-density of eight pigs/pen. Results of this study indicate that pen density during the growing-finishing period may affect subsequent reproductive and maternal performance of gilts.

Animals↗