Parity of female goats does not influence their estrous and ovulatory responses to the male effect

The objective of the present study was to determine whether parity is a factor that influences the estrous and ovulatory responses of female goats when they are stimulated by males that show increased sexual activity. To stimulate sexual activity, four adult male goats were subjected to photoperiodic treatment for 2.5 months comprising long days, with the treatment commencing on 1 November. On 14 April at 1900 h, a group of multiparous females (n = 21) and a group of 16 months-old nulliparous females (n = 19) were exposed to four bucks (two per group) for 15 days. Throughout the study period, the estrous behavior of these female goats was detected twice on a daily basis. Ovulations of the female goats were determined by ecography on days 7 and 18 after exposure to males. The sexual behavior of males was recorded twice every day from 0800 to 0900 h and from 1730 to 1830 h during the first 4 days after introduction in the pen of females. The total cumulative proportion of multiparous females that had ovulations (100%) and displayed estrous behavior (100%) during the 15 days of exposure to males did not differ (P > 0.05) from that of nulliparous females (100% and 95%, respectively). The interval between introduction of males and onset of estrous behavior did not differ (P > 0.05) between multiparous (1.9 ± 0.1 days) and nulliparous (1.7 ± 0.2 days) females. The proportion of females displaying a short estrous cycle was greater (P < 0.05) in multiparous (13/21, 62%) than in nulliparous (5/19, 26%) females. Duration of these shorter than typical estrous cycles did not differ (P > 0.05) between groups (multiparous: 5.2 ± 0.3 days, nulliparous: 4.5 ± 0.1 days). The number of anogenital sniffings was greater (P < 0.001) in males exposed to nulliparous than in those exposed to multiparous females. In contrast, the number of mounting attempts was greater (P < 0.01) in males that were introduced to multiparous than in those that were introduced to nulliparous does. The number of flehmen, nudging, self-marking with urine, and mounts was not different (P > 0.05) between males that were in contact with multiparous and nulliparous females. These results indicate that regardless of parity, female goats respond to male introduction if they are stimulated by males that were previously exposed to artificial long days to increase their sexual behavior.     

Biopsied and vitrified bovine embryos viability is improved by trans10, cis12 conjugated linoleic acid supplementation during in vitro embryo culture

Bovine embryos cultured in serum-containing media abnormally accumulate lipids in the cytoplasm. This is well known to contribute to their higher susceptibility to cryopreservation and biopsied embryos are even further susceptible. We aimed to improve in vitro produced (IVP) embryos resistance to micromanipulation and cryopreservation by supplementing serum-containing media with trans-10, cis-12 conjugated linoleic acid (t10, c12 CLA). The effect of t10, c12 CLA on lipid deposition and embryonic development was also tested. After in vitro maturation and fertilization (IVF day = D0), zygotes were cultured on granulosa cells + M199 + 10% serum + 100 μM GSH supplemented with 100 μM of t10, c12 CLA (CLA group, n = 1394) or without supplementation (control group, n = 1431). Samples of D7/D8 embryos were observed under Nomarsky microscopy for lipid droplets evaluation while others were biopsied and vitrified (group B-Control, n = 24; group B-CLA, n = 23). Non-biopsied embryos were also frozen (group NB-Control, n = 49; group NB-CLA, n = 45). Biopsied cells were used for embryo sex determination. Postwarming embryo survival and viability were determined at 0 and 24 h of culture, respectively. Supplementation of t10, c12 CLA did not influence cleavage, embryo sex ratio, D7/D8 embryo rate or morphological quality. CLA embryos had higher number of small lipid droplets (P ≤ 0.003) and a smaller (P < 0.001) fat embryo index being leaner (P = 0.008) than control embryos. Embryo postwarming survival was higher in B-CLA than in B-control group (95.0 ± 7.0% versus 62.5 ± 7.9%; P < 0.001). After 24 h of culture, the viability (expansion rate) of biopsied embryos and nonbiopsied embryos, cultured with t10, c12 CLA was higher than control embryos (B-CLA = 64.6 ± 4.4% and B-control = 27.5 ± 2.5%, P = 0.01; NB-CLA = 86.0 ± 3.5% and NB-Control = 68.6 ± 7.0%, P = 0.05). Results showed that supplying t10, c12 CLA to serum-containing media decreases embryo cytoplasmic lipid deposition during in vitro culture and significantly improves resistance of IVP embryos to micromanipulation and cryopreservation.     

Effects of Tasco (a seaweed extract) and heat stress on N metabolism and meat fatty acids in wether lambs fed hays containing endophyte-infected fescue

Wether lambs (n = 27, average BW = 40 kg) were used to test response to forage treated with Tasco-Forage (an extract of the brown kelp Ascophyllum nodosum) prior to conserving, or to direct feeding of the extract (Tasco-EX). Hays made from endophyte (Neoyphodium coenophialum)-infested tall fescue (Festuca arundinacea)-based pasture received 0 or 3 kg of Tasco/ha prior to harvest. Lambs, blocked by weight, were randomly allotted to three diets: (1) control hay, (2) treated hay, and (3) #1 + Tasco-EX fed at 1% of the diet. Hays were low in CP (<7%) so all lambs were fed soybean meal (12% of the diet) in addition to trace mineralized salt. Diets were fed at 1.5% BW to prevent refusals. Total collections (7 d) were made during periods without or with applied heat stress. After each period, rumen contents were obtained to determine pH, NH₃ and VFA. Lambs were sacrificed post-trial. A subset was used to evaluate sensory traits and muscle fatty acids. Lambs were in negative N balance during the study and Tasco treatments did not affect N metabolism. Fecal N tended (P < 0.10) to increase with short duration heat stress causing a concomitant decrease (P < 0.05) in apparent N digestibility (58.6 versus 56.1%; S.E. = 0.7). Urinary N loss decreased (P < 0.001) with heat stress (8.0 versus 5.9 g/d; S.E. = 0.2), resulting in increased (P < 0.001) N retention (−2.1 versus −0.3 g/d; S.E. = 0.2). Apparent OM digestibility was not affected by heat stress but was greater (P < 0.05) for lambs fed Tasco-EX treatment than those fed treated hay. Treatment diets decreased (P < 0.05) ruminal butyrate. Heat stress increased (P < 0.05) acetate and total VFA and decreased (P < 0.01) ruminal pH. A tendency (P < 0.11) of increased 14:1ω5, decreased (P < 0.05) 18:0 and total saturated fatty acids in muscle was observed with Tasco diets. Meat sensory characteristics were not affected by treatment. Tasco may alter some aspects of rumen or lipid metabolism but has no effect on N metabolism or meat sensory characteristics of sheep fed restricted, low-quality diets.     

Regrouping in lactating goats increases aggression and decreases milk production

With the aim of testing the hypothesis that regrouping decreases milk production in French Alpine goats that were lactating, a study was done using two groups (n = 8, 7). During their third month after parturition, four goats from each group were exchanged (first regrouping) between pens and left for 2 weeks, then the same two subgroups of four goats were taken back to their original pen for another 2 weeks (second regrouping). In the third regrouping, the two groups were all placed in the one pen. Milk production and social behaviour were measured daily before and after each regrouping. All regroupings led to an increase in aggressive behaviours that last by 1–2 days. Mean daily milk production decreased after first (2.82 ± 0.2 kg versus 2.53 ± 0.2 kg; P < 0.05) but not after second and third regrouping. It is concluded that aggressive behaviour increases after all regroupings, whereas milk production decreases only after the first regrouping, suggesting an important capacity of adaptation to a novel and stressful managements in the French Alpine goat. The study highlights the importance of considering effects of common practices in herd managements on social behaviour and production.     

Different effects of ATP on the contractile activity of mice diaphragmatic and skeletal muscles

Apart from acetyl-choline (Ach), adenosine-5′-trisphosphate (ATP) is thought to play a role in neuromuscular function, however little information is available on its cellular physiology. As such, effects of ATP and adenosine on contractility of mice diaphragmatic and skeletal muscles (m. extensor digitorum longa—MEDL) have been investigated in in vitro experiments. Application of carbacholine (CCh) in vitro in different concentrations led to pronounced muscle contractions, varying from 9.15 ± 4.76 to 513.13 ± 15.4 mg and from 44.65 ± 5.01 to 101.46 ± 9.11 mg for diaphragm and MEDL, respectively. Two hundred micromolars of CCh in both muscles caused the contraction with the 65% (diaphragm) to 75% (MEDL) of maximal contraction force—this concentration was thus used in further experiments. It was found that application of ATP (100 μM) increased the force of diaphragmatic contraction caused by CCh (200 μM) from 335.2 ± 51.4 mg (n = 21) in controls to 426.5 ± 47.8 mg (n = 10; P < 0.05), but decreased the contractions of MEDL of CCh from 76.6 ± 6.5 mg (n = 26) in control to 40.2 ± 9.0 mg (n = 8; P < 0.05). Application of adenosine (100 μM) had no effect on CCh-induced contractions of these muscles.

Resting membrane potential (MP) measurements using sharp electrodes were done at 10, 20 and 30 min after the application of ATP and adenosine. Diaphragm showed depolarization from 75 ± 0.6 down to 63.2 ± 1.05, 57.2 ± 0.96 and 53.6 ± 1.1 mV after 10, 20 and 30 min of exposition, respectively (20 fibers from 4 muscles each, P < 0.05 in all three cases). Adenosine showed no effect on diaphragmatic MP. Both agents were ineffective in case of MEDL.

The effects of ATP in both tissues were abolished by suramin (100 μM), a P2-receptor antagonist, and chelerythrin (50 μM), a specific protein-kinase C (PKC) inhibitor, but were not affected by 1H-[1,2,4]-oxadiazolo-[4,3-]-quinoxalin-1-one (ODQ, 1 μM), a guanylyl-cyclase inhibitor, or by adenosine-3,5-monophosphothioate (Rp-cAMP, 1 μM), a protein-kinase A (PKA) inhibitor.

Besides the action on contractile activity, ATP (100 μM) led to a significant (P < 0.001) depolarization of diaphragm muscle fibers from 74.5 ± 2.3 down to 64 ± 2.1, 58.2 ± 2.2 and 54.3 ± 2.4 mV after 10, 20 and 30 min of incubation, respectively. Incubation of MEDL with the same ATP concentration showed no significant change of MP.

Denervation of the muscles for 28 days led to a decrease of CCh-induced contractions of diaphragm down to 171.1 ± 34.5 mg (n = 11, P < 0.05), but increased the contractile force of MEDL up to 723.9 ± 82.3 mg (n = 9, P < 0.01). Application of ATP elevated the contractility of denervated diaphragm caused by CCh up to normal values (311.1 ± 79.7 mg, n = 6, P > 0.05 versus control), but did not significantly affect of contractility of MEDL, which became 848.1 ± 62.7 mg (n = 6).

These results show that the effects of ATP on both diaphragmatic and skeletal muscles are mediated through P2Y receptors coupled to chelerytrin-sensitive protein-kinase C.     

The effect of a combination of permanent breeding cage and low housing density on the reproductive success of farmed blue foxes

Social factors are known to affect the reproduction of many canids both in the wild and in farms. For example, reproduction in farmed silver foxes is regulated by social stress; foxes seem to benefit from noncramped housing conditions and permanent breeding cages. However, no comparable studies have been carried out in farmed blue foxes.

The aim of our experiment was to create an alternative, improved, economically viable and practical housing solution for blue foxes. Therefore, we compared reproductive performance of blue foxes in permanent breeding cages with low animal densities (L group, N = 79) and traditional housing with its changing social environment with high animal density (H group, N = 74). The reproductive data from the L and H groups were compared separately for primiparous and multiparous vixens because the reproductive performance in primiparous vixens was substantially lower (P < 0.001) than in multiparous vixens.

Altogether, 41 and 39% of the primiparous vixens in the H and L group whelped (P > 0.05), but only 28 and 34%, respectively, weaned at least one cub (P > 0.05), i.e., 72 and 66% of the primiparous vixens did not reproduce in the H and L group, respectively (P > 0.05). The total reproductive performance, expressed as cubs at weaning per breeding female, was 1.7 ± 3.5 for the H and 1.6 ± 2.9 for the L group (P > 0.05). In the primiparous vixens, the only statistically significant difference observed between the two housing systems was that the onset of oestrus occurred five days earlier in the H than in the L group (P < 0.05).

All multiparous vixens in the L group exhibited oestrus compared to 94% in the H group (P > 0.05). Furthermore, there was a nonsignificant (ns) trend for fewer barren females (9% versus 17%), more successfully reproducing vixens (83% versus 74%) and a higher number of live-born cubs (10.9 ± 4.7 versus 9.4 ± 3.9) in the L than in H group in the multiparous vixens (for all P > 0.05). This resulted in 1.7 and 1.4 cubs more per breeding and per mated vixen, respectively, at weaning in the L group (7.3 ± 5.0) compared to the H group (5.6 ± 4.2), but also this difference was nonsignificant.

Although our present results lack statistical significance, they are promising enough to encourage field experiments with sufficiently large number of animals to prove or disprove these preliminary findings that lower housing density and permanent breeding cage, together or separately, may enhance reproduction particularly in multiparous blue fox vixens.     

Prolactin regulation of testicular development and sexual behavior in yearling Suffolk rams

The aim of this study was to determine how the yearly prolactin rhythm might affect the sexual development of Suffolk rams (latitude 50°N). Five rams were injected daily with bromocriptine (35–45 μg kg⁻¹ body weight) for 1 year, beginning in January (early winter) when rams were 11 months of age. Five control rams each received daily injections of the vehicle. In the controls, blood prolactin was <7.5 ng ml⁻¹ in winter, increased (P < 0.01) to a peak of 172.6 ± 11.9 ng ml⁻¹ after the spring equinox, and remained high during summer before declining (P < 0.01) to 29.6 ± 6.6 ng ml⁻¹ at the autumn equinox. Suppression of the seasonal rise in prolactin secretion with bromocriptine slowed testicular growth (50%; P < 0.05) in April and May (spring), thus delaying the time of peak testis size and sperm production by 1 month. Serum testosterone level was lower (50%; P < 0.01) in the treated rams than the controls in June and July (early summer), due mainly to reduced stimulation of the testes by smaller (P < 0.01) LH pulse releases or to smaller (P < 0.01) testosterone responses to LH releases, respectively. Suppression of prolactin also seemed to disrupt the central activation of gonadotropin secretion in that seasonal increases in serum FSH level and LH pulse amplitude and frequency were unusually slow (P < 0.05). These anomalies did not affect testis growth, which was normal from June until development was complete. Rams were sexually inexperienced when libido was first tested in July (non-breeding season). Both groups were equally capable of learning and expressing sexual behavior (i.e. normal mounting and ejaculation frequencies), which was more intense in September (breeding season; P < 0.05). Results support the hypothesis (based on the location of prolactin receptors) that the spring increase in prolactin secretion could target both the testes and the hypothalamic–pituitary system and be involved in the seasonal regulation of sexual function in the young adult Suffolk ram.     

Apoptotic-like changes in equine spermatozoa separated by density-gradient centrifugation or after cryopreservation

The objective was to evaluate apoptotic markers in ejaculated equine spermatozoa after separation by density-gradient centrifugation and after cryopreservation. Subpopulations of percoll-separated equine spermatozoa differed (P < 0.05) in the percentage of live, caspase-activated spermatozoa (2.9 ± 0.7% vs 14.2 ± 6.4%; mean ± S.E.M.), low mitochondrial membrane potential (MMP; 6.8 ± 1.1 vs 23.8 ± 3.7), altered plasma membrane permeability (1.3 ± 0.2 vs 3.0 ± 0.5), DNA fragmentation (2.0 ± 1.3 vs 14.3 ± 3.6), total motility (81.8 ± 3.3 vs 35.1 ± 5.4), and progressive motility (66.3 ± 4.3 vs 24.1 ± 4.5) for high-density versus low-density subpopulations, respectively. Phosphatidylserine externalization did not differ (P = 0.67) between the high- and low-density subpopulations (2.6 ± 0.7 vs 3.1 ± 0.9). After cryopreservation, equine spermatozoa differed (P < 0.01) in the percentage of active caspases (19.1 ± 1.6 vs 52.1 ± 2.8), low MMP (18.2 ± 2.5 vs 48.7 ± 2.6), altered plasma membrane permeability (6.8 ± 1.7 vs 17.6 ± 2.0), total motility (75.5 ± 2.4 vs 45.2 ± 5.6), and progressive motility (53.9 ± 3.1 vs 28.3 ± 4.5) for pre-freeze versus cryopreserved spermatozoa. There was no difference (P = 0.21) in percentage of DNA fragmented cells before (5.5 ± 1.2) versus after cryopreservation (6.6 ± 1.1). We concluded that apoptotic-like changes were detectable in ejaculated equine spermatozoa and were more prevalent after cryopreservation.     

PAH-DNA adducts in environmentally exposed population in relation to metabolic and DNA repair gene polymorphisms

Epidemiologic studies indicate that prolonged exposure to particulate air pollution may be associated with increased risk of cardiovascular diseases and cancer in general population. These effects may be attributable to polycyclic aromatic hydrocarbons (PAHs) adsorbed to respirable air particles. It is expected that metabolic and DNA repair gene polymorphisms may modulate individual susceptibility to PAH exposure. This study investigates relationships between exposure to PAHs, polymorphisms of these genes and DNA adducts in group of occupationally exposed policemen (EXP, N = 53, males, aged 22–50 years) working outdoors in the downtown area of Prague and in matched “unexposed” controls (CON, N = 52). Personal exposure to eight carcinogenic PAHs (c-PAHs) was evaluated by personal samplers during working shift prior to collection of biological samples. Bulky-aromatic DNA adducts were analyzed in lymphocytes by ³²P-postlabeling assay. Polymorphisms of metabolizing (GSTM1, GSTP1, GSTT1, EPHX1, CYP1A1-MspI) and DNA repair (XRCC1, XPD) genes were determined by PCR-based RFLP assays. As potential modifiers and/or cofounders, urinary cotinine levels were analyzed by radioimmunoassay, plasma levels of vitamins A, C, E and folates by HPLC, cholesterol and triglycerides using commercial kits. During the sampling period ambient particulate air pollution was as follows: PM10 32–55 μg/m³, PM2.5 27–38 μg/m³, c-PAHs 18–22 ng/m³; personal exposure to c-PAHs: 9.7 ng/m³ versus 5.8 ng/m³ (P < 0.01) for EXP and CON groups, respectively. The total DNA adduct levels did not significantly differ between EXP and CON groups (0.92 ± 0.28 adducts/10⁸ nucleotides versus 0.82 ± 0.23 adducts/10⁸ nucleotides, P = 0.065), whereas the level of the B[a]P-“like” adduct was significantly higher in exposed group (0.122 ± 0.036 adducts/10⁸ nucleotides versus 0.099 ± 0.035 adducts/10⁸ nucleotides, P = 0.003). A significant difference in both the total (P < 0.05) and the B[a]P-“like” DNA adducts (P < 0.01) between smokers and nonsmokers within both groups was observed. A significant positive association between DNA adduct and cotinine levels (r = 0.368, P < 0.001) and negative association between DNA adduct and vitamin C levels (r = −0.290, P = 0.004) was found. The results of multivariate regression analysis showed smoking, vitamin C, polymorphisms of XPD repair gene in exon 23 and GSTM1 gene as significant predictors for total DNA adduct levels. Exposure to ambient air pollution, smoking, and polymorphisms of XPD repair gene in exon 6 were significant predictors for B[a]P-“like” DNA adduct. To sum up, this study suggests that polymorphisms of DNA repair genes involved in nucleotide excision repair may modify aromatic DNA adduct levels and may be useful biomarkers to identify individuals susceptible to DNA damage resulting from c-PAHs exposure.     

Caprine luteinizing hormone isoforms during the follicular phase and anestrus

The relative proportion of the circulating luteinizing hormone isoforms in goats during follicular phase (pre-ovulatory peak; F) and anestrus (A) was investigated. Estrus was synchronized in six goats with a prostaglandin analogue. After estrus was detected, blood samples were taken at 1 h intervals for 24 h. Four anestrous goats received 100 μg i.v. of GnRH and blood samples were collected every 15 min for 5 h. Samples with the greatest LH concentration in follicular phase and after GnRH administration (anestrus) were analyzed by chromatofocusing and eluted with a pH gradient from 10.5 to 3.5. For quantification purposes eluted LH was grouped into basic (pH ≥ 7.5), neutral (pH 7.4–6.5) and acidic isoforms (pH ≤ 6.4) as well as by pH unit. In both physiological conditions (PC), basic and acidic isoforms were greater than the neutral. With this grouping criteria, there was an interaction between PC and pH group, with the proportion of neutral isoforms being greater (p < 0.05) in A (12.0 ± 0.8%) as compared with F (5 ± 2%). Analysis by pH unit showed a very basic group of eluted isoforms (pH ≥ 10), which amounted to a percentage of 6.0 ± 0.4% of the total observed during A, and 3 ± 1% during F (p < 0.05). Predominant isoforms in A eluted in the pH range 9.99–9.0 (42 ± 3%) as compared to 7 ± 3% (p < 0.01) in that pH range in F. In contrast, the predominant isoforms in F eluted in the pH range 8.99–8.0, representing 55 ± 8%, while in A the proportion was 11 ± 2% (p < 0.01). Isoforms eluted at the pH range 7.9–7 represented a significantly greater proportion during A (5.0 ± 0.6%) as compared with F (3 ± 1%). This is the first report on goat LH circulating isoforms. During A the LH isoforms secreted by the pituitary are more basic than during F.     

Effect of organic or inorganic trace mineral supplementation on follicular response, ovulation, and embryo production in superovulated Angus heifers

We determined whether source of trace mineral supplementation prior to embryo collection affected embryo production and quality. Angus half-sibling heifers (n = 20) originating from a common herd were assigned to three treatment groups using a 3 × 3 latin square design replicated in time (3×) and space (6× complete and 1× incomplete): (1) heifers received no added mineral to their diet (control; n = 53); (2) heifers received a commercially available organic mineral supplement (organic; n = 52); or (3) heifers received an all inorganic mineral supplement (inorganic; n = 55). All heifers had ad libitum access to hay and were fed a supplement containing corn and soybean meal. Treatments were initiated 23 days prior to embryo recovery. Heifers were given a 45-day adaptation period of no mineral supplementation before initiating a new treatment. Ovarian structures were evaluated using transrectal ultrasonography to determine the presence and number of follicles and CL on each ovary. The mean number of recovered ova/embryos was similar among treatments (4.1 ± 0.7, 3.8 ± 0.7, and 3.3 ± 0.7 for control, inorganic, and organic treatments, respectively), the number of unfertilized oocytes was greater (P < 0.05) for inorganic (2.3 ± 0.5) and control (1.6 ± 0.5) treated heifers than organic (0.4 ± 0.4) treated heifers. No differences among treatments existed for the number of degenerate or transferable embryos, but individual heifer influenced the total number of embryos/ova, unfertilized ova, and transferable embryos recovered. We conclude that heifer accounted for the greatest differences in embryo production and quality. Source of trace mineral supplementation did not significantly alter embryo number or quality in superovulated purebred Angus heifers fed a well-balanced diet, meeting all trace mineral requirements.     

The relationship between heart rate and energy expenditure in Alpine, Angora, Boer and Spanish goat wethers consuming different quality diets at level of intake near maintenance or fasting

Six Alpine (AL; 38.4 ± 3.0 kg), Angora (AN; 23.1 ± 2.7 kg), Boer (BO; 40.8 ± 4.5 kg) and Spanish (SP; 33.6 ± 2.2 kg) wethers (1.5 yr of age) were used to determine the effects of time of the day and potential interactions between time, genotype and diet quality on energy expenditure (EE), heart rate (HR) and EE:HR when fed near maintenance and fasting. The experiment consisted of four simultaneous crossovers, with 21 d for adaptation before measures. Diets were 60% concentrate (CON: 15% CP) and ground alfalfa hay (FOR: 23% CP), offered in two meals at 8:00 and 16:00 h. Energy expenditure was determined from O₂ consumption and production of CO₂ and CH₄ over 2-day periods in fed and fasting states (total 4-day fasting period). Fasting EE was higher during the day than night, with values generally highest at 16:00–17:00 h. Animal within breed affected EE, HR and EE:HR (P < 0.05). The diurnal pattern in EE varied with diet (P < 0.05), although total daily EE was not different between diets. Before the morning meal, there were a number of hours during which EE was greater for CON than for FOR. However, at both meals the rise in EE was considerably greater for FOR versus CON, lasting for 3–4 h. The same general pattern in HR was observed, although the period of time when there was a dietary difference after the afternoon meal was shorter. For both fed and fasted goats, EE:HR differed among hours of the day (P < 0.05). EE:HR tended (P < 0.09) to differ between diets (5.99 and 6.21 for CON and FOR, respectively) and to be affected (P < 0.09) by an interaction between breed and diet (AL: 5.84 and 6.38; AN: 5.91 and 5.73; BO: 6.05 and 6.58; and SP: 6.17 and 6.15 kJ/(kg BW^0.75 × day):heart beats/min) for CON and FOR, respectively. In conclusion, for use of HR to predict EE by goats, it appears desirable to determine the ratio of EE:HR with a diet similar to that consumed during prediction and over an extended period of time.     

Chromosomal aberrations by fluorescence in situ hybridization (FISH)--Biomarker of exposure to carcinogenic PAHs

The fluorescence in situ hybridization (FISH) technique with whole chromosome painting for chromosomes #1 and #4 was used to study the impact of air pollution containing higher concentrations of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) in three European cities, Prague (Czech Republic), Kosice (Slovakia) and Sofia (Bulgaria). In each site were followed an exposed group, who were police officers or bus drivers who work usually through busy streets for at least 8 h, and a reference group, who spent more than 90% of their daily time indoors.

In Prague, a significant increase was observed in percentage of aberrant cells (% AB.C.) in the police officers compared to the reference group (0.33 ± 0.25 versus 0.24 ± 0.18, p < 0.05). In Kosice, the exposed group differed from reference in the endpoints F_G/100 1.52 ± 1.18 versus 1.12 ± 1.30, p < 0.05; % AB.C. 0.30 ± 0.19 versus 0.21 ± 0.20, p < 0.05; t/1000 3.91 ± 3.18 versus 2.84 ± 3.10, p < 0.05. In Sofia were followed two exposed groups: police officers and bus drivers. All FISH endpoints were significantly higher in police officers compared to reference group (F_G/100 1.60 ± 0.99 versus 0.82 ± 0.79, p < 0.01; % AB.C. 0.25 ± 0.14 versus 0.13 ± 0.13, p < 0.01; t/1000 4.19 ± 2.65 versus 2.13 ± 2.05, p < 0.05; rcp 1.46 ± 1.07 versus 0.70 ± 0.76, p < 0.05). In bus drivers compared to reference there was an increase in % AB.C. (0.25 ± 0.18 versus 0.13 ± 0.13, p < 0.05).

This is the first study when FISH method was used to analyze the impact of environmental air pollution. According to the original hypothesis it is expected that the most important group of chemicals responsible for the biological activity of air pollution represent c-PAHs.     

Effects of ensiled forage legumes on performance of store finishing lambs

Male Beulah speckled face lambs (initial live weight (LW) 28.8 ± 0.31 kg) were allocated to three dietary treatments to evaluate the performance of store lambs of a hill breed when offered ensiled lucerne (Medicago sativa), red clover (Trifolium pratense) or ryegrass. Second-cut silage bales (wilted and inoculated) were prepared from 3-year old lucerne and red clover stands and a 1-year old ryegrass sward. All the lambs were group-housed and offered ad libitum ryegrass silage during a 3-week co-variate period. This was followed by a week of dietary changeover period, after which the lambs were housed individually and offered their treatment diet ad libitum. All the lambs received a flat rate supplement of pelleted molassed sugarbeet (250 g fresh weight/day). Individual intakes were determined daily, and weekly measurements of LW and body condition score (CS) were made. Additional measurements were taken by scanning the lambs for depth of Longissimus dorsi (LD) muscle and subcutaneous fat. Over an experimental period of 7 weeks, the lambs offered red clover silage had a higher voluntary silage dry matter (DM) intake, total DM intake and metabolisable energy (ME) intake (P < 0.001) than lambs offered either lucerne or ryegrass silage. This resulted in a faster (P < 0.001) growth rate and increase (P < 0.001) in CS, with no difference between lucerne and ryegrass silages. The feed conversion efficiency (FCE) was 8.0 ± 0.61 kg feed/kg gain for lambs fed red clover silage, compared with 16.6 ± 2.82 and 10.6 ± 1.94 kg feed/kg gain for lucerne and ryegrass silage, respectively. The CP intake was higher (P < 0.001) for lambs fed the lucerne and red clover silages than for the ryegrass silage treatment. The concentration of plasma total protein (TP) was higher (P < 0.05) for lambs offered ryegrass silage versus lucerne and red clover silage. Urea concentrations were highest for lambs fed lucerne silage and lowest for those fed ryegrass silage (P < 0.05). The glucose concentration was higher (P < 0.05) for lambs offered red clover silage, whereas non-esterified fatty acids (NEFA) concentration was higher (P < 0.05) for lambs offered lucerne silage. Substituting ryegrass silage with red clover silage has the potential to improve the performance of finishing store lambs.     

Interaction of calf suckling, use of oxytocin and milk yield with reproductive performance of dairy buffaloes

Calf suckling and oxytocin injections are commonly used for pre-milking stimulus in dairy buffaloes under field conditions. A study was conducted to investigate effect of these treatments on reproductive performance. Fifty one Nili-Ravi buffaloes were monitored from parturition up to 150 days postpartum through rectal examination. Data on milk yield, body condition score (BCS) and reproductive parameters were recorded weekly. Postpartum ovulation interval (POI) was determined by presence of an ovulation depression or a very soft corpus luteum haemorrhagicum and was confirmed through milk progesterone levels (MPL). Suckling was used to stimulate milk let down, and where the calf had died, injection of oxytocin was resorted to. Milk samples were analyzed for MPL using radioimmunoassay (RIA) and fat; and milk yield was converted to 4% fat corrected milk (FCM). The mean postpartum uterine involution length (PUI) was 34.30 ± 1.33 days. Mean POI was 59.37 ± 4.76 days and mean postpartum estrus interval (PEI) was 69.03 ± 6.03 days. Suckling period averaged 26.40 ± 5.57 days and correlated with POI (r = 0.19, P < 0.01) and PEI (r = 0.23, P < 0.01). POI was shortest in buffaloes suckled for one month (P < 0.05). Oxytocin was used with a mean dosage of 7.50 IU, delaying placental expulsion time (PET) and POI but shortening PEI. BCS shortened PET, POI and PEI (P < 0.01). Mean FCM was 14.50 ± 0.20, ranging from 2 to 35 kg/d; and was higher in estrus group; correlating positively with POI (r = 0.31, P < 0.01). MPL were 1.37 ± 0.17 ng/ml and increased after ovulation, remaining greater than 1.5 ng/ml from Day 4 to 14 of the estrus cycle, followed by a rapid decline up to next estrus. BCS in buffaloes resuming oestrus was constantly higher than those failing to resume ovarian cyclicity. Live weight, prepartum was 510.0 ± 5.9 kg with a loss of 3.7 ± 2.12 kg, 30 days postpartum. The present study suggests a lower reproductive efficiency of dairy buffaloes under the peri-urban farming system reflected by ovarian cyclicity in 68.63% buffaloes within 150 days postpartum and silent estrus in 51.5% of the cases. Increasing suckling duration and use of oxytocin delayed POI, however, POI was shortest in buffaloes suckled for one month. The high yielding buffaloes also manifested better reproductive cyclicity; while moderate yielder showed shorter ovulation intervals and higher conception rate.     

Examination of cyclic changes in bovine luteal echotexture using computer-assisted statistical pattern recognition techniques

B-mode sonography is a well-established diagnostic tool for determination of cycle stage in gynaecology. The aim of this study was to determine whether computer-assisted texture analysis of B- mode sonographic images of bovine luteal glands provides further information about the animal's plasma progesterone concentration and cycle stage. Four Simmenthal cows were examined during two consecutive estrous cycles with an ultrasound device equipped with a 7.5 MHz microconvex probe. During each examination three B-mode images of the corpus luteum (CL) were digitized and analyzed off-line using a computer-assisted texture analysis program. Size, echogeneity, and echotexture of the CL were characterized by the following texture parameters: area of cross-sectional planes of the CL (A), mean gray level (MGL), correlation (CORR), run percentage (RPERC), and long-run emphasis (LREM). Plasma progesterone levels (P4) were also determined. All parameters showed characteristic changes during the estrous cycle (P < 0.05). Variance component estimates for the effect of Day of estrous cycle on A, MGL, CORR, RPERC, and LREM were 56.6%, 64.6%, 77.6%, 89.9%, and 86.0%, respectively, and 20.6%, 24.5%, 7.2%, 0.0%, and 14.0% for the influence of the individual cow. The factor estrous cycle within cows was responsible for 22.8%, 10.9%, 15.2%, 10.1%, and 0.0% of the variability of A, MGL, CORR, RPERC and LREM values, respectively. Cyclic changes were similar in A and P4. In contrast to P4, which decreased already between Days –5 and –3 (Day 0 = ovulation), A stayed at constant high values until Day –3. Mean MGL values were higher (P < 0.05) on Days 7, 9, and 13 compared to Days 3 and –3. Mean CORR values were constantly high (P > 0.05) during the first days after ovulation and decreased continuously (P < 0.05) between Days 5 and 13. Thereafter, mean CORR values remained low (P < 0.05) until the next ovulation, except on Day –3 (P < 0.05). Mean RPERC rose between Days 1 and 9 from low to high values (P < 0.0001) remained at these high values (P > 0.05) between Days 9 and 15, and decreased (P < 0.05) afterwards to baseline values on Day –1. Mean LREM inclined steeply (P < 0.0001) from minimum to maximum between Days 1 and 5. From Days 7 to –3, mean LREM remained (P > 0.05) at a constant level close below the maximum value, and decreased to baseline values on Day –1. The results of this study show that statistical pattern recognition techniques provide new information about the luteal glands, thus facilitating a more accurate differentiation between different cycle stages in cows.     

Effect of strategic supplementation with multi-nutrient urea molasses blocks on body weight and body condition score of Lohi sheep owned by tenants of Pakistan

The effect of strategic supplementation with multi-nutrient urea molasses blocks (MNUMB) on BW and body condition score (BCS) in Lohi ewes (treated, n = 514) during late gestation and lactation was compared with those (control, n = 391) grazing on only post-harvest crop residues and road side in the irrigated district of Okara in central Punjab (Pakistan). Analysis of variance revealed highly significant (P < 0.01) differences in body weight (BW) and body condition score (BCS) of ewes of various ages with different reproductive status and seasons under both flocks. Analysis of variance also revealed a significant interaction (P < 0.05) between reproductive status and seasons in favor of BCS. Ewes aged 48 months in average constituted the highest (34.5% and 35.6%), whereas those aged 60 months had the smallest (10% and 4%) proportion in the control as well as in the treated flock. Mean BW and BCS in ewes of control flock was 33.5 and 2.08 kg, and lower (P < 0.05) than 35.0 and 2.31 in ewes in the treated flock, respectively. Ewes aging 12, 24 and 36 months treated with strategic supplementation of MNUMBs were not only heavier (P < 0.01) but also had highest BCS of 2.34. Lactating ewes constituted highest proportion (39%, 51%) followed by pregnant (35%, 32%) ewes in both flocks, respectively. Proportion of dry (16%) and freshly conceived (9.5%) ewes tended to be higher in the control than in the treated flock. BW was 8–11% higher (P < 0.01) in pregnant than in lactating or dry ewes in both flocks with similar BCS. Seasons of autumn and summer were found to affect BW more (P < 0.01) than BCS. Pregnant ewes in treated flocks had gained highest BW, 10–12% higher than ewes under control (P < 0.01) or than non-pregnant ewes (P < 0.05) but lost at a rate of 5–6% at lambing. BW in lactating ewes in treated flock was higher (P < 0.01) than ewes in control. Lambs suckling ewes with strategic supplementation of MNUMBs grew at a faster rate (122 g/day) with 10–15% higher survival rate than those (97 g/day) in the control flock during lactation of 16 weeks but non-significantly. Based on this improvement it can be concluded that supplementation with appropriate sources of energy and N exerts desirable effects on the traits of economic importance in sheep.     

Control of postpartum anestrous with an intra-vaginal progesterone device plus eCG or calf removal for 120 h in suckled crossbred cows managed in a pasture-based system

To control postpartum anestrus and reduce calving to conception interval, 167 crossbred non-pregnant cows that were 90–130 days postpartum were allotted randomly to one of the following treatments: PH (n = 59), intra-vaginal sponge with 250 mg of medroxyprogesterone acetate (MAP) for 7 days plus 50 mg of MAP and 5 mg 17-β estradiol (17β-E) in the first day of treatment (day −8), 500 UI eCG (day −3) and 1.5 mg 17β-E in 24 h after sponge removal (day 0); CR (n = 57), temporary calf removal for 120 h; CG (n = 51), control group without treatment. Estrus rate differed among treatments (P < 0.01) being greater in PH (78.2%), followed by CR (52.0%) and CG (22.9%). A greater proportion of cows in the PH (80.0%) and CR (54%) groups had ovulations when compared to CG (35.4%). Intervals to first estrus were 13.5 ± 6.3 days, 26.1 ± 6.4 days and 52.5 ± 7.5 days for the PH, CR and CG groups, respectively. First insemination conception was similar in the three groups. Postpartum intervals to first breeding (PFS) and to conception (PCI) were longer in CG than PH and CR groups (P < 0.05; P < 0.01). The PH and CR groups had a similar PFS but PCI was different (P < 0.02). Accumulated pregnancy rate at 30 and 60 but not at 90 days were different (30 days: P < 0.09; P < 0.01; P < 0.09; 60 days: P < 0.06; P < 0.01; P < 0.03) among treatments. After 90 days post-treatment, 9%, 18% and 33% of cows from the PH, CR and CG groups had not conceived. Similarly, 5.4%, 6.0% and 12.5% of cows from the PH, CR and CG groups, respectively, were culled from the herd because of lack of pregnancy after 180 days post treatment. In the group of cows evaluated by ultrasonography, only those cows having larger ovaries and dominant follicles had ovulations. It was concluded that the hormonal treatment was more efficient in inducing a fertile estrus and reducing calving to conception interval followed by the calf removal for 120 h. Each method can be considered as an important tool to reduce the postpartum anestrous period in dual purpose herds when AI is conduct in the tropics.     

Development to the blastocyst stage of immature pig oocytes arrested before the metaphase-II stage and fertilized in vitro

In vitro fertilization (IVF) and embryonic development of mature and meiotically arrested porcine oocytes were compared in the present study. After in vitro maturation (IVM) of cumulus-oocyte complexes for 48 h, 75.4% of them extruded a visible polar body (PB). Most of the oocytes with a first polar body (PB+ group) were at the metaphase-II (M-II) stage (91.4%). Most of the oocytes without a visible polar body (PB− group) appeared to be arrested at the germinal vesicle (GV) (41.6%) and metaphase-I (M-I) (34.0%) stages. After IVF of oocytes (day of IVF = Day 0), there was no difference between PB⁺ and PB⁻ groups in rates of sperm penetration, mono-spermy, however oocyte activation rate after penetration was greater in the PB+ than in the PB− group (P < 0.05). On Day 2, there was no difference between rates of embryos cleaved at the 2–4 cell stages in PB+ and PB− groups (42.1 ± 48.8% and 33.6 ± 2.1%, respectively). On Day 4, the rate of PB+ embryos developing beyond the 4-cell stage was greater than that of PB− embryos (P < 0.05, 31.7 ± 3.9% and 14.1 ± 1.5%, respectively), and PB+ embryos had more cells than the PB− embryos (P < 0.05, 8.3 ± 0.4 and 6.0 ± 0.8 cells, respectively). On Day 6, a greater proportion of PB+ embryos developed to the blastocyst stage than did PB− embryos (P < 0.05, 34.6 ± 2.4% and 20.7 ± 2.8%, respectively). However, when the GV oocytes of the PB− group were not included in recalculations, there was no difference in blastocyst rates between M-I arrested and M-II oocytes (35.3 and 34.6%, respectively). The number of blastomere nuclei in embryos obtained from the PB+ group (52.0 ± 2.5) was greater than that from the PB− group (P < 0.05, 29.1 ± 2.8). The proportion of degenerated parts in the blastocysts, as determined by morphological appearance, was the same in the PB+ and PB− groups. Although the quality of PB+ embryos was enhanced as compared with that of the PB− group, the proportion of inner cell mass and trophectoderm cells in PB+ and PB− blastocysts did not differ (1:1.9 and 1:2.2, respectively). Chromosome analysis revealed that PB+ blastocysts had more diploidy (P < 0.05, 69.7%) than did PB− blastocysts (44.0%), whereas PB− blastocysts had more triploid cells (P < 0.05, 34.0%) than did PB+ oocytes (8.4%). These results indicate that pig oocytes arrested before the M-II stage (M-I oocytes) undergo cytoplasmic maturation during maturation culture and have the same ability to develop to blastocysts after IVF as M-II oocytes, but some of them resulted in degeneration or delayed development with poor embryo quality.     

Chromosomal aberrations in tire plant workers and interaction with polymorphisms of biotransformation and DNA repair genes

We evaluated chromosomal aberrations in lymphocytes of 177 workers exposed to xenobiotics in a tire plant and in 172 controls, in relation to their genetic background. Nine polymorphisms in genes encoding biotransformation enzymes and nine polymorphisms in genes involved in main DNA repair pathways were investigated for possible modulation of chromosomal damage. Chromosomal aberration frequencies were the highest among exposed smokers and the lowest in non-smoking unexposed individuals (2.5 ± 1.8% vs. 1.7 ± 1.2%, respectively). The differences between groups (ANOVA) were borderline significant (F = 2.6, P = 0.055). Chromosomal aberrations were higher in subjects with GSTT1-null (2.4 ± 1.7%) than in those with GSTT1-plus genotype (1.8 ± 1.4%; F = 7.2, P = 0.008). Considering individual groups, this association was significant in smoking exposed workers (F = 4.4, P = 0.040). Individuals with low activity EPHX1 genotype exhibited significantly higher chromosomal aberrations (2.3 ± 1.6%) in comparison with those bearing medium (1.7 ± 1.2%) and high activity genotype (1.5 ± 1.2%; F = 4.7, P = 0.010). Both chromatid- and chromosome-type aberration frequencies were mainly affected by exposure and smoking status. Binary logistic regression analysis revealed that frequencies of chromatid-type aberrations were modulated by NBS1 Glu185Gln (OR 4.26, 95%CI 1.38–13.14, P = 0.012), and to a moderate extent, by XPD Lys751Gln (OR 0.16, 95%CI 0.02–1.25, P = 0.081) polymorphisms. Chromosome-type aberrations were lowest in individuals bearing the EPHX1 genotype conferring the high activity (OR 0.38, 95%CI 0.15–0.98, P = 0.045). Present results show that exposed individuals in the tire production, who smoke, exhibit higher chromosomal aberrations frequencies, and the extent of chromosomal damage may additionally be modified by relevant polymorphisms.