Search Results (33)

The early-stage feeding of calves significantly impacts their lifelong productive performance. During this period, the calves’ digestive tracts are in a dynamic state of development, making nutritional regulation a key factor in optimizing their growth potential. This research investigated the influence of mannan-rich fraction (MRF) supplementation on pre-weaning calves. Sixty healthy Holstein calves were randomly divided into a control group and three MRF-supplemented groups (seven males and eight females per group) with low (L-MRF, 2.5 g/calf per day), medium (M-MRF, 5 g/calf per day), and high (H-MRF, 10 g/calf per day) doses. Growth performance, serum biochemical indicators, organ indices, intestinal morphology, and short-chain fatty acid (SCFA) concentrations were measured over a 42-day experiment. Compared with the control group, the M-MRF group had 4.9% higher overall body weight, body length, and starter intake, alongside a reduced diarrhea incidence by 4.6%. At day 14, MRF-supplemented groups exhibited significantly lower Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels, along with significantly higher Interleukin-12 (IL-12), growth hormone (GH), and Immunoglobulin G (IgG) levels. By day 42, IL-6 and Interleukin-1β (IL-1β) levels were also significantly decreased. Additionally, the lung and liver indices were higher and villus height was greater in both the jejunum and colon with MRF supplementation. In terms of SCFAs, the acetate level in the jejunum and the butyrate level in the colon were significantly higher in the MRF-supplemented calves. Both acetate in the jejunum and butyrate in the colon showed a significantly positive correlation with growth performance. Taken together, these findings suggest that MRF supplementation (particularly at 5 g/day) supports calf growth, gut health, and immunity, making it a promising nutritional strategy for pre-weaning calves. Full article

A phytobiotic extract (PE; proprietary blend of garlic, anise, cassia, rosemary, and thyme) has been shown to enhance dry matter intake (DMI) and gut health, while ExCell (EX), a probiotic (Lactobacillus acidophilus fermentation product), has been shown to improve gut health and growth performance of growing Holstein calves. The hypothesis was the combination could be synergistic for enhancing post-weaning calf growth performance. Seventy-seven Holstein male calves (73.6 BW ± 7.5 kg SD) at 49 d of age were blocked by body weight (BW) and randomly assigned to four treatments using a randomized complete block design with a 3 wk experimental period. Treatments were: (1) Control (CN): calf starter (CS) without PE or EX; (2) PE: CS with 275.6 g/ton Apex to supply 0.6 g/d; (3) EX: CS with 0.22% EX to supply 5 g/d; and (4) PEEX: CS with PE and EX added at the same rates. Individual calf BW was weighed weekly and they were fed ad libitum a 22% CP CS with amounts fed and orts recorded daily. Body weight was greater (p < 0.05) for calves fed EX (81.3, 80.8, 84.8, and 84.2 kg for CN, PE, EX, and PEEX, respectively) compared with calves fed CN and PE with calves fed PEEX being intermediate and similar (p > 0.10). Average daily gains (ADGs) showed a trend (p < 0.10) for calves fed EX (965.5, 984.3, 1052.8, and 989.1 g/d) compared with calves fed the remaining treatments. Dry matter intake (DMI; 2.19, 2.18, 2.31, and 2.14 kg/d) and feed conversions (0.45, 0.46, 0.45, and 0.45 kg BW gain/kg DMI) were similar (p > 0.10) among calves fed all treatments. Blood urea nitrogen concentrations (14.7, 14.6, 14.9, and 13.4 mg/dL) were similar (p > 0.10) among calves fed all treatments. Feeding a probiotic improved BW gains of post-weaning Holstein male calves, but the PE alone or in combination with EX (i.e., PEEX) was not beneficial for enhancing post-weaning growth performance. These results demonstrated that feeding specific additives alone or in combination was not beneficial to calf growth performance. Full article

This study hypothesized that combining oregano essential oil (OEO) and yeast cultures (YCs) would modulate rumen microbiota to promote gastrointestinal homeostasis and function. Twenty-four newborn, healthy, disease-free, crossbred Simmental male calves (birth weight ≥ 35 kg) were assigned to one of four treatments based on birth data. Treatments were as follows: (1) Control (CON), calves fed calf starter without additives; (2) OEO, calves fed calf starter containing 60 mg/kg body weight (BW) of OEO per day; (3) YCs, calves fed calf starter containing 45 mg/kg BW of YC per day; and (4) MIX, calves fed calf starter with OEO (60 mg/kg, BW) and YC (45 mg/kg, BW) combination. The experimental period lasted 70 days. Rumen fluid was collected on the final day, and 16S rRNA sequencing was performed to assess alterations in rumen microbiota. Calves fed MIX exhibited significantly greater microbial richness, species diversity, and lineage diversity (p < 0.05) compared with calves in the other groups. MIX-fed calves also showed changes (p < 0.05) in the relative abundance of certain rumen species, identified as through LEfSe analysis (LDA > 4, p < 0.05). These biomarkers included f_Rikenellaceae, g_Rikenellaceae_RC9_gut_group, g_Erysipelotrichaceae_UCG-002, c_Saccharimonadia, o_Saccharimonadales, f_Saccharimonadaceae, and g_Candidatus_Saccharimonas. Pathways enriched (p < 0.05) in MIX-fed calves involved nucleotide metabolism, lipid metabolism, glycan biosynthesis and metabolism, amino acid metabolism, terpenoids and polyketides metabolism, antimicrobial drug resistance, xenobiotic biodegradation and metabolism, antineoplastic drug resistance, and excretory system pathways. In conclusion, this study demonstrates that the OEO and YC combination enhances rumen microbial community modulation in calves more effectively than OEO or YCs fed individually or with the control diet. Full article

Currently, in dairy farming, there is growing concern for the welfare of calves during the critical period between the separation from their dams and weaning. During weaning, rationed feeding is a practice used to improve feed efficiency and control the calves’ growth, but it could also have negative consequences associated with hunger and feed restriction behavior. One such consequence could be the performance by calves of stereotyped behaviors indicative of poor welfare, such as non-nutritive oral behaviors. We hypothesized that making a Total Mixed Ration (TMR) available to calves, in addition to the standard pelleted starter diet, thanks to its structural and nutritional characteristics, could help to focus the oral behavior of the subjects towards nutritional activities and therefore limit the development of stereotyped behaviors, even when the amount of starter is restricted. To test this hypothesis, 30 female Holstein calves (equipped with an accelerometer based on an ear tag), were randomly assigned to one of three treatments: a control diet (CTR) with an ad libitum calf starter but without TMR; Treatment 1 (TRT1) with both ad libitum calf starter and ad libitum TMR; Treatment 2 (TRT2) with ad libitum TMR and a restricted amount of a calf starter (50% of the intake starter of the control group day by day). All animals were kept in individual cages equipped with a slow-flow teat bucket apparatus for milk feeding and with access to separated buckets (one for drinking water, one for the starter, and one for the TMR) placed on the outside of the front gate of each cage. Sucking behavior, as well as resting, ruminating and activity behavior, was recorded individually from 7 days of life to weaning (63 d of age) by an automated monitoring system based on ear-tag accelerometers (SCR eSense, Allflex, Irving, TX, USA). The results showed that in the CTR group, there was a greater sucking activity compared to the TRT1 group (26.25 min/head/day vs. 16.83 min/head/day, p = 0.0181), while the TRT2 group showed intermediate values (20.41 min/head/day). We hypothesized that this increased sucking activity may be explained by the oral activity directed at sucking the Milk Bar tube observed only in CTR calves after complete consumption of available milk and could indicate a higher stress level than in the TRT1 group. The time spent resting was significantly lower for the CTR group compared to the TRT1 group (9.20 h/day vs. 11.15 h/day, p = 0.0049) while the TRT2 group was in an intermediate situation (10.65 h/day). Furthermore, the increase in time dedicated to rest observed in TRT1, in light of the good vitality of the calves shown by the daily patterns of resting behavior and daily activity, also seems to suggest an improvement in welfare conditions compared to calves receiving pelleted starter alone. Based on these results, we can deduce that providing TMR ad libitum in the diet of weaning calves could be an effective strategy to improve calf welfare due to the reduction in stereotyped oral activity. However, further studies are needed to establish threshold values useful for distinguishing physiological from pathological resting times in weaning calves raised in individual cages. Full article

Oxidative stress may affect new born calves due to high stress suffered around birth. We hypothesized that maternal supplementation with micronutrients and vitamins in late gestation enhance the neonatal calf’s antioxidant system, decreasing the occurrence and duration of diarrhea, and improving growth from birth through weaning. To test this hypothesis, 80 multiparous cows were cluster-assigned to treatment groups. Treated group (TG) cows received mineral and vitamin supplementation while control group (CG) cows received saline solution. Feed intake and fecal score were measured daily until the ninth week. Weight and body measurements were registered weekly, and blood samples were collected from postpartum cows and calves after birth and at 7, 14, and 63 days of life. Although CG calves had greater fecal scores (p = 0.01), diarrhea characteristics did not differ. Calves in the TG showed greater starter intake (p = 0.04). Feed efficiency showed a trend with treatment-age interaction (p = 0.06). Calves in the CG had wider hips in the first week (p = 0.03), but not by the ninth week. Total antioxidant status, thiobarbituric acid reactive substances, and haptoglobin did not differ between treatment groups. Serum metabolites showed no differences. Supplementation did not impact calf antioxidant system or growth in the first two months. Full article

We compared the effects of milk-feeding in 288 Holstein calves (72 per group) which were fed twice (2F) or thrice (3F) daily, with or without the addition of hydrogenated fat-embedded calcium gluconate (G) supplemented in the starter food and in the daily diet up to the age of 9 months, on the calves’ metabolism, growth, health, and reproductive efficiency up to first pregnancy. The calves received 6 L of milk replacer (130 g/L) and had ad libitum access to water and textured calf starter with or without gluconate. Gluconate supplementation promoted a “catch-up” in growth in supplemented calves compared to their counterparts that did not receive gluconate. Gluconate appeared to reduce animal metabolic stress during key events, such as weaning and transfer into open-door pens, reducing fructosamine (352.61 vs. 303.06 in 3FG and 3F, respectively; p = 0.028) and urea (3F revealed the highest values compared with the other three groups: 19.06 for 3F vs. 13.9 (2F), 13.7 (2FG), and 14.3 (3FG), respectively, p = 0.002) from weaning onwards. The feeding of dairy calves with milk replacer three rather than two times per day tended to be associated with better health from weaning to 4 months old; parameters such as ultrasound lung score and calf health score improved over time (p < 0.001). Thrice-daily feeding with milk replacer tended to reduce the number of artificial inseminations per pregnancy in heifers by 0.2 points (p = 0.092). We confirmed significant correlations between early health and growth parameters and reproductive efficiency and a positive correlation between body weight and average daily weight gain and the thickness of the back fat layer in young heifers (r = 0.245; p < 0.0001; r = 0.214; p < 0.0001 respectively). Our study was conducted on a commercial farm with reasonably effective animal management, so baseline welfare was likely satisfactory. Full article

The aim of the current study was to evaluate the effect of the starter restriction and of the ad libitum TMR (total mixed ration) inclusion on intake, growth performance, rumination time (RT), and health condition of Holstein dairy calves during weaning. We randomly assigned thirty female Holstein calves (with an average weight of 38.5 ± 1.96 kg at birth) to one of three treatments. From 21 days of age, the calves were fed one of three treatments as follows: a control diet (CTR) with an ad libitum calf starter but without TMR; Treatment 1 diet (TRT1) with both an ad libitum calf starter and ad libitum TMR; Treatment 2 diet (TRT2) with ad libitum TMR and a restricted amount of a calf starter (50% of the intake recorder in the control group day by day). Calves in the TRT2 group, between 56 and 63 days of age, had a lower body weight (80.1; 79.5; 75.6 kg for the CTR, TRT1, and TRT2 groups, respectively) compared with CTR and TRT1 calves. This outcome is ascribed to the average daily gain (0.759; 0.913; 0.508 kg/day for the CTR, TRT1, and TRT2 groups, respectively), resulting also in TRT2 being lower than CTR or TRT1 calves. The inclusion of ad libitum TMR increased the rumination time, especially after weaning (15.28 min/h, 18.38 min/h, and 18.95 min/h for the CTR, TRT1, and TRT2 groups, respectively). Concerning the rumen metabolism and inflammometabolic response, overall, no differences were observed between the three dietary treatments. In conclusion, the results indicated that a TMR could partially replace a calf starter in weaning dairy calves, since neither growth performance nor health status were impaired. In addition, providing TMR (with or without concentrate restriction) led to a better rumen development and likely a better rumen fermentation efficiency in post-weaning. Full article

The objective of this study was to assess the potential effects of supplementing difructose anyhdride III (DFAIII) during the first days of life on the absorption of immunoglobulin G (IgG) and growth performance of calves early in life fed colostrum with a high IgG concentration. Sixty-six healthy new-born Holstein calves were randomly assigned to three treatments consisting of no supplementation (control), supplementation of 12 g/d (DFA12), or 36 g/d (DFA36) of DFAIII during the first 7 d of life via colostrum and milk replacer (MR). Calves were separated from dams at birth and bottle-fed colostrum in two meals, each targeting 2.5 L within the first 18 h of birth. Colostrum had been previously collected from other dams (and preserved frozen) within the first 2 h of calving and had a Brix value ≥32%. Daily consumption of starter concentrate and MR (and colostrum on the first day) were individually monitored. Calves were body weighed using an electronic scale at birth and on a weekly basis thereafter until the end of study at 42 d of age. A sample of colostrum fed to each calf and a blood sample from the jugular vein of the calves were collected at 12 and 24 h of life to determine the IgG concentration. The mean colostrum IgG concentration fed in the current study was 110 ± 33.7 g/L (mean ± SD). No differences in animal performance were found among the treatments. Calves on all treatments consumed the same amount of colostrum with a similar concentration of IgG, and thus the amount of IgG consumed was also similar. Serum IgG concentrations were greater at 24 than at 12 h but did not differ among treatments. However, the apparent efficiency of absorption of colostral immunoglobulins was greater in DFA12 and DFA36 at 12 h of life than in control calves, with no differences observed at 24 h. Even when feeding high-quality colostrum, in terms of IgG concentration, supplementation with difructose anhydride III may pose an additional advantage in promoting the passive transfer of immunoglobulins in neonatal Holstein calves during the first 12 h of life. Full article

This study was conducted to investigate the impact of probiotic supplementation using Lactobacillus plantarum DSA 20174 and/or Bacillus toyonensis ATCC 55050 on growth performance, blood parameters, hematological measures, and fecal microbiota in pre-weaning Holstein calves. Thirty-two four-day-old male calves with a similar genetic background, weighing an average of 38.27 ± 0.12 kg, were randomly assigned to four groups. The groups consisted of a control group (CON) without supplementation, a group receiving B. toyonensis (BT) at 3 × 10⁹ cfu/calf/day, a group receiving L. plantarum (LP) at 1 × 10¹⁰ cfu/calf/day, and a group receiving a combination of LP and BT (LP + BT) at half the dosage for each. The study found that calves supplemented with LP and LP + BT experienced significant improvements in average daily gain and final body weight compared to the control group. The LP + BT group showed the most positive effects on TDMI, starter intake, and CP intake. RBC counts tended to be higher in the probiotic groups, with the LP + BT group having the highest values. The LP + BT group also had higher total protein, albumin, globulin, and hematocrit concentrations. All probiotic groups showed higher serum IgG concentrations. Probiotic supplementation led to increased total bacterial count and decreased levels of E. coli, salmonella, and clostridium. The LP + BT group had a significant decrease in coliform count, while both LP and LP + BT groups had increased Lactobacillus populations. In conclusion, LP + BT probiotic supplement showed the most beneficial effects on growth, feed efficiency, blood constituents, and modulation of fecal microbiota composition. Full article

The omasum is the third compartment of the ruminant stomach, which is also considered a water absorption organ and participates in the absorption of volatile fatty acids (VFA), minerals, electrolytes, and fluids. The most important morphological parameter of the omasum is the available absorption area, which depends on the size and number of the omasal laminae, and is variable among different ruminants and based on differences in their daily diets. Optimal omasum development in the transition period to ruminant life can enhance animal performance, so identifying the best diet for this period is crucial for producers. The objective of this study was to determine the effect of two diets based on 8 L of milk replacer with the inclusion of concentrate or forage on the development of the omasum in twenty newborn male Holstein calves divided into two groups. The first group was fed alfalfa hay, and the second was administered a balanced commercial starter feed, both groups ad libitum. After standard dissection of the omasum of both calf groups, the omasal laminae were classified as primary, secondary, and tertiary, and their surface area was calculated. Regarding the number of first-, second-, and third-order laminae, a significant difference was only observed in the number of third-order laminae in favor of the forage-fed group (p = 0.04). The laminar surface area indicated that the area of the primary, secondary, and tertiary sheets, and the total laminar area, were greater in the forage group (p < 0.05). The length of the omasal papillae recorded with the scanning electron microscope showed that the papillae near the ostium reticulo-omasicum tended to be significantly longer in the forage-fed group (p = 0.05). In conclusion, this study demonstrates that significant anatomical differences can be observed between two groups of animals of the same species and rearing stage that were fed with two different diets within a period of less than two months. This highlights the remarkable plasticity and adaptability of the ruminant stomach. Full article

The study aimed to evaluate the effect of maternal or formulated transition milk with colostrum powder on the performance and health of dairy calves. After receiving 12% of their birth weight in high-quality colostrum, 36 Holstein calves (17 males and 19 females) were blocked according to sex, birth date and birth weight (29.16 kg ± 1.34) and randomly distributed into three treatments: (1) Milk: supplying 4 L/d of whole milk (WM) for three days (n = 12); (2) Transition milk (TM): supplying 4 L/d of maternal transition milk for three days (n = 12); (3) Formulated transition milk (FTM): supplying 4 L/d of whole milk enriched with 280 g/d of colostrum powder, for three days (n = 12). Daily feeding was split into two feedings, and after the sixth feeding of the transition diet calves were fed 6 L/d of whole milk and had ad libitum access to water and calf starter until 56 d, when the study ended. Calves fed TM or FTM presented a higher total solids intake (p < 0.05). Concentrations of glucose (p = 0.096) and lactate (p = 0.063), evaluated from 0 h to 72 h, tended to be higher in WM-fed calves compared to TM. There were no effects on calf’s health or performance and weight; at the week 8 averaged 65.06 kg ± 1.85. All treatments resulted in adequate performance and good health, however, the potential benefits of providing TM or FTM were not seen in this study. The transition milk composition and the number of meals after colostrum feeding need more investigation. Full article

This study aimed to investigate the interaction of fatty acid (FA) source [calcium salt of soybean oil (n-6 FA) vs. calcium salt of linseed oil (n-3 FA) both 3% DM basis] with protein content (18% vs. 22% CP, based on DM) on growth performance, blood metabolites, immune function, skeletal growth indices, urinary purine derivatives (PD), and microbial protein synthesis (MPS) in young dairy calves. Forty 3-day-old calves (20 females and 20 males) with a starting body weight (BW) of 40.2 kg were assigned in a completely randomized block design in a 2 × 2 factorial arrangement of treatments. Experimental diets were: (1) n-6 FA with 18% CP (n-6-18CP), (2) n-6 FA with 22% CP (n-6-22CP), (3) n-3 FA with 18% CP (n-3-18CP), and (4) n-3 FA with 22% CP (n-3-22CP). Starter feed intake and average daily gain (ADG) were not influenced by experimental diets (p > 0.05). However, before weaning and the entire period, feed efficiency (FE) was greater in calves fed n-3 FA compared to n-6 FA (p < 0.05). Heart girth (weaning, p < 0.05) and hip height (weaning, p < 0.05 and final, p < 0.01) were highest among experimental treatments in calves who received n-3-22CP diets. The greatest blood glucose (p < 0.05) and insulin (p < 0.01) concentrations in the pre-weaning period and the lowest serum concentration of tumor necrosis factor (before weaning, p < 0.05) were observed in calves fed the n-3-22CP diet. However, the greatest blood urea N (before weaning, p < 0.05; after weaning, p < 0.05) and urinary N excretion (p < 0.05) were found in calves fed n-6-22CP diets compared to other experimental arrangements. In conclusion, offering calves with Ca-salt of n-3 FA along with 22% CP content may be related to improved nitrogen efficiency and immune function. Full article

This study aimed to evaluate the effects of coconut oil and palm oil in milk replacer (MR) on the growth performance, blood lipids, rumen fermentation, rumen microbiota, and fatty acid profile of hepatic and muscle of suckling calves. Thirty-six Holstein male calves were randomly assigned to three treatments. Three milk replacers containing different fat sources were as follows: control group (CON, milk fat), coconut oil group (CCO, coconut oil powder as fat), and palm oil group (PLO, palm oil powder as fat). Calves were weighed and blood sampled at 14, 28, 42, and 56 days old, respectively, and the feed intake and fecal score were recorded daily. Fat sources in milk replacers had no effects on body weight, ADG, DMI, fecal score, or days of abnormal fecal in suckling calves among the three groups, while the PLO group tended to decrease starter intake compared with the other groups. Serum concentrations of TC, HDL-C, LDL-C, and VLDL-C in the CCO group increased compared with those of the CON group. Palm oil also decreased the serum GLU concentration of calves but had no effects on serum lipids compared with milk fat. Coconut oil or palm oil had no effects on rumen fermentation, rumen chyme enzyme activity, rumen bacterial community richness and diversity, and dominant phyla and genera when compared with milk fat. However, compared with the CON group, the CCO group increased the proportion of MCFAs and n-6 PUFAs, and decreased the proportion of UFAs and MUFAs in liver tissue, while the PLO group increased the proportion of PUFAs and decreased the proportion of n-3 PUFAs in liver tissue. In addition, compared with the CON group, the CCO group increased the proportion of MCFAs, and decreased the proportion of UFAs and n-3 PUFAs in longissimus dorsi, while the PLO group increased the proportion of PUFAs and decreased the proportion of n-3 PUFAs in longissimus dorsi. In conclusion, compared with milk fat, coconut oil or palm oil in MR had no effects on growth performance, rumen fermentation, and rumen microflora but significantly increased serum lipids concentration and changed some proportions of MCFAs and PUFAs in liver and longissimus dorsi in suckling calves. These results indicate that coconut oil or palm oil as the sole fat source for MRs has no adverse effect on calf rumen fermentation and rumen microbiota but has a detrimental effect on n-3 PUFAs deposition in the liver and longissimus dorsi muscle. Full article

The objective was to determine the impact of feeding MCE on ruminal and intestinal morphology and microbiota composition of calves. A total of 10 male and 10 female crossbred (dairy × beef) calves (6 d of age) were assigned randomly to control (CTL; n = 10) or MCE-supplemented (TRT; n = 10) groups. The MCE was fed in the milk replacer and top-dressed on the calf starter during pre-weaning (6 to 49 d) and post-weaning (50 to 95 d) periods, respectively. Calves were slaughtered at 95 d to collect rumen and intestinal samples to determine volatile fatty acid (VFA) profile, mucosal morphology, and microbiota composition. The effects of MCE were analyzed by accounting for the sex and breed effects. Feeding MCE increased rumen papillae length (p = 0.010) and intestinal villus height: crypt depth (p < 0.030) compared to CTL but did not affect rumen VFA profile. The TRT had a negligible impact on microbial community composition in both the rumen and the jejunum. In conclusion, feeding MCE from birth through weaning can improve ruminal and small intestinal mucosa development of calves despite the negligible microbiota composition changes observed post-weaning. Full article

This study examined the effects of Sangrovit^®, a Macleaya cordata plant extract (MCE) preparation on feed intake, growth, blood chemistry, and tissue-residue levels of calves. Twenty male and 20 female calves (~5 d of age) were assigned to one of four daily Sangrovit^® doses: 0.0 and 0.0 (CTL), 2.0 and 4.0 (D1), 5.0 and 10.0 (D2), and 10.0 and 20.0 (D3) g/calf in pre-weaning (5 to 49 d of age) and post-weaning (50 to 95 d of age) periods, respectively. Sangrovit^® doses were fed in milk replacer pre-weaning and top-dressed on calf starter post-weaning. Milk replacer and calf starter intake was recorded daily. Body weight, hematology, and serum chemistry were measured at 5, 49, and 95 d of age. Calves were slaughtered at 95 d of age for MCE tissue residue analysis. Compared to CTL, D1 increased milk-replacer intake (4.90 to 5.09 L/day), but decreased calf starter intake pre- (0.65 to 0.53 kg/d) and post-weaning (3.42 to 3.20 kg/d). No Sangrovit^® dose affected average daily gain. The hematology and blood chemistry of all treatment groups fell within the ranges of healthy calves. Results showed no adverse effects of MCE on health and growth performance of calves when fed up to 10.0 g/calf/day pre-weaning and up to 20.0 g/calf/day post-weaning. Full article