Reduced Milk Intake Research Articles

Can a gradual weaning and separation process reduce weaning distress in dam-reared dairy calves? A comparison with the 2-step method

The weaning and separation phase remains one of the biggest challenges for cow-calf-contact systems, but a gradual process that better mimics the naturally occurring reduction in milk intake has not yet been scientifically investigated. Therefore, the aim of our study was to compare behavioral and physiological indicators of distress in 3 mo-old dam-reared dairy calves (with previous full-time cow-calf contact) weaned and separated either via gradual reduction of contact time with the dam (GR, 1 week half day contact, 1 week morning contact, 1 week fence-line contact before complete separation, n = 18) or via 2-step weaning using a nose flap (NF, 2 weeks access to dam with a nose flap, 1 week fence-line contact before complete separation, n = 18). Behavior was recorded 1 week before (or for lying 3 weeks before) weaning start and during the 3 week weaning and separation period with direct observations on 4 d per week or via accelerometers (locomotor play, lying behavior). Blood and fecal samples were taken twice per week from weaning start until 3 weeks after weaning start. Calves were weighed weekly. Statistical analysis was conducted using (generalized) linear mixed models. Over the whole weaning and separation phase, NF calves showed a stronger decrease in the number of lying bouts, amount of locomotor play and average daily weight gains, as well as a higher increase in total mixed ration feeding time compared with GR calves, whereas GR calves vocalized more often and showed more searching behavior than NF calves. Also, the neutrophil:lymphocyte ratio of NF calves was elevated on d 3 after insertion of the nose flaps compared with baseline, but showed no change for GR calves on any sampling day. Overall, results point toward a favorable effect of a gradual weaning strategy on reduction of weaning and separation distress in dam-reared dairy calves, but the method requires further improvement from the protocol used in our study.

Behavioral responses of dairy cows and their calves to gradual or abrupt weaning and separation when managed in full- or part-time cow-calf contact systems

There is growing interest in managing cow and calf together for a prolonged period, but concerns remain about how best to wean and separate the cow and calf to minimize stress. One approach is to progressively reduce suckling opportunity over time, as in nature. There is also interest in part-time contact (suckling for part of the day) to improve milk yield for the farmer and potentially reduce stress at weaning and separation. The primary objective of this study was to compare the behavioral responses of dairy cows to gradual or abrupt weaning and separation, when managed either full or part time with their calves; a secondary focus was the vocal responses of calves under these management conditions. In a 3 × 2 factorial design (n = 14/ treatment), dairy cows and their calves (n = 84 in 7 blocks of 12 cow-calf pairs) were assigned to one of 3 dam-contact treatments at birth: (1) full-time contact between the dam and calf, apart from milking times (total 23 h/d) (2) part-time contact between the dam and calf, between morning and afternoon milking only (total 10 h/d); (3) no contact, where the dam and calf were separated after leaving the maternity pen and had no further contact. At wk 8, one of 2 weaning treatments was assigned: (1) gradual weaning by reduced contact time (50%, then 25% of original dam-contact time in wk 8 and 9, respectively), or gradually reduced milk allowance for no-contact calves (50%, then 25% of estimated 12-L milk intake in wk 8 and 9, respectively) until complete milk removal and dam-calf separation at wk 10; (2) abrupt weaning where milk removal occurred simultaneously with dam-calf separation at wk 10, or only milk removal for no-contact calves. Overall, part-time contact did not reduce weaning and separation distress for cows or calves for either weaning method. Part-time cows showed reduced behavioral responses to separation (greater lying time and less searching behavior), especially on the day of and 24 h after separation, but they showed a similarly strong vocal response to separation as full-time cows. Part-time calves made substantially more high-pitched vocalizations than full-time calves at 24 h after separation. Furthermore, gradual weaning by reducing contact time did not seem to better prepare cows or calves for complete milk removal and separation; most behavioral and vocal responses occurred on the day of separation for gradual-weaning cows and calves, but 24 h later, the reverse occurred for abrupt-weaning cows and there was no difference between gradual- and abrupt-weaning calves. Our results suggest that part-time contact and gradual-weaning conditions likely resulted in hunger and expectation for reunion, which together may have exaggerated behavioral responses at separation. Temporary daily separations may not have increased independence of cow and calf, and the gradual-weaning method here may not have reduced milk intake by calves. These elements are important criteria to facilitate the weaning process, so future work should explore ways to gradually reduce milk intake and promote social independence of cow and calf to minimize weaning distress.

Gradually weaning goat kids may improve weight gains while reducing weaning stress and increasing creep feed intakes.

Most dairy goat farms rear kids on ad libitum milk replacer; calf research suggests this improves growth and welfare, but solid feed intakes are problematic. Weaning can be gradual (incremental milk reduction) or abrupt (sudden, complete milk removal, which evidence suggests reduces welfare). Three treatments were created: abrupt weaning (AW: ad libitum milk until weaning) and gradual weaning [milk ad libitum until day 35, then milk unavailable 3.5 h/day until day 45 when milk removal was a 7 h/day block (gradual weaning 1: GW1) or two 3.5 h/day blocks (gradual weaning 2; GW2)]; complete milk removal occurred at day 56 for all. Experiment 1 investigated on-farm feasibility, behavior, and average daily gain (ADG). Experiment 2 investigated feed intakes, behavior, and ADG for AW and GW2. Experiment 1 had 261 kids (nine pens of 25-32), CCTV recorded 6 h/day, and group-level scan sampling recorded target behaviors. Kruskal-Wallis tests showed GW2 kids spent more time feeding on solids during weaning (p = 0.001) and displayed lower levels of 'frustrated suckling motivation' PostWean (p = 0.008). However, feeding competition differed PreWeaning (p = 0.007). ADG data from 159 female kids analyzed by a general linear model (fixed factor: treatment; covariate: day 34 weight) found GW2 had the highest ADG from day 35-45 (p ≤ 0.001) and no differences from day 45 to 56, and AW had the highest ADG PostWean (day 56-60). Experiment 2 had two AW pens (9 kids/pen) and two GW2 pens (8 and 9 kids/pen). A computerized feeder recorded milk intakes from day 22 to 56. Pen-level solid feed/water intakes were recorded from day 14-70. General linear models (fixed factor: treatment; covariate: PreWean value) found GW2 kids had higher ADG (p = 0.046) and lower milk intake (p = 0.032) from day 45-55, and PostWean (day 56-70) trended toward GW2 higher ADG (p = 0.074). Mann-Whitney U tests showed pen-level feed intake differences: AW had higher creep and straw throughout, GW2 showed higher creep during weaning (day 35-55), and higher water PostWean (>56 d). Behavioral observations suggest that gradually weaned kids may have enhanced welfare. Pen-level gradual weaning is feasible and, while weight gain results were mixed, it reduced milk intake, increased creep intake, and therefore combined with behavioral evidence can be recommended.

80 To Transfuse or Not to Transfuse: Choosing blood transfusions wisely in young children hospitalized with iron deficiency anemia

Abstract Background Nutritional iron deficiency anemia (IDA) peaks in prevalence at 6to 36 months of age. Children with severe IDA often present to emergency departments and may be hospitalized. Currently, little is known about the management and use of packed red blood cell transfusion in hospitalized children with severe IDA. The current Canadian Paediatric Society (CPS) Practice Point on iron requirements in the first 2 years of life (February 2021) provides guidance on prevention of iron deficiency and iron therapy; however, there is no guidance on the use of blood transfusion in children with severe IDA. Choosing Wisely Canada provides guidance on blood transfusions for adults; however, there are no recommendations on transfusion in children. In contrast, the joint American Society of Hematology and American Society of Pediatric Hematology/Oncology Choosing Wisely Task Force recently published (January 2022) recommendations, including avoiding packed red blood cell transfusion for asymptomatic children with IDA and no active bleeding. Objectives To describe the rate of blood transfusion and characteristics of young children hospitalized with IDA. Design/Methods Data from children, 6 to 36 months, hospitalized with IDA (2001-2020) was abstracted from health records using a standardized data collection form. Eligibility criteria were discharge diagnosis of IDA according to International Classification of Diseases codes, and laboratory evidence of IDA (hemoglobin < 110 g/L and at least two abnormal markers such as MCV, ferritin, transferrin, iron). Descriptive statistics were used. Results Of 79 children hospitalized with nutritional IDA (mean age 18.5 months), 34 (43%) received a blood transfusion. Of those receiving a transfusion, the initial mean hemoglobin was 32g/L (range 17-56g/L). Volume of blood given was: 5mL/kg (n=23, 68%), 10mL/kg (n=8, 23%), and >10mL/kg (n=3, 9%). Two children experienced adverse reactions: allergic reaction; non-hemolytic transfusion reaction. Characteristics of the entire cohort (n=79) were: female (n=51, 65%); previously healthy (n=69, 87%); received iron therapy prior to hospitalization (n=6, 8%); tachycardia on presentation (n=47, 59%); daily milk intake (mean 1638mL, range 236-9000mL). Initial laboratory results (mean) were: hemoglobin 40g/L (range 15-85g/L); MCV 51fL; platelet count 574x109/L; ferritin 3ug/L. Management included dietitian consultation with recommendation to reduce milk intake (n=69, 87%) and all patients received oral iron therapy on discharge (n=79, 100%). No child received intravenous iron therapy during their admission. Conclusion Our findings suggest high rates of blood transfusion among young children hospitalized with iron deficiency anemia. Future research includes examining factors associated with transfusion and practices at other Canadian centres. Our overall aim is to help inform future CPS and Choosing Wisely Canada recommendations.

Administration of spruce bark (Picea abies) extracts in young lambs exhibits anticoccidial effects but reduces milk intake and body weight gain

BackgroundEimeria spp. are widespread apicomplexan parasites known to cause coccidiosis in livestock, resulting in reduced animal welfare and productivity, particularly in sheep. The treatment options are limited, and there is an emerging development of resistance against registered pharmaceuticals. Spruce bark is rich in plant secondary metabolites (PSM), such as condensed tannins, which are bioactive compounds previously shown to have antiparasitic activity. Here, we examined the anticoccidial properties of bark extract of Norway spruce (Picea abies) against a field isolate of ovine Eimeria spp. by treating Eimeria-infected pre-ruminant lambs with water-extracted bark daily for 12 days. We hypothesised that the bark extract would reduce the faecal oocyst excretion and, consequently, the severity of diarrhoea.ResultsOral administration of spruce bark extract significantly reduced the excretion of Eimeria oocysts in milk-fed lambs post treatment till the end of the trial 22 days post infection. This difference in oocyst excretion between the treated and the untreated infected animals increased with time.Compared to the untreated and the sham-infected control group, the group treated with bark extract had softer faeces and reduced milk intake during the treatment period. After discontinuing the treatment, the treated animals got a more solid and formed faeces compared to that of the untreated control group, and the milk intake increased to the level of the sham-infected, untreated control group. The bark extract treated animals had a lower body weight and a lower mean daily body weight gain throughout the whole duration of the experiment.ConclusionsBark extract from Norway spruce showed marked anticoccidial properties by reducing the faecal oocyst count and associated diarrhoea in young lambs. Simultaneously we experienced detrimental effects of the treatment, displayed as reduced feed intake and daily body weight gain. Therefore, we suggest conducting similar studies with lower bark extract dosage to explore the possibilities of a better trade-off to reduce the negative impact while maintaining the antiparasitic effect.

Relation of the C/T-13910 LCT Polymorphism with Body Composition Measures and Their Modulation by Dairy Products in a Caucasian Men.

The C/T-13910 LCT is closely associated with lactase persistence and LCT has emerged as a new candidate gene for obesity, in particular in northern Europeans. The aim of this research is to investigate to what degree sex determines the association between the LCT variant and anthropometric traits in a cohort of healthy individuals. We recruited 1000 (500 males and 500 females aged 18–65 years) healthy blood donors. The C/T-13910 LCT polymorphism was genotyped using TaqMan assays. All individuals were phenotyped with respect to anthropometric characteristics. Prevalence of genotypes was 22.7% CC (lactase non-persistent, LNP), 58.6% CT, and 18.7% TT. LNP genotype was present less frequently among men p = .0005; OR 0.582 [0.425–0.794]. Therefore, in addition statistical calculations were performed separately for men and women. Additional analysis demonstrated an association between the CC genotypes and higher chest (p = .03), waist (p = .005), and forearm circumference (p = .0004) or more lean body mass (p = .04), than T-allele carriers in males. In females, they were not significantly different. Men consumed more milk (p = .003), while women ate more yoghurt (p = .001). Pearson’s correlation analysis showed that the higher intake of milk and dairy products was associated with higher fat body mass among men with lactase persistence. In Caucasian men, the LNP genotype is associated with reduced milk intake and dairy products, but more fat-free mass and higher forearm circumference, which may be relevant to dietary management for lactose intolerant.

Environmental interventions to reduce the consumption of sugar-sweetened beverages and their effects on health.

Environmental interventions to reduce the consumption of sugar-sweetened beverages and their effects on health.

A theory-based behavioural intervention to reduce formula-milk intake and prevent excessive weight gain during infancy (The Baby Milk Trial): a randomised controlled trial

BackgroundExcessive weight gain during infancy is associated with obesity in later life. We aimed to assess the efficacy of a theory-based behavioural intervention to prevent excessive weight gain in babies fed formula milk. MethodsIn this single (assessor) blind, parallel group, individually randomised controlled trial conducted in England, we recruited healthy babies who were fed formula milk and their parents within 14 weeks of birth. The behavioural intervention was informed by social cognitive theory and aimed to reduce formula-milk intake, promote responsive feeding, and monitor growth to prevent excessive weight gain (≥0·67 SD score [SDS]). The intervention was delivered by trained research nurses to infants up to the age of 6 months through three face-to-face interactions, two telephone contacts, and written materials. The control group received the same number of contacts during which general topics were discussed. The primary outcome was change in weight SDS from birth to 12 months. Analysis was by intention to treat. Ethics approval was given and parents gave written informed consent. This trial is registered with Current Controlled Trials, number ISRTCN20814693. FindingsBetween March 1, 2011, and June 30, 2015, we randomised 340 babies to the intervention group and 329 to the control group. Retention was 93% (n=622) at 6 months and 88% (586) at 12 months; programme engagement was high (94% attended four or five sessions). The intervention reduced milk intake at 3 (by 14%), 4 (12%), 5 (9%), and 6 (7%) months compared with the control group. The intervention slowed weight gain from baseline to 6 months (mean change 0·32 SDS vs 0·42; baseline-adjusted difference between intervention and control −0·08 SDS, 95% CI −0·17 to −0·004) but had no effect on weight change from birth to 12 months (baseline-adjusted difference −0·04 SDS, −0·17 to 0·10). By 12 months, 137 babies in the intervention group (40·3%) and 151 in the control group (45·9%) showed excessive weight gain (odds ratio 0·84, 95% CI 0·59 to 1·17). There were no differences in trial-related safety outcomes between the groups. InterpretationThe Baby Milk intervention was acceptable and safe, and it successfully reduced milk intake and weight gain to age 6 months; however, it had no effect on weight gain up to 12 months. Interventions to avoid excessive weight gain in infancy are urgently required but need to be sustained and scalable. FundingNational Prevention Research Initiative (grant MR/J000361/1).

Use of day level feeding behaviors to detect illness in group housed automatically fed pre-weaned dairy calves

Group housing and automatic feeding of dairy calves is gaining in popularity among dairy producers, yet disease detection remains a significant challenge of this management system. Software programs currently aim to assist in the detection of sick calves through such methods as flagging calves when there has been a 25% reduction in milk intake or in drinking speed as compared to a 3-day average. However, research suggests that using simple deviations in daily averages may not be useful, as calves have been shown to change behaviors only on the day of illness detection. The greater aim of our research program is to determine if we can use different approaches to examine feeding behavior that may improve the sensitivity and timeliness of detecting sick calves. The objective of the current study is to identify which feeding behaviors are most different between matched pairs of healthy and sick calves, and to determine if these changes differ by disease diagnosis.

Epidemiology of bladder stone of children: precipitating events.

Urological surgery evolved from the ancient practice of removing primary bladder stones from young boys. Bladder stones, once ubiquitous, long ago disappeared from the developed world while pockets of disease still exist in developing countries. Two epidemiological studies identified as precipitating events of bladder stone formation the practice of substitutive carbohydrate feedings to newborns. In Southeast Asia, masticated rice is fed to newborns in stone-endemic villages while in England, during the eighteenth and nineteenth centuries pap or panada was used to hand-feed infants when breast milk was not available. Fresh milk from dairy animals was deemed preferable to pap. Lack of access to dairy cattle enhanced need for hand-feeding. In an epidemiological study, during mid-nineteenth century in England the prevalence of dairy cattle was inversely related to the prevalence of bladder stones. These epidemiological data relate stone formation to nutrition during the first few days or weeks of life. It is surmised that frequent use of or exclusive reliance on carbohydrate foods replacing milk feedings leads to a relative dietary deficiency in phosphates and the formation of insoluble urinary salts. Girls, with short, nontortuous urethras may pass much of the calculus debris without retaining nuclei in the bladder. In some males, stone nuclei are formed and retained. The growth of stones is determined thereafter by the net effect of depository and resorptive mechanisms operating over time distributing over many years the age that patients present for surgical stone removal. The role of early introduction of carbohydrate foods and reduced milk intake of neonates has not been incorporated into recommendations for feeding newborns in endemic countries nor comprehensively modeled in animals.

Use of precision dairy technologies to detect illness in group housed automatically fed pre-weaned dairy calves

Precision dairy management is the use of sensor derived parameters to measure physiological, behavioral, and production indicators on individual animals to improve management strategies and farm performance. Automated milk feeding systems for group housed pre-weaned calves may offer some benefits including reallocation of labor, earlier socialization of calves, and an easy way to deliver more milk. However, there are some important disadvantages including increased risk for morbidity and mortality as well as delays in disease detection. Software programs aim to assist in the detection of sick calves through such methods as flagging calves when there has been a large reduction in milk intake or large changes in drinking speed over the last 24 hr period as compared to the previous 72 hr period. However, early research suggests that these simplistic algorithms may not be any more sensitive or timely than a human observer, and in some cases may miss detecting sick calves altogether. The greater aim of our research program is to determine if we can use different algorithms or approaches to examine feeding behavior that may improve the sensitivity and timeliness of detecting sick calves. As a first step towards this aim, the objective of the current preliminary study was to identify which feeding behaviors are most different between healthy and sick calves.

Early leptin intervention reverses perturbed energy balance regulating hypothalamic neuropeptides in the pre- and postnatal calorie-restricted female rat offspring.

Pre- and postnatal calorie restriction is associated with postnatal growth restriction, reduced circulating leptin concentrations, and perturbed energy balance. Hypothalamic regulation of energy balance demonstrates enhanced orexigenic (NPY, AgRP) and diminished anorexigenic (POMC, CART) neuropeptide expression (PN21), setting the stage for subsequent development of obesity in female Sprague-Dawley rats. Leptin replenishment during the early postnatal period (PN2-PN8) led to reversal of the hypothalamic orexigenic:anorexigenic neuropeptide ratio at PN21 by reducing only the orexigenic (NPY, AgRP), without affecting the anorexigenic (POMC, CART) neuropeptide expression. This hypothalamic effect was mediated via enhanced leptin receptor (ObRb) signaling that involved increased pSTAT3/STAT3 but reduced PTP1B. This was further confirmed by an increase in body weight at PN21 in response to intracerebroventricular administration of antisense ObRb oligonucleotides (PN2-PN8). The change in the hypothalamic neuropeptide balance in response to leptin administration was associated with increased oxygen consumption, carbon dioxide production, and physical activity, which resulted in increased milk intake (PN14) with no change in body weight. This is in contrast to the reduction in milk intake with no effect on energy expenditure and physical activity observed in controls. We conclude that pre- and postnatal calorie restriction perturbs hypothalamic neuropeptide regulation of energy balance, setting the stage for hyperphagia and reduced energy expenditure, hallmarks of obesity. Leptin in turn reverses this phenotype by increasing hypothalamic ObRb signaling (sensitivity) and affecting only the orexigenic arm of the neuropeptide balance.

Thyroid and iodine nutritional status: a UK perspective

Iodine is an essential component of the thyroid hormones, which play a crucial role in brain and neurological development. At least one-third of the world's population is estimated to be iodine deficient predominantly in developing countries. Recently concern had also been expressed about the iodine status in industrialised countries such as the UK. A recent survey of the UK iodine status found that that more than two-thirds of schoolgirls aged 14-15 years were iodine deficient due to the reduced milk intake. Maternal iodine deficiency in pregnancy is correlated with cognitive outcomes such as intelligence quotient and reading ability in offspring. No randomised trial data exist for iodine supplementation in mild-moderate iodine-deficient pregnant women. It is possible to combine population interventions to reduce population salt intake with salt iodisation programmes in order to maintain adequate levels of iodine nutrition.

Hyperactivation of Alk induces neonatal lethality in knock-in AlkF1178L mice.

The ALK (Anaplastic Lymphoma Kinase) gene encodes a tyrosine kinase receptor preferentially expressed in the central and peripheral nervous systems. A syndromic presentation associating congenital neuroblastoma with severe encephalopathy and an abnormal shape of the brainstem has been described in patients harbouring de novo germline F1174V and F1245V ALK mutations. Here, we investigated the phenotype of knock-in (KI) mice bearing the AlkF1178L mutation (F1174L in human). Although heterozygous KI mice did not reproduce the severe breathing and feeding difficulties observed in human patients, behavioral tests documented a reduced activity during dark phases and an increased anxiety of mutated mice. Matings of heterozygotes yielded the expected proportions of wild-type, heterozygotes and homozygotes at birth but a high neonatal lethality was noticed for homozygotes. We documented Alk expression in several motor nuclei of the brainstem involved in the control of sucking and swallowing. Evaluation of basic physiological functions 12 hours after birth revealed slightly more apneas but a dramatic reduced milk intake for homozygotes compared to control littermates. Overall, our data demonstrate that Alk activation above a critical threshold is not compatible with survival in mice, in agreement with the extremely severe phenotype of patients carrying aggressive de novo ALK germline mutations.

LCT 13910 C/T polymorphism, serum calcium, and bone mineral density in postmenopausal women

LCT 13910 CC genotype is associated with lactose intolerance, a condition often resulting in reduced milk intake. Women with the CC genotype were found to have decreased serum calcium and reduced bone mineral density. The CC genotype of the 13910 C/T polymorphism of the LCT gene is linked to lactose intolerance and low calcium intake. We studied 595 postmenopausal women, including 267 osteoporotic, 200 osteopenic, and 128 healthy subjects. Genotyping, osteodensitometry, and laboratory measurements were carried out. Frequency of aversion to milk consumption was 20% for CC genotype and 10% for TT + TC genotypes (p = 0.03). The albumin-adjusted serum calcium was 2.325 +/- 0.09 mmol/L for CC genotype and 2.360 +/- 0.16 mmol/L for TT + TC genotypes (p = 0.031). Bone mineral density (BMD; Z score) was lower in the CC than TT + TC genotypes, respectively, at the radius (0.105 +/- 1.42 vs 0.406 +/- 1.32; p = 0.038), at the total hip (-0.471 +/- 1.08 vs -0.170 +/- 1.09; p = 0.041), and at the Ward's triangle (-0.334 +/- 0.87 vs -0.123 +/- 0.82; p = 0.044). LCT 13910 C/T polymorphism is associated with decreased serum calcium level and lower BMD in postmenopausal women.

Social interactions alter proinflammatory cytokine gene expression and behavior following endotoxin administration

Sick animals display a constellation of behaviors, including anhedonia, anorexia, and reduced social interactions. Acute infection eliminates female mating behavior, but fails to attenuate mating behavior in male rats. These results have been attributed to the different reproductive strategies and parental investment of the two sexes. Males putatively suppress the symptoms of infection in order to “deceive” females into mating. We sought to investigate the mechanisms responsible for this suppression. Adult male CD-1 mice were treated with lipopolysaccharide (LPS; a component of bacterial cell walls; 400 μg/kg), then paired 2 h later with a receptive female or juvenile male or remained isolated. Blood samples and brains of the males were collected 3 h post-LPS; hypothalamic interleukin-1 ( IL- 1) and tumor necrosis factor-α ( TNFα) gene expression was measured using RT-PCR. Contrary to our prediction, exposure to a female increased hypothalamic IL- 1 and TNFα gene expression. LPS treatment significantly decreased testosterone and increased corticosterone secretions. Social interactions altered absolute corticosterone concentrations in saline-injected animals only. In order to determine whether increased production of hypothalamic cytokines reflected increased severity of sickness responses, body temperature was monitored in a second group of mice implanted with telemetric transmitters. Body mass, food intake, and consumption of sweetened condensed milk (a highly favored food) were also monitored in these mice for 72 h post-injection. LPS injections reduced milk intake, an effect that was modulated by social interactions; however, fever was unaltered relative to isolated animals. These results suggest that social interactions can adjust behavioral responses to infection although the ultimate cause of this adjustment remains unspecified.

Challenges for establishing a modern reindeer dairy industry (In Norwegian with Summary in English)

To achieve efficient milk ejection has been a recurrent problem in machine milking of reindeer does. The field season 2004 was a breakthrough for an efficient and complete milk let down in reindeer. The proportion of residual milk was reduced as lactation progressed; from around 40-50% at start of the milking in mid June to around 10-15% in late August, suggesting that habituation and training are important factors for triggering the ejection. We performed an experiment including 3 treatments; 1) Calves equipped with a "kjevle" (a wooden stick placed in the mouth of the calves making them unable to suckle but keeping their grazing ability intact) for 8 - 14 hrs dependent of lactation stage, followed by milking of the does, 2) Physically separation of the mothers and their calves for 8 - 14 hrs dependent of lactation stage, followed by milking of the does and 3) Permanent separation of females and calves at start of the milking period and females milked twice per day. The females and calves in group 1 and 2 were rejoined after the "kjevle" and separation period. The females in these two groups were milked every second day. The "kjevle" treatment apparently works better than physical separ¬ation according to welfare parameters and proportion milk ejected in the first part of the milking period. Permanent separation did also work well and permits that the whole production after separation can be utilized. However, in order to keep up the milk production frequent milkings are required during the first days of separation. The growth of the calves was high and did not differ between treatments. This suggests that the calves are able to compensate the reduced milk intake by increasing their intake of forages.

Role of serotonergic mechanisms in leptin-induced suppression of milk intake in mice

Effects of leptin on milk consumption in food-deprived mice were investigated. In this feeding model, systemic administration of leptin reduced milk intake of mice dose-dependently. Decreases in milk intake elicited by leptin were significantly reduced by the serotonin (5-HT) synthesis inhibitor p-chlorophenylalanine (PCPA). The suppressive effects of leptin on milk intake were antagonized by the 5-HT 2B/2C receptor antagonist SB206553, while the 5-HT 1B receptor antagonist GR55562 and the 5-HT 2A receptor antagonist ketanserin did not affect it. Our results indicated that the 5-HT depleter PCPA and the 5-HT 2B/2C receptor antagonist SB206553 attenuated leptin-induced suppression of milk intake. Therefore, leptin-induced hypophagic effects may be mediated by enhancement of serotonergic neurons, resulting in activation of the 5-HT 2B/2C receptor.

Distinct Roles for Cyclooxygenases 1 and 2 in Interleukin-1-Induced Behavioral Changes

Interleukin-1 (IL-1) induces hypophagia, which can be reduced by cyclooxygenase (COX) inhibitors. Earlier studies with COX knockout (COXko) mice suggested that COX2 was more important for hypophagia than COX1. However, behavioral responses occur long before COX2 is induced. Hypophagia was assessed in mice by measuring the intake of sweetened milk in a brief period. The intake was reduced within 30 min after intraperitoneal injection of IL-1beta and was depressed for about 2 h. When milk intake was measured 30 to 40 min after IL-1beta, COX1ko mice showed an attenuated response, whereas COX2ko mice responded more like wild-type animals. By contrast, 90 to 120 min after IL-1beta COX1ko mice responded normally, whereas COX2ko mice showed only small responses. The COX2-selective inhibitor, celecoxib, failed to alter the response to IL-1beta 30 min after administration, but low doses antagonized the effects of IL-1beta at 90 to 120 min. The COX1-selective inhibitor, SC560, attenuated both the early and late responses, but a larger effect at 30 min than at 90 min suggested a role for COX1 at the earlier time. These results suggest that shortly after IL-1beta administration, COX1 is the major enzyme involved in the reduction of milk intake, whereas at later times COX2 is more important, paralleling its induction. Celecoxib also attenuated the milk intake response observed 2 h after lipopolysaccharide (LPS), and the reductions of food pellet intake and body weight induced by IL-1beta and LPS in the subsequent 24 h, suggesting that the role of COX2 may be more significant biologically than that of COX1.

GH and IGF-I binding in adipose tissue, liver, and skeletal muscle in response to milk intake level in piglets

Two experiments were undertaken to get a better understanding of the regulation of the GH/IGF-I axis by nutritional status in suckling piglets. In experiment 1, 18 newborn unsuckled piglets were bottle-fed low (L), intermediate (I), or high (H) levels of sow colostrum and milk from birth to 7 days of age. L and H levels corresponded to maintenance requirement and ad libitum intake, respectively. Plasma IGF-I and 43–39 kDa IGFBP levels decreased ( P<0.05) with the reduction of milk intake. Specific binding of 125 I -bGH in liver decreased ( P<0.01) with decreasing milk intake. It did not differ ( P>0.1) between the groups in skeletal muscle. Specific binding of 125 I -IGF-I increased ( P<0.05) with decreasing milk intake in skeletal muscle but did not differ ( P>0.1) between the three groups in liver. In experiment 2, variation in milk intake was induced by litter size manipulation. In the 24 h following birth, the litter sizes of six litters were normalized to 6 (L6) or 12 piglets (L12). Animals were killed at 21 days of age. Plasma IGF-I concentrations ( P<0.001) and 43–39 kDa IGFBP levels ( P<0.05) were lower in L12 than in L6. Specific binding of 125 I -bGH in adipose tissue, liver, and skeletal muscle did not differ ( P>0.1) between the two groups. Specific binding of 125 I -IGF-I in liver was lower ( P<0.001) in L12 than in L6, whereas it did not differ ( P>0.05) between groups in other tissues. In conclusion, the present report shows that undernutrition consistently decreases plasma IGF-I and 43–39 kDa IGFBP levels but produces variable responses at the GH and IGF-I binding levels in piglets.