Maternal behavior of dairy cows and suckling behavior of dairy calves in different cow-calf-contact conditions

Cow-calf contact (CCC) has been suggested as an alternative to the common practice of early separation of dairy cow and calf. Increasing CCC poses challenges by reducing the machine milk yield and increasing separation stress. Part-time CCC may prove more feasible than full-time contact for farmers but may affect the maternal behavior of the cows. Gradually reducing the daily contact could gradually wean the calf off milk, preparing it for separation. This study aims to investigate 1) how cows' maternal behaviors toward their own calf are affected by part-time contact, and 2) whether calves' suckling behavior is reduced by reducing daily cow contact. Fifty-six dairy cows and their calves were assigned to either full-time (23 h/d) or part-time (10 h/d) cow-calf contact for 7 weeks (main rearing period). This was followed by 2 weeks of either reduced contact (50% in wk 8, then 25% of original contact time in wk 9) or unchanged contact. First, the maternal behavior of full and part-time cows was observed for 24 h in the third week of the main rearing period. Part-time cows spent less time nursing and grooming their own calf than full-time cows did. However, the amount of nursing in the inverse parallel position and the probability of a cow nursing a calf other than her own did not differ between the 2 treatments. Second, calf suckling behavior was observed for 24 h in both weeks of the reduced contact period. Averaged across both observations, total suckling time (i.e., time spent suckling any cow) was lower in part-time calves that experienced reduced contact compared with part-time calves with unchanged contact. In wk 9, time spent suckling only the dam was lower for full-time calves with reduced contact compared with part-time calves with unchanged contact. In conclusion, although we found a lower nursing and grooming time in part-time cows compared with full-time, we found no difference between treatments with regards to nursing in the inverse parallel position and nursing a calf other than the cow's own. The effect of gradually reducing cow-calf contact on calves' suckling time requires more research.

Intracellular Regulation Limits the Response of Intestinal Ferroportin to Iron Status in Suckling Rats

SCOPE

Iron status is regulated via iron absorption as there is no active iron excretion. Divalent metal-ion transporter-1 (DMT1) and ferroportin (FPN) are two key proteins vital for iron absorption, but the regulation of them in suckling mammals differs from that in adults. This study aims to explore regulation of iron transporters under different iron conditions during suckling.

METHODS AND RESULTS

This study developed suckling rats under different iron conditions. Unexpectedly, unchanged FPN at different iron status are detected. Since FPN is the only known iron exporter for mammals, unchanged FPN limits iron exported into blood during suckling. Thus, factors regulating FPN at transcriptional, post-transcriptional, and post-translational levels are detected. Results showed that Fpn mRNA is upregulated, while micro RNA-485(miR-485) which could silence Fpn mRNA is upregulated at low iron status limiting translation of Fpn mRNA. Besides, serum hepcidin and liver Hamp mRNA are upregulated, but ring finger protein 217( Rnf217) mRNA remained unchanged at high iron status leading to FPN not downregulated as adults.

CONCLUSIONS

Overall, this study indicates that translational regulation limits intestinal FPN protein response to iron deficiency and Rnf217 cannot effectively mediate the degradation of FPN at high iron status, which provides a reference for maintaining iron homeostasis during suckling.

Evolution, diversification and function of the maternal-infant dyad in mammalian feeding

The evolution of the mother/infant dyad providing a source of nutrition for infants is essential for the origin and subsequent diversification of mammals. Despite the importance of this dyad, research on maternal and infant function is often treated independently. Our goal is to synthesize the work on maternal and infant function, discuss our own studies of suckling, and compare the origins of lactation and suckling with their ensuing diversification. Our central premise is that while extensive work has demonstrated variation across mammals in the maternal aspect of this system, very little has been done to address how this relates to infant function. We start with a discussion of the fundamental anatomy and physiology of both mother and infant. We next discuss the origin of mammary glands and milk, and infant suckling, which is distinct from their subsequent diversification. We then discuss the diversification of maternal and infant function, highlighting the evolutionary diversity present in maternal function (both anatomically and physiologically), before arguing that the diversity of infant function is unexplored, and needs to be better studied in the future. We end by discussing some of the holes in our understanding, and suggestions for future work that can address these lacunae. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.

Exploring the interaction of viscosity and nipple design on feeding performance in an infant pig model

Infant feeding behaviors are modulated via sensorimotor feedback, such that sensory perturbations can significantly impact performance. Properties of the nipple and milk (e.g., nipple hole size and viscosity) are critical sources of sensory information. However, the direct effects of varying milk and nipple properties on infant motor output and the subsequent changes in feeding performance are poorly understood. In this study, we use an infant pig model to explore the interaction between nipple hole size and milk viscosity. Using high-speed videofluoroscopy and electromyography, we measured key performance metrics including sucks per swallow and suck duration, then synchronized these data with the onset and offset of activity of jaw opening and closing muscles. The combination of a small nipple hole and thick milk resulted in negative effects on both suck and swallow performance, with reduced feeding efficiency compared to the other treatments. It also appears that this combination of viscosity and hole size disrupts the coordination between correlates of tongue and jaw movements. We did not see a difference in feeding efficiency between viscosities when infants fed on the large-hole nipple, which may be the result of non-Newtonian fluid mechanics. Our results emphasize the importance of considering both fluid and nipple properties when considering alterations to an infant's feeding system.

Proposed methods for estimating loss of saleable milk in a cow-calf contact system with automatic milking

Cow-calf contact (CCC) systems, although beneficial in many respects, introduce additional challenges to collect reliable data on milk production, which is important to assess individual cow efficiency and dairy farm profitability. Apart from weighing calves before and after each feeding, the amount of saleable milk lost due to calf suckling is practically impossible to measure. Here, we assess 2 indirect methods for estimating loss of saleable milk when housing cows and calves together in a robotic milking unit. In our study, treatment (CCC) cows and calves were kept together full time until the calves were 127 ± 6.6 d old (mean ± SD). Control cows were separated from their calves within 12 h of birth and then kept in the same unit as the treatment cows but with no access to either their own or treatment calves. Milk yield recording of both groups was performed from calving until pasture release at 233 ± 20 d in milk. The first estimation method relied on observed postseparation milk yield data, which were fed into a modified Wilmink regression model to determine the best-fitting lactation curve for the preseparation period. The second method was based on the cows' daily energy intake postseparation, calculated by measuring the daily feed intake and analyzing the energy content of the ration. The calculated energy intake was used to determine the average ratio between energy intake and the observed milk yield the following day for each individual cow, assuming constant rates of mobilization and deposition of body fat. The obtained ratio was then used to calculate the expected daily milk yield based on daily energy intake data during the preseparation period. In this paper, we analyzed data from 17 CCC cows kept together with their calves and 16 control cows; both groups calved from September to October 2020 and were followed up until release to pasture in May 2021. Saleable milk yield was lower in CCC cows than in control cows, both before and after separation. The 2 methods were used on data for control cows and showed milk yield loss using the lactation curve method (average of -3.4 ± 2.8 kg/d) and almost no loss using energy intake data (average of -1.4 ± 2.7 kg/d). Milk yield loss for CCC cows was estimated at average 11.3 ± 4.8 and 7.3 ± 6.6 kg milk/d, respectively. The proposed lactation curve estimation method tends to overestimate milk yield loss, whereas the method based on energy intake is more accurate. However, collecting detailed energy intake data per individual cow requires additional effort and equipment, which is not always feasible on commercial farms. Further research is needed to improve milk loss estimation and to better understand trade-offs in CCC systems.

Nipple properties affect sensorimotor integration during bottle feeding in an infant pig model

Infant feeding is a critical neurological milestone in development defined by the coordination of muscles, peripheral nerves, and brainstem nuclei. In infants, milk flow rate is often limited to improve feeding performance without treating the underlying deficiencies in the sucking and swallowing processes. Modification of the neuromotor response via sensory information from the nipple during bottle feeding is an unexplored avenue for physiology-based interventions. In this study, we assessed how differences in nipple hole size and nipple stiffness affect sucking muscle activation and subsequent movement. We fabricated four bottle nipples of varying hole size and stiffness to determine how variation in nipple properties affects the sucking behavior of infant pigs. Our results demonstrate that sensory information from the nipple affects sucking motor output. Nipple hole sizes and stiffnesses with a larger milk flow rate resulted in greater muscle activity and kinematic movement. Additionally, our results suggest that sensorimotor interventions are better directed toward modulating tongue function rather than the mandible movements due to a greater response to sensory information. Understanding how sensory information influences infant feeding is instrumental in promoting effective infant feeding.

Stachydrine, N-acetylornithine and trimethylamine N-oxide levels as candidate milk biomarkers of maternal consumption of an obesogenic diet during lactation

We aimed to evaluate whether improving maternal diet during lactation in diet-induced obese rats reverts the impact of western diet (WD) consumption on the metabolome of milk and offspring plasma, as well as to identify potential biomarkers of these conditions. Three groups of dams were followed: control-dams (CON-dams), fed with standard diet (SD); WD-dams, fed with WD prior and during gestation and lactation; and reversion-dams (REV-dams), fed as WD-dams but moved to SD during lactation. Metabolomic analysis was performed in milk at lactation days 5, 10, and 15, and in plasma from their male and female offspring at postnatal day 15. Milk of WD-dams presented, throughout lactation and compared to CON-dams, altered profiles of amino acids and of the carnitine pool, accompanied by changes in other polar metabolites, being stachydrine, N-acetylornithine, and trimethylamine N-oxide the most relevant and discriminatory metabolites between groups. The plasma metabolome profile was also altered in the offspring of WD-dams in a sex-dependent manner, and stachydrine, ergothioneine and the acylcarnitine C12:1 appeared as the top three most discriminating metabolites in both sexes. Metabolomic changes were largely normalized to control levels both in the milk of REV-dams and in the plasma of their offspring. We have identified a set of polar metabolites in maternal milk and in the plasma of the offspring whose alterations may indicate maternal intake of an unbalanced diet during gestation and lactation. Levels of these metabolites may also reflect the beneficial effects of implementing a healthier diet during lactation.

Investigation of exacerbating factors for postpartum hair loss: a questionnaire-based cross-sectional study

Background

Although postpartum hair loss is believed to be common, there is little reliable information.

Objective

We sought to examine the factors that were associated with postpartum hair loss and to elucidate factors correlated with its pathogenesis.

Methods

We carried out a questionnaire-based cross-sectional study. The study participants were women who delivered at 2 facilities and filled the questionnaire 10-18 months after delivery. The survey questionnaire included baseline characteristics, pregnancy details, delivery, childcare, and extent of postpartum hair loss. We divided participants into 2 groups according to the absence or presence of postpartum hair loss and performed logistic regression analyses.

Results

A total of 331 (21.0%) responses were analyzed; among these 304 (91.8%) women had postpartum hair loss. The average time for the start, peak, and end of hair loss was 2.9, 5.1, and 8.1 months, respectively. Women with hair loss had an earlier time of delivery, a lower birth weight, a higher preterm labor rate, and longer-term breastfeeding. Logistical regression analyses revealed that longer-term breastfeeding and preterm labor were independent predictors of postpartum hair loss. The adjusted odds ratio for postpartum hair loss in women who ended breastfeeding 6-12 months postpartum versus those who ended it after 12 months or more was 5.96 (95% confidence interval [CI] [1.68, 21.09]) and 6.37 (95% CI [1.95, 20.76]) compared with those who stopped breastfeeding within 6 months postpartum.

Limitations

Finer details such as pregnancy complications and delivery information may not be accurate since all results are based on questionnaire responses. There may be a sampling bias because women who suffer from postpartum hair loss may tend to participate more frequently.

Conclusion

Over 90% of women experienced postpartum hair loss. Our data show that long-term breastfeeding and preterm labor correlate with postpartum hair loss.

Mechanisms of lactation-induced infertility in female mice

Lactation in mammals is associated with a period of infertility, which serves to direct maternal metabolic resources towards caring for the newborn offspring rather than supporting another pregnancy. This lactational infertility is characterized by reduced pulsatile luteinizing hormone (LH) secretion and lack of ovulation. The mechanisms mediating suppression of LH secretion during lactation are unclear. There are potential roles for both hormonal cues such as prolactin and progesterone, and pup-derived cues such as suckling, on the inhibition of reproduction. To enable future studies using transgenic animals to investigate these mechanisms, in the present study our aim was to characterize lactational infertility in mice, and to investigate the effect of removing pup-derived cues on LH secretion, time to ovulation and kisspeptin immunoreactivity. We firstly confirmed that C57BL/6J mice experience prolonged anestrus during lactation, which is dependent on establishment of lactation, as removal of pups on the day of parturition led to immediate resumption of pulsatile LH secretion and normal estrous cycles. Once lactation is established, however, the lactational anestrus persisted for several days even after premature removal of pups. Pharmacological suppression of prolactin following premature weaning significantly reduced this period of lactational infertility. Progesterone does not appear to play a significant role in the suppression of fertility during lactation in mice, as levels measured during lactation were not different from non-pregnant mice. These data suggest that prolactin plays a key role in mediating anestrus during early lactation in mice, even in the absence of the suckling stimulus.

Exposure of suckling rats to hexavalent chromium (CrVI) alters bone formation at the base of the alveolus causing a delay in tooth eruption

OBJECTIVES

Hexavalent chromium (CrVI)-exposure of suckling rats has been shown to delay tooth eruption. However, the effects of CrVI-exposure on bone formation at the base of the alveolus, which provides a motive force for tooth eruption in the early stages of the process, remain unknown. The present work sought to evaluate the effect of CrVI-exposure on bone formation at the base of the alveolus during the intraosseous stage of tooth eruption in suckling rats, using histomorphometric and immunohistochemical studies.

METHODS

Experimental animals received 12.5 mg/kg-bw/day of potassium dichromate dissolved in saline solution by gavage starting on day 4 of the experiment; controls similarly received an equivalent volume of saline. All the animals were euthanized at the age of 9 days. The base of the developing alveolus at the level of the mesial root of the first lower molar was analyzed histomorphometrically and immunohistochemically. Data were statistically analyzed using student's t-test, with statistical significance set at p <0.05.

RESULTS

CrVI-exposed animals showed lower bone volume and height at the base of the alveolus, a significant preponderance of bone rest on the surface adjacent to the dental follicle, and a significantly lower percentage of positive Runt-related transcription factor-2 (RUNX2+) osteoblasts and a significantly higher number of mesenchymal-like RUNX2+ cells at the latter site.

CONCLUSION

CrVI-exposure during lactation affects bone formation at the base of the developing alveolus, delaying tooth eruption. These findings underscore the importance of controlling drinking water levels of toxic substances since their effects can alter the growth and development of individuals exposed during early childhood.

Galacto-Oligosaccharides Increase the Abundance of Beneficial Probiotic Bacteria and Improve Gut Architecture and Goblet Cell Expression in Poorly Performing Piglets, but Not Performance

Poorly performing piglets receiving commercial milk replacers do not benefit from the naturally occurring probiotic galacto-oligosaccharides otherwise found in sow milk. Study objectives were to investigate the effects of complete milk replacer supplemented with galacto-oligosaccharides on the microbiome, gut architecture and immunomodulatory goblet cell expression of poorly performing piglets that could benefit from milk replacement feeding when separated from sows and housed with fit siblings in environmentally controlled pens. The study is novel in that it is one of the first to investigate the effects of supplementing complete milk replacer with galacto-oligosaccharides in poorly performing piglets. Gastrointestinal tract samples were collected from piglets, and the microbiome composition was assessed by 16s ribosomal ribonucleic acid gene sequencing. Gut architectural features, villus/crypt ratio and enumeration of goblet cells in tissues were assessed by histopathological techniques. The most abundant taxa identified at the genus level were Lactobacillus, Streptococcus, Prevotella, Lactococcus and Leuconostoc. Milk replacer plus galacto-oligosaccharides significantly improved gut architectural features and villus/crypt ratio throughout the gastrointestinal tract, increased the number of goblet cells and revealed a differential abundance of beneficial probiotic bacteria, particularly Lactobacillus and Bifidobacterium. In these respects, galacto-oligosaccharide-supplemented milk replacer may be a useful addition to animal husbandry in poorly performing, non-thriving animals when moved to environmentally controlled pens away from sows and fit siblings, thereby modulating the microbiome and gastrointestinal tract performance.

Impact of liquid diet supplementation while suckling and weaning age on nutritional status, intestinal health, and immunity of piglets pre- and post-weaning

New strategies are needed to enhance piglets' robustness and proper functional development and maturation of piglets' intestine before weaning, to reduce the number of antibiotic treatments of diarrheic disorders in newly weaned piglets. It was hypothesized that a liquid nutritional supplement during the suckling period, and/or an increased weaning age, would beneficially impact piglets' gut health and enhance piglets' nutritional status before weaning. Further, it was hypothesized that a high intake of colostrum during the first 24 h after birth would be more advantageous for piglets' growth and robustness when compared to a low colostrum intake (CI). A 2 × 2 factorial design with two nutritional strategies (± supplementation with milk/feed, i.e., milk provided from day 2 shifted to wet feed at day 12 of age) and two weaning ages (days 24 vs. 35) was used. In total, 460 piglets from 24 sows were used for estimation of the individual CI after birth. Provision of the nutritional supplement and the increased weaning age improved the nutritional status of piglets' post-weaning assessed by their blood plasma concentration of albumin (P = 0.04), triglycerides (P = 0.004), and nonesterified fatty acids (P = 0.02). Piglets with high CI demonstrated improved nutritional status when compared to low CI (P = 0.04). Villous height and crypt depth were greater in piglets weaned at day 35 of age in contrast to day 24 of age (P < 0.001) irrespective of the nutritional intervention (P = 0.82). The concentration of branched-chain fatty acids in piglets' digesta was reduced in groups provided the nutritional supplement (P = 0.01), while total short-chain fatty acids were elevated at weaning in large intestinal digesta of piglets weaned at day 35 of age compared to piglets weaned at day 24 of age (P = 0.05). The weaning age in combination with the nutritional supplement had pronounced beneficial effect on gene expression of all investigated genes: interleukin-6, interleukin-10, nuclear factor kappa-beta, occludine, prostaglandin-endoperoxide synthase-2, tumor necrosis factor-alpha, and zonula occludens-1 (ZO-1) (P = 0.04). In conclusion, nutritional supplementation preweaning combined with increased weaning age could be considered as a strategy for improvement of the intestinal health, function, and maturation in piglets pre- and post-weaning, and a high CI enhanced piglets' robustness before weaning.

The effect of stiffness and hole size on nipple compression in infant suckling

During infant feeding, the nipple is an important source of sensory information that affects motor outputs, including ones dealing with compression of the nipple, suction, milk bolus movement, and swallowing. Despite known differences in behavior across commercially available nipples, little is known about the in vivo effects of nipple property variation. Here we quantify the effect of differences in nipple stiffness and hole size on an easily measured metric representing infant feeding behavior: nipple compression. We bottle-fed 7-day old infant pigs (n = 6) on four custom fabricated silicone nipples. We recorded live X-ray fluoroscopic imaging data of feeding on nipples of two levels of hardness/stiffness and two hole sizes. We tested for differences in nipple compression at the nipple's maximum compression across different nipple types using a mixed model analysis of variance. Stiffer nipples and those with smaller holes were compressed less than compliant nipples and nipples with larger holes (p < 0.001). We also estimated the force applied on the nipple during feeding and found that more force was applied to the compliant nipple with disproportionately larger strains. Our results suggest that infant pigs' nipple compression depends on material type and hole size, which is likely detected by the infant pigs' initial assessment of compressibility and flow. By isolating nipple properties, we demonstrated a relationship between properties and suckling behavior. Our results suggest that sensory information affects feeding behaviors and may also inform clinical treatment of poor feeding performance.

Neonatal oxytocin gives the tempo of social and feeding behaviors

The nonapeptide oxytocin (OT) is a master regulator of the social brain in early infancy, adolescence, and adult life. Here, we review the postnatal dynamic development of OT-system as well as early-life OT functions that are essential for shaping social behaviors. We specifically address the role of OT in neonates, focusing on its role in modulating/adapting sensory input and feeding behavior; both processes are involved in the establishing mother-infant bond, a crucial event for structuring all future social interactions. In patients and rodent models of Prader-Willi and Schaaf-Yang syndromes, two neurodevelopmental diseases characterized by autism-related features, sensory impairments, and feeding difficulties in early infancy are linked to an alteration of OT-system. Successful preclinical studies in mice and a phase I/II clinical trial in Prader-Willi babies constitute a proof of concept that OT-treatment in early life not only improves suckling deficit but has also a positive long-term effect on learning and social behavior. We propose that in early postnatal life, OT plays a pivotal role in stimulating and coordinating the maturation of neuronal networks controlling feeding behavior and the first social interactions. Consequently, OT therapy might be considered to improve feeding behavior and, all over the life, social cognition, and learning capabilities.

The transfer of passive immunity in calves born at pasture

Calf and dam separation is an area of growing public interest, and timely separation is also a practical challenge for pastoral farmers to achieve for all calves. Very few studies have investigated the success of leaving calves with their dams in pastoral conditions, so this observational study assessed serum total protein (STP) in calves born at pasture and left to suckle from their dams for up to 24 h. It also investigated failure of transfer of passive immunity (FPT) once calves had been provided colostrum from the farmer and some factors that may contribute to the risk of FPT. Over 2 years, 8 farms (4 in the North Island, 4 in South Island of New Zealand) were involved in an observational study where cows and calves were observed for 24 h a day for 2 wk per farm. Observers recorded the time from birth to first suckling, number of suckling events, time of calf removal from the dam, and ambient temperature. Calves were blood sampled on arrival at housing, before receiving colostrum from the farmer (d 1), and again 2 d later (d 3) to test for STP concentration. On d 1, 689 calves had blood samples collected, at a median of 11.5 (interquartile range 5.6 to 19.2) hours postbirth. Of these, 283 calves [41.1%; 95% confidence interval (CI) 37.4 to 44.9%] had STP >52 g/L (proportion by farm ranged from 10 to 78%). On d 3, 680 blood samples were collected, of which 16.0% (95% CI 13.5 to 19.0) had FPT (STP ≤52 g/L) with proportion by farm ranging from 2.5 to 31.6%. The FPT risk at d 3 in calves that did not suckle before housing was 2.91 (95% CI 2.04 to 4.13) times the risk in calves that suckled. For every hour longer postbirth that it took for a calf to have its first suckling event, odds of FPT at d 3 increased by 1.21 (95% CI 1.08 to 1.36) times, and compared with calves that only suckled once, calves that suckled 2, 3-5, or >5 times had 0.42 (95% CI 0.15 to 0.99), 0.35 (95% CI 0.15 to 0.76), and 0.10 (95% CI 0.005 to 0.47) times the odds of FPT, respectively. For every 1-percentage-point increase in the Brix % of the colostrum, the odds of FPT decreased by 33% (95% CI 24- to 42). Calves that suckled in the paddock and were fed colostrum with ≥22% Brix had the highest STP, and lowest odds of FPT, of any suckling/Brix % combination. There was a trend for STP to be greater in calves that suckled in the paddock and fed <22% Brix compared with calves that did not suckle in the paddock and fed ≥22% Brix. However, the calves in the former group also tended to have a greater risk of FPT at d 3, and a greater STP variability. There were very large between-farm variabilities for rates of suckling, colostrum feeding, and FPT risk that urgently require further investigation for calves born at pasture.

Reverting to a healthy diet during lactation normalizes maternal milk lipid content of diet-induced obese rats and prevents early alterations in the plasma lipidome of the offspring

Scope

This study aims to assess in rats whether normalizing maternal diet during lactation prevents the harmful effects of western diet (WD) consumption during the whole perinatal period on the lipidomic profile in maternal milk and offspring plasma.

Methods and Results

Control dams (CON‐dams), fed with standard diet (SD); WD‐dams, fed with WD prior and during gestation and lactation; and reversion dams (REV‐dams), fed as WD‐dams but moved to SD during lactation are followed. Lipidomic analysis is performed in milk and plasma samples from pups. Milk of WD‐dams presents a different triacylglycerol composition and free fatty acid (FA) profile compared to CON‐dams, including an increased ratio of pro‐inflammatory to anti‐inflammatory long‐chain polyunsaturated FA. Such alterations, which are also present in the plasma of their offspring, are widely reversed in the milk of REV‐dams and the plasma of their pups. This is related with the recovery of control adiponectin expression levels in the mammary gland, and the presence of decreased expression of pro‐inflammatory factors.

Conclusion

Implementing a healthy diet during lactation prevents early alterations in the plasma lipidome of pups associated to the maternal intake of an obesogenic diet, which may be related to the normalization of milk lipid content and the inflammatory state in the mammary gland.

Effect of Type of Cow-Calf Contact on Health, Blood Parameters, and Performance of Dairy Cows and Calves

Prolonged cow-calf contact (CCC) could potentially improve dairy calf welfare. However, it is currently unknown how different types of CCC affect animals' biological functions. We evaluated health and performance parameters of dairy calves and their dams, where calves: (i) had no contact with their dam (NC), in which the calf was removed from the dam directly after birth (n = 10); (ii) were allowed to have partial contact (PC) with their dam, in which the calf was housed in a calf pen adjacent to the cow area allowing physical contact on the initiative of the dam but no suckling (n = 18); (iii) were allowed to have full contact (FC) with their dam, including suckling, in which calves were housed together with their dams in a free-stall barn (n = 20). Throughout the first 7 weeks postpartum, data were collected on the health status, fecal microbiota, hematological profile, immune and hormonal parameters, and growth rates of calves, and on the health status, metabolic responses, and performance of dams. Overall, FC calves had more health issues (P = 0.02) and a tendency for higher antibiotic usage (P = 0.07) than NC calves. Additionally, FC calves showed elevated levels of erythrocytes, hematocrit, hemoglobin, and leukocytes on day 49 compared to NC calves (P < 0.001). Calf fecal microbiota changed over time, and we found preliminary evidence that fecal microbiota is affected by the type of CCC, as reflected by differences in relative abundances of taxa including Lactobacillus in FC calves compared to NC and PC calves except on days 7 and 66. The FC calves had a greater average daily gain in body weight than NC and PC calves (P = 0.002). Cow health was not affected by the type of CCC, although in the first 7 weeks of lactation FC cows had a lower machine-gained milk yield accompanied by a lower fat percentage than NC and PC cows (P < 0.001). These results indicate that full contact posed a challenge for calf health, presumably because the housing conditions of FC calves in this experimental context were suboptimal. Secondly, ad libitum suckling leads to higher weight gains and negatively affected milk fat content besides machine-gained yields. More research into strategies to improve cow-calf housing and management in CCC systems is warranted.

Relationship between foal daily gain, suckling behavior, and the distance between foals and their mares in the first 40 days of life of Hokkaido native horses kept outdoors year-round

In this study, we investigated suckling behavior and the distance between a foal and its mare as indicators of foal growth in Hokkaido native horses (HKD) during the first 40 days of life. Direct observations were made of 22 mare and foal pairs from two consecutive days 1 and 2, 5 and 6, 10 and 11, 20 and 21, 30 and 31, and 40 and 41 after birth by focal animal sampling for 3 h per day. Suckling behavior was continuously recorded, along with the terminator. The distance between the foal and its mare was determined using the instantaneous sampling method (1 min), and the percentage was calculated within 4 m while the foal was recumbent (DPW4FR). In the first week after birth, the duration and frequency of suckling terminated by the foal were negatively correlated with foal daily gains (duration, -0.49, p = 0.028; frequency, -0.53, p = 0.017). The DPW4FR and daily gain during 10-40 days after birth showed significant negative correlation (-0.47, p = 0.031). It is suggested that in HKD reproduction systems, suckling behavior termination by the foal and the distance between the foal and mare may be indicators of early foal growth.

Postnatal Maturation of Glutamatergic Inputs onto Rat Jaw-closing and Jaw-opening Motoneurons

Motoneurons that innervate the jaw-closing and jaw-opening muscles play a critical role in oro-facial behaviors, including mastication, suckling, and swallowing. These motoneurons can alter their physiological properties through the postnatal period during which feeding behavior shifts from suckling to mastication; however, the functional synaptic properties of developmental changes in these neurons remain unknown. Thus, we explored the postnatal changes in glutamatergic synaptic transmission onto the motoneurons that innervate the jaw-closing and jaw-opening musculatures during early postnatal development in rats. We measured miniature excitatory postsynaptic currents (mEPSCs) mediated by non-NMDA receptors (non-NMDA mEPSCs) and NMDA receptors in the masseter and digastric motoneurons. The amplitude, frequency, and rise time of non-NMDA mEPSCs remained unchanged among postnatal day (P)2-5, P9-12, and P14-17 age groups in masseter motoneurons, whereas the decay time dramatically decreased with age. The properties of the NMDA mEPSCs were more predominant at P2-5 masseter motoneurons, followed by reduction as neurons matured. The decay time of NMDA mEPSCs of masseter motoneurons also shortened remarkably across development. Furthermore, the proportion of NMDA/non-NMDA EPSCs induced in response to the electrical stimulation of the supratrigeminal region was quite high in P2-5 masseter motoneurons, and then decreased toward P14-17. In contrast to masseter motoneurons, digastric motoneurons showed unchanged properties in non-NMDA and NMDA EPSCs throughout postnatal development. Our results suggest that the developmental patterns of non-NMDA and NMDA receptor-mediated inputs vary among jaw-closing and jaw-opening motoneurons, possibly related to distinct roles of respective motoneurons in postnatal development of feeding behavior.

Kittens That Nurse 7 Weeks or Longer Are Less Likely to Become Overweight Adult Cats

Simple Summary

Most pet cats are separated from the queen during the suckling period and before they are fully weaned. Weaning is characterized by rapid growth and development of the kitten and marks the transition from a fully milk-based diet to a solid-food diet. Early-life feeding is known to influence the development of the digestion system, eating behavior, and dietary patterns. The aim of this study was to examine the effects of the suckling period length (SPL) on adult weight status and whether a deficiency during a critical period of development—as a short SPL can be considered - may influence body weight regulation, control of appetite and energy expenditure. Our findings show that a shorter SPL increases the risk of overweight in cats. The odds for overweight was three times lower in cats with a SPL > 6 weeks (OR = 0.33, 95% CI = 0.10–0.99). The suckling period length (SPL) could be an easy modifiable risk factor in the primary prevention of overweight in cats.

Abstract

The aim of this study was to examine the effect of the suckling period length (SPL) on weight status among adult cats while taking into account putative risk factors. To this end, the body fat percentage of 69 client-owned cats was determined. A body fat percentage of >30% was used for overweight classification. Cat owners were interviewed using a standardised questionnaire to collect information about the SPL, age, breed, sex, feeding amount and frequency, daily playing and outdoor access. SPL was categorized into four groups (0–6, 7–11, 12–16, 17–24 weeks). Logistic regression was used to estimate the association between overweight and SPL after adjusting for identified risk factors. Of the 69 cats, 37 were overweight. The odds for overweight was three times lower in cats with a SPL > 6 weeks (OR = 0.33, 95% CI = 0.10−0.99). This study identified a possible novel, modifiable early life risk factor for overweight in cats; the SPL. The results of this study indicate that allowing cats to nurse longer than 12 weeks might be a simple intervention to improve cat health and welfare.

Investigations on Transfer of Pathogens between Foster Cows and Calves during the Suckling Period

Simple Summary

Regarding the increasing importance of alternative calf rearing systems, such as the foster cow system, better knowledge about the transfer of pathogens via suckling calves would be very helpful. In this context, the present study was conducted on a large organic dairy farm practising calf rearing on foster cows. For microbiological examinations, quarter milk samples were collected both from foster cows and biological dams. Additionally, swabs were taken from the oral cavities of the associated foster calves. The concordance of pathogens between cows and calves was further examined by strain comparisons. The same strains of isolates were detected for Pasteurella multocida, Staphylococcus aureus, S. sciuri and Streptococcus (Sc.) suis. Based on the present results and the available literature, transmission of P. multocida and S. aureus via suckling calves is considered very likely. Transmission of pathogens from the dam to the foster cow with the suckling calf as a vector could not be detected.

Abstract

To date, there have been few studies on the health effects of foster cow systems, including the transmission of mastitis-associated pathogens during suckling. The present study aimed to compare the pathogens detected in the mammary glands of the foster cow with those in the oral cavities of the associated foster calves and to evaluate the resulting consequences for udder health, calf health and internal biosecurity. Quarter milk sampling of 99 foster cows from an organic dairy farm was conducted twice during the foster period. Oral cavity swabs were taken from 345 foster calves. Furthermore, quarter milk samples were collected from 124 biological dams to investigate possible transmission to the foster cows via the suckling calves. All samples were microbiologically examined and confirmed by MALDI-TOF (matrix-assisted laser desorption time-of-flight mass-spectrometry). Using RAPD-PCR (randomly amplified polymorphic DNA polymerase chain reaction), strain similarities were detected for Pasteurella multocida, Staphylococcus aureus, S. sciuri and Streptococcus (Sc.) suis. Transmission of P. multocida and S. aureus probably occurred during suckling. For S. sciuri and Sc. suis, environmental origins were assumed. Transmission from dam to foster cow with the suckling calf as vector could not be clearly demonstrated.

Oxytocin and cortisol release during suckling, hand-milking and machine milking in camels

This research paper addresses the hypothesis that oxytocin (OT) could be released during suckling and during milking with and without the presence of a calf and that this release could be regulated by maternal behaviour. Plasma concentration patterns of OT and cortisol (CORT) were measured in six Tunisian dromedary camels during 2 suckling episodes, 2 manual milking episodes with calves beside the mother and 2 machine milking episodes without calves present. Various patterns of OT release were observed between each camel including specific two peak release patterns. Higher plasma OT concentrations were found during the suckling and hand-milking episodes with simultaneous suckling of calves, than during the machine milking episodes without calves. Exclusive mechanical milking episodes also evoked significant mean OT release, although greatly reduced compared to suckling and hand milking. The low basal levels and classical CORT release patterns suggested non-stressful management practices were used and there were very limited differences in udder stimulation between managements. The OT release induced by exclusive suckling and suckling together with hand-milking gives a reference point for what a good milk ejection stimulation is in camels. The important and specific reduction of OT release during machine milking without the calf present could be a physiological consequence of the maternal behaviour (selectivity for the own young) and to a lesser extent explained by a lower stimulation by machine milking.

Increased viscosity of milk during infant feeding improves swallow safety through modifying sucking in an animal model

Infants experiencing frequent aspiration, the entry of milk into the airway, are often prescribed thickened fluids to improve swallow safety. However, research on the outcomes of thickened milk on infant feeding have been limited to documenting rates of aspiration and the rheologic properties of milk following thickening. As a result, we have little insight into the physiologic and behavioral mechanisms driving differences in performance during feeding on high viscosity milk. Understanding the physiologic and behavioral mechanisms driving variation in performance at different viscosities is especially critical, because the structures involved in feeding respond differently to sensory stimulation. We used infant pigs, a validated animal model for infant feeding, to test how the tongue, soft palate, and hyoid respond to changes in viscosity during sucking and swallowing, in addition to measuring swallow safety and bolus size. We found that the tongue exhibited substantive changes in its movements associated with thickened fluids during sucking and swallowing, but that pharyngeal transit time as well as hyoid and soft palate movements during swallowing were unaffected. This work demonstrates the integrated nature of infant feeding and that behaviors associated with sucking are more sensitive to sensorimotor feedback associated with changes in milk viscosity than those associated with the pharyngeal swallow, likely due to its reflexive nature.

Investigating cow-calf contact in a cow-driven system: performance of cow and calf

In this research communication we describe the performance of dairy cow-calf pairs in two cow-driven CCC-systems differing in cows' access to the calves through computer-controlled access gates (smart gates, SG). We investigated cows' machine milk yield in the automatic milking system (AMS), calf growth, and intake of supplemental milk and concentrate. Two groups each with four cow-calf pairs were housed in a system with a cow area, a calf creep and a meeting area. SG's controlled cow traffic between the meeting area and the cow area where cows could obtain feed, cubicles and the AMS. Calves had ad libitum access to supplemental milk and concentrate. During the suckling phase of 31 d, cow access to the meeting area was free 24 h/d (group 1) or restricted (group 2) based on milking permission. Following the suckling phase, cow access was gradually decreased over 9 d (separation phase). During the suckling phase, cows' machine milk yield (mean ± sd) in the AMS was 11.4 ± 6.38 kg/d. In the separation phase, the yield increased to 25.0 ± 10.37 kg/d. Calf average daily gain (ADG) was high during the suckling phase: 1.2 ± 0.74 kg. During the separation phase, ADG decreased to 0.4 ± 0.72 kg which may be related to a low intake of supplemental milk. Calves' concentrate intake increased with age, and all calves consumed >1 kg/d after separation. We conclude that cows nurse the calf in a cow-directed CCC system well resulting in high ADG, and AMS milk yields were, at least, partially maintained during the suckling phase. Although the AMS yields increased in response to separation, calf ADG was decreased. A low sample size limits interpretation beyond description but provides a basis for hypotheses regarding future research into CCC-systems.

Investigating cow-calf contact in cow-driven systems: behaviour of the dairy cow and calf

Research is needed on how technology can facilitate cow-calf contact (CCC). This research communication describes the behaviour of dairy cow-calf pairs in two cow-driven CCC-systems differing in cows' access to the calves through computer-controlled access gates (smart gates, SG). Specifically, cow traffic through SG when visiting their calves, allogrooming, suckling and cross-suckling, cows' eating and resting behaviour and finally vocal response to separation were assessed. After 3 d in an individual calving pen, pairs (n = 8) were moved to the CCC compartment with a cow area, a calf creep and a meeting area. During the next 31 d calves could suckle the cows whenever they visited the meeting area (suckling phase). Cows had free (group 1, n = 4 pairs) or restricted access to the calves based on previous activity in the automatic milking system (group 2, n = 4 pairs). SG's controlled cow traffic between the meeting area and the cow area, in which the cows could access resources such as feed, cubicles, and the automatic milking system. Following the suckling phase cow access into the meeting area was gradually decreased over 9 d (separation phase). During the suckling phase, cows paid frequent and short visits to their calves. Pairs spent in total approximately one h/d suckling and allogrooming. However, the duration and frequencies of these events varied among pairs and groups, as did the vocal response to separation. Restricted access - cows performed more (unrewarded) attempts to visit the calves who cross-suckled more. Collectively, free access to the calves may have been more intuitive and welfare friendly. Although a low sample size limits interpretation beyond description and enabling hypothesis formulation for future research, the results indicate that the cow is motivated to visit her calf, albeit through a SG, thus facilitating particular behaviours for which cow-calf pairs are highly motivated.

Neonatal Suckling, Oxytocin, and Early Infant Attachment to the Mother

The neuropeptide oxytocin (OT) promotes maternal care and social affiliation in adults but its importance in infant attachment still remains unknown. True animal models of infant attachment are extremely rare, and the sheep (in complement to non-human primates) is one of the few that provides the opportunity to investigate its neuroendocrinological basis. In the lamb, access to the udder has strong rewarding properties for the establishment of a preferential relationship with the mother. Therefore, the present study explored the possible involvement of OT through its release during close social contacts with the mother. The first experiment revealed that lambs having free access to the udder from birth onward developed, by 12 h of age, a clear preference for their mothers over another maternal ewe. Delaying access to the udder for six, four or even only 2 h starting at birth, by covering the ewe's udder, resulted in the lack of such a preference without affecting general activity. These effects persisted in most cases at 24 h but by 72 h of age a bond with the mother was clearly expressed. Experiment two showed that social interactions with the mother were followed by a release of OT in the plasma when lambs had the possibility to suckle. Non-nutritive interactions were without effects. Preliminary data on two subjects suggested that OT might also increase in the cerebrospinal fluid after suckling. Finally, in the third experiment, oral administration of a non-peptide OT receptor antagonist (L-368-899, Merck) over the first 4 h after birth led to decreased exploration of the mother's body compared to lambs receiving saline, and impaired the expression of a preference for the mother at 24 h. The effects were no longer observed at 48 h. Our findings demonstrate that both delayed access to the mother's udder and OT receptor antagonist alter the onset of mother preference in newborn lambs. This suggests that central OT facilitates the development of filial attachment through its release during suckling.

Effects of Creep Feed Provision on Behavior and Performance of Piglets Around Weaning

Creep feed provision may ease weaning, hence we determined the impact of providing fibrous creep feed before weaning and adding this feed to the post-weaning diet on piglet behavior and performance. Pre-weaning, litters with on average 12 piglets were given creep feed (CF, n = 12 litters) or not (NF, n = 10 litters). Post-weaning, piglets (n = 8 pens with 4 piglets/treatment) were given a weaner diet (CON) or weaner diet supplemented with creep feed (CS). Behaviors were scored in the home pen at d11, 16, 22 and 27 after birth and at wk 1 and 2 post-weaning. Feed intake, growth and fecal consistency were measured up to d14 post-weaning. A blood sample was taken at d2, 15 and 29 after birth and d2, 5 and 14 post-weaning. CF-piglets consumed on average 397 ± 71 g creep feed before weaning. CF-piglets grew faster in the last week before weaning than NF-piglets (249 ± 7 vs. 236 ± 11 g/d, F _{(1, 18)} = 5.81, P = 0.03). However, CF- and NF-piglets did not differ in weaning weight, within-litter coefficient of variation in weaning weight, behaviors in the farrowing and weaner pen, and haptoglobin concentrations. Creep feed supplementation enhanced feed exploration at wk 2 post-weaning (0.29 ± 0.08 vs. 0.11 ± 0.03%, F _{(1, 27)} = 5.27, P = 0.03), but did not affect other post-weaning behaviors. Pre-weaning creep feed provision and post-weaning creep feed supplementation did not affect overall feed intake, growth, feed efficiency and fecal consistency for the first 14 days post-weaning, neither body weight at d14 post-weaning. Nevertheless, CF-piglets had a lower within-pen coefficient of variation in body weight at d14 post-weaning than NF-piglets (13.6 ± 1.9 vs. 15.1 ± 1.5%, F _{(1, 26)} = 6.89, P = 0.01). In conclusion, pre-weaning creep feed provision and post-weaning creep feed supplementation had no clear effects on piglet behavior and performance.

Suckling, Feeding, and Swallowing: Behaviors, Circuits, and Targets for Neurodevelopmental Pathology

All mammals must suckle and swallow at birth, and subsequently chew and swallow solid foods, for optimal growth and health. These initially innate behaviors depend critically upon coordinated development of the mouth, tongue, pharynx, and larynx as well as the cranial nerves that control these structures. Disrupted suckling, feeding, and swallowing from birth onward-perinatal dysphagia-is often associated with several neurodevelopmental disorders that subsequently alter complex behaviors. Apparently, a broad range of neurodevelopmental pathologic mechanisms also target oropharyngeal and cranial nerve differentiation. These aberrant mechanisms, including altered patterning, progenitor specification, and neurite growth, prefigure dysphagia and may then compromise circuits for additional behavioral capacities. Thus, perinatal dysphagia may be an early indicator of disrupted genetic and developmental programs that compromise neural circuits and yield a broad range of behavioral deficits in neurodevelopmental disorders.

Effects of Birth Weight and Postnatal Nutritional Restriction on Skeletal Muscle Development, Myofiber Maturation, and Metabolic Status of Early-Weaned Piglets

Piglets with light weaning weight commonly have a slow post-weaning growth rate due to impaired skeletal muscle development. Therefore, the present study aimed to investigate the impact of birth weight and nutrient intake on skeletal muscle development, myofiber maturation, and metabolic status of early-weaned piglets. Twelve pairs of normal birth weight and intrauterine growth-retarded (IUGR) piglets (seven days old) were randomly assigned to receive adequate nutrient intake or restricted nutrient intake for 21 days. Serum and muscle samples were collected for further analysis. The results indicated that muscle weight, cross-sectional areas, and muscular glycogen were lower (p < 0.05) in both IUGR and restricted fed piglets. Nutrient restriction decreased the contents of RNA, the RNA to DNA ratio, and the percentages of myosin heavy chain (MyHC) IIx (p < 0.05), whereas increased the activity of β-hydroxy-acyl-CoA-dehydrogenase (HAD), the ratio of HAD to citrate synthase, as well as the percentages of MyHC I (p < 0.05). In addition, nutrient restriction significantly decreased muscular glycogen, mRNA levels of fatty acid transport protein 1, cationic amino acid transporter 1, and glucose transporter 4 in IUGR piglets compared with the other groups (p < 0.05). The results of the present study showed that IUGR impaired skeletal muscle growth and disturbed the hormone and mRNA expression of genes related to energy metabolism, which led to a more severe energy deficit when receiving postnatal nutritional restriction. Postnatal nutritional restriction resulted in delayed myofiber maturation of the piglets, which may be associated with the transformation of MyHC isoform and the change of metabolic status.

In polytocous mammals, weakling neonates, but not their stronger littermates, benefit from specialized foraging

Adjusting foraging strategies is a common phenomenon within groups of animals competing for the same resource. In polytocous mammals, neonates concurrently compete for limited milk and alternate between two foraging (suckling) strategies: adaptable exploratory foraging with random sampling of teats, and ordered foraging with a tendency towards exploiting a particular suckling position. Some theoretical (game theory) models have shown that weaker siblings in particular benefit from foraging specialization (suckling order). Neonate piglets establish a well-defined suckling order that develops gradually and fluctuates throughout the lactation period, implying the existence of inter-individual differences in foraging strategies. We therefore analyzed suckling behavior in pigs to determine whether one foraging strategy was more beneficial to neonates in terms of their body weight and foraging environment. We found that intermediate and heavy littermates tended to adjust their suckling strategy according to the foraging environment; however, the selected foraging strategy did not affect their overall growth performance. Lighter individuals that consumed significantly less milk did not greatly alternate their foraging strategy according to the foraging environment, but their growth rate was significantly higher whenever they performed less-exploratory foraging behavior. Although suckling order appeared to be a relatively stable behavioral phenotype, it was beneficial exclusively for weaklings. These results confirm theoretical predictions and indicate that specializing in a suckling position is a beneficial strategy for weaker, light neonates. These findings suggest that physically weaker neonates might have driven the evolution of neonatal foraging specialization.

Developing Gut Microbiota Exerts Colonisation Resistance to Clostridium (syn. Clostridioides) difficile in Piglets

Clostridium (syn. Clostridioides) difficile is considered a pioneer colonizer and may cause gut infection in neonatal piglets. The aim of this study was to explore the microbiota-C. difficile associations in pigs. We used the DNA from the faeces of four sows collected during the periparturient period and from two to three of their piglets (collected weekly until nine weeks of age) for the determination of bacterial community composition (sequencing) and C. difficile concentration (qPCR). Furthermore, C. difficile-negative faeces were enriched in a growth medium, followed by qPCR to verify the presence of this bacterium. Clostridium-sensu-stricto-1 and Lactobacillus spp. predominated the gut microbiota of the sows and their offspring. C. difficile was detected at least once in the faeces of all sows during the entire sampling period, albeit at low concentrations. Suckling piglets harboured C. difficile in high concentrations (up to log₁₀ 9.29 copy number/g faeces), which gradually decreased as the piglets aged. Enrichment revealed the presence of C. difficile in previously C. difficile-negative sow and offspring faeces. In suckling piglets, the C. difficile level was negatively correlated with carbohydrate-fermenting bacteria, and it was positively associated with potential pathogens. Shannon and richness diversity indices were negatively associated with the C. difficile counts in suckling piglets. This study showed that gut microbiota seems to set conditions for colonisation resistance against C. difficile in the offspring. However, this conclusion requires further research to include host-specific factors.

Biostimulation in primiparous postpartum acyclic early weaned beef cows: introducing the bulls at weaning advances cyclic rebreeding

Weaning and biostimulation promote an early cyclic postpartum rebreeding. Although the signals and mechanisms by which weaning and biostimulation differ, both end stimulating LH secretion. The aim of the experiment was to determine if weaning and biostimulation have additive effects advancing the postpartum rebreeding in primiparous postpartum anoestrous cows. The experiment was performed during late spring – early summer with 51 primiparous Hereford cows. Six weeks after parturition calves were weaned, and cows were managed in two experimental groups: WB (n = 22) and WDB (n = 29). Bulls were joined with WB cows at weaning, but joining was delayed one week in WDB cows. The presence of corpora lutea in the ovaries was recorded weekly with ultrasound, and 28 and 50 days after the end of the exposure period, pregnancy was determined by ultrasound. The percentage of cyclic cows was greater in WB than in WDB on Weeks 8 (36.4 vs 0%), 9 68.2 vs 13.8%), 10 (86.4 vs 27.6%) and 11 (100.0 vs 37.9%) (P < 0.001 in all). Cows that were weaned and biostimulated simultaneously rebred earlier than WDB cows (Week 9.1 ± 0.2 vs Week 11.0 ± 0.2; P < 0.0001). At the end of the experiment 46/51 (90.2%) of the animals were cycling. Pregnancy rate tended to be greater in WB than WDB cows 28 days after the end of the breeding period 18/22 vs 17/29, P = 0.077), but there was no difference at the end of the study (20/22 vs 24/29, ns). In conclusion, the application of weaning and biostimulation simultaneously advances postpartum rebreeding more than weaning alone in beef cows.

Carcass characteristics and meat quality of Nellore bulls submitted to different nutritional strategies during cow-calf and stocker phase

There have been few studies realized that evaluate the effects of adopting different nutritional systems in more than one phase of cattle production on carcass and meat characteristics. This study was realized to evaluate carcass and meat characteristics from bulls submitted to different nutritional systems during two production phases. The experiment was conducted at Figueira's farm during two production phases: I (cow-calf) - 80 calves (99.6±2.72 days of age and 109.7±2.99 kg of BW) with their mothers were randomly assigned into two supplemental diets: cow-calf mineral supplement (n=40) or cow-calf creep-feeding (n=40); II (stocker) - the same 80 calves (201.2±2.11 days of age and 190.2±3.37 kg of BW) were redistributed into two production systems: stocker pasture (n=40) or stocker feedlot (SF; n=40). After, all 80 animals were kept on a pasture system (III) for 290 days, and then finished in a feedlot system (IV) for more 33 days. Then, they were slaughtered at an average 764.2±3.06 days of age and at 499.2±3.33 kg of final BW. After slaughter, the average daily gain was calculated, and the carcass and meat characteristics were measured. The statistical model design used was completely randomized in a 2×2 factorial arrangement (two treatment groups on cow-calf phase and two treatment groups on stocker phase). The single effects between the groups in each phase and the interactions between both phases (cow-calf v. stocker) were analyzed. The results were compared by Fisher's test, using the R statistical software. A cow-calf by stocker phases interaction occurred for carcass conformation and fiber diameter. For single effects, the greatest influences observed were in the stocker phase. The feedlot group was slaughtered 17 days earlier, with greater final BW (3.8%), hot carcass weight (5.7%), average daily gain (6.9%), dressing percentage (1.8%), carcass length (1.8%), carcass width (1.5%), longissimus muscle area (4.8%) and muscle depth (2.3%) than pasture group. The SF group also had influence on fat color; showing higher L* and lower b* values. These results reveal that bulls reared in feedlot at the stocker phase have higher muscle development and that the stocker phase has the greatest potential to influence carcass characteristics and meat quality.

Production, Absorption, and Blood Flow Dynamics of Short-Chain Fatty Acids Produced by Fermentation in Piglet Hindgut during the Suckling⁻Weaning Period

Luminal short-chain fatty acids (SCFA) are rapidly absorbed from the intestine and subsequently utilized by the host as substrate for metabolic energy production. In pigs, the energy contribution of SCFA is thought to be 30⁻76%. However, since absorption and blood flow dynamics of SCFA in pigs, particularly during the suckling⁻weaning period, remain unclear, we aimed to elucidate these phenomena. Thirty-two piglets were used in the present work. Cecal vein blood and digesta, and portal and abdominal vein blood were sampled from suckling (7-, 14-, 21- and 28-day-old) and weaned (weaning at 21 and 28 days of age) piglets. Four piglets from each group were euthanized. SCFA concentrations in blood samples were analyzed by a highly sensitive gas chromatography-mass spectrometry technique. Age at weaning tended to affect SCFA absorption. For example, acetate and propionate concentrations in the cecal vein tended to be higher in piglets weaned at day 21 than at day 28. SCFA concentrations in the abdominal vein tended to differ from those in other veins. Mucosal gene expression analysis suggested that monocarboxylate transporter 1 and occludin were associated in absorption of SCFA from the lumen into the blood of piglets.

Circadian Rhythms and Clock Genes in Reproduction: Insights From Behavior and the Female Rabbit's Brain

Clock gene oscillations are necessary for a successful pregnancy and parturition, but little is known about their function during lactation, a period demanding from the mother multiple physiological and behavioral adaptations to fulfill the requirements of the offspring. First, we will focus on circadian rhythms and clock genes in reproductive tissues mainly in rodents. Disruption of circadian rhythms or proper rhythmic oscillations of clock genes provoke reproductive problems, as found in clock gene knockout mice. Then, we will focus mainly on the rabbit doe as this mammal nurses the young just once a day with circadian periodicity. This daily event synchronizes the behavior and the activity of specific brain regions critical for reproductive neuroendocrinology and maternal behavior, like the preoptic area. This region shows strong rhythms of the PER1 protein (product of the Per1 clock gene) associated with circadian nursing. Additionally, neuroendocrine cells related to milk production and ejections are also synchronized to daily nursing. A threshold of suckling is necessary to entrain once a day nursing; this process is independent of milk output as even virgin does (behaving maternally following anosmia) can display circadian nursing behavior. A timing motivational mechanism may regulate such behavior as mesolimbic dopaminergic cells are entrained by daily nursing. Finally, we will explore about the clinical importance of circadian rhythms. Indeed, women in chronic shift-work schedules show problems in their menstrual cycles and pregnancies and also have a high risk of preterm delivery, making this an important field of translational research.

Distinctive features of Phox2b-expressing neurons in the rat reticular formation dorsal to the trigeminal motor nucleus

Phox2b encodes a paired-like homeodomain-containing transcription factor essential for development of the autonomic nervous system. Phox2b-expressing (Phox2b⁺) neurons are present in the reticular formation dorsal to the trigeminal motor nucleus (RdV) as well as the nucleus of the solitary tract and parafacial respiratory group. However, the nature of Phox2b⁺ RdV neurons is still unclear. We investigated the physiological and morphological properties of Phox2b⁺ RdV neurons using postnatal day 2-7 transgenic rats expressing yellow fluorescent protein under the control of Phox2b. Almost all of Phox2b⁺ RdV neurons were glutamatergic, whereas Phox2b-negative (Phox2b^-) RdV neurons consisted of a few glutamatergic, many GABAergic, and many glycinergic neurons. The majority (48/56) of Phox2b⁺ neurons showed low-frequency firing (LF), while most of Phox2b^- neurons (35/42) exhibited high-frequency firing (HF) in response to intracellularly injected currents. All, but one, Phox2b⁺ neurons (55/56) did not fire spontaneously, whereas three-fourths of the Phox2b^- neurons (31/42) were spontaneously active. K⁺ channel and persistent Na⁺ current blockers affected the firing of LF and HF neurons. The majority of Phox2b⁺ (35/46) and half of the Phox2b^- neurons (19/40) did not respond to stimulations of the mesencephalic trigeminal nucleus, the trigeminal tract, and the principal sensory trigeminal nucleus. Biocytin labeling revealed that about half of the Phox2b⁺ (5/12) and Phox2b^- RdV neurons (5/10) send their axons to the trigeminal motor nucleus. These results suggest that Phox2b⁺ RdV neurons have distinct neurotransmitter phenotypes and firing properties from Phox2b^- RdV neurons and might play important roles in feeding-related functions including suckling and possibly mastication.

A Note on Suckling Behavior and Laterality in Nursing Humpback Whale Calves from Underwater Observations

Simple Summary

Nursing in large baleen whales and specifically the humpback whale is not well documented and difficult to capture in real time. Using underwater video documentation techniques, we collected digital video footage of humpback whale nursing events. From this, we provide an enhanced descriptive account of humpback whale suckling and recorded milk in the water near a nursing mother and calf column for the first time. As part of our investigation into nursing behaviors, we assessed if humpback calves demonstrated any patterns of laterality during nursing events. A pattern of laterality was noted in that all suckling events had a right side bias. Nursing bouts were short and intermittent, which coincides with what is known of larger terrestrial mammals such as the African elephant and other baleen whales. These shorter nursing periods are likely are due to the energetics of baleen whale milk coupled with the calf′s short respiration cycle before it has to return to the surface to breathe. Our study shows that underwater observations in marine mammal science provide valuable insight into real time events not easily accessible from vessel or aerial platforms.

Abstract

We investigated nursing behavior on the Hawaiian breeding grounds for first year humpback whale (Megaptera novaeangliae) calves. We observed and video-documented underwater events with nursing behavior from five different whale groups. The observed nursing events include behaviors where a calf positions itself at a 30–45° angle to the midline of the mother’s body, with its mouth touching her mammary slit (i.e., suckling position). On two occasions, milk in the water column was recorded in close proximity to a mother/calf pair, and on one occasion, milk was recorded 2.5 min after suckling observed. Nursing events, where the calf was located in the suckling position, were found to be short in duration with a mean of 30.6 s (range 15.0–55.0, standard deviation (SD) = 16.9). All observations of the calf in the suckling position (n = 5, 100%) were with the calf located on the right side of the mother, suggesting a potential for right side laterality preference in the context of nursing behavior. Our study provides insight into mother/calf behaviors from a unique underwater vantage. Results supplement previous accounts of humpback whale nursing in Hawaiian waters, validate mother/calf positioning, document milk in the water column, and introduce the potential for laterality in nursing behavior for humpback whale calves.

A novel fecal stable isotope approach to determine the timing of age-related feeding transitions in wild infant chimpanzees

OBJECTIVES

Determining nutritional development in wild primates is difficult through observations because confirming dietary intake is challenging. Physiological measures are needed to determine the relative contributions of maternal milk and other foods at different ages, and time of weaning. We used fecal stable carbon and nitrogen isotopes (δ¹³ C, δ¹⁵ N) and fecal nitrogen concentrations (%N) from wild chimpanzees at Ngogo, Uganda, to derive physiological dietary indicators during the transition from total reliance on maternal milk to adult foods after weaning.

MATERIALS AND METHODS

We analyzed 560 fecal samples collected non-invasively from 48 infants, their mothers, and 6 juvenile siblings. Most infant and juvenile samples (90%) were matched to samples collected from mothers on the same day. Isotopic assessments were compared with observations of nursing and feeding.

RESULTS

Infants ≤1 year old showed average δ¹⁵ N, δ¹³ C and %N ratios that were 2.0‰, 0.8‰ and 1.3% greater than their mothers, respectively, interpreted as trophic level effects. Although data collected on newborns were few, results suggest that solid foods were consumed within 2-5 months after birth. Trophic level differences decreased steadily after 1 year, which indicates a decreasing relative contribution of milk to the diet. Isotopic results indicated infants were weaned by 4.5 years old-more than a year earlier than observations of nipple contacts ceased, which revealed the occurrence of "comfort nursing." Juvenile isotopic signatures indicate no nursing overlap between siblings.

DISCUSSION

Our results resemble the stable isotope differences of human babies. This study contributes to a model of chimpanzee nutritional development required to understand early life history patterns in hominins.

Dairy goat kids fed liquid diets in substitution of goat milk and slaughtered at different ages: an economic viability analysis using Monte Carlo techniques

The aim of this study was to analyze the economic viability of producing dairy goat kids fed liquid diets in alternative of goat milk and slaughtered at two different ages. Forty-eight male newborn Saanen and Alpine kids were selected and allocated to four groups using a completely randomized factorial design: goat milk (GM), cow milk (CM), commercial milk replacer (CMR) and fermented cow colostrum (FC). Each group was then divided into two groups: slaughter at 60 and 90 days of age. The animals received Tifton hay and concentrate ad libitum. The values of total costs of liquid and solid feed plus labor, income and average gross margin were calculated. The data were then analyzed using the Monte Carlo techniques with the @Risk 5.5 software, with 1000 iterations of the variables being studied through the model. The kids fed GM and CMR generated negative profitability values when slaughtered at 60 days (US$ -16.4 and US$ -2.17, respectively) and also at 90 days (US$ -30.8 and US$ -0.18, respectively). The risk analysis showed that there is a 98% probability that profitability would be negative when GM is used. In this regard, CM and FC presented low risk when the kids were slaughtered at 60 days (8.5% and 21.2%, respectively) and an even lower risk when animals were slaughtered at 90 days (5.2% and 3.8%, respectively). The kids fed CM and slaughtered at 90 days presented the highest average gross income (US$ 67.88) and also average gross margin (US$ 18.43/animal). For the 60-day rearing regime to be economically viable, the CMR cost should not exceed 11.47% of the animal-selling price. This implies that the replacer cannot cost more than US$ 0.39 and 0.43/kg for the 60- and 90-day feeding regimes, respectively. The sensitivity analysis showed that the variables with the greatest impact on the final model's results were animal selling price, liquid diet cost, final weight at slaughter and labor. In conclusion, the production of male dairy goat kids can be economically viable when the kids diet consists mainly of either cow milk or fermented colostrum, especially when kids are slaughtered at 90 days of age.

Behavioral comparisons of male and female pups of prairie voles (Microtus ochrogaster) and meadow voles (M. pennsylvanicus)

Sexual dimorphism in mammals typically is reduced in monogamous species relative to polygynous species, with promiscuous species being intermediate. This pattern of dimorphism characterizes adult behavior and body mass of prairie voles, a monogamous species, when compared with meadow voles, a closely related polygynous or promiscuous species. We examined whether the pattern also applies to young of the two species by observing individual pups living in family groups in seminatural environments. Observations during the second week of life revealed no sex differences in pup behavior or body mass. However, we detected species differences in suckling behavior, jockeying for position within the huddle (especially among males), and body mass that replicate and extend our previous observations. These data indicate that patterns of sexual dimorphism associated with different mating systems may not be evident in juvenile mammals, but that species differences in behavior and body mass can be obvious at this stage.

Suckling and salsolinol attenuate responsiveness of the hypothalamic-pituitary-adrenal axis to stress: focus on catecholamines, corticotrophin-releasing hormone, adrenocorticotrophic hormone, cortisol and prolactin secretion in lactating sheep

In mammals, the responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis to stress is reduced during lactation and this mainly results from suckling by the offspring. The suckling stimulus causes a release of the hypothalamic 1-metyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (salsolinol) (a derivative of dopamine), one of the prolactin-releasing factors. To investigate the involvement of salsolinol in the mechanism suppressing stress-induced HPA axis activity, we conducted a series of experiments on lactating sheep, in which they were treated with two kinds of isolation stress (isolation from the flock with lamb present or absent), combined with suckling and/or i.c.v infusion of salsolinol and 1-methyl-3,4-dihydro-isoqinoline (1-MeDIQ; an antagonistic analogue of salsolinol). Additionally, a push-pull perfusion of the infundibular nucleus/median eminence (IN/ME) and blood sample collection with 10-min intervals were performed during the experiments. Concentrations of perfusate corticotrophin-releasing hormone (CRH) and catecholamines (noradrenaline, dopamine and salsolinol), as well as concentrations of plasma adenocorticotrophic hormone (ACTH), cortisol and prolactin, were assayed. A significant increase in perfusate noradrenaline, plasma ACTH and cortisol occurred in response to both kinds of isolation stress. Suckling and salsolinol reduced the stress-induced increase in plasma ACTH and cortisol concentrations. Salsolinol also significantly reduced the stress-induced noradrenaline and dopamine release within the IN/ME. Treatment with 1-MeDIQ under the stress conditions significantly diminished the salsolinol concentration and increased CRH and cortisol concentrations. Stress and salsolinol did not increase the plasma prolactin concentration, in contrast to the suckling stimulus. In conclusion, salsolinol released in nursing sheep may have a suppressing effect on stress-induced HPA axis activity and peripheral prolactin does not appear to participate in its action.

Suckling and non-nutritive sucking habit: what should we know?

Correct breast feeding can be considered a tool for the post-natal prophylaxis of craniofacial abnormalities, or at least a way of reducing their extent.

Inadequate bottle feeding forces the tongue and cheek muscles to develop a compensating and atypical function, in order to obtain the milk. As a result, there can be an adaptation change of the dental and bone structures, leading to malocclusions.

Finger-sucking is normal in the first two-three years of life. It gives the child a feeling of relaxation; that is why it is usually practiced before sleeping. The effects of non-nutritive sucking on the developing dentition are minor in the child under 3 years of age and are usually limited to changes in the incisor position. Some upper or lower incisors (depend on how the finger has been sucked) become spontaneously tipped toward the lips, and/or others are prevented from erupting. Normally children abandon this habit between 2 and 4 years of age. If it persists after this age, it will be the cause for some dental-maxillary anomalies: open-bite, narrow maxilla with upper protrusion, cross-bite; all these could be accompanied by retrognathic mandible.

Acetaldehyde involvement in ethanol's postabsortive effects during early ontogeny

Clinical and biomedical studies sustains the notion that early ontogeny is a vulnerable window to the impact of alcohol. Experiences with the drug during these stages increase latter disposition to prefer, use or abuse ethanol. This period of enhanced sensitivity to ethanol is accompanied by a high rate of activity in the central catalase system, which metabolizes ethanol in the brain. Acetaldehyde (ACD), the first oxidation product of ethanol, has been found to share many neurobehavioral effects with the drug. Cumulative evidence supports this notion in models employing adults. Nevertheless very few studies have been conducted to analyze the role of ACD in ethanol postabsorptive effects, in newborns or infant rats. In this work we review recent experimental literature that syndicates ACD as a mediator agent of reinforcing aspects of ethanol, during early ontogenetic stages. We also show a meta-analytical correlational approach that proposes how differences in the activity of brain catalase across ontogeny, could be modulating patterns of ethanol consumption.

Paralemniscal TIP39 is induced in rat dams and may participate in maternal functions

The paralemniscal area, situated between the pontine reticular formation and the lateral lemniscus in the pontomesencephalic tegmentum contains some tuberoinfundibular peptide of 39 residues (TIP39)-expressing neurons. In the present study, we measured a 4 times increase in the level of TIP39 mRNA in the paralemniscal area of lactating mothers as opposed to nulliparous females and mothers deprived of pups using real-time RT-PCR. In situ hybridization histochemistry and immunolabeling demonstrated that the induction of TIP39 in mothers takes place within the medial paralemniscal nucleus, a cytoarchitectonically distinct part of the paralemniscal area, and that the increase in TIP39 mRNA levels translates into elevated peptide levels in dams. The paralemniscal area has been implicated in maternal control as well as in pain perception. To establish the function of induced TIP39, we investigated the activation of TIP39 neurons in response to pup exposure as maternal, and formalin injection as noxious stimulus. Both stimuli elicited c-fos expression in the paralemniscal area. Subsequent double labeling demonstrated that 95% of neurons expressing Fos in response to pup exposure also contained TIP39 immunoreactivity and 91% of TIP39 neurons showed c-fos activation by pup exposure. In contrast, formalin-induced Fos does not co-localize with TIP39. Instead, most formalin-activated neurons are situated medial to the TIP39 cell group. Our data indicate that paralemniscal neurons may be involved in the processing of maternal and nociceptive information. However, two different groups of paralemniscal neurons participate in the two functions. In particular, TIP39 neurons may participate in the control of maternal functions.

Nursing stimulation is more than tactile sensation: It is a multisensory experience

Novel sensory experiences, particularly those associated with epochal developmental events like nursing alter cortical representation, affecting memory, perception and behavior. Functional MRI was used here to test whether the sensoricortical map of the ventrum is modified during lactation. Three stimuli were used to drive cortical activation in primiparous rats: natural, artificial suckling stimulation and general mechanical rubbing of the skin of the ventrum. These stimuli significantly activated the somatosensory cortex of dams. Of the three stimuli, artificial and pup suckling robustly activated much of the cerebrum, most notably the visual, auditory and olfactory cortices. Surprisingly, activation occurred even in the absence of pups, with artificial suckling. This finding suggests that incoming information from a single modality was sufficient to drive activity of others. Enhanced sensitivity across the cortical mantle during nursing may help the dam to perceive, process, and remember stimuli critical to the care and protection of her young.

Cocaine- and amphetamine-regulated transcript (CART) expression is differentially regulated in the hypothalamic paraventricular nucleus of lactating rats exposed to suckling or cold stimulation

Neural stimuli, such as suckling or cold exposure, increase TRH mRNA in the paraventricular nucleus (PVN) of the rat hypothalamus, yet only suckling induces prolactin secretion. As TRH co-localizes with cocaine- and amphetamine-regulated transcript (CART) in hypophysiotropic neurons of the PVN, and CART inhibits TRH-induced prolactin release but not TRH-induced TSH release in adenohypophyseal cell cultures, we raised the possibility that differential regulation of CART gene expression in the PVN may explain the differences in prolactin secretion following each of the two stimuli. Primiparous female rats were mated and handled daily during the pre- and postpartum periods. After delivery, the litter was adjusted to 8 pups and at mid-lactation, dams were separated from their pups for 8 h and exposed to either 1 h of cold or 30 min of suckling. Long-term effects of suckling were studied by separating pups from their mothers for 24 h, followed by a 12 h period of continuous suckling. Serum TSH levels increased in response to cold exposure, while prolactin levels were increased by suckling and diminished by cold exposure. CART mRNA levels increased in rostral and mid parts of the medial parvocellular PVN following cold exposure but not after suckling stimulation. These data demonstrate a differential regulation of CART gene expression in hypophysiotropic neurons in response to stimuli that increase TRH mRNA levels, and suggest that CART activation in the PVN may contribute to the decrease in PRL release when the thyroid axis is activated by cold exposure.

Role of the midbrain periaqueductal gray in maternal nurturance and aggression: c-fos and electrolytic lesion studies in lactating rats

the upright, crouched, or kyphotic, nursing posture of lactating rats is dependent on suckling stimulation from pups. Because of the neuroanatomical connections of the periaqueductal gray (PAG) and its sensorimotor integration of the analogous lordosis posture displayed by sexually receptive female rats, the possible role of the PAG in kyphosis was investigated using c-fos immunocytochemistry and electrolytic lesions. Lactating rats interacting with and nursing a litter of suckling pups showed greater Fos-immunoreactive nuclei in the lateral and ventrolateral caudal PAG (cPAGl,vl) compared with dams receiving nonsuckling somatosensory, distal, or no stimulation from pups. In contrast, this pattern was not evident in the rostral PAG, where the highest Fos levels occurred in nonsuckled dams, or in five other brainstem sites with either no group differences (peripenduncular, dorsal raphe, and pontine nuclei) or negligible Fos (ventral tegmental area, spinal trigeminal nuclei). After bilateral electrolytic lesions of the cPAGl,vl during gestation or on day 7 postpartum, active maternal behaviors, such as retrieval and licking of pups, and total nursing time were essentially normal. Kyphotic nursing, however, was reduced by 85%, nursing in prone and supine postures increased substantially, and 24 hr litter weight gains were reduced, particularly early in lactation (by 26%). Furthermore, lesioned rats attacked a strange male twice as often as controls did, which is suggestive of reduced fearfulness. These results extend the known roles of the PAG in reproductive and defensive behaviors to the postural control of suckling-induced kyphotic nursing and the modulation of maternal aggression.