Abrupt Weaning Research Articles

PSII-1 Weaning as prenatal stress: preliminary study on indicators of calf resiliency

Abstract Maternal stressors have been reported to alter fetal development in many species. During pregnancy beef cattle are subjected to different potential stressors, such as weaning their current offspring, as part of beef production practices. The objective of this study was to investigate the relationship between weaning method as a prenatal maternal stress and the effect on offspring resiliency. Multiparous cows were weaned of their calves in the fall of 2022 using either abrupt (A), fenceline (F), or nose-flap (N) weaning methods (n = 30 per group). Calves born from these cows the following spring (2023) were followed for birthweights, morbidity, and mortality. Mean estimated fetal age at exposure was 126 d (range 66 to 219 d) using breed averages for gestational length. Cognitive tests were performed at 2 mo of age using an outdoor arena to continuously monitor calves during 2 min of initial isolation, 2 min exposed to a novel object, and 1 min of exposure to a human in the arena. Tests were performed sequentially, and treatments were balanced across days. Prenatal exposure to A was associated with a 74.8 (2.5 to 2,237.3, P < 0.01) and 21.5 (1.2 to 385.7, P = 0.03) times increase in the odds of calves being stillborn or failure to thrive within 24 h of birth compared with F or N, respectively. There was no difference in morbidity or mortality during d 1 to 60. Birthweights were available on one-half of the calves from each group and showed no statistical difference; however, there was a 4.53 kg numerical difference between A and N groups. Behavioral data from a subset of 36 calves (A = 14, F = 11, and N = 11) was assessed for time spent standing, moving, exploring, duration in the open center vs. perimeter of the arena. There was a tendency for A exposed calves to spend more time in the perimeter after being confronted with a novel object compared with N exposed calves (mean difference of percent of total test time in perimeter from isolation to novel object test: A = 24.0 ± 23.9 %, N = -2.9 ± 22.1 %, P = 0.08). Fenceline exposed calves spent more time moving during initial isolation than either abrupt or nose-flap (69.3 ± 14.7 %, 50.6 ± 11.9 %, and 69.9 ± 17.8 % for A, F, N, respectively (P = 0.01 for A vs F and F vs N). These behavioral and physiological indicators support a potential divergence in survivability and coping mechanisms associated with prenatal exposure to different weaning methods. Future research will evaluate different dimensions of cognitive performance as well as increasing sample size.

Growing up side by side: Social attachment between twin lambs and the role of the mother's presence

Twin lambs establish a social attachment soon after birth, which implies that they prefer to interact with each other during the suckling period. However, the role of the mother's presence in maintaining the social attachment between twins has been scarcely studied. The aims of this study were to characterize the dynamics of the distance between twin lambs during lactation until three months after weaning, and to determine the impact of the mother in this regard. The study was performed with 11 East Friesian multiparous ewes, nine Finnish Landrace multiparous ewes, and their twin lambs under grazing conditions. The distances among all lambs of the flock were measured from aerial pictures taken with a drone in three periods: before weaning (on 33, 49, 62 and 78 days of age); before and after a temporary maternal separation (on 79, 81, 82 and 83 days of age) and immediately before and after weaning [ 94, 95, 96, 98 (weaning day), 99, 110, 124, 145 and 186 days of age]. The mothers and their lambs were temporarily separated at 81, 82, and 83 days of age to determine if the distance between siblings differed when the mother was absent. Distances between siblings vs the mean distance from each twin to the other lambs of the flock, and the distance between siblings vs the distance from each twin lamb to its' mother, were compared separately during the aforementioned periods. The sibling lambs were closer to each other than the other lambs of the flock before and after weaning (P < 0.0001, for both). While the distance between siblings increased from 49 to 78 days of age (P = 0.01), the distance from each twin lamb to its' mother did not change. After the temporary maternal separation, the distance between siblings was shorter than the mean distance from each twin to the other lambs of the flock (P < 0.0001). The distance between siblings increased from 33 to 78 days of age (P ≤ 0.03), while the mean distance from each twin to the other lambs of the flock did not change. The distance between siblings and the mean distance from each twin to the other lambs of the flock decreased from 94 to 96–98 days of age (P < 0.0001). From 98–110 days of age, the distance between siblings and the mean distance from each twin to the other lambs of the flock increased (P < 0.0001). In conclusion, twins had a preferential social attachment to each other, that was gradually weakened during their development. The social attachment between siblings was likely because of their mother’s presence, as it gradually disappeared after abrupt weaning.

The Impact of Abrupt and Fenceline-Weaning Methods on Cattle Stress Response, Live Weight Gain, and Behaviour.

The impact of abrupt (AB) and fenceline (FL) weaning methods on cattle stress response, live weight gain, and behaviour were determined across 14 days. Thirty-two cow-calf pairs were fitted with ear tag sensors (to continuously record behaviour) and allocated to two weaning treatments. After separation, FL calves were maintained in a pen adjacent to the FL cow paddock. The AB calves were transported to a pen removing all contact with the cows. After 7 d, FL cows were transported away from all calf pens. Body weights and salivary samples were collected for all animals on experimental days 0, 7, and 14. Fenceline-weaned calves had a greater duration of rest and rumination with reduced high activity across the first 3 days after separation as compared to abruptly weaned calves in line with the greater occurrences of pacing observed for AB calves. Fenceline-separated cows had greater levels of rest across the first 7 days but similar levels of rumination compared to abruptly separated cows. Fenceline-separated cow activity levels tended to be greater and eating levels were similar across the first three days. Body weight (BW) and cortisol concentrations were similar for AB and FL cattle, but FL cows had lower overall weight gain than the abrupt cows likely due to reduced eating time on days four to seven. Together, these results suggest that calves be fenceline-weaned for three days followed by total separation.

How to Wean: A Case Report of Abrupt Weaning and Acute Dystonia

World Health Organization (WHO) recommends exclusive breastfeeding for the first 6 months, followed by continued breastfeeding with complementary foods until 2 years of age or beyond. Despite these recommendations, there is limited research on the timing and methods of breastfeeding cessation, with abrupt weaning potentially causing unforeseen consequences. This report describes a case involving a 33-month-old girl who experienced acute dystonic reaction following the abrupt cessation of breastfeeding. It was learned that medication containing chlorpheniramine was given to the child to alleviate the uneasiness that developed due to abrupt cessation of breastfeeding. Patient’s symptoms were consistent with an acute dystonic reaction due to medication side effects, which improved with successful medical intervention. Breastfeeding initiation, continuation, and cessation influence the mental and physical health of the mother-baby pair. Abrupt weaning can pose challenges. While there are no strict guidelines for weaning, gradual weaning is generally considered a more comfortable approach for both mother and baby. To safeguard the well-being of the mother-baby pair, healthcare professionals should inform mothers about the discontinuation of breastfeeding and support a gradual weaning process. The presented case highlights the importance of careful consideration and professional guidance during the weaning process to prevent adverse outcomes.

Review of yeast culture concerning the interactions between gut microbiota and young ruminant animals.

Microorganisms inhabit the gastrointestinal tract of ruminants and regulate body metabolism by maintaining intestinal health. The state of gastrointestinal health is influenced not only by the macro-level factors of optimal development and the physiological structure integrity but also by the delicate equilibrium between the intestinal flora and immune status at the micro-level. Abrupt weaning in young ruminants causes incomplete development of the intestinal tract resulting in an unstable and unformed microbiota. Abrupt weaning also induced damages to the microecological homeostasis of the intestinal tract, resulting in the intestinal infections and diseases, such as diarrhea. Recently, nutritional and functional yeast culture has been researched to tackle these problems. Herein, we summarized current known interactions between intestinal microorganisms and the body of young ruminants, then we discussed the regulatory effects of using yeast culture as a feed supplement. Yeast culture is a microecological preparation that contains yeast, enriched with yeast metabolites and other nutrient-active components, including β-glucan, mannan, digestive enzymes, amino acids, minerals, vitamins, and some other unknown growth factors. It stimulates the proliferation of intestinal mucosal epithelial cells and the reproduction of intestinal microorganisms by providing special nutrient substrates to support the intestinal function. Additionally, the β-glucan and mannan effectively stimulate intestinal mucosal immunity, promote immune response, activate macrophages, and increase acid phosphatase levels, thereby improving the body's resistance to several disease. The incorporation of yeast culture into young ruminants' diet significantly alleviated the damage caused by weaning stress to the gastrointestinal tract which also acts an effective strategy to promote the balance of intestinal flora, development of intestinal tissue, and establishment of mucosal immune system. Our review provides a theoretical basis for the application of yeast culture in the diet of young ruminants.

Effects of weaning age and pace on blood metabolites, cortisol concentration, and mRNA abundance of inflammation-related genes in gastrointestinal, adipose, and liver tissue of Holstein dairy calves

The objective of this study was to evaluate the effects of weaning age and pace on blood metabolites, cortisol concentration, and mRNA abundance of inflammation-related genes in Holstein dairy calves. A total of 70 1-d-old calves (38.8 ± 4.4 kg BW ± SD), blocked by sex and birth BW, were randomly assigned to a 2 × 2 factorial arrangement of treatments. The first factor was weaning age, which was either early (6 wk) or late (8 wk). The second factor was weaning pace, which was either abrupt (4 steps down over 3 d; the initial milk replacer was 7.6 L, which was reduced by 1.9 L in each step-down) or gradual (7 steps down over 14 d; the initial milk replacer was 7.6 L, which was reduced by 1.09 L in each step-down), generating early-abrupt (EA), early-gradual (EG), late-abrupt (LA), and late-gradual (LG) treatments. All treatments had 10 female and 8 male calves, except EA that had 1 fewer male calf. Milk replacer (24% CP, 17% fat) was bottle fed, up to 1,200 g/d, twice daily (0600 h and 1800 h). The EA and EG treatment calves received 46.2 kg of milk replacer, and the LA and LG treatment calves received 63 kg of milk replacer. The study had 2 cohorts (2020, n = 40; 2021, n = 31), and each cohort included all treatments. Blood was collected from the jugular vein at 0900 h at 3 and 7 d of age, and a day before starting and a day after weaning completion. Male calves were humanely killed a day after weaning. Rumen, jejunum, large intestine, liver, omental adipose and perirenal adipose tissues were sampled to determine the mRNA abundance of inflammation-related genes. Weaning pace, age, pace × age, birth BW, and sex were included as fixed and cohort was included as random effects in the model. Blood metabolites and cortisol were analyzed as repeated measures, and sampling day, pace × sampling day, and age × sampling day were also included as additional fixed effects. Significance was noted at P ≤ 0.05 and tendencies when 0.05 <P ≤ 0.10. The EA calves showed a tendency to have the greatest nonesterified fatty acid (NEFA) concentration compared with all other treatments. We observed a pace × day effect on serum NEFA and BHB; calves weaned at an abrupt pace had an increased level of NEFA after weaning compared with those weaned gradually. Calves weaned at the gradual pace showed the greatest serum BHB after weaning. Most mRNA abundances for inflammation-related genes affected by treatments showed a similar pattern. They were downregulated by the abrupt (liver IL-1β) and early weaning (jejunum TNF-α and ICAM), and in some cases, the interaction intensified the effect, demonstrating a weakened immune response in calves experiencing more stressful conditions (EA: IL-6 in the liver and NF-κB in the perirenal adipose tissue). Overall, the downregulation of the mRNA abundance of inflammation-related genes in EA calves may be attributed to the suppression of the immune system and an immature immune response. Furthermore, the greater NEFA in EA calves could be attributed to a reduced starter intake, less developed rumen, or shorter time during the weaning transition.

Effects of corn grain processing method in starter ration and weaning strategy on performance, nutrient digestion, rumen fermentation, and blood metabolites of Holstein calves

This research explored how corn processing methods and weaning protocols interact and impact calf performance, digestibility, ruminal fermentation, and blood metabolites. Forty-eight 3-day-old Holstein calves (24 females and 24 males; body weight = 38.2 ± 1.56 kg) were allocated to one of the four treatment groups using a 2 × 2 factorial design. The physical form of corn grain [steam-flaked corn (SFC) or ground corn (GC)] and weaning protocol [abrupt weaning (AW) or gradual weaning (GW)] were the experimental factors and resulted in the following treatments: 1) a starter diet containing SFC + AW protocol (SFC/AW), 2) a starter diet containing SFC + GW protocol (SFC/GW), 3) a starter diet containing GC + AW protocol (GC/AW), and 4) a starter diet containing GC + GW protocol (GC/GW). The starter feeds had similar feed ingredients (50.4% corn grain, 35.1% soybean meal, plus 5% chopped wheat straw) and were different only in the physical form of corn grain (SFC vs. GC). In the AW protocol, calves were given 4 L of milk/d from days 3 to 15, then increased to 7 L/d from days 16 to 67. Weaning occurred abruptly from days 68 to 69 by decreasing milk to 3.5 L/day. In the GW protocol, calves received 4 L of milk/day from days 3 to 15, followed by 7 L/day from days 16 to 59. Weaning occurred gradually from days 60 to 69, with this reduction schedule: 6 L/d from days 60–61, 5 L/d from days 62–63, 4 L/d from days 64–65, 3 L/d from days 66–67, 2 L/d on day 68, and 1 L/d on day 69. Total starter intake (d 1 to 90) remained unaffected by the corn grain processing method, but weaning strategy and corn processing method interacted for starter feed intake, as the greatest intake was observed in calves assigned in SFC/GW treatment. Feeding a starter diet containing SFC rather than GC increased DM and NDF digestion. Calves that were fed an SFC-based starter diet grew faster than calves fed a GC-based starter diet. The average daily gain (from d 1 and 90) was greater in calves assigned to GW vs. AW protocol. Calves fed an SFC-based starter feed and assigned to AW protocol converted nutrients toward growth more efficiently throughout the experiment (d 1 to 90). Feeding a GC- vs. SFC-based starter feed resulted in greater rumen ammonia-N concentration. Ruminal pH on day 80 was greater in calves weaned gradually compared to those weaned abruptly. Calves fed GC- vs. SFC-based starter diet had higher blood urea-N and β-hydroxybutyrate concentrations on day 60. Overall, an SFC- vs. GC-based starter feed (containing 5% chopped wheat straw) promoted faster calf growth and improved nutrient utilization. Feeding an SFC-based starter diet in combination with GW protocol resulted in the greatest starter feed intake.

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.

406 Awardee Talk: Extended Effects of Sequential Weaning and Backgrounding Management in Southeastern U.S. Beef Calves on Performance, Health, and Immunological Responses Through the Feedyard

Abstract Understanding post-weaning management strategy impacts on calf performance and health can help producers add value to their operations and further strengthens the viability of the beef supply chain. A series of research and Extension studies were conducted to: 1) validate perceptions and determine motivations for pre- and post-weaning calf management strategies used in Southeast US cow-calf operations and 2) assess the collective effects these practices have on calf health and performance through the feedyard phase. An interactive, online survey (n = 214 responses) was distributed to Alabama beef producers to assess factors influencing the use of pre- and post-weaning management and management systems. Key challenges producers face in their operations who practice managed weaning and backgrounding strategies include input costs, land availability and market predictability. Developing demonstration data models to address cost-benefits of weaning and backgrounding may help producers evaluate areas of challenges identified in this survey. Subsequently, a two-year study was conducted using 427 Angus-crossed steer calves (294.2 kg) from three Auburn University research farms. Calves were assigned to one of three weaning methods for a 14-d experimental period: fenceline, nose-flap, or abrupt weaning. Response variables included initial and final body weight following the 14-d period, vaccination, and acute phase protein response. In both years of the study, fenceline weaned calves had the greatest average daily gain at 1.08 kg/d (P &amp;lt; 0.0001) and abruptly weaned calves had the lowest average daily gain losing 0.15 kg/d during the 14-d observation period. After the weaning study, calves were brought to a centralized farm and began a 60-d backgrounding period where they were assigned to one of three nutritional management strategies in a 3×3 factorial design: cool-season baleage, bermudagrass hay, or grazing mixed warm-season annuals. All diets were supplemented with 1% BW of DDGS. Body weights and blood samples were again collected throughout the backgrounding period. In the backgrounding period, fenceline weaned calves had the greatest average daily gain (P = 0.02) in the first 30 d of the backgrounding period regardless of backgrounding diet type. Calves fed the hay-based diet also had a greater average daily (P &amp;lt; 0.0001) than both the grazing and baleage groups in the first 30d of backgrounding. From d 30 to 60 of backgrounding in each year, steers on grazing and baleage diets supported greater ADG (P &amp;lt; 0.0001) than hay diets during the last 30-d of the backgrounding period (0.74 kg/d and 0.77 kg/d vs. 0.31 kg/d, respectively). Following the backgrounding, steers were transported to a commercial feedyard where they remained for the finishing phase. Effects of backgrounding management on feedyard performance were only observed during the first 35d in the feedyard. Results indicate that weaning and backgrounding management strategies can influence calf performance during the transition period into the feedyard phase.

Stress responses in pigs postweaning: Effect of heavier hybrid and weaning intact litters

Early and abrupt weaning of pigs is a stressful event. In addition, the use of hyperprolific sows with increasing numbers of live born piglets has decreased the average pig’s birth weight, colostrum intake and weaning weight. The aim of this study was to investigate whether behavioural (tail posture, agonistic and abnormal behaviour), clinical (ear and tail lesions) and physiological (saliva cortisol) indicators of stress postweaning can be minimised by 1) using a pig hybrid that is heavier at birth and weaning, and 2) trough specific-stress-free housing where intact litters of pigs stay in the pen of birth after removing the sow at weaning. The study was a 2 × 2 factorial design, with pigs from Topigs Norsvin TN70 (TN) sows as a heavier alternative to the lighter pigs from DanBred LY sows (DB), and the specific-stress-free (SSF) weaning strategy as an alternative to the conventional weaning strategy (CON) where pigs are regrouped and moved to weaner pens. Fiftyseven litters, on average 26 days of age, were included. Behaviour recordings on the day (d) of weaning (d0), showed that the rate of fights and attacks were 23 and 42 times higher in CON compared to SSF, respectively. Furthermore, on d+1 pig in CON had a 9 (in DB) to 13 (in TN) times higher odds of having clinical ear lesions compared to SSF. Only on d+2, saliva cortisol was lower in TN-SSF than TN-CON, but not lower that DB-SSF. A higher rate of high tail posture was seen in CON d+1, which may reflect higher arousal due to mixing and moving. The rate of belly nosing was 5 times higher in the lighter hybrid (DB compared to TN), but increased from d+7 to d+14 in both hybrids. On d+7 the rate of ear directed behaviour tended to be higher in DB than TN, but the rate increased from d+7 to d+14 in TN to a similar rate as in DB. The rate of tail directed behaviour increased from d+7 to d+14 and tended to be higher in CON than SSF. In conclusion, specific-stress-free weaning reduced agonistic behaviour and ear lesions and tended to reduce tail directed behaviour postweaning. Using the heaver hybrid TN reduced belly nosing postweaning. However, since belly nosing and tail directed behaviour increased over time for both hybrids and weaning strategies additional measures are needed to reduce stress associated with early and abrupt weaning.

Homesickness: Its Particular Relevance to Children of Separation and Divorce

ABSTRACT This article addresses the similar effects on the very young child of abrupt weaning after breastfeeding, and overnight parenting access with the father when the mother is the primary caretaker and the child is primarily attached to the mother’s home as their home. The role of the young child’s unconscious fantasies is considered, particularly in perceiving the mother in these situations as rejecting, hostile and persecutory towards the young child, as well as the short-term and long-term effects of these early experiences on child, adolescent and adult development. The conflict existing between the application of sound psychoanalytic child development theory and research and the legal Best Interests of the Child standard is raised for discussion. Finally, how these adverse experiences impact on the creation and use of nostalgia are addressed.

Progressive weaning alters behaviour and biomarkers of stress in weaned lambs subjected to social isolation

The mother-young contact during suckling influences the development of the offspring and their stress-coping abilities. Progressive weaning reduces the stress response in lambs as the separation time increases gradually until permanent maternal deprivation. The aim of this study was to determine if repeated maternal deprivation in suckling lambs alters their behavioural, physiological and immunological responses to social isolation after weaning. Twenty-four Saint Croix single born-lambs remained with their mothers for their first 29 days of age. Thereafter, 12 lambs were temporarily separated from their mothers every day for 4 weeks, during 4 h/d the first week, increasing 4 h weekly until they were separated 16 h/day (progressive weaning group: PW). During the progressive separation, PW lambs were moved to an enclosed pen, where they did not have visual or olfactive communication with their mothers. The other 12 lambs remained in permanent contact with their mothers until the definitive separation of both groups at 61 days old (abrupt weaning group: AW). At day 90 of age, all lambs were individually isolated for 10 min in a novel place, alternating one lamb from each group. Lambs’ behaviour was video recorded during the test. Cortisol concentration and haematological measurements were determined before and after the test. The PW lambs crossed more lines (P = 0.007), attempted to escape more times (P = 0.009), displayed more freezing behaviour (P = 0.01) and tended to vocalise more than AW lambs (P = 0.054). The AW lambs tended to sniff more times (P = 0.09) than the PW lambs. Cortisol concentration and the percentage of monocytes were lower in PW than in AW lambs (P ≤ 0.04). In conclusion, lambs repeatedly deprived of their mother displayed a more intensive behavioural response to social isolation one month after the definitive separation from their mothers. Progressive weaning reduced the cortisol concentration and the percentage of monocytes. These results call attention to the importance of further studies being undertaken in reference to the short and long-term effects of different procedures applied in order to better improve mother and the lamb welfare before artificial weaning.

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.

Plasma metabolomics reveals major changes in carbohydrate, lipid, and protein metabolism of abruptly weaned beef calves

1H NMR-based metabolomics was used to study the effect of abrupt weaning on the blood metabolome of beef calves. Twenty Angus calves (258 ± 5 kg BW; 5 to 6 months old) were randomly assigned to a non-weaned (NW) group that remained grazing with their dam or a weaned (W) group that underwent abrupt separation from their dam to a separate paddock on d 0 of the study. Body weight, behaviour, and blood samples for cortisol and metabolomics were measured at d 0, 1, 2, 7, and 14 of the study. On d 1 and 2, W calves spent less time grazing and ruminating, and more time vocalising and walking, had a greater concentration of cortisol, NEFA, 3-hydroxybutyrate, betaine, creatine, and phenylalanine, and lesser abundance of tyrosine (P < 0.05) compared to NW calves. Compared to NW calves at d 14, W calves had greater (P < 0.01) relative abundance of acetate, glucose, allantoin, creatinine, creatine, creatine phosphate, glutamate, 3-hydroxybutyrate, 3-hydroxyisobutyrate, and seven AA (alanine, glutamate, leucine, lysine, phenylalanine, threonine and valine) but lesser (P < 0.05) relative abundance of low density and very low-density lipids, and unsaturated lipids. Both PCA and OPLS-DA showed no clustering or discrimination between groups at d 0 and increasing divergence to d 14. Blood metabolomics is a useful tool to quantify the acute effects of stress in calves during the first 2 days after abrupt weaning, and longer-term changes in carbohydrate, lipid and protein metabolism due to nutritional changes from cessation of milk intake and greater reliance on forage intake.

190 Assessment of Weaning Management on Growth Performance and Health in Southeastern Beef Calves

Abstract The beef calf weaning period is a time of transition in the cow-calf production cycle and can be one of the most stressful stages in the life of a beef calf. This transition can have a major impact on both calf short- and long-term health, growth performance and economic returns. There are several different weaning management strategies cattle producers can use in this transition period. The objective of this study was to assess the effects of weaning management practices on beef calf performance and health before backgrounding. A two-year study was conducted using 427 steer calves (216 year 1, average BW 297 kg; 213 year 2, average BW 291 kg) from three Auburn University research farms were randomly assigned based on weaning weight to one of three different weaning method groups for a 14-day observation period: fenceline, nose-flap, or abrupt weaning. On day 0, all calves assigned to the abrupt weaning group traveled 3 hours to one central location. Calves in the fenceline and nose-flap groups traveled to the same location on day 14 of study. Calves were weighed on day 0, day 14 and 24 hours following any travel event. Blood samples were also collected to determine haptoglobin concentrations surrounding the travels events and blood titers following vaccinations. In both years of the study, fenceline weaned calves had the greatest average daily gain at 1.08 kg/d (P &amp;lt; 0.0001) and abruptly weaned calves had the least average daily gain, losing 0.15 kg/d during the 14-d observation period. In Year 1, steers had a significantly greater (P &amp;lt; 0.0001) gain across all treatments than calves in Year 2, with Year 1 calves gaining 7.72 kg more during the weaning period than Year 2 calves. Over both years of the study, fenceline weaned calves gained more (P =0.0008) than both nose-flap and abruptly weaned calves. In Year, abruptly weaned calves had greater blood concentrations of haptoglobin (0.084mg/mL; P &amp;lt; 0.0001) than both the fenceline and noseflap weaned calves (0.023mg/mL; 0.020mg/mL). This data demonstrates how weaning management strategies may influence calf growth performance and the transition into the post-weaning period.

144 Assessment of Backgrounding Management on Growth Performance and Health in Southeastern Beef Calves

Abstract The backgrounding period is a post-weaning management strategy to add weight and build the health status in beef calves. This phase is used to prepare beef calves to enter the next phase of the production supply chain. Weaning and backgrounding management methods can be strategies to reduce calf morbidity and mortality in the feedlot. The objective of this study was to assess beef calf growth performance based on weaning management strategy and subsequent backgrounding using commonly used forage-based diets by Alabama beef producers. A two-year study was conducted using 427 steers (n = 216, year 1, average BW 306kg; n = 213, year 2, average BW 294kg). Steer calves from three Auburn University research farms were randomly assigned based on weaning weights to one of three different weaning method groups: fenceline weaning, nose-flap weaning, or abrupt weaning. After the weaning period calves were brought to a centralized farm and began a 60-d backgrounding period where they were randomized according to previous weaning management, farm of origin and body weight to one of three nutritional management strategies in a 3×3 factorial design: cool-season baleage (oats, ryegrass and crimson clover) and 1% BW dried distillers’ grains (DDGS), bermudagrass hay and 1% BW DDGS, or grazing mixed warm-season annuals and 1% BW DDGS. Body weights were collected on d 0, 30 and 60 of the backgrounding phase. In both years, fenceline weaned calves had the greatest average daily gain (year 1, 0.76 kg/d; year 2, 1.03 kg/d; P = 0.0225) in the first 30 days of the backgrounding period regardless of backgrounding diet type. Calves fed the bermudagrass hay-based diet also had a greater average daily (year 1, 0.78 kg/d; year 2, 1.24 kg/d; P &amp;lt; 0.0001) than both the grazing and baleage diet groups in the first 30 days of backgrounding. From d 30 to 60 of backgrounding in each year, calves on the hay-based diet had the least average daily gain (year 1, 0.19 kg/d; year 2, 0.42 kg/d; P &amp;lt; 0.0001). Steers on both the warm-season annual grazing and cool-season baleage diets supported greater average daily gains (P =0.0041) during the last 30 days of the backgrounding period (0.74 kg/d and 0.75 kg/d, respectively). Steers in year 2 had a greater total gain (year 1, 45.55kg; year 2, 51.56 kg; P = 0.0042) than steers in year 1. However, results in both years indicate that weaning and backgrounding management strategies may influence calf performance during the transition period into the post-weaning phase.

Optimal oxygen use in neonatal advanced cardiopulmonary resuscitation-a literature review.

Oxygen (O2) use during neonatal cardiopulmonary resuscitation (CPR) remains a subject of controversy. The inspired O2 concentration during neonatal CPR, that hastens return of spontaneous circulation (ROSC), allows adequate cerebral and myocardial O2 delivery, and enhances survival to discharge, is not known. The optimal FiO2 during CPR should decrease incidence of hypoxia but also avoid hyperoxia, and ultimately lead to improved neurodevelopmental outcomes. Due to infrequent need for extensive resuscitation, and emergent circumstances surrounding neonatal CPR, conducting randomized clinical trials continues to be a challenge. The goal of this study was to review the evolution of oxygen use during neonatal CPR, the evidence from animal and clinical studies on oxygen use during neonatal CPR and after ROSC, the pertinent physiology including myocardial oxygen consumption and cerebral oxygen delivery during CPR, and outcomes following CPR in the DR and in the neonatal intensive care unit. This narrative review is based on recent and historic English literature in PubMed and Google scholar over the past 35 years (January 1, 1985 - May 1, 2021). Several studies in animal models have compared ventilation with different inspired O2 concentrations (mostly 21% and 100%) during chest compressions and after ROSC. These studies reported no difference in short-term outcomes, even with as low as 18% O2. However, in lamb models of cardiac arrest and CPR, 100% O2 during chest compressions is associated with better oxygen delivery to the brain compared to 21% O2. Abrupt weaning to 21% O2 following ROSC followed by titration to achieve preductal SpO2 of 85-95% minimizes systemic hyperoxia and oxidative stress compared to slow weaning from 100% O2 following ROSC. Clinical research is needed to arrive at the best strategy for assessment of oxygenation and choice of FiO2 during neonatal CPR that lead to improved survival and outcomes. In this article, we have reviewed the literature on evidence behind O2 use during neonatal advanced CPR and after ROSC.

Effects of improved early-life conditions on health, welfare, and performance of pigs raised on a conventional farm

Nowadays, most pigs are raised indoors, on intensive farms providing a poor environment. In these conditions, the risk of the occurrence of damaging behaviours is high, with dramatic consequences for animal health and welfare as well as economic losses for farmers. Early-life conditions may predispose individuals to develop damaging behaviours later in life. In contrast, reinforcing affiliative behaviours between piglets before weaning might help to prevent tail-biting episodes. In this field study, we aimed at improving early-life conditions of piglets on a commercial farm by completely suppressing painful procedures and staggering their exposure to weaning stress factors. The alternative early-life management strategy combined housing in free-farrowing pens with temporary crating of the sow, socialisation during the lactation period with whole-life maintenance of the hierarchical groups, and delayed transfer to the postweaning room after sow removal. Control conditions included birth in farrowing crates, tail docking, absence of socialisation during the lactation period, abrupt weaning with immediate transfer to the postweaning room and mixing with non-littermates. We evaluated the health, welfare, and performance of alternatively raised pigs (n = 80) as compared to controls (n = 75). Visits were made throughout the lifespan of individuals to evaluate their growth and health status. Body and tail lesions were scored as proxy measures of aggressiveness and impaired welfare. Blood and bristle samples were periodically collected to evaluate stress, inflammation and immune competence. While the whole-life performance of pigs was similar among groups, the alternative early-life conditions prevented the growth slowdown usually observed after weaning. In addition, alternatively raised pigs displayed more neutrophils, eosinophils and monocytes the day after weaning, as well as higher C-Reactive Protein levels. One week later, their monocytes displayed greater phagocytic capacity. Altogether, these data suggest an enhanced innate immune competence for alternatively raised pigs around weaning. Piglets reared under alternative conditions also exhibited fewer and less severe body lesions than standard pigs, one week after weaning. In contrast, they showed more tail lesions on days 36 and 66 associated with greater levels of acute phase proteins (C-Reactive Protein and haptoglobin). To conclude, alternative early-life management better prepared piglets for weaning. However, the whole-life maintenance of early-established social groups was not sufficient to prevent the occurrence of damaging behaviours in undocked pigs.

Does Parity Influence the Magnitude of the Stress Response of Nellore Cows at Weaning?

Most studies investigate the impact of stress at weaning on calves; however, little is known about the responses of cows, and whether they would differ according to parity. This study aims to investigate whether parity would influence the weaning stress response in beef cows. Thirty pregnant Nellore cows with their respective calves were randomly allocated to five paddocks and two females from each parity group were placed in the paddocks. There was an interaction (p < 0.05) between parity and evaluation days regarding cortisol, where on d + 7, the higher concentration was observed for multiparous cows. There was an interaction (p < 0.05) between parity and evaluation day for red blood cells (RBC), hematocrit (HCT), and hemoglobin (HB), whereby higher RBC counts on d + 4 were observed for multiparous cows. For HCT and HB, on all post-weaning collection days, higher values were observed for multiparous cows. The day of evaluation had an (p < 0.05) effect on all recorded behaviors, except for rumination (p > 0.05). Nellore cows, regardless of parity, underwent behavioral and physiological changes on abrupt weaning. Physiological parameters indicated that the magnitude of stress was greater in multiparous cows.

Randomized Trial of 21% versus 100% Oxygen during Chest Compressions Followed by Gradual versus Abrupt Oxygen Titration after Return of Spontaneous Circulation in Neonatal Lambs

The combination of perinatal acidemia with postnatal hyperoxia is associated with a higher incidence of hypoxic-ischemic encephalopathy (HIE) in newborn infants. In neonatal cardiac arrest, current International Liaison Committee on Resuscitation (ILCOR) and Neonatal Resuscitation Program (NRP) guidelines recommend increasing inspired O2 to 100% during chest compressions (CC). Following the return of spontaneous circulation (ROSC), gradual weaning from 100% O2 based on pulse oximetry (SpO2) can be associated with hyperoxia and risk for cerebral tissue injury owing to oxidative stress. We hypothesize that compared to gradual weaning from 100% O2 with titration based on preductal SpO2, abrupt or rapid weaning of inspired O2 to 21% after ROSC or use of 21% O2 during CC followed by upward titration of inspired O2 to achieve target SpO2 after ROSC will limit hyperoxia after ROSC. Nineteen lambs were randomized before delivery and asphyxial arrest was induced by umbilical cord occlusion. There was no difference in oxygenation during chest compressions between the three groups. Gradual weaning of inspired O2 from 100% O2 after ROSC resulted in supraphysiological PaO2 and higher cerebral oxygen delivery compared to 21% O2 during CC or 100% O2 during CC followed by abrupt weaning to 21% O2 after ROSC. The use of 21% O2 during CC was associated with very low PaO2 after ROSC and higher brain tissue lactic acid compared to other groups. Our findings support the current recommendations to use 100% O2 during CC and additionally suggest the benefit of abrupt decrease in inspired oxygen to 21% O2 after ROSC. Clinical studies are warranted to investigate optimal oxygen titration after chest compressions and ROSC during neonatal resuscitation.