Effect of feeding fungal endophyte (Acremonium coenophialum )-infected tall fescue seed on reproductive performance in CD-1 mice through continuous breeding

This study was designed to assess the effect of endophyte-infected (Acremonium coenophialum ) tall fescue (KY-31) seed (80% infected) on reproductive performance in CD-1 mice by continuous breeding. Twenty-four pairs of 70-d-old CD-1 mice were randomly allocated to four diets: 1) mouse chow ad libitum; 2) 40% infected fescue seed and 60% chow (w/w); 3) reduced intake (100% chow) similar to the intake, adjusted daily, in Diet 2; and 4) 60% infected fescue seed and 40% chow. Males and females were randomly paired (six pairs/treatment) and placed on the above diets. The mice were fed the corresponding diets for 80 d, although the pairs were separated on Day 60 (prior to the birth of the 3rd litter) and the females were monitored for one additional gestation period (20 d). The pregnancy data (litters produced) among the four treatments were 100.0 (18), 77.8 (14), 100.0 (18) and 80.0% (12) respectively. Similarly, the average number of pups born per litter among the four treatments was 11.8, 9.3, 10.1, and 9.8. When the chow treatment (1 and 3) and the fescue treatments (2 and 4) were pooled and compared, the percent pregnancy was 100.0 (n = 36) and 78.8 (n = 26), and the pups born per litter (means +/- SEM) were 11.0 +/- 0.5 and 9.5 +/- 0.6, respectively. Also the intervals between the three litters born during the 60-d cohabitation period were 21.6 +/- 1.1 and 24.5 +/- 0.9 d for the chow and fescue treatments, respectively. The results point out that 40 and 60% infected fescue seed in the diet of mice does influence (P < 0.05) their reproductive capacity as measured by percent pregnancy and litter size.     

Effect of feeding tall fescue seed infected by endophytic fungus (Acremonium coenophialum ) on reproductive performance in male rats

An experiment was conducted to determine the effect of feeding tall fescue seed infected by an endophytic fungus Acremonium coenophialum on the reproductive performance of male rats. Thirty 70-day-old rats were randomly allocated to four treatments: (I) fed 50% rat chow and 50% healthy fescue seed ad libitum (control; N=9; (II) same as I but restricted to the daily feed intake of III (N=7; (III) 50% fungal-infected fescue seed and 50% chow (N=7); and (IV) a mixture of 50% laboratory chow, 25% healthy fescue seed and 25% fungal-infected fescue seed (N=7). The rats were fed these diets for 42 days. During this time, body weights were taken weekly and feed intake was taken daily. At the end of the experiment, the rats were sacrificed and the testes and epididymides were excised and measured. Sperm parameters were assessed (concentration, percentage of motility and progressive motility) at the site of the cauda epididymis; the testes were homogenized and assessed for daily sperm production potential (DSP). Concentrations of spermatozoa (x 10(6)) among the various treatments were 645.6, 486.5, 387.4 and 457.1; motility and progressive motility measurements ranged from 48 to 50% and 2.3 to 2.4 (0-4), respectively. DSP values (per gram) and testicular weight were reduced (P<0.05) in Diet III. The data suggests that 50% fungal-infected fescue seed in the diet of rats does influence the DSP, testicular parechyma and epididymal weight in the rat.     

A polymorphism in XKR4 is significantly associated with serum prolactin concentrations in beef cows grazing tall fescue

Fescue toxicosis is a common syndrome of poor growth and reproductive performance of beef cattle grazing endophyte‐infected tall fescue infected with Lolium arundinaceum Schreb. Together with decreased feed intake, decreased growth rates and tissue necrosis due to vasoconstriction, depressed circulating serum prolactin concentrations are typically observed in cattle afflicted with fescue toxicosis. Polymorphisms within the XK, Kell blood group complex subunit‐related family, member 4 (XKR4) gene located on BTA14 have been previously reported to be associated with rump fat thickness, residual feed intake, average daily feed intake and average daily gain in cattle. Associations also have been reported between XKR4 genotype and effectiveness of the dopamine antagonist iloperidone as a treatment of schizophrenia in humans. Domperidone, a related dopamine antagonist, mediates effects of fescue toxicosis on livestock, including restoring depressed concentrations of prolactin. A mixed‐breed population of 592 beef cattle grazing endophyte‐infected tall fescue was used to examine the association between XKR4 genotype and circulating prolactin concentrations. The SNP rs42646708 was significantly (P = 0.0002) associated with serum prolactin concentrations and explained 2.45% of the phenotypic variation. Effect of genotype at the SNP was tested across five breeds, with significant associations within both Angus (P = 0.0275) and Simmental (P = 0.0224) breeds. These results suggest XKR4 may play a role in mediating the negative effects of fescue toxicosis, and polymorphisms within this gene may be useful markers for selection for genetic resistance to the debilitating effects of endophyte‐infected tall fescue.     

Growth and ovarian function of weanling and yearling beef heifers grazing endophyte-infected tall fescue pastures

Growth and ovarian function of crossbred beef heifers grazing low and high endophyte-infected tall fescue pastures were studied for 2 successive years. In April of each year, 20 weanling and 20 yearling heifers were included in the study. All heifers were weighed at 28-d intervals for 112 d. Blood samples were collected from each heifer on Day 0 and +7 of each of five 28-d periods and analyzed for progesterone concentration. Heifers with progesterone concentrations >/= 1.5 ng/ml on either or both Day 0 and +7 were classified as having normal cyclic ovaries. High endophyte-infected fescue pastures adversely altered the ovarian activity (P < 0.05) of weanling heifers in both years. In each trial, average weight gains were lower (P < 0.05) in yearling and weanling heifers grazing the high endophyte-infected pastures than in heifers grazing low endophyte-infected pastures. In 1992, heifers were synchronized with PGF(2alpha) administered on Days 101 and 112. Blood samples were collected on 0, 4, 8 and 12 d after the second PGF(2alpha) injection for progesterone analysis. Heifers grazing high and low endophyte-infected pastures were pastured separately with 4 bulls each and were given heatmount detectors. At 96 h, less estrus activity was observed (P < 0.10; power=0.63) in weanling heifers grazing the high vs. low endophyte pastures although pregnancy rates were similar for all groups. Progesterone concentrations suggested that weanling heifers on the high endophyte pastures had a higher incidence of luteal dysfunction after PGF(2alpha) synchronization. In summary, high endophyte-infected pastures decreased growth in both weanling and yearling heifers, ovarian activity and luteal function were adversely altered in weanling heifers with subsequent decreased estrus response to estrus synchronization.     

The effect of grazing location and oronasal treatment with bull urine on reproductive performance and serum prolactin concentrations of beef heifers

Grazing location and biostimulatory treatments were imposed on 55 Brangus and crossbred heifers in a 2 x 2 x 2 factorial arrangement. Grazing locations (postweaning) were semi-desert rangeland with supplementation or irrigated small grains pasture. Biostimulatory treatment involved either weekly oronasal application of bull urine or no treatment (control). The duration of bull urine treatments was 8 weeks. Grazing location affected heifer weights from February through August (P < 0.01). Rate of weight gain on irrigated pasture exceeded native range (P < 0.01). Cyclicity was similar between the location groups before the treatment period. Post-treatment cyclicity rates of heifers were 25 and 78% for native range and irrigated pasture, respectively (P < .01). Twenty-five percent of cyclic heifers grazing native range went into anestrus during this treatment period, while no loss of cyclicity was observed in the heifers on irrigated pasture (P < 0.10). Heifers maintained on irrigated pasture exhibited more standing estrus following synchronization (P < 0.10), higher pregnancy rates following breeding (P < 0.05), heavier fall weights (P < 0.01), higher body condition scores (P < 0.01), and greater pelvic widths (P < 0.05) than those on native range. Cyclic heifers grazing native range had prolactin levels twice those of irrigated pasture heifers. Serum growth hormone levels were not consistently affected by treatments. Heifers which became pregnant while grazing irrigated pasture had much lower prolactin concentrations in serum collected in January than the noncyclic heifers.     

The effect of feeding tall fescue seed infected by Acremonium coenophialum on pregnancy and parturition in female rats

1. Female Sprague-Dawley rats (Rattus norvegicus) were randomly assigned to various dietary treatments containing: (1) 100% Purina rodent chow, ad libitum; (2) same as 1, but restricted to daily intake of 7; (3) 50% rodent chow (w/w) and 50% endophyte-free tall fescue (Festuca arundinacea) seed; (4) same as 3, but restricted to intake of 5; (5) 50% rodent chow, 25% endophyte-free tall fescue seed and 25% endophyte-infected (Acremonium coenophialum) tall fescue seed; (6) 50% rodent chow, 12.5% endophyte-free and 37.5% endophyte-infected tall fescue seed; and (7) 50% rodent chow and 50% endophyte infected tall fescue seed. 2. Average daily feed intakes and average daily weight gains decreased with higher levels of endophyte infected seed. 3. Frequency of litter production was affected by all endophyte-infected containing diets. 4. Conception was reduced only in dietary treatment (7). 5. Litter weights, number of pups per litter and weight per pup were proportionally reduced as higher levels of infected seed were incorporated in the ingested diets.     

The effect ofAcremonium coenophialum on the growth and nematode infestation of tall fescue

The presence of the endophytic fungusAcremonium coenophialum Morgan-Jones et Gams in tall fescue (Festuca arundinacea Schreb.) induces toxicity when this grass is grazed by cattle; however, there is evidence that removing the endophyte reduces the stand vigor and longevity of fescue. A field trial was conducted to determine the effects of water supply and the presence of the endophytic fungus on plant growth, drought tolerance, and soil nematode populations in Kentucky 31 tall fescue. The design included two factors, level of endophyte infection (0 and 75%) and irrigation regime (none, low, and high). Where water deficits occurred, herbage yield and leaf area were lower, and percentage dead tissue and canopy minus air temperature were greater in endophyte-free compared with endophyte-infected fescue. Soil populations ofPratylenchus scribneri andTylenchorhynchus acutus were substantially higher in the noninfected than in the endophyte-infected plots. The endophyte apparently confers drought tolerance to Kentucky 31 tall fescue, and this effect may be at least partially mediated through enhanced resistance to soil-borne nematodes.Published with the approval of the Director of the Ark. Agric. Exp. Stn.     

Effects of feeding endophyte-infected (Acremonium coenophialum ) KY-31 fescue hay on the reproductive development of Holstein bulls

This study was designed to assess the effect of endophyte-infected (Acremonium coenophialum ) tall fescue (KY-31) on reproductive development in bulls. Eighteen Holstein bull calves (2 mo old) were randomly allocated to one of two dietary treatments consisting of 1) noninfected KY-31 fescue hay (NON) supplemented with grain (n=9) and 2) infected (67% infected by Acremonium coenophialum ) KY-31 fescue hay (INF) supplemented with grain (n=9). Both dietary treatments consisted of equal amounts of hay and grain. Data were collected every 14 d. Body weight, hip height and scrotal circumference did not differ (P>0.05) in the two treatments. Mean rectal temperatures also were not different in bulls (P = 0.12); however the infected bulls experienced higher rectal temperatures in all but four collection periods. Animals were sacrificed at 13 mo of age. Testicular weight and dimensions, epididymal weight and length as well as seminal vesicle weight were not different (P>0.05). Maturity of spermatozoa taken from each cauda epididymides was assessed by the incidence of cytoplasmic droplets and was not different (P>0.05) between treatments. Daily sperm production potential was not different (P>0.05) between treatments; however, large variations were noted among the infected bulls. Blood testosterone levels were not different (P=0.29) between the two dietary treatments, but were different over time (P<0.001) with NON and INF bulls having 2.14 +/- 0.21 and 2.41 +/- 0.22 ng/ml, respectively. Prolactin levels were different (P<0.02) between the NOn and INF bulls, 29.35 +/- 3.35 vs 18.31 +/- 3.39 ng/ml, respectively; and over time (P<0.001). The data generated in this study showed some important biological trends. Overall, the results indicate that endophyte infected KY-31 fescue hay fed to growing bulls did not appear to have severe detrimental effects on body growth or reproductive development. However, additional studies will be necessary to further delineate the patterns established in this study.     

Impact of consuming tall fescue seeds infected with the endophytic fungus,Neotyphodium coenophialum,on reproduction of chickens

Most of the 14 million hectares of pastures of tall fescue (Festuca arundinacea) planted in the United States are infected with the endophytic fungus, Neotyphodium coenophialum. I examined whether the consumption of fescue seed infected with this fungus had an adverse impact on reproduction in birds. Chickens were used as the model; they were maintained on a diet of chick starter mixed in equal amounts with either infected fescue seed (fungus-fed chickens) or uninfected fescue seed (control chickens). Consumption of infected fescue seed slowed the growth rates of female chicks but not males. Fungus-fed hens gained weight more slowly than control hens and also produced fewer eggs. Egg weight and fertility were similar in both groups of hens. Fungus-fed hens were more likely than control hens to produce eggs which lacked a shell. Naive hens exhibited an aversion for infected fescue seed when the seed was first presented to them, but the aversion disappeared after the hens were placed on a diet which included fescue seed for 3 or 6 months. Hens did not discriminate between feed containing infected seed and feed containing uninfected seed.     

Effect of treatment with ivermectin on reproductive performance of yearling beef heifers

To determine the effect of treatment with ivermectin on reproductive parameters, 78 fall-born, yearling heifers were allotted to either an ivermectin treatment group or to the control, non-treatment group. The heifers were treated in June and October when they were approximately 7 and 11 mo old, respectively. Ivermectin effectively lowered fecal egg counts in the treated heifers compared with that of the controls. In heifers that were maintained on a marginal plane of nutrition, treatment with ivermectin not only improved weight gains during each recording period but also hastened the onset of puberty and improved the pregnancy rate during a 60-d breeding season. The positive effect of ivermectin on these reproductive characteristics could not be explained by increased weight gain alone, because the correlation between weight gain and puberty was not significant. Treatment with ivermectin positively affected pelvic area but not uterine score when compared with those of the controls.     

Endophytic fungi (Neotyphodium coenophialum) affect the growth and mineral uptake, transport and efficiency ratios in tall fescue (Festuca arundinacea)

Neotyphodium coenophialuminteracts mutualistically with its host grasses. Tall fescue (Festuca arundinacea Schreb.) plants infected by the fungal endophyte,Neotyphodium coenophialum(Morgan-Jones and Gams) Glenn, Bacon and Hanlin, often perform better than non-infected plants, especially in limited resource environments. However, there is a scarcity of information about endophyte-grass ecotypes interaction in Andisols of temperate regions. Clones of three tall fescue ecotypes (Fukaura, Koiwai and Showa) either infected with N. coenophialum (E+) or noninfected (E–) were grown in Andisols (Black Andisol: naturally low content of phosphorus, high in other nutrients; Red Andisol: naturally high content of phosphorus, low in other nutrients) for 133 days in a controlled environment. Cumulative shoot dry weight, daily regrowth rates (tiller number, plant height and shoot dry matter) after clippings and nutrient uptake, transport and efficiency ratios were measured. In Black Andisol, E+ plants had significantly higher cumulative shoot dry weight as well as daily regrowth rates than E– plants, while in Red Andisol the reverse was true. Among the ecotypes studied, Showa had the highest shoot growth. Significantly higher phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) uptake as well as transport were identified in E+ vs. E– plants grown in Black Andisol. With few exceptions, values for nutrient efficiency ratios were not significantly different between E+ and E– plants grown in both soils. Significant three-way interaction (endophyte × ecotype × soil) for cumulative shoot dry weight and regrowth rate revealed that the ecotype specific regrowth responses to endophyte infection were depended on soil nutrient conditions. Vegetative growth and nutrient acquisition in tall fescue varied with ecotype and were modified by abiotic (soil fertility status) as well as biotic (endophyte infection) factors.     

The effect of feeding endophyte infected tall fescue seed on reproductive performance in female rats

Female Sprague-Dawley rats (Rattus norvegicus) were randomly assigned to diets containing mixtures of rat chow and tall fescue (Festuca arundinacea) seed with 0, 5, 10, 20 and 40% infection levels of Acremonium coenophialum to assess the effect of the diets on the reproductive potential of rats. Rats fed 40% infected seed had decreased body weight, decreased mean percent body weight of uteri, failed to maintain normal estrous cycles and were unable to become pregnant. Animals fed a diet of 20% infected fescue seed had extended estrous cycles. There were no significant differences among the 0, 5 and 10% dietary treatments.     

Production, Characterization, and Use of Monoclonal Antibodies Against Acremonium coenophialum

Monoclonal antibodies were produced using intact mycelium of the fungus Acremonium coenopbialum as the immunogen. During the initial stages of characterization, the antibodies were found to react to A. coenophialum, A. loliae, Epichloe typhina , and also to cross-react with some other fungi normally associated with tall fescue. Careful selection of the ELISA system in which the antibodies were used eliminated reactions to all but the two Acremonium spp. and E. typhina. Asa result it was possible to detect Acremonium spp. (presumably A. coenophialum ) sensitively and unambiguously in leaf tissue of tall fescue.     

Influences of diet during gestation on potential postpartum reproductive performance and milk production of beef heifers

The influences of nutritional protein and energy during early and mid pregnancy on milk production and postpartum reproductive parameters were determined in 70 beef heifers of two composite breeds (Bos indicus X Bos taurus). At artificial insemination (AI), heifers were divided into four dietary treatment groups identified by the level of protein, and to a lesser extent energy, fed during the first and second trimesters: high/high (HH), high/low (HL), low/high (LH), and low/low (LL). Milk production was lower in the heifers receiving high treatment in first trimester than that in heifers receiving the low treatment (P = 0.01). Milk production was negatively associated with dam body condition score (BCS; P = 0.01), nonesterified fatty acids (P = 0.001), and leptin (P = 0.02) and positively associated with urea (P < 0.001) concentrations during lactation. Increased dietary protein in the first trimester increased or decreased concentrations of colostral protein dependent upon genotype (P = 0.03). Colostral protein was positively associated with bovine pregnancy associated glycoprotein from late gestation (P = 0.007). Milk fat was negatively associated with BCS (P = 0.007) and influenced by genotype (P = 0.003). Dietary treatment did not affect the postpartum reproductive performance of beef heifers. Gestation length (P < 0.001) and the postpartum interval to first estrus (PPI; P = 0.02) were positively associated with calf size. Placental size was negatively associated with placental expulsion time (P < 0.01). Prepartum BCS of the heifers was negatively associated with PPI (P = 0.01). Overall, high levels of nutrition during early gestation are detrimental to milk production in beef heifers.     

Effects of feeding endophyte-infected tall fescue seed on reproductive performance in male CD-1 mice by competitive breeding

The objective of this study was to assess the effects of endophyte-infected tall fescue (KY-31) seed (80% infected, containing Acremonium coenophialum ) on the reproductive performance of male CD-1 mice measured by competitive breeding. Sixteen mature CD-1 male mice were randomly allocated to one of two dietary treatments containing 50% mouse chow and either 1) 50% noninfected tall fescue seed, restricted to the daily feed intake of dietary treatment 2, or 2) 50% infected tall fescue seed (w/w) fed ad libitum. Mice were preconditioned on their respective diets for 50 d prior to 96 h of cohabitation with 10 mature CD-1 females. Following removal of males, the females were carried to full term. Males were sacrificed, and testicular, epididymal weights, sperm motility and progressive sperm motility were assessed. The results showed no differences (P>0.05) in average daily weight gain (ADG) and body weight changes during the course of the experiment between the two dietary treatments. There were significant reductions (P<0.05) in total testes weight (0.238 vs 0.214 g), epididymal weight (0.087 vs 0.073 g), sperm motility (82.5 vs 58.7%), and progressive motility (3.7 vs 2.6; scale 0 to 4) between dietary treatments 1 and 2, respectively. Similarly, significant differences in pregnancy rates were 53.8 and 45.0%, and the average numbers of pups born per litter were 10.67 and 9.84, respectively. These data suggest that 50% endophyte-infected fescue seed in the diet of male CD-1 mice can affect their reproductive capacity by influencing the testicular-epididymal weights, and subsequently, the quality of spermatozoa and overall fecundity.     

Creep-feeding to stimulate metabolic imprinting in nursing beef heifers: impacts on heifer growth,reproductive and physiological variables

This experiment compared growth, physiological, and reproductive responses of beef heifers with (MI) or without (CON) access to a creep-feeder, as a manner to stimulate metabolic imprinting while nursing their dams. On day 0, 60 Angus×Hereford heifers were ranked by BW and age (140±3 kg and 68±3 days), and assigned to pairs so all ranking criteria were similar between heifers within each pair. On day 1, pairs were randomly assigned to MI (n=15) or CON (n=15). From day 1 to 51, MI pairs and their dams were allocated to 15 drylot pens where heifers had ad libitum access to a corn-based supplement through a creep-feeder. The CON pairs and their dams were maintained in an adjacent single drylot pen. From day 52 to 111, treatments were managed as a single group on a semiarid range pasture. On day 111, heifers were weaned and allocated to two pastures (one pasture/treatment), receiving hay and a corn-based concentrate until day 326. Heifer BW was recorded before and at the end of the creep-feeding period (day 1 to 51), and on days 112 and 326. On days 0, 51, 111, 187, 261, and 325, jugular blood was collected and real-time ultrasonography for longissimus muscle depth and backfat thickness assessment was performed. Blood was also collected every 10 days from days 113 to 323 for puberty evaluation via plasma progesterone. Liver and subcutaneous fat biopsies were performed on days 51, 111, 261 and 325. Average daily gain was greater (P<0.01) for MI than CON from day 1 to 51, tended (P=0.09) to be greater for CON than MI from day 112 to 326, while BW on day 326 was similar between treatments. On day 51, MI had greater (P⩽0.01) plasma IGF-I and glucose concentrations, as well as mRNA expression of hepatic pyruvate carboxylase and adipose fatty acid synthase than CON. On days 261 and 325, plasma insulin concentrations were greater (P⩽0.03) in CON than MI. Mean mRNA expression of hepatic IGF-I and adipose peroxisome proliferator-activated receptor gamma were greater (P⩽0.05) in MI than CON. No treatment effects were detected for puberty attainment rate. In conclusion, supplementing nursing heifers via creep-feeding for 50 days altered physiological and biochemical variables suggestive of a metabolic imprinting effect, but did not hasten their puberty attainment.     

Effects of feeding endophyte infected tall fescue seed on reproductive performance of female CD-1 mice via competitive breeding

This study was conducted to determine the effects of feeding endophyte-infected (Acremonium coenophialum ) tall fescue (Festuca arundinacea ) seed on the growth and reproductive performance of female CD-1 mice via competitive breeding. One hundred sixty female mice were randomly allocated to groups of ten and fed one of two diets. Diet 1 consisted of 50% mouse chow and 50% noninfected Ky-31 tall fescue seed (w/w). Diet 2 contained 50% chow and 50% tall fescue seed that was 80% infected with A. coenophialum . After 50 d of preconditioning on their respective diets, a single male was introduced into each group of 10 females and allowed to cohabitate for 96 h. The males were removed after the cohabitation period and the females continued through gestation on their respective diets. Body weight of dams and litter weights were recorded at parturition. There were no differences (P>0.05) in pregnancy rates between dietary Treatments 1 and 2 (50% vs 48.8%, respectively). However, the average number of pups born per litter (11.10 pups) and average total litter weight (17.21 g) was greater for those females consuming Diet 1 than for females consuming Diet 2 (9.33 pups per litter and 13.97 g total litter weight). The incidence of dead and cannibalized pups was more frequent with Diet 2 than Diet 1 (0.13 vs 0.0 dead; 0.21 vs 0.03 cannibalized, respectively). The obtained data suggest that although the pregnancy rate was similar between the two dietary treatments, the reproductive capacity (litter size and litter weight) of female CD-1 mice was affected by the consumption of endophyte infected fescue seed.     

A histological study of corpora lutea from superovulated beef heifers

There is great variability between animals in the number of viable embryos produced following different superovulation regimens. It is not clear if all the follicles that ovulate produce healthy oocytes and form normal corpora lutea (CL) following superovulation. The objective of this study was to assess and compare CL from heifers undergoing three superovulatory regimes with CL from unstimulated heifers on the basis of morphology and morphometric analysis of luteal cells.Beef heifers were superovulated using either: (a) 24 mg porcine follicle stimulating hormone (pFSH) given twice daily over a 4 day period in decreasing doses commencing on day 10 of the oestrous cycle; (b) a single injection of 2000 IU pregnant mare serum gonadotrophin (PMSG) given on day 10 of the cycle; (c) as in (b) but followed by 2000 IU anti-PMSG (IgG to neutralise endogenous PMSG) at the time of the first insemination which was 12–18 h after the onset of oestrus (n = 33 per treatment). Luteolysis was induced 48 h after initial gonadotrophin administration and CL were collected on day 7 of the subsequent cycle and from ten unstimulated heifers (controls) at the same stage of the oestrous cycle. CL morphology was studied at light and electron microscopy levels. Morphometric analysis was performed on luteal cells. Subcellular morphology was similar in heifers from all groups. However, CL from superovulated heifers had more connective tissue than CL from control heifers; the connective tissue content of CL in the anti-PMSG-treated group was particularly marked. Both large and small luteal cells in the heifers receiving anti-PMSG had significantly smaller (P < 0.001) area and sphere volume than similar cells from CL of heifers in the other groups.     

Effects of feeding endophyte-infected tall fescue seed on the reproductive performance in male and female CD-1 mice by combination crosses

The present study was undertaken to assess the effects of endophyte-infected Acremonium coenophialum tall fescue (KY 31) seed (80% infected) on the reproductive performance of male and female CD-1 mice by combination crosses. Forty-eight male and 48 female 30-d-old mice were randomly allocated to two diet treatments. Twenty-four males and 24 females were fed Diet 1, consisting of 50% non-infected fescue and 50% mouse chow; the remaining animals were fed Diet 2, containing 50% infected fescue. At the end of 50 d, the animals were paired in groups (n = 12) as follows: 1) Diet 1 males and females; 2) Diet 2 males and Diet 1 females; 3) Diet 1 males and Diet 2 females; and 4) Diet 2 males and females. The pairs were maintained on the diets of their female partners and were allowed to cohabitate for 96 h. After this period the males were removed and the females were carried to term. Pregnancy rates among the four treatment groups were 100, 83.3, 75.0 and 54.5%, respectively. Similarly, the average number of pups born per litter among the four groups were 11.5, 8.0, 9.7, and 7.5, respectively. Also, the weights (grams) of pups born per litter were 17.5, 12.6, 12.4, and 9.8, respectively. The results point out that the reproductive capacity of both male and female mice are affected (P < 0.05) by the ingestion of endophyte-infected fescue seeds. Such negative effects were more severe in the female than the male (P < 0.05).