Search results for "litter"
showing 10 items of 315 documents
Environmental enrichment prevents pup mortality in laboratory mice.
2018
Early death of mouse pups is a commonly known problem in breeding mice colonies, which is still often regarded as ‘normal’ or is even overlooked due to the counting procedures applied. As reduced breeding performance probably indicates reduced well-being, this seems to be an underestimated welfare issue in laboratory mouse breeding. The present study compares the influence of three different forms of enrichment in breeding cages on infant survival rate and development of C57BL/6J mice. Our data reveal that lack of enrichment results in greater preweaning pup mortality, reduced weight and delayed development. Changing the environmental conditions after birth cannot prevent litter loss but i…
Decomposition Rate of Old Nest Material in Tree Holes
2011
Abstract. We experimentally tested whether old nest material could decompose fast enough to clear tree holes between the consecutive seasons. To mimic the nest material we filled litter-bags with either 1 g of cellulose, or with 0.5 g of dog moulted hair. In August 2009 we placed pairs of these bags in 23 tree holes used by breeding birds in a deciduous forest in SW Poland. For reference, we placed the same sets of bags in the litter, at 23 random sites in the forest. The bags were removed in March 2010. After seven months of exposure almost all cellulose (median 92%) and most of hair (median 57%) disappeared from bags in the holes. These values were as high as (for cellulose) or even highe…
Parity and number of repeated doe-litter-separation treatments affect differently the reproductive performances of lactating does.
2010
[EN] Using data from three different experiments, the effects of oestrus synchronisation by doe-litter separation (DLS), applied 48 hours befare artificial insemination from day 9 to day 11 post partum, on productive performance of free nursing rabbit does and their litters in relation to parity and number of successive DLS treatments were evaluated. lnitially, 200 New Zealand White does of different parity were homogeneously and definitively distributed in two groups (DLS and Control). On the whole, DLS improved fertility (+23.9%, Ps0.001 ), but reduced the growth of young rabbits from day 9 to weaning (-1.7 g/d, Ps0.01) and their weaning weight (-38 g, Ps0.01) at day 35. DLS also increase…
EFFECT OF A 48H DELAYED INSEMINATION WITH OR WITHOUT A 48H DOE-LITTER SEPARATION ON PERFORMANCE OF NON-RECEPTIVE RABBIT DOES
2010
[EN] The effectiveness of delayed artificial insemination (DAI) of non-receptive (R-) does, with or without oestrus synchronisation by doe-litter separation (MLS), was studied and compared with receptive (R+) does. During 10 months, 105 NZW does, in three homogeneous groups (A, B, C), were artificially inseminated (Al) according to a 42-day reproduction rhythm in two batches. Every 21 days, two Al were effected, the second 48 hours alter the first. The R+ does of ali groups were inseminated al the first Al, while the R- does were treated, in relation to theirgroup, as follows: inseminated at the first Al (A); 48-hour DAI (B); 48-hour MLS by closing the nestbox before Al, when lactating, and…
Detection of genomic regions underlying milk production traits in Valle del Belice dairy sheep using regional heritability mapping
2021
The aim of this study was to identify genomic regions underlying milk production traits in the Valle del Belice dairy sheep using regional heritability mapping (RHM). Repeated measurements for milk yield (MY), fat percentage and yield (F% and FY) and protein percentage and yield (P% and PY), collected over a period of six years (2006-2012) on 481 Valle del Belice ewes, were used for the analysis. Animals were genotyped with the Illumina 50k SNP chip. Variance components, heritabilities, and repeatability within and across lactations were estimated, fitting parity, litter size, season of lambing, and fortnights in milk, as fixed; and additive genetic, permanent environment within and across …
The influence of age at slaughter and litter size on some quality traits of kid meat
2002
Abstract To study variations in the carcass characteristics of Girgentana kids slaughtered at 25 or 35 days of age and litter size (single or twin), 27 male kids were slaughtered and body components, carcass joints, pelvic limb tissue composition, meat fatty acid composition and M. longissimus dorsi (LD) colour were evaluated. Girgentana kids slaughtered at 35 days had greater live weights (6.4 kg versus 5.0 kg; P ≤0.01), carcass weights (4.5 kg versus 3.6 kg; P ≤0.01), muscle contents (57.6% versus 54.9%; P ≤0.01) but similar dressing percentages (70.1% versus 70.6%) as compared to kids slaughtered at 25 days. Twin kids had a higher muscle percentage (57.3% versus 55.2%; P ≤0.05) and simil…
Use of weaning concetrate in the feeding of suckling kids: effects on meat quality
2006
A study was conducted to investigate the effect of a feeding supplementation with starter concentrate on “Capretto” meat production and its qualitative characteristics. To this end, 31 Girgentana kids, slaughtered at 59 days of age from two feeding groups (concentrate group (CG) and milk group (MG)) were utilised. Carcass measurements (body components, carcass joints, pelvic limb tissue composition, meat fatty acid composition and M. longissimus dorsi (LD) physical characteristics), body weight at birth, and at slaughter, were evaluated. The effect of concentrate supplementation did not influence the slaughter weight, slaughter and dissection data, tissue composition and meat chemical compo…
Manipulation of offspring number and size: benefits of large body size at birth depend upon the rearing environment
2003
Summary 1. Allocation of reproductive effort between the number and size of offspring determines the immediate rearing environment for the growing young. As the number of offspring increases, the amount of parental investment per individual offspring decreases, and the quality of the rearing environment is expected to decrease. This may result in a lower quality of offspring reared in such conditions. 2. We studied the effects of the rearing environment on the quality of juvenile bank voles, Clethrionomys glareolus , with different initial body sizes at birth in a 2 〈 2 factorial experiment. The rearing environment was manipulated by enlarging both the litter size by two extra pups, and mea…
Effect of controlled nursing with one-day fasting on rabbit doe performance.
2008
This work studied whether the expected better subsequent reproduction for permanent controlled nursing versus free nursing could be further improved by a caloric biostimulation with temporary fasting and re-feeding of does before artificial insemination (AI) and how it influences the development of current litters. A total of 240 females were randomly assigned at first day of lactation to one of three groups each with 80 does in a balanced manner according to the number of kits, litter weight, newborn kit weight after adjusting to 8 rabbits per litter, doe body weight and parity. Rabbits in the control group (C) were fed ad libitum and nursed freely up to weaning at 35 days of age. In the g…
Is the reproductive potential of wild house mice regulated by extrinsic or intrinsic factors?
2007
The regulation of reproductive performance in small mammals may be determined by extrinsic or intrinsic parameters. In a large-scale, replicated field experiment we monitored the seasonal fluctuation in food availability and tested the effects of food addition on the reproductive performance of wild house mice (Mus domesticus) in south-eastern Australia. Ovulation rates and litter size increased during spring and peaked in October/November. Ovulation rate was consistently higher than litter size by approximately 1.2 embryos (19%). None of the extrinsic parameters measured (food quality and quantity, mouse abundance) had an impact on reproductive performance. The addition of food did not pre…