Egg removal by cuckoos forces hosts to accept parasite eggs

2014 ◽  
Vol 46 (3) ◽  
pp. 275-282 ◽  
Author(s):  
Osamu K. Mikami ◽  
Nozomu J. Sato ◽  
Keisuke Ueda ◽  
Keita D. Tanaka
Keyword(s):  
1991 ◽  
Vol 23 (7-9) ◽  
pp. 1517-1524 ◽  
Author(s):  
M. M. Saqqar ◽  
M. B. Pescod

The paper presents data on total and faecal coliform removal and on intestinal nematode egg removal achieved in the Al-Samra stabilization ponds in Jordan during the winter period December 1986 to March 1987. A total retention of 34 days in the series of 10 ponds was able to achieve complete removal of nematode eggs at the pond temperature 12-15°C but was not able to meet the WHO guideline value for faecal conforms of ≤ 1000/100 ml. In addition to retention time having a positive effect on faecal conform die-off, it was shown that surface organic loading, pond pH, BOD5 concentration, and depth, influenced the rate of faecal coliform die-off. It became apparent that interactions existed among the operational and environmental parameters but that the simple time-and-temperature-dependent model for faecal conform die-off was no longer appropriate.


1984 ◽  
Vol 103 (2) ◽  
pp. 251-256 ◽  
Author(s):  
A. R. Goldsmith ◽  
S. Burke ◽  
J. M. Prosser

ABSTRACT Prolactin and LH concentrations were measured in the plasma of female canaries sampled during the breeding cycle and after disruption and reinitiation of incubation behaviour. The late incubation period was characterized by low LH and high prolactin concentrations, and canaries separated from their nests at this stage showed an increase in LH and a decline in prolactin within 3 h. In one experiment mean (±s.e.m.) concentrations before and 24 h after nest deprivation were: prolactin 397 ± 86 and 18 ± 5 μg/l; LH 1·04±0·21 and 2·03±0·17 μg/l. Female canaries which abandoned their nests after the eggs had been removed also showed an increase in LH together with a fall in prolactin 24 h after egg removal. When nest-deprived canaries were allowed to resume incubation, plasma prolactin increased again within 5 h and after 2 days had reached levels normal for incubating birds (398± 46 μg/l). Concentrations of LH changed more gradually but had decreased 2 days after the resumption of incubation. Thus prolactin and LH show inverse changes after the disruption and reinitiation of incubation behaviour; it is not clear, however, if the change in one is dependent on the other or if both hormones are responding to the same external stimulus. J. Endocr. (1984) 103, 251–256


Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1725
Author(s):  
Giovanni Franzo ◽  
Wessel Swart ◽  
Miren Arbe Ugalde ◽  
Higor Cotta ◽  
Mathilde Lecoupeur ◽  
...  

Day-old chick quality is an essential element for the overall profitability of the broiler productive cycle and has been associated with the growth performance and feed conversion rate. An effect on the development of the immune system was also reported, which could likely account for reduced susceptibility to infectious diseases and improved animal welfare parameters. Besides direct cost reduction, lower antimicrobial use and improved animal welfare are crucial in the directive of European Union legislation and are at the forefront of customer choices. Several factors contribute to determining the chick quality. Breeder flocks genetics, health, and management affect the egg features, quality, and bacterial load. However, hatchery practices play a pivotal role, since adequate hygiene and handling are fundamental in reducing egg contamination and cross-contamination. The presence of rotten eggs is often regarded as a major risk, since the internal bacterial load can contaminate the needle used for in-ovo vaccination, the nearby eggs, and the whole incubator/hatching room when broken. In the present multicentric study, representative of 40 hatcheries located in 11 European countries, a remarkable impact of the rotten egg percentage on the hatchery productive parameters, representative of the hatchability, embryo mortality, and level of contamination, was demonstrated. Efficient rotten egg removal and the application of appropriate detection and removal tools should thus provide remarkable benefits for hatchery performance and indirectly for downstream poultry production.


1993 ◽  
Vol 57 (1) ◽  
pp. 1 ◽  
Author(s):  
Petra Bohall Wood ◽  
Michael W. Collopy
Keyword(s):  

The Auk ◽  
1997 ◽  
Vol 114 (2) ◽  
pp. 212-220 ◽  
Author(s):  
D. Glen McMaster ◽  
Spencer G. Sealy
Keyword(s):  

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 481-489
Author(s):  
Tony D. Williams ◽  
Melinda Miller

Abstract We investigated individual and resource-dependent variation in ability of female Zebra Finches (Taeniopygia guttata) to lay supranormal clutches in response to egg removal, and effect of continuous laying on (1) egg composition and (2) plasma yolk precursor levels. Egg removal significantly increased the number of eggs that individual females laid, but that response was diet-dependent: on a high-quality (egg-supplemented) diet, females laid 12.4 ± 1.0 more eggs compared with their pretreatment clutch size; whereas on the low-quality (seed-only) diet, females laid only 4.9 ± 1.2 more eggs. Removal clutch size (i.e. total number of eggs laid in response to egg removal) was positively correlated with pretreatment mean egg mass and clutch size on the low-quality diet, but not on the high-quality diet. That suggests that there is interindividual variation in egg-laying ability (“large-egg” females had a greater capacity to respond to egg removal than “small-egg” females), but that higher resource levels can overcome individual differences. Egg mass did not vary with laying sequence in supra-normal clutches (up to 22 eggs); however, there was a significant decrease (6%) in yolk protein content of additional eggs that was apparent by the tenth egg laid (i.e. only 4–5 more than the normal clutch size). Plasma levels of the two yolk precursors, vitellogenin and very-low-density lipoprotein (VLDL), were independent of diet and did not differ in individual birds at the 1 egg stage versus the 14 egg stage. However, there was a systematic change in relationship between yolk lipid content and plasma VLDL levels, from nonsignificant for third-laid eggs to significant and positive for sixteenth-laid eggs. We propose a possible mechanism linking female condition and egg-laying ability: good quality females, capable of laying extended clutches, are able to maintain production of generic VLDL for their own metabolic needs, as well as producing yolk-targeted VLDL, whereas poor quality females are not.


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