Sexual activity and body and testis growth in prepubertal ram lambs of Friesland, Chios, Karagouniki and Serres dairy sheep in Greece

Abstract Sexual activity, body size and testis growth in the prepubertal period (120±210 days of age) were studied in ®ve male lambs of each of four dairy sheep breeds. Sexual responses developed earlier in Friesland than in Chios and Karagouniki and latest in Serres ram lambs. Friesland lambs expressed interest in females at 127 days of age and 34 kg live weight 18±36 days younger and 3.4±6.3 kg lighter than the three Greek breeds. Puberty (®rst mounting with ejaculation occurred) of ram lambs appeared to be more closely associated with body weight than with chronological age. Age at puberty averaged 179 days in Friesland, 8, 10 and 30 days younger (P < 0.05) than in Karagouniki, Chios and Serres, respectively. On the other hand, weight at puberty averaged 50 kg for Friesland and Chios compared to about 44 kg for the two other breeds (P < 0.05). In the four breeds studied there was a 41±52 days interval between the time when lambs ®rst expressed interest in females and the time puberty occurred, the longest was that of Friesland lambs. There was a signi®cant breed difference in scrotal circumference. At puberty the scrotal circumference was 33.9 cm in Friesland lambs, 4±6 cm greater than in the three Greek breeds. Friesland ram lambs had a greater scrotal circumference throughout the entire period studied.

Reproductive efficiency of three estrus synchronization schemes comprising fixed-time insemination in dairy cows

The objective of this field trial was to compare the odds of pregnancy at 25 days (P25) and at 60 days (P60), of embryonic death (ED) between 25 and 60 days, and of non-pregnant cows returning to heat 20-25 days after artificial insemination (AI). Three fixed-time insemination protocols involving combined administration of either double gonadotrophin-releasing hormone (GnRH) and prostaglandins (A) or GnRH, human chorionic gonadotrophin (hCG) and prostaglandins (B), or double treatment with prostaglandins (C) were used. Cows included in the trial were selected from five herds, comprising a total of 735 (herd size range 85-250, median 120) Holstein dairy cows. Animals used for the study were multiparous, 4-7 years of age, had expressed at least one overt postpartum heat, were between 60 and 120 days of lactation and had at least one palpable corpus luteum and no gross morphological anomalies of their reproductive tracts. They were randomly allocated to receive treatment A (n = 89), B (n = 93), or C (n = 65). Pregnancy of cows not observed in heat 18-24 days post AI was diagnosed by transrectal ultrasonography at 25-30 days and confirmed by rectal palpation at 60-75 days post AI. Those that were detected in heat in the normal period post AI were re-inseminated. No differences were detected among the three treatment groups concerning the odds of P25 (P = 0.5), P60 (P = 0.2) and ED (P = 0.13). In contrast, non-pregnant cows that were administered treatment A were less likely to exhibit estrous signs in the normal period post AI than those administered treatments B (P = 0.02) or C (P = 0.005)

Ram seminal plasma and fertility: Results from an ongoing field study

The effects of partial replacement of ram semen diluent with ram seminal plasma on the fertility of ewes were studied. Crossbred Chios ewes (n = 152) were assigned to six groups. The oestrous cycles of the ewes were synchronised at the peak (Groups A, B, C and D) and at the end (Groups E and Fl of the breeding season by means of intravaginal sponges impregnated with fluorogestone acetate (FGA) for 14 days. Four hundred IU of PMSG were injected intramuscularly at the time of sponge removal. Ewes of Groups A, C and E were artificially inseminated with ram semen diluted with skim milk extender, while those of Groups B, D and F with ram semen diluted with 50% skim milk and 50% ram seminal plasma. The addition of ram seminal plasma induced a significant increase (P < 0.05) in litter size in Groups B and D when compared with that of Groups A and C (1.85 and 1.88 vs. 1.39 and 1.52, respectively). This increase was not significant when insemination was performed at the end of the breeding season (2.0 vs. 1.4). These results indicate that the addition of seminal plasma can influence the fertility of ewes or the fertilising capacity of extended ram semen to some extent

Effect of aflatoxin B1 on blood serum oestradiol-17β and progesterone concentrations during the luteal phase and the synchronized oestrus of goats

The effect of prolonged aflatoxin B1 (AFB1) administration on blood serum oestradiol-17β and progesterone concentrations in goats during the luteal phase and the synchronized oestrus was investigated. Thirty-six Greek indigenous primiparous goats were used, during the oestrus period; 12 goats received, per os, 50 μg (treated group T50) and 12 goats received 100 μg (treated group T100) AFB1/day/head, respectively, for approximately 1.5 month, while 12 goats served as controls (C). On day 36 of the experiment, each goat was injected, i.m, 0.5 ml prostaglandin F2α (PGF2α). Blood samples were collected from each goat twice a week, before PGF2α injection, as well as every 4 hours from the onset to the end of the synchronized oestrus. Oestradiol-17β and progesterone concentrations in blood serum were determined using radioimmunoassay. During the whole luteal(s) phase(s), linear regression analysis revealed a significant negative dependence (P &lt; 0.05) of oestradiol-17β and a significant positive dependence (P &lt; 0.05) of progesterone over group (C = 0, T50 = 50, T100 = 100), in a dose dependent manner. During the synchronized oestrus, multiple linear regression analysis revealed a significant negative dependence (P &lt; 0.05) of oestradiol-17β, as well as a significant positive dependence (P &lt; 0.05) of progesterone over group (C = 0, T50 = 50, T100 = 100) and over time (hours, from the onset to the end of the synchronized oestrus). No significant differences were noticed among the three groups, regarding the body weight of the goats from the onset to the end of AFB1 administration, the occurrence or the duration of the synchronized oestrus presented by the goats (P &gt; 0.05). In conclusion, prolonged AFB1 administration at doses of 100 or even of 50 μg/day/head changes the hormonal pattern in blood during the luteal phase and the synchronized oestrus of goats, being in oestrus period. © 2018 Official journal of the Brazilian College of Animal Reproduction

Effect of prolonged aflatoxin B-1 administration on blood serum oestradiol-17 beta and progesterone concentrations of goats during the anoestrus period

The effect of prolonged aflatoxin B-1 (AFB(1)) administration on blood serum oestradiol-17 beta and progesterone concentrations in goats during the anoestrus period was investigated. Thirty Greek indigenous goats were used; 10 goats received, per os, 50 mu g (treated group T50) and 10 goats received 100 mu g (treated group T100) AFB(1)/day/head, respectively, for 31 days, while 10 goats served as controls (C). Blood samples were collected from each goat twice a week to determine serum oestradiol-17 beta and progesterone concentrations by radioimmunoassay. Multiple linear regression analysis revealed a significant (P < 0.05) positive dependence of blood serum oestradiol-17 beta concentration over group (C = 0, T50 = 50, T100 = 100), in a dose-dependent manner, and a significant (P < 0.05) negative dependence over time (0-31 days, from the onset to the end of AFB(1) administration). Linear regression analysis revealed a significant (P < 0.05) positive dependence of blood serum progesterone concentration over group (C = 0, T50 = 50, T100 = 100), in a dose-dependent manner. Pearson's correlation coefficient revealed a significant (P < 0.05) positive correlation between blood serum oestradiol-17 beta and progesterone concentration, but only in the goats of the control group. In conclusion, the prolonged administration of 100 or even of 50 mu g AFB(1)/day/head during the anoestrus period, increased blood serum oestradiol-17 beta and progesterone concentrations of goats, in a dose-dependent manner, and in the treated groups disturbed the positive correlation between oestradiol-17 beta and progesterone concentration shown in the goats of the control group

Formation of a secondary corpus luteum after ultrasound-guided follicular aspiration in cows

This paper reports the observed formation of a secondary corpus luteum (CL) in the presence of the cyclic corpus luteum, on the ovaries of a cow after ultrasound-guided follicular aspiration for oocyte recovery. The secondary structure, although smaller and lighter (4.97g vs. 6.02g) than the natm al one, had the typical macroscopic appearance of a corpus luteum. Histological examination of the structure using electron microscopy revealed typical structural features of a natural CL. Mean tissue progesterone concentration was significantly lower in the secondary CL (31.15 +/- 3.11 compared with 58.29 +/- 6.32 mu g/g tissue of the cyclic CL) and oestradiol-17 beta significantly higher than in the natural CL (108 +/- 11.6 compared with 74.2 +/- 7.81 pg/g tissue). P450(scc) and P450(17 alpha) mRNA was detected in both structures while P450(arom) and full-length mRNA FSH receptor were detected only in the secondary structure

Effects of aflatoxin B1 administration on Greek indigenous goats' milk

Aflatoxins are toxic metabolites of the fungi Aspergillus spp. After aflatoxin B1 (AFB1) is consumed by lactating animals, it is metabolized to aflatoxin M1 (AFM1), which is excreted into the milk. The present study investigates the AFM1 excretion into the milk and the milk composition of Greek goats after AFB1 administration. Thirty Greek goats were divided into 3 groups of 10 animals each; one group of controls and two groups of treated animals. Each goat of the treated groups received per os 50 or 100 mu g of AFB1 per day, respectively, for 35 days. Individual milk samples were analyzed for AFM1 concentration and milk components. The results indicate the excretion of AFM1 into the milk at concentrations higher than the maximum European Union's limit and a significant decrease of milk fat content due to the higher AFM1 concentration into the milk samples and to the higher AFB1 administration in goats. (C) 2011 Elsevier Ltd. All rights reserved