Zinc metabolism--a factor in canine aggression?

In order to test the hypothesis of zinc-deficiency as a factor in canine aggression, we examined sera of dangerously aggressive dogs and of behaviourally normal (non-aggressive) dogs for their zinc-contents. The results showed distinctly higher zinc-concentrations (mean +/- SD) in aggressive dogs (1.69 +/- 0.49 micrograms/ml) than in normal non aggressive dogs (0.76 +/- 0.16 microgram/ml).     

Hatching success of ostrich eggs in relation to setting, turning and angle of rotation

1. Three trials were designed to study the effects of axis of setting, turning frequency and axis and angle of rotation on the hatching success of ostrich eggs. The joint effects of axis of setting and angle of rotation were investigated in a fourth trial. 2. The hatchability of fertile ostrich eggs artificially incubated in electronic incubators (turned through 60 degrees hourly) was improved substantially in eggs set in horizontal positions for 2 or 3 weeks and vertically for the rest of the time. 3. The hatchability of fertile eggs set in the horizontal position without any turning was very low (27%). It was improved to approximately 60% by manual turning through 180 degrees around the short axis and through 60 degrees around the long axis at 08.00 and 16.00 h. A further improvement to approximately 80% was obtained in eggs automatically turned through 60 degrees around the long axis in the incubator. Additional turning through 180 degrees around the short axis twice daily at 08.00 and 16.00 h resulted in no further improvement. 4. The hatchability of fertile eggs set vertically in electronic incubators and rotated hourly through angles ranging from 60 degrees to 90 degrees around the short axis increased linearly over the range studied. The response amounted to 1.83% for an increase of 10 (R2=0.96). 5. The detrimental effect of rotation through the smaller angle of 60 degrees around the short axis could be compensated for by setting ostrich eggs in the horizontal position for 2 weeks before putting them in the vertical position.     

Dietary energy source at two feeding levels during lactation of primiparous sows: I. Effects on glucose, insulin, and luteinizing hormone and on follicle development, weaning-to-estrus interval, and ovulation rate

Our objective was to study the effects of dietary-induced insulin enhancement during and after lactation on the reproductive performance of primiparous sows. During a 21-d lactation period, 48 sows were allotted to a 2x2 factorial experiment. Treatments were feeding level (high or low; 44 MJ or 33 MJ NE/d) and dietary energy source (fat or starch). After weaning, all sows received the same amount of feed (31 MJ NE/d from weaning to estrus and 17.5 MJ NE/d from breeding until slaughter) of the same energy source as fed during lactation. On d 7, 14, and 21 of lactation and d 22 (weaning), blood samples were taken every 12 min for 12 h and analyzed for plasma glucose, insulin, and LH. Sows were slaughtered on d 35 of the subsequent pregnancy, and ovulation rate was assessed. During lactation, postprandial plasma glucose and insulin concentrations were higher for sows fed the starch diet than for those fed the fat diet (P<.001), whereas feeding level had no effect. Basal and mean LH concentrations were not affected by treatments. The LH pulse frequency on d 7 of lactation was greater for sows fed the starch diet than for those fed the fat diet (.52 vs .17 pulses/12 h; P = .03). The high compared with the low feeding level resulted in a greater LH pulse frequency on d 21 of lactation (.89 vs .47 pulses/12 h; P = .05) and on d 22 (8.63 vs 5.77 pulses/12 h; P = .02), in a higher percentage of sows that exhibited estrus within 10 d after weaning (96 vs. 63%; P = .01), and a tendency for a higher ovulation rate (18.0 vs. 16.2; P = .09). Plasma glucose and insulin concentrations were not related to any of the LH traits. The LH pulse frequency after weaning was related to the weaning-to-estrus interval (WEI) and was best explained by a linear-plateau model. In sows fed the low feeding level, follicle size after weaning was correlated with LH pulse frequency after weaning and with the WEI, whereas in sows fed the high feeding level these correlations were not significant. Our results indicate that an improved dietary-induced insulin status during and after lactation does not overcome the inhibitory effects of lactation on subsequent reproduction at any of the feeding levels.     

Dietary energy source at two feeding levels during lactation of primiparous sows: II. Effects on periestrus hormone profiles and embryonal survival

Our objective was to study the effects of dietary energy source (fat or starch) on periestrus hormone profiles and embryonal survival in primiparous sows. During lactation, 48 primiparous sows were fed either a starch-rich or a fat-rich diet, at either a high (44 MJ NE/d) or a low (33 MJ NE/d) feeding level. After weaning, all sows received the same amount of feed (31 MJ NE/d from weaning to estrus and 17.5 MJ NE/d from breeding to slaughter) of the same dietary energy source fed during lactation. Around estrus, blood samples were taken to analyze the preovulatory LH surge, estradiol (E2), and progesterone (P4). Sows were inseminated on each day of standing estrus. On d 35 after last insemination, all 35 pregnant sows were slaughtered and their reproductive tracts were removed. The number, weight, and length of the embryos and placentas were determined as well as the weight and length of the uterus. The LH, E2, and P4 profiles were similar for the treatment groups, except for the E2 levels at 16, 12, and 8 h before the LH surge, which were lower in the sows fed the fat-rich diet at a low level. Ovulation rate tended to be higher in sows fed the high compared to the low feeding level during lactation (18.0 vs. 16.2; P = .09), but the number of total and viable embryos as well as embryonal survival rate were not influenced by the treatments. Neither uterine length and weight nor length and weight of the embryos and placentas were affected by treatments. However, after removal of the embryo-placental units, uterine weight was greater in sows fed the high than in those fed the low feeding level during lactation (1.8 vs. 1.6 kg; P = .03). Plasma insulin concentration during lactation was not related to any of the uterine, placental, or embryo traits. Mean progesterone concentration between 24 and 250 h after the LH surge was positively correlated with embryonal survival. Differences in progesterone concentration between sows with high and low embryonal survival were evident from 172 h after the LH surge. From the present study, we conclude that altering feeding level during lactation or dietary energy source from farrowing until d 35 of subsequent pregnancy did not affect embryonic development and embryonal survival.     

Incidence of clinical mastitis on farms with low somatic cell counts in bulk milk

A total of 1140 clinical cases of mastitis, with at least one inflamed quarter, were reported on 125 farms with somatic cell counts in bulk milk less than 150,000/ml. The average annual incidence was 17.9 cases per 100 cows and ranged from none to 80 cases per 100 cows. The microorganisms most frequently isolated were Escherichia coli (16.2 per cent), coagulase negative staphylococci (13.0 per cent), Staphylococcus aureus (9.6 per cent) and Streptococcus uberis (8.0 per cent). Only two cases of Streptococcus agalactiae were found. As the incidence of clinical mastitis increased, the proportion of S aureus also increased, while the proportions of E coli, S uberis and Streptococcus dysgalactiae remained about the same. Most of the clinical cases of mastitis occurred in early lactation, in November, December and January. However, after correction for the number of calvings per month, the incidence of mastitis was highest in the early summer months.     

Intramammary infections and risk factors for clinical mastitis in herds with low somatic cell counts in bulk milk

Ten herds with low somatic cell counts in bulk milk had an incidence of clinical mastitis of only 2.2 per 100 cows whereas 10 other herds with similarly low cell counts had an incidence of 53.6 per 100 cows. The major pathogens in the herds with a high incidence were Escherichia coli, Streptococcus uberis, Staphylococcus aureus and the coagulase-negative staphylococci. The percentage of uninfected quarters in the herds with a high incidence of clinical mastitis was 21.4 per cent compared with 12.2 per cent in the herds with a low incidence of clinical mastitis. The prevalence of coagulase-negative staphylococci, Corynebacterium bovis and Micrococcus species was higher in the herds with a low incidence of clinical mastitis. There was a significant linear relationship between the percentage of uninfected quarters and the incidence of clinical mastitis in the herds with a high incidence of clinical mastitis. In herds with a low incidence of clinical mastitis significantly less teat disinfection after milking was practised. The results suggest that infections with minor pathogens tend to protect cows against mastitis, and that teat disinfection after milking may increase the percentage of uninfected quarters and lead to an increased risk of clinical mastitis in herds with low somatic cell counts in bulk milk.     

Porcine Luteal Function in Relation to IGF-1 Levels Following Ovulation During Lactation or After Weaning

Contents This study presents relationships between peripheral progesterone and Insulin-like Growth Factor-1 (IGF-1) concentrations during the early luteal phase in sows. Data were derived from three experiments, one with primiparous weaned sows (n = 21) and two with multiparous sows that either ovulated during lactation (n = 23) or after weaning (n = 12). The sows that ovulated during lactation did so due to an intermittent suckling regime (inhibition of suckling for 12 h each day from day 14 of lactation) or due to treatment with PG600. IGF-1 concentrations varied considerably among experiments, and were the lowest in the multiparous sows, regardless of whether they were weaned or lactating: 68 ± 5 and 85 ± 8 ng/ml in the two experiments with multiparous sows vs 188 ± 15 ng/ml in the primiparous sows. Progesterone concentrations were lowest for the lactating sows. Overall, the increase in progesterone during the early luteal phase was strongly correlated with IGF-1 concentrations (r = 0.7). However, the correlation was low in multiparous lactating sows (r = 0.28; p < 0.10) and nonsignificant in multiparous weaned sows (r = 0). The weaned multiparous sows had IGF-1 levels comparable to lactating multiparous sows, but higher progesterone levels. In conclusion, these data show a positive relationship between peripheral IGF-1 and progesterone concentrations in vivo during the early luteal phase. In lactating sows, IGF-1 concentrations are probably a limiting factor for progesterone secretion, although other factors may be involved.     

Morphological diagnosis of infective larvae of Libyostrongylus douglassii (Cobbold, 1882) Lane, 1923 and L. dentatus Hoberg, Lloyd and Omar, 1995 (Nematoda: Trichostrongylidae) of ostriches

The differentiation of the species of the Libyostrongylus genus is only possible with the obtainment of the adult parasites in the ostriches proventriculus and gizzard. The present work confirms that it is possible to differentiate the infective larvae of L. douglassii and L. dentatus allowing the differential diagnosis of these species by fecal culture. To show this, adult females from both species were collected from ten proventriculus from adult ostriches and separated by species. Both groups were macerated individually added to sterilized feces for standard fecal cultures. The infective larvae were recovered, identified, quantified and measured. All proventriculus analyzed were parasitized by Libyostrongylus spp. and a clear heterogeneous location for each species was observed. The infective larvae from the fecal cultures of macerated L. douglassii presented a mean total length of 874.3+/-33.80 microm, and a short sheath tail (29.5+/-4.11 microm) with acute termination. The infective larvae from the macerated L. dentatus presented mean total length of 856.0+/-43.63 microm, long sheath tail (61.2+/-9.52 microm) with filamentous termination. The mean measures of the tails of both species had a significant difference. The differentiation of the infective larvae of L. douglassii and L. dentatus by fecal cultures will facilitate the diagnosis of both species for further understanding the Libyostrongylus biology.     

Thermal decomposition,chemical composition,in vitro digestibility and gas production and in situ degradability of oilseed residues from the biofuel industry

Thermal analysis could rapidly and easily predict nutritional value of ruminant feeds. The hypothesis is that crambe meal (CM) has a quality similar to that of soybean meal (SM), and the objective of this study was to determine the nutritional characteristics of CM and compare them to those of SM. CM had greater concentrations of phytic acid (26.3 vs. 16.0 g/kg) and phenol compounds (615 vs. 393 mg gallic acid (GAE)/kg) than SM. In vitro dry matter (DM) digestibility was lower for CM than SM (752 vs. 975 g/kg DM). Cumulative in vitro gas production at 48 h of incubation (14.1 vs. 19.4 mL/100 mg substrate DM), and energy release (4.5 vs. 5.7 kJ/g substrate DM) were lower for CM than SM. CM had a higher concentration of low digestible fiber, hence degradability of DM was lower and the proportion of indigestible fraction was greater for CM than SM. High concentrations of indigestible compounds were likely responsible for lower gas production of CM compared to SM. These results suggest CM quality is lower than that of SM and that thermal analysis is a useful tool to precisely determine the nutritive value of oilseed residues.