171 resultados para Offspring welfare
Resumo:
Life-history theory predicts an optimal offspring size, irrespective of reproductive effort; however, in some species offspring size correlates positively with maternal size. We examine hypotheses for why this latter situation should occur in the whelk Buccinum undatum. The trade-offs between aspects of reproduction in whelks are complicated due to the provision of protective egg capsules. Many eggs are placed within each capsule but c. 99% of these eggs are consumed by the remaining developing young. Large maternal size results in more eggs, larger eggs, more eggs consumed per hatchling, more capsules, larger capsules, more eggs per capsule, a larger number of hatchlings per capsule and larger hatchlings. Increased intra-capsule and post-hatch sibling competition may decrease the marginal value for additional young and select for larger young, however, our data do not support this explanation. Instead, packaging constraints within each capsule limit the size of hatchlings but this constraint is relaxed for medium to large females because they produce large capsules. Small females appear to produce young below optimum size because of the space constraint thus explaining the correlation between maternal size and offspring size.
Resumo:
In many bird species with biparental care for young in the nest, hungry chicks beg repeatedly and parents adjust their feeding rate to the call rate of young. Repetitive calling also occurs in fledglings and in some mammals where offspring follow provisioners. It is not yet clear whether, in mobile systems with dispersed young where adults cannot compare the vocal behaviour of all young simultaneously, the calls represent a signal of need. We investigated repetitive begging by cooperatively reared meerkat, Suricata suricatta, pups that foraged with the group. Pups produced two types of begging calls: repeat calls over long periods and high-pitched calls mainly confined to feeding events. Food-deprived pups stayed closer to feeders, and begged for longer and more intensely by calling at a higher rate. Hungry pups increased both the rate of repeat calls, which were given continually, and the number of high-pitched bouts, but adults increased their food allocation only in relation to the rate of repeat calls. Our study indicates that hunger may lead to several changes in vocal behaviour, only some of which may be used by adults to assess need.
Influence of post-calving regrouping strategy on welfare and performance parameters in dairy heifers
Resumo:
Thirty-six Holstein Friesian heifers (dairy herd replacements) were assigned to one of three regrouping treatments during the post-calving period. In Treatment 1, heifers were introduced individually to an established group of cows and heifers within 24 h of calving ('Single-day 1'). In Treatment 2, heifers were housed individually in a straw pen for I week after calving before being added individually to the group ('Single-day 7'). In Treatment 3, two heifers were housed together in a straw pen for 1 week after calving before being added as a pair to the group ('Pair-day T). The size of the resident group remained constant at 16 animals (10 mature cows and 6 first-lactation heifers). The behaviour of the heifers was assessed during their first 8 h and first month in the resident group, and milk yield parameters, body condition loss and live weight loss were assessed during the first month post-calving. Reproductive performance was assessed during the post-calving period, and hoof health parameters were measured I month prior to calving, and at I and 3 months post-calving. Heifers in the 'Pair-day 7' treatment appeared to associate closely during their first month in the group by spending more time than expected in the same pen area and in adjacent cubicles (P
Resumo:
The objective of the present study was to determine the effect of plane of nutrition in early pregnancy (EP) and mid-pregnancy (W), on the productive performance of 1- and 2-year-old ewes and their offspring. Over 2 successive years, between days 0 and 39 after synchronized mating (EP), 1- (n=117) and 2- (n=52) year-old ewes were allowed 60% (low, L-EP), 100% (medium, M-EP) or 200% (high, H-EP) of requirements for maintenance (M). Between days 40 and 90 (MP), 1-year-old ewes were allowed 140% (M-MP) or 200% (H-MP), while 2-year-old ewes were allowed 80% (M-MP) or 140% (H-MP) of their M requirement. After day 90, all ewes were fed to meet requirements for late pregnancy. Increasing the plane of nutrition between days 0 and 39 resulted in increases in live weight (LW) (PM-EP>LEP), differences that in 1-year-old ewes were sustained to lambing (P0.05). These ewes exhibited more positive maternal behaviours (e.g. increased grooming frequency and duration, P
Resumo:
This experiment investigated the effect of providing access to straw in racks on the welfare of sows in large dynamic groups. Two treatments were applied: (1) access to two racks containing chopped barley straw (offering an average of 0.3 kg straw/sow/day) and (2) control, with no straw racks. Treatments were applied to two separate dynamic groups each containing 35 ( 3) sows. Approximately 9 sows were replaced in each of these groups at 3-week intervals (each replacement constituting a replicate of the study). Peak rack usage was shown between 08:00 and 12:00 h, where on average 6% of sows were observed at each rack. On average over a 24-h period, 27% of sows that were observed at the racks were newly introduced. This percentage was significantly greater in the pre- rather than post-feeding yard (P 0.05). A greater proportion of sows performed sham chewing behaviour in the post- rather than the pre-feeding yard (P 0.05). Overall, providing access to straw in racks led to a reduction in pen-directed exploratory behaviour, and this may reflect the fact that sows were provided with an outlet for exploratory and/or foraging behaviour. However, the fact that sham chewing behaviour was not affected suggests that welfare benefits associated with the straw rack treatment were limited. (C) 2007 Elsevier B.V. All rights reserved.
Resumo:
The objective of this study was to determine the effects of plane of nutrition during early and mid-pregnancy on the performance of mature ewes and their offspring. From day 0 to day 39 post mating (early pregnancy, EP), 82 multiparous ewes were fed to provide either 60% (low, L), 100% (medium, M) or 200% (high, H) of predicted metabolisable energy (ME) requirements for maintenance, following a synchronised mating. From day 40 to day 90 (mid-pregnancy, MP), ewes were provided with either 80% (M) or 140% (H) of ME requirements. After 90 days of gestation, all ewes were fed to meet requirements for late pregnancy. During EP, mean live weight (LW) and body condition score (BCS) change of ewes were -6.3, -0.8 and +6.0kg and -0.02, +0.10 and +0.22 units in the L-, M- and H-EP treatments, respectively. During MP, mean LW and BCS change were -0.8 and +4.9kg and -0.09 and +0.09 units in the M- and H-MP treatments, respectively (P 0. 05) on conception rate, although there tended to be an inverse relationship (P = 0.085) between plane of nutrition in EP and plasma progesterone concentrations at day 42 of gestation. EP nutrition influenced foetal development with lambs from ewes offered diet L-EP being smaller (P
Resumo:
The objective of this study was to determine the effects of selenium (Se) supplementation of mature ewes in the period from day - 14 to day 90 post mating on Se status, productivity and viability of ewes and their offspring. Multiparous crossbred ewes (n = 82) were randomly assigned to receive a standard dried grass-based diet (control) or dried grass diet supplemented with 1 g of selenised yeast (Selplex (R)), providing 0.5 mg Se per ewe per day. After day 90 post mating, all ewes were offered grass-based diets supplemented with a standard multivitamin and mineral mix, up to lambing. Ewes that were fed additional Se had increased (P 0,05). Supplemented ewes weaned lambs on average 2 kg heavier than control ewes, due to the higher (P
Resumo:
This experiment investigated the effects of providing access to grass silage on the welfare of sows introduced to a large dynamic group. Two treatments were applied: (1) access to racks containing grass silage (offering an average of 1.9 kg silage/sow/day), and (2) control treatment with no grass silage racks. Treatments 1 and 2 were applied to two separate dynamic groups, each containing 37 (2) sows. Approximately 9 sows were replaced in both groups at 3-week intervals, and each of these replacements constituted a replicate of the study. The study was replicated six times using a total of 108 sows. In a time-based cross-over design, treatments were swapped between the two dynamic groups after three replicates. Highest levels of rack usage were shown between 08:00 and 14:00 h. During peak periods, 9.8% of sows were observed at the racks at a given time. On average, 78.5% of sows observed at the racks were newly-introduced animals. Overall levels of aggression to which newly-introduced sows were exposed on the day of introduction to the group were low, and did not differ significantly between treatments (P > 0.05). In addition, injury levels measured 1-week post-introduction to the group did not differ significantly between treatments (P > 0.05). Sham chewing behaviour was more prevalent in the post-rather than the pre-feeding yard (P
Resumo:
This study assessed the effect of increasing fibre levels in the concentrate ration on the welfare of sows housed in a large dynamic group. One hundred and twelve Large White x Landrace sows were allocated to one of two treatments over six replicates. Treatments were as follows: (i) High Fibre diet (similar to 15% CF [Crude Fibre]), and (ii) Control diet (similar to 5% CF). Treatments were applied to two separate dynamic groups each containing 33 (+/- 3) sows in a cross-over design, after three replicates the treatments were switched between the groups. Approximately nine sows were replaced in each of these groups at 3-week intervals (each replacement constituting a replicate of the study). Sows on the high fibre diet spent a greater percentage of time lying (High Fibre: 43.8, Control. 28.0, SEM 3.25%), while sows on the control diet spent more time sham chewing (High Fibre: 7.2, Control: 28.8, SEM 1.55%). Sows newly introduced to the group on the high fibre treatment spent proportionally more time in the kennel areas compared to newly introduced sows in the control treatment (High Fibre. 0.893, Control. 0 788, SEM 5 10) In general, aggression occurred at a very low frequency and overall levels did not differ between treatments (High Fibre: 0.005, Control: 0.003, SEM 0.0007 [occurrences per min)). However, sows in the control treatment performed head thrusting (High Fibre: 0.02, Control: 0.00, SEM 0.001 [occurrences per mini), and biting behaviour (High Fibre. 002, Control. 0.01, SEM 0.002 [occurrences per min]) more frequently than sows on the high fibre diet. There was no effect of treatment on physiological parameters such as plasma cortisol (High Fibre: 1.34, Control: 1.44, SEM 0.114 ng ml(-1)) or haptoglobin levels (High Fibre. 0.73, Control. 0.64, SEM 0.080 mg ml(-1)). In summary, provision of a high fibre diet had a positive effect on the welfare of group-housed dry sows Sows on the high fibre treatment spent more time resting in the kennel areas, less time performing stereotypic behaviours and showed a reduction in some aggressive behaviours relative to sows fed the control diet.
Influence of social status on the welfare of growing pigs housed in barren and enriched environments
Resumo:
One hundred and twenty-eight pigs were reared in barren or enriched environments from birth to slaughter at 21 weeks of age. Pigs remained as litter-mate groups until 8 weeks of age when they were mixed into groups of eight animals. These groups were balanced for gender and weight and contained two pigs from each of four different litters. Each pig was assigned high or low social status on the basis of relative success in aggressive interactions at mixing. Injury levels were assessed on a weekly basis from 8 to 2 1 weeks of age. Pigs were exposed to two group food competition tests after a period of food restriction at 10 weeks of age, and to an individual novel pen test at 11 weeks of age. Behavioural and plasma cortisol responses to both types of test were recorded. Low social status was associated with increased injuries to the head, neck and ears, and therefore reduced welfare. Pigs with low social status showed reduced resource-holding ability in the food competition test, and greater avoidance of a novel object during the novel pen test. It is suggested that avoidance of the novel object reflected 'learned' fearfulness in these individuals. Environmental enrichment did not negate the effect of low social status on injury levels, but did appear to reduce the negative influence of low social status on stress during food restriction, and led to a reduction in fearfulness in response to the novel pen test. These results suggest that environmental enrichment may improve the we/fare of growing pigs with low social status.
Resumo:
This experiment investigated the effects of replacing 10, 20, 30 or 40% of a dynamic group of forty sows on the welfare of newly-introduced animals. The experiment was replicated five times, using a total of 200 multiparous sows. Replacements took place at 3 week intervals, and 3 days prior to sows being added to the group the same number of animals were removed from the group. Sows were added to the dynamic group as pre-formed groups of four animals which had resided together for a period of 5 weeks beginning directly after their piglets were weaned. Replacement rate did not appear to influence overall levels of aggression to which newly-introduced animals were exposed on the day of mixing, however aggression among newly-introduced animals increased significantly as replacement rate increased between 20 and 40% (P
Resumo:
Forty-eight Large White x Landrace multiparous sows were mixed into twelve groups of four animals after their piglets were weaned. These groups were defined as static, with no animals being added to or removed from the groups after their formation. Aggressive and submissive behaviours were recorded continuously for 9 h after the sows were mixed, and the sows were assigned high or low social status on the basis of their relative aggressiveness and success in aggressive interactions. After five weeks, each static group was mixed into a dynamic group of 40+/-2 sows for an 11-week period. Three static groups (ie 12 animals) at a time were added to the dynamic group at three-week intervals; the same number of animals was removed at these time-points in order to maintain the group number at 40+/-2. Injury levels increased significantly with the transition from static groups to the dynamic group (P
Resumo:
Three hundred and twenty pigs were reared from birth to slaughter at 21 weeks in either barren or enriched environments. The barren environments were defined as intensive housing (slatted floors and minimum recommended space allowances) and the enriched environments incorporated extra space including an area which contained peat and straw in a rack. Behavioural observations showed that environmental enrichment reduced time spent inactive and rime spent involved in harmful social and aggressive behaviour (P
Resumo:
Facultative automictic parthenogenesis has only recently been confirmed in the most ancient jawed vertebrates, the chondrichthyan fishes (sharks, batoids, and chimeras). To date, however, in both documented cases, the females have only produced a single parthenogen offspring, and none of these have lived for more than 3 days. We present a genetically verified case of automictic parthenogenesis by a white-spotted bamboo shark (Chiloscyllium plagiosum), in which at least 2 parthenogens were produced and survived for 5 years or more. These findings demonstrate that some female sharks are capable of producing, multiple, viable offspring through parthenogenesis.
Resumo:
Is a Confucian cultural climate hostile to gender equality in families and public decision-making? What is the impact of gender equality legislation in East Asia? Approaches to these welfare regimes have ignored gender, while gendered accounts of welfare have neglected East Asia. Comparisons with Western welfare states show strong economies with life expectancy in Japan and South Korea above those of Western social democracies but in contrast there are extremely large gender gaps in employment, earning, unpaid work and parliamentary representation and conjoined with this low fertility rates and and minimal public social spending on childcare and early education.
In this volume, contributors address questions about gender equality in a Confucian context across a wide and varied social policy landscape, from Korea and Taiwan, where Confucian culture is deeply embedded, through China, with its transformations from Confucianism to communism and back, to the mixed cultural environments of Hong Kong and Japan. Overall, the collections asks: Has East Asia's rapid economic transformation been accompanied by social and cultural transformation?