Comb size, shape complexity and laterality of laying hens reared in environments varying in resource choice

The comb is an ornament involved in signalling condition in domestic fowl. We hypothesised that comb size, comb shape complexity (i.e., rugosity, the comb perimeter jaggedness), and comb laterality of laying hens would be influenced by the degree of environmental enrichment experienced during juvenile development in the form of resource choice. We conducted a 2 × 2 factorial crossover experiment with pullets reared in pens containing four perches of equal length and four litter areas of equal size. Pullets were exposed to a single choice vs multiple choices of perch and litter types (i.e., all the same vs all different) during Weeks 1-4 (Period 1) and/or Weeks 5-15 (Period 2) of rearing (n = 4 pens/treatment combination) prior to transfer to standard adult laying pens for Weeks 16-27 (Period 3). In Week 27, combs were photographed, and comb laterality (hanging on left or right side) was noted. Using a custom-made image analysis programme, we captured comb area (mm2), perimeter length (mm), and rugosity ((perimeter length - horizontal length) / horizontal length) from comb photographs of 6-7 randomly selected hens/pen. We predicted that hens reared in the multi-choice environment during Periods 1 and 2 would have larger, more complex, and left-side-biased combs than those in the other treatment groups, reflecting lower allostatic load. The predicted comb side bias was based on a possible bias in head posture/movements associated with greater right eye/ear use and left-brain hemispheric dominance. Contrary to our predictions, we detected an overall right-side bias in comb laterality, and no associations between resource choice treatment in Period 1 or Period 2 and comb area, perimeter length, rugosity, or laterality of the adult hens. Thus, variation in allostatic load resulting from the rearing treatments was insufficient to modify the trajectory of comb morphological development, possibly due to a ceiling effect when comparing environmental treatments on the positive end of the welfare spectrum. We found that left-lopping combs had shorter perimeters than right-lopping combs. However, among hens with left-lopping combs, those with larger combs were heavier and had less feather damage, while among hens with right-lopping combs, those with longer-perimeter combs were heavier and tended to have less comb damage. In conclusion, comb characteristics were related to physical condition at the individual level but did not serve as sensitive integrated indicators of hen welfare in response to basic vs enhanced resource choice during rearing.

Coeliac disease in the Trøndelag Health Study (HUNT), Norway, a population-based cohort of coeliac disease patients

PURPOSE

Coeliac disease (CD) is a common disorder and affects about 1% of the population worldwide. CD in the Trøndelag Health Study (HUNT) is a population-based cohort study which was established to provide new knowledge about CD that can improve the diagnostics and management, prevent the onset or progression and expand the knowledge about the role of genetics of the disease.

PARTICIPANTS

The cohort is based on the fourth wave of the population-based HUNT study (HUNT4), Norway, performed during 2017-2019, also including linkage to hospital records and the Norwegian Patient Registry (NPR). A total of 54 541 HUNT4 participants with available sera were screened for CD by serology. All seropositive participants were invited to a clinical assessment, including endoscopy with duodenal biopsies, during 2019-2023.

FINDINGS TO DATE

A total of 1107 HUNT4 participants (2%) were seropositive for CD and 1048 were eligible for clinical assessment, including biopsy. Of these, 724 participants attended the clinical assessment and 482 were identified with CD. In addition, 371 participants with CD were identified through the hospital records and NPR. In total, 853 participants in HUNT4 with biopsy-verified CD diagnosis were identified.

FUTURE PLANS

All participants in the study will be invited to a follow-up assessment after at least 1 year, including repeated standard serological testing, endoscopy and tissue sampling. The collected data and material will be used to establish the true population-based prevalence of CD. The consequences of CD, including symptoms, deficiencies and comorbidity, will be investigated and possible triggers and predictors, will be studied. With access to serum samples from the previous HUNT surveys in HUNT Biobank, serological signs of CD in prediagnostic samples of seropositive individuals will be used. Genetic studies will identify new CD markers, assess genotype-phenotype links and explore gene-environment correlations.

REGISTRATION

clinicaltrials.gov identifier: NCT04041622.

Can a super sow be a robust sow? Consequences of litter investment in purebred and crossbred sows of different parities

The aim of this project was to study the consequences of litter investment on physical characteristics in primiparous and multiparous sows in 3 Norwegian breeds (Norsvin Duroc [ = 12], Norsvin Landrace [ = 12], and crossbreeds [Norsvin Landrace and Swedish Yorkshire { = 15}]). We predicted that the maternal sow line (Norsvin Landrace) would invest more in their litter in term of higher weight at birth, resulting in a higher litter weight of weaned piglets but with the consequence of greater loss in body condition and a higher prevalence of shoulder lesions. It was predicted that this should be more pronounced in primiparous sows than in multiparous sows. As predicted, the maternal pure line (Norsvin Landrace) had higher litter investment in terms of litter weight at birth ( = 0.003) and litter weight at weaning ( = 0.050) as well as higher total litter investment (litter weight at weaning plus weight of dead piglets [stillborn and mummified piglets and weight of piglets that died after farrowing but before weaning]; = 0.050) and suffered larger losses of body condition ( = 0.016) and had a higher prevalence of shoulder lesions ( = 0.008) during lactation than other breeds. Moreover, only in Norsvin Landrace was development of shoulder lesions related to inadequate feed consumption ( = 0.006). This has become a major welfare concern of modern pig breeding. Although primiparous and multiparous sows had similar litter sizes, primiparous sows had lower litter investment in terms of litter weight at birth ( = 0.032) and litter weight at weaning ( = 0.007) as well as total litter investment ( = 0.008). Primiparous sows suffered greater losses in body condition ( = 0.012) and developed more shoulder lesions ( = 0.026) due to lower total feed consumption ( < 0.001) during lactation than multiparous sows. Especially in the highly productive maternal line (Norsvin Landrace), development of shoulder lesions during the lactation period was more pronounced in primiparous sows than in multiparous sows ( < 0.001). The selection program has shifted the balance to greater investments in earlier life, when sows still need resources for their own growth and development. This has resulted in a larger number of weaned piglets but at a higher sow welfare cost in terms of higher losses in body condition and a higher prevalence of shoulder lesions. Our results pinpoint the importance of improving the balance between economic traits and traits that improve welfare and longevity of the sows.

Invited review: piglet mortality: management solutions

Preweaning mortality varies greatly among herds and this is partly attributed to differences in farrowing house management. In this review, we describe the various management strategies than can be adopted to decrease mortality and critically examine the evidence that exists to support their use. First, we consider which management procedures are effective against specific causes of death: intrapartum stillbirth, hypothermia, starvation, disease, crushing, and savaging. The most effective techniques include intervention to assist dystocic sows, measures to prevent and treat sow hypogalactia, good farrowing house hygiene, providing newborn piglets with a warm microenvironment, early fostering of supernumerary piglets, methods that assist small and weak piglets to breathe and obtain colostrum, and intervention to prevent deaths from crushing and savaging. The provision of nest-building material and modifications to the pen to assist the sow when lying down may also be beneficial, but the evidence is less clear. Because most deaths occur around the time of farrowing and during the first few days of life, the periparturient period is a particularly important time for management interventions intended to reduce piglet mortality. A number of procedures require a stockperson to be present during and immediately after farrowing. Second, we consider the benefits of farrowing supervision for preweaning mortality in general, focusing particularly on methods for the treatment of dystocia and programs of piglet care that combine multiple procedures. Third, we discuss the need for good stockmanship if farrowing supervision is to be effective. Stockmanship refers not only to technical skills but also to the manner in which sows are handled because this influences their fearfulness of humans. We conclude that piglet survival can be improved by a range of management procedures, many of which occur in the perinatal period and require the supervision of farrowing by trained staff. Although this incurs additional labor costs, there is some evidence that this can be economically offset by improved piglet survival.

Piglet mortality: the impact of induction of farrowing using prostaglandins and oxytocin

Induction is usually carried out by administering prostaglandins (prostaglandin F2α or a synthetic analogue). Other hormones, most commonly oxytocin, may also be given. The primary objective is to increase the synchrony of farrowing. This facilitates farrowing supervision, early fostering and 'all in, all out' management of the farrowing house, all of which have the potential to decrease piglet mortality. However, there are also risks, including decreased piglet viability when farrowing is induced too early and an increased probability of dystocia associated with oxytocin use. What are the effects of induction procedures on mortality in pigs? With respect to prostaglandins, studies show that the date of induction and the level of supervision provided are important factors affecting piglet mortality. We recommend administering prostaglandins no earlier than 2d before the expected farrowing date for the herd. Some studies have reported that prostaglandin induction decreases stillbirth and live-born mortality and this is probably due to increased farrowing supervision. The incidence of postpartum dysgalactia syndrome is also decreased in herds with a high prevalence of this condition. Inconsistent effects on the progress of farrowing are reported following the routine administration of oxytocin 20-24h after prostaglandin. Although there is generally no effect on stillbirth rate, dystocia may increase. Earlier administration of low doses may decrease stillbirths, but this requires further research. Carbetocin, a long-acting analogue of oxytocin, is a possible alternative. We recommend that prostaglandin induction be used in conjunction with skilled farrowing supervision to decrease piglet mortality.

Feed intake and competition in ewes on ad libitum or semi-restricted feeding of grass silage and hay

The aim of the present experiment was to investigate the effect of feeding level and type of roughage on feed intake, feeding behavior and competition of ewes. A 2 × 2 factorial experiment was conducted with amount of roughage available (ad libitum or semi restricted) and type of roughage (grass silage or hay) as main factors. Forty-eight ewes were randomly assigned to 8 groups of 6 ewes. All groups were subjected to all 4 treatments, each treatment period lasted 7 d, and the order of treatments was rotated systematically. The ewes were video recorded for the 2 last days of each treatment period and feeding and general activity were scored every 10 min. All aggressive interactions and displacement at the feed barrier were scored continuously the first 3 h after feeding. Daily feed intake (P < 0.0001) and DMI (P < 0.0001) were both greater in the silage than in the hay treatment. Ewes in the semi-restricted treatment spent less time feeding (P < 0.0001), had a greater individual variation in feeding time (P < 0.05) and spent more time queuing for feed (standing maximum 1.5 m from the feeding barrier with the head towards the feed; P < 0.0001). Individual data showed that 5 ewes fed hay and 3 ewes fed silage reduced their time spent feeding more than 50% when the feeding level was reduced. When fed hay, the level of feeding did not affect number of aggressive interactions or displacements, but when fed silage the number of aggressive interactions (P < 0.01) and the number of displacements (P < 0.05) were much greater in the semi-restricted than in the ad libitum treatment. We conclude that even a minor restriction in the level of feeding will decrease time spent feeding and increase queuing and number of aggressive interactions when feeding space is also restricted, and that the increase in aggressive interactions is mainly for ewes fed grass silage.

Neonatal piglet traits of importance for survival in crates and indoor pens

The primary aim of the present study was to investigate whether the same piglet traits contributed to the same causes of neonatal piglet mortality in crates (CT) and pens (PN). Gilts originating from 2 distinct genetic groups that differed in breeding value for piglet survival rate at d 5 (SR5) were used. These were distributed to farrow in either PN or CT as follows: high-SR5 and CT (n = 30); low-SR5 and CT (n = 27); high-SR5 and PN (n = 22); and low-SR5 and PN (n = 24). Data on individual piglets were collected at birth, including interbirth interval; birth order; birth weight; rectal temperature at birth, 2 h after birth, and 24 h after birth; cordal plasma lactate; and latency to first suckle. Based on autopsy, causes of mortality were divided into stillborn, bitten to death, starvation, crushed, disease, and other causes. Potential risk factors of dying were estimated using a GLM with a logit link function. No significant effect (NS) of housing was observed on the odds of a piglet being stillborn (F(1,73) = 0.1, NS), being crushed (F(1,53) = 1.4, NS), or dying of starvation (F(1,53) = 0.3, NS). No significant differences were observed between the 2 genetic groups for any category of mortality. Piglet traits for pre- and postnatal survival were the same for CT and PN. The odds of being stillborn were increased in piglets born late in the birth order (F(1,1061) = 33.5, P < 0.0001), after a long interbirth interval (F(1,1061) = 19.2, P < 0.0001), and with a lighter birth weight (F(1,1061) = 9.2, P = 0.003). The lighter the birth weight of the piglets, the greater were the odds of being crushed (F(1,1050) = 18, P < 0.0001) and dying of starvation (F(1,1050) = 19, P < 0.0001). The lower the rectal temperature 2 h after birth, the greater were the odds of being crushed (F(1,1050) = 4.6, P = 0.03), starving (F(1,1050) = 16.6, P < 0.0001), or dying of diseases (F(1,1050) = 4.9, P = 0.03). Increased cordal plasma lactate increased the odds of dying from starvation (F(1,1050) = 18, P < 0.0001). In both CT and PN, the birth weight, body temperature 2 h after birth, and birth process were important traits related to crushing, starvation, and disease. Neither housing nor breeding value influenced mortality or traits of importance for the inborn viability of piglets. The results emphasize that the microclimate in the PN for newborn piglets and its heat-preserving properties are more important for survival than whether the sow is crated or penned.