The possibility of lessening the adverse welfare impact of artificial rearing was assessed in thirty Comisana lambs under conditions of ad libitum feeding. The lambs were assigned to a control dam-suckled group (DS) or to one of two test groups, each consisting of 10 animals. 18-24h after parturition, test lambs were separated from their dams: during the first postseparation week 10 subjects (EM) were offered ewe milk and the other 10 (MX) a 50:50 mix of ewe milk and a milk substitute. An artificial feeding system, to which the test lambs had free access, was filled with milk twice daily. After the first week, a transition from EM or MX to 100 per cent (reconstituted) milk substitute was carried out over 3 days in both test groups, gradually reducing the proportion of ewe's milk. In vivo cell-mediated immune response of lambs to phytohemagglutinin percutaneous injection were evaluated at 5, 15 and 25 days of age. At 10 and 20 days of age, all lambs were subjected to 15min isolation tests, during which latency to move, duration of movement and number of bleats were recorded. Blood samples were collected immediately before the test and 15 and 60min after, in order to assess the effect of differential rearing on the Cortisol response of animals at different ages. In addition, the weight gain of lambs was recorded during the first 35 days of age at weekly intervals. Latency to move and duration of movement were not significantly affected by the experimental treatment, whereas the number of bleats was higher (P < 0.001) in dam-suckled lambs compared to test lambs at both 10 and 20 days of age. Neither immune response nor Cortisol levels were affected by milk source. Although weight gain increased with increasing amounts of ewe's milk in the diet, the overall differences between the three groups were small and not significant. These findings suggest that the provision of ewe milk or a mix of ewe milk and a milk substitute during the first post-separation week can be a suitable strategy to sustain the welfare and production performance in the artificially reared lamb.

Artificial rearing involves removing piglets from their mother at seven days of age and feeding them milk replacer until weaning. Early-life rearing conditions can influence piglets’ mental development, as reflected by their emotional state and reactivity. This study compared the post-weaning emotional state and reactivity of pigs which were either sow-reared or artificially reared pre-weaning. Behavioural tests (startle test, novel object test, human-animal relationship test and open door test) were conducted one week post-weaning (weaner 1, 34 [± 0.6] days old), one week after movement to weaner 2 (69 [±1.2] days old) and to finisher (100 [± 1.3] days old) stages. Qualitative Behavioural Assessments (QBA) were conducted on the same days in weaner 2 and finisher stages. QBA descriptors were computed by PCA and all other data were analysed using linear models. Artificially reared pigs were less fearful of human contact in weaner 1 (45.1 [± 8.43] vs 81.3 [± 7.89]%) and finisher (25.8 [± 5.19] vs 45.7 [± 6.00]%) stages; but there was no difference in the other tests. Artificially reared pigs had a higher QBA score (more positive) than sow-reared pigs in weaner 2 (54.49 [± 10.102] vs 17.88 [± 9.94]) but not in finisher (70.71 [± 8.860] vs 52.76 [± 9.735]) stage. In conclusion, artificially reared pigs appeared to have a more positive emotional state transiently post-weaning and a lower fearfulness towards humans, which are likely mediated by their pre-weaning conditions. These data emphasise the need to consider the entire life of the animals to fully evaluate the long-term impacts of a rearing system.

Early life nutrition fundamentally influences neonatal development and health. Human milk oligosaccharides (HMO) are key components of breast milk but not standard infant formula that support the establishment of the newborn gut microbiota. Using an artificial rearing system, our objective was to test the effect of two HMO on the whole body and organ growth, adiposity, glucose tolerance and faecal microbiota in young rat pups. From postnatal days 4 to 21, Sprague–Dawley rats were randomised to receive one of: (1) CTR (rat milk substitute); (2) 2′FL (CTR + 1·2 g/l 2′-fucosyllactose); (3) 3′SL (CTR + 1·2 g/l 3′-sialyllactose) and (4) 2′FL + 3′SL (CTR + 0·6 g/l 2′-FL + 0·6 g/l 3′-SL). Body weight (BW), bowel movements and food intake were monitored daily, faecal samples collected each week and oral glucose tolerance, body composition and organ weight measured at weaning. No significant differences were observed between groups in growth performance, body composition, organ weight and abundance of dominant faecal microbes. A decreased relative abundance of genus Proteus in week 1 faecal samples and Terrisporobacter in week 3 faecal samples (P < 0·05) was suggestive of a potential pathogen inhibitory effect of 3′SL. Longitudinal changes in the faecal microbiota of artificially reared suckling rats were primarily governed by age (P = 0·001) and not affected by the presence of 2′-FL and/or 3′-SL in rat milk substitutes (P = 0·479). Considering the known protective effects of HMO, further investigation of supplementation with these and other HMO in models of premature birth, extremely low BW or malnutrition may show more pronounced outcomes.

Eristalinus aeneus (Scopoli, 1763) is a suitable candidate for artificial rearing due to its pollination efficiency and subcosmopolitan distribution. However, the high mortality found at the larval stage of this species needs to be overcome. In this research, two different larval media were used to study the life cycle of E. aeneus: brewery spent grain (BSG) from a local craft-beer factory and soaked oat grains (SOG). The age-stage, two-sex life table method was used to analyze the results, which were compared using the paired bootstrap test. The greatest mortality was found at the larval stage with both media. Individuals fed on SOG presented a shorter preadult developmental time (22.05 days) than those reared with BSG (26.97 days). This fact had a direct impact on the total preoviposition period, it being shorter with SOG (34.36 days) than BSG (38.29 days), although the second provided a larger total number of eggs (19,242 eggs) and a faster adult maturation (10.67 days). The population parameters indicated that both populations will display a positive growth under the studied conditions, being the mean generation time (T) significantly shorter when using SOG (38.71 days) than BSG (45.95 days). Despite the preadult results pointing to SOG being a more efficient medium, the promising fecundity values provided by BSG, as well as it's lower cost and ecological benefits, suggest that this second medium could be improved and used as an alternative to SOG in the near future.

The quality of biological control agents used in augmentative releases may be affected by rearing conditions due to inbreeding or laboratory adaptation, or to phenotypic effects of the rearing environment. We hypothesized that individuals from a wild population would be in better body condition and kill more prey than individuals from a commercially produced population. We caught wild Orius majusculus (Reuter) in a maize field and compared their initial body mass, survival, and prey reduction capacity to commercially produced O. majusculus. Predation capacity and survival were compared in short-term Petri dish tests with Frankliniella tenuicornis (Uzel) thrips, Ephestia kuehniella (Zeller) moth eggs, or Rhopalosiphum padi (L.) aphids as prey, and in longer-term outdoor mesocosms containing live seedling wheat grass with thrips or aphids as prey. Wild-caught O. majusculus were typically heavier and overall had higher survival during tests than commercially produced O. majusculus. Females were heavier than males and typically killed more prey. However, we found no difference between wild-caught and commercially produced individuals on prey reduction, neither in Petri dishes nor in mesocosms. Our study suggests that commercially produced O. majusculus have lower body condition than wild O. majusculus due to their lower body mass and survival, but that this does not have any negative effect on the number of pest prey killed over the timelines and conditions of our tests. Commercially produced O. majusculus thus did not have a lower impact on pest prey numbers than wild-caught individuals and therefore had similar biological control value under our study conditions.

As a result of the selection for genotypes with greater sow prolificacy, litter size increased and, concomitantly, average litter birth weight and early postnatal survival rates of low birth weight (L-BtW) offspring decreased. This study compared the impact of l-carnitine (CAR) and l-arginine (ARG) supplemented with a milk replacer and fed to L-BtW piglets born from large litters from days 7 to 28 of age on growth performance, carcass composition, organ and Semitendinosus muscle (STM) development. A total of 30 female and castrated Swiss Large White piglets weaned at 7 days of age were assigned to three milk replacer diets containing either no supplement (CON), CAR (0.40 g/piglet per day) or ARG (1.08 g/kg BW per day). Piglets were kept in pairs in rescue decks (0.54 m2). They were weighed daily and daily allowance of both, feed and ARG, was adjusted accordingly. Thus, feed allowance depended on growth. Each day, the milk replacer was prepared with water (1:4). Feed (allowance: 60 g dry matter/kg BW per day) was offered daily in six equal rations. Feed intake and feed efficiency was assessed for the pairs and apparent total tract-energy and -protein digestibility was determined from days 21 to 28 of age. On day 28, piglets were euthanized, blood samples were collected and the whole STM and organs were weighed. In STM, the size and metabolic properties of myofibers were determined. No difference in growth performance was found between dietary treatments, but piglets from the CAR group tended (P<0.10) to grow faster during the 1st experimental week and consume more feed from days 14 to 21 as compared with piglets of the CON group. A setback in growth in the last week in the CAR group coincided with the lower (P<0.05) energy and protein digestibility. Dietary treatments had no effect on STM and organ weight and myofiber size. Compared with the other groups, there were trends (P<0.10) for blood serum urea and glucose level to be greater in CAR and for non-esterified fatty acid level to be greater in ARG piglets. The greater (P<0.05) ratio of lactate dehydrogenase to either citrate synthase or β-hydroxyacyl-CoA dehydrogenase indicated that the relative importance of the glycolytic compared with the oxidative pathway was greater in STM of CAR and ARG compared with CON piglets. These results suggest that ARG and CAR supplements were beneficial for muscle maturation whereas findings on phenotypic traits were rather unsystematic.

The aim of this study was to investigate the BW and immune status of lambs reared under natural conditions or under artificial conditions fed two different colostrum amounts. In this study, 60 lambs were randomly divided into groups according to treatment. Twenty lambs remained with their dams (natural rearing (NR) group). Forty lambs were removed from their dams at birth. Lambs were bottle-fed with a pool of sheep colostrum, receiving either 4 g of IgG/kg of BW at birth (C4 group) or 8 g of IgG/kg of BW at birth (C8 group). The total colostrum amount was equally divided into three meals at 2, 14 and 24 h after birth. After this period, lambs were bottle-fed a commercial milk replacer. Blood plasma sample analysis and BW recordings were carried out before feeding at birth and then at 1, 2, 3, 4, 5 and 20 days after birth. Another blood sample analysis and BW recording was carried out when animals reached 10 kg of BW. During weaning (30 days), sampling was carried out every 5 days. Blood plasma was used to determine the concentrations of IgG and IgM and the complement system activity – total and alternative pathways. The NR group showed greater BW than the C4 and C8 groups during milk feeding period, whereas the C4 and C8 groups had greater BW than the NR group at the end of weaning period. The C8 and NR groups had greater plasma IgG and IgM concentrations than the C4 group during milk feeding period. In addition, C4 and C8 groups showed similar IgG concentrations and greater IgM concentrations than the NR group at the end of the weaning period. Complement system activity was greater in the NR group than in the C4 and C8 groups during the first 3 days after birth. In conclusion, lambs fed amounts of colostrum equivalent to 8 g of IgG/kg of BW showed similar immune variables compared to lambs reared under natural conditions, obtaining a greater BW at the end of the weaning period. Nevertheless, this study shows that not only the colostrum amount but also the management during the milk feeding and weaning period, such as stress produced by dam separation, milk quality and suckling frequency, can affect the final immune status of lambs.

The South American fruit fly Anastrepha fraterculus (Wiedemann) is an important pest in many countries. The sterile insect technique is an effective method of controlling Ceratitis capitata (Wiedemann) in Argentina and has been proposed for use against A. fraterculus. Because this technique relies on sterile mass-reared males mating with wild females, it is essential to verify that artificial rearing does not reduce male mating competitiveness. Several morphometric characters were evaluated to detect differences between a wild population and a laboratory strain that was derived from it and reared artificially since 1997. Eight morphometric traits were analysed as indicators of body size, head shape and potential mobility: Thorax Length, Head Width, Face Width, Eye Length, Wing Length, Wing Width, Third Tibia Length and Femur Length. The results were analysed using multivariate analysis of variance, linear multiple regression and logistic multiple regression. In general, laboratory flies were larger than wild ones (possibly because the larval diet was supplied ad libitum). Laboratory males had significantly larger Head Width and Eye Length and a smaller Wing Width than wild males. Laboratory females differed from wild ones only by having narrower wings. These results could be due to environmental and genetic factors, or as a consequence of genetic drift (for the latter) during colony establishment plus gradual adaptation to laboratory conditions, where flight ability is most likely less important (resources are found easily at close distances). Also, short-distance interactions among individuals are more frequent in a colony, possibly favouring increased facial trait sizes by sexual selection. Because long-term morphological changes could represent the beginning of intraspecific differentiation, they should probably be worthy of some consideration if a large mass-rearing colony is established.

A consequence of increasing litter size in sheep is that a portion of the lambs have to be reared artificially. Detailed information about the pattern of milk consumption of artificially reared lambs would help improve their management. The purpose of this study is to describe the individual and group feeding behaviour of 94 Romane artificially reared lambs from 5 to 28 days of age using an electronic automatic lamb feeder. Animals were located in four pens of 8 to 15 lambs of similar age with one teat per pen. They were fed ad libitum. In our experimental situation (group rearing, continuous lightning) on average a lamb made 1.4±0.7 visits to the teat per meal and 9.5±3 meals per day. Mean meal duration was 247±158 s and the mean daily time spent feeding was 38±25 min. The mean quantity of milk intake was 176±132 ml per meal and 1.68±0.8 l per day. With age, the number of daily meals and their duration decreased while the quantity of milk consumed per meal and per day increased. Females tended to make more visits to the teat per meal and perform more meals per day but their milk consumption per meal was lower. The feed conversion ratio was 1.36±0.2. Synchrony in feeding (group meal) was estimated as the percentage of lambs that wanted to access the teat within the same short period (relative group meal size). On average 65% of lambs in the pen wanted to access the teat within the same period, but for 35% of group meals the relative group meal size was >90%. There was no consistency in the order in which lambs accessed the teat during a group meal. Our evaluation suggested that electronic automatic lamb feeders are tools that can provide, on a large scale, data describing the feeding behaviour of artificially reared lambs. It is then possible to study factors influencing these traits in order to improve the outcome of artificially reared lambs.