Effect of roughage level in a total mixed ration on feed intake, ruminal fermentation patterns and chewing activity of early-weaned calves with ad libitum access to grass hay

The Effect of Feeding a Total Mixed Ration with an ad libitum or Restricted Pelleted Starter on Growth Performance, Rumination Behavior, Blood Metabolites, and Rumen Fermentation in Weaning Holstein Dairy Calves

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.

The age at first consumption of forage in calves and its effect on growth and rumination in the short- and long-term

BACKGROUND

Previous investigations into the effect of dietary forage on calf performance have been inconsistent, and there is a paucity of information exploring the effect of age on the growth performance and rumination of calves. Eighty-four female Holstein calves (41.5 ± 4.2 kg) were enrolled at birth, a subset of the calves were fed calf starter only (CON, n = 21) while the rest (n = 63) were classified into three treatment groups: the early (EHAY, n = 26, 5.1 ± 0.8 d), the middle (MHAY, n = 21, 7.9 ± 0.8 d) and the late (LHAY, n = 16, 12.1 ± 1.4 d) hay consumers. The short-term effect of the age at first forage consumption (AFF) on calves' feed intake was monitored until d 84. In addition, the long-term effects of AFF on body weight, structural growth and rumination behavior were recorded until d 196. Rumen samples were collected on d 1, 7, 35, 84 and 196 to analyze the rumen fermentation, while fecal samples were collected from d 78 to 84 to estimate digestibility parameters.

RESULTS

Treatment had no effect on feed intake. While, the EHAY calves tended to have lower BW and ADG compared to LHAY and CON calves. Several total-tract apparent digestibility parameters and digestible nutrients intake were significantly lower in EHAY calves compared with CON and LHAY calves. Calves in the EHAY group tended to begin ruminating ealier, while CON calves were the latest (12.3 vs. 15.5 days of age). A treatment and time interaction was present for rumination time due to greater rumination in calves consuming hay compared to CON calves in week 10 to 12, the differences in rumination disappeared afterwards, no long-lasting significant differences in the rumination and rumen fermentation parameters were found between treatments.

CONCLUSIONS

In conclusion, this study showed that hay consumption earlier in life (in the first week, around 5 days of life) could negatively affect the growth of the calf in the short and long term. Compared to consuming hay from the second week (around 12 days of life) or feeding concentrate only without hay, starting to consume hay from the first week could compromise nutrient digestibility and digestible nutrient intake independent of developing rumination behaviour and rumen fermentation.

Growth Rates, Carcass Traits, Meat Yield, and Fatty Acid Composition in Growing Lambs under Different Feeding Regimes

A total of 75 male Awassi (mean BW 23.5 ± 2.0 kg; 3 months old) were used in an 84-day trial to investigate the effects of different feeding regimes on productive performance, carcass characteristics, and meat quality, and the fatty acid profile of growing lambs. Animals were randomly allocated into 3 groups of 25 lambs each. The dietary treatments were as follows: (1) whole barley grain (60%) plus alfalfa hay (40%; GB-AH; the basal diet); (2) a concentrate pelleted diet plus alfalfa hay (CP-AH); and (3) a complete pelleted diet (CPD). Feed intake was measured weekly, and all lambs were weighed every two weeks for an evaluation of the productive parameters. Blood samples were collected from all lambs for the measurement of biochemical and enzymatic variables. At the end of the experiment, 13 lambs from each treatment were slaughtered to evaluate the carcass characteristics, meat quality, and fatty acid composition. The final body weight, body weight gain, average daily gain, and feed efficiency of lambs were lowest (p < 0.05) in lambs on the grain and alfalfa diet compared with the other groups. Feeding lambs either the CP-AH or CPD diets resulted (p < 0.05) in increases in slaughter weight, carcass weights (hot and cold), the percentage of liver and shoulder, carcass length, back fat thickness, and the area of longissimus thoracis muscle compared with those lambs on the GB-AF diet. The proportion of saturated fatty acids in meat was greater (p = 0.04) in lambs fed on the GA-AH diet than in those of lambs fed on the pelleted diets. Lambs on the CP-AH diet had (p < 0.05) the highest ratios of PUFA to SFA and omega 6 to omega 3, and the proportion of omega 6. The atherogenic and thrombogenic indexes were lower (p < 0.05) in the CP-AH group compared with the GB-AH group. In conclusion, the results indicate that feeding growing lambs on concentrate pellets instead of whole barley grain improves the growth rate, traits, meat quality, and fatty acid profile, which have important implications for productivity, efficiency, and profitability in the livestock industry.

Effects of Feeding Different Levels of Sprouted Barley on Fermentation Characteristics, Bacterial Quantification, and Rumen Morphology of Growing Lambs

The objective of the present study was to investigate the effects of sprouted barley inclusion level on the growth performance, digestibility, volatile fatty acids, bacterial quantification, and rumen morphology of growing lambs. Five dietary treatments with sprouted barley (0, 25, 50, 75 and 100%) and nine replicates per dietary treatment were performed on forty-five Awassi lambs (90 days old). The average weight gain, intake, and digestibility of dry and organic matter were recorded. The pH, color, volatile fatty acids, bacterial quantification, and rumen histomorphometry were also determined. The results showed that the average dry and organic matter intake in T2 to T4 and the average weight gain in T4 decreased linearly. In contrast, the digestibility of dry and organic matter by sprouted barley (T2 to T4) was higher. The pH values and rumen color were not affected. Concentrations of formic acid, acetic acid, butyric acid, and the ratio of acetic acid to propionic acid were increased, while lactic acid and total volatile fatty acids were lower in all levels of sprouted barley. In addition, lambs fed T4 had a higher quantification of Anaerovibrio Lipolytica, Butyrivibrio Fibrisolvens, and Streptococcus Bovis quantification. Selenomonas Ruminantium was higher in T1, T2, and T4, whereas Megashpaera Elsdenii was lower in T1 to T3. The rumen histomorphometric was improved by sprouted barley (T2 and T3). Sprouted barley improved digestibility and rumen histomorphometry and increased the concentration of some volatile fatty acids and rumen bacteria but resulted in a decrease in average dry and organic matter intake, which negatively affected weight gain in lambs fed 100 % sprouted barley. Further studies are required to determine the potential effects on growing lambs fed sprouted barley.

Effect of the Length of Oat Hay on Growth Performance, Health Status, Behavior Parameters and Rumen Fermentation of Holstein Female Calves

The aim of this study was to evaluate the effect of the length of oat hay on the performance, health, behavior, and rumen fermentation of dairy calves. For this purpose, two hundred and ten healthy two-day-old Holstein dairy calves were randomly allocated into three groups: basic diet (calf starter) without hay (CON), or a basic diet with oat hay at either long (OL: 10-12 cm) or short (OS: 3-5 cm) length cut. The basic diet was fed from day 4, while the hay was offered from day 14. All calves were weaned at day 56 and remained in their individual hutches till the end of the trial (day 70). Calf starter intake and fecal scores were recorded daily. Bodyweight, body size, and rumen fluid samples were collected biweekly before weaning and weekly after weaning. Overall, providing oat hay (OS and OL) in the diet increased the body weight, starter intake, and average daily gain compared to the CON group. Similarly, feeding oat hay improved rumen fermentation. More specifically, hay enhanced the rumen pH and changed the rumen fermentation type. Hay fed calves spent more time on rumination but less time performing abnormal behaviors compared to control. As it can be concluded, feeding oat hay to calves enhances the growth performance, rumen fermentation, and normal calf behaviors, implying improved animal welfare irrespective of the hay length.

Effects of Sunflower Hulls on Productive Performance, Digestibility Indices and Rumen Morphology of Growing Awassi Lambs Fed with Total Mixed Rations

Forty-eight growing Awassi lambs were used in a 70-day trial to investigate the effects of different levels of dietary sunflower hulls (SFH) on growth, rumen morphology, fiber digestibility and meat characteristics of lambs. Animals were randomly allocated to 4 groups with 3 replicates of 4 lambs each. The diet was composed of total mixed ration (TMR) without SFH (control group), and the TMR diet supplemented with SFH at a level of 5% (SFH5), 10% (SFH10) and 15% (SFH15). Lambs in the treatment groups had greater BW changes (p = 0.04) and ADG (p = 0.04) than the lambs in the control group. Intake of dry matter, acid detergent fiber (ADF) and neutral detergent fiber (NDF) were also significantly (p < 0.05) higher in SFH15 compared to SFH10. Digestibility of ADL and empty stomach weight were also significantly (p < 0.05) higher in SFH10 and SFH15, respectively. Cooking loss, blood total cholesterol and total protein decreased significantly (p < 0.05) in SFH15. Ruminal lightness (L) and yellowness (b) also increased significantly (p < 0.05) in SFH15. We concluded that the TMR diet supplemented with up to 15% SFH improved weight gain, digestibility, meat cooking loss and rumen color in Awassi lambs.

Increasing grass hay inclusion level on weaned dairy calf growth, intake, digestibility, and ruminal fermentation

The objective was to determine effects of increasing grass hay (GH) inclusion level on weaned dairy calf growth, intake, digestibility, and ruminal fermentation. Holstein calves (n = 45) were randomly assigned to 1 of 3 total mixed rations with increasing GH [10, 17.5, or 25% on a dry matter (DM) basis; LGH, MGH, or HGH, respectively]. Calves were weaned at 6 wk of age, housed individually, and studied from 7 to 16 wk of age. Rations, consisting of texturized calf starter (20% crude protein) and coarsely chopped GH, were offered ad libitum as separate components from 7 to 9 wk of age. After 9 wk, feed was offered as a total mixed ration containing the assigned level of GH and fed according to the clean bunk feeding strategy as a means of limiting refusals. Initial 9-wk body weight was 81.6 ± 9 kg (mean ± standard deviation). Intake and growth were measured weekly. Blood samples were collected at 9, 10, 12, 14, and 16 wk of age for analysis of plasma glucose and β-hydroxybutyrate. Total fecal collection (12 calves; 4 per treatment) was conducted at 11 and 15 wk of age for 4 d consecutively. Rumen samples were collected over the final 24 h of each fecal collection period to evaluate pH and volatile fatty acid profile. Feeds and feces were evaluated for DM, neutral detergent fiber, acid detergent fiber, and starch to estimate total-tract digestibility. Intake and weight gain were analyzed from 7 to 9 wk and 9 to 16 wk, representing pretreatment and treatment periods. No differences were observed between treatments from 7 to 9 wk. However, differences were found from 9 to 16 wk. Final body weight, average daily gain, DM intake, and metabolizable energy intake all decreased with increased GH. However, skeletal frame measurements did not vary between treatments. Plasma β-hydroxybutyrate tended to decrease with increased GH. No differences were observed in DM or starch digestibility, but neutral detergent fiber and acid detergent fiber digestibility increased with increased GH. Mean rumen pH and total volatile fatty acid did not change with increasing GH inclusion; however, there was an interaction with time indicating that ruminal fermentation patterns throughout the day were different for calves offered MGH and HGH versus those offered LGH. These results indicate that feeding levels of GH >10% reduce growth and intake before 16 wk and alter ruminal fermentation patterns.

Effect of oat hay provision method on growth performance, rumen fermentation and blood metabolites of dairy calves during preweaning and postweaning periods

The comparison of the effects of all forage offering methods would be particularly useful information in modeling growth performance and rumen fermentation of dairy calves. Therefore, this study attempted to evaluate the effects of methods of oat hay provision on growth performance, rumen fermentation and biochemical blood indices of dairy calves during preweaning and postweaning periods. At birth, 40 female Polish Holstein-Friesian calves (3 days of age; 39.6 ± 0.39 kg BW) were randomly assigned to four treatment groups differing in the access to chopped oat hay: CON (control, starter without oat hay), OH (starter feed containing 10% DM basis oat hay), OH-FC (starter feed containing 10% DM basis oat hay and oat hay fed as free-choice provision in different buckets) and FC (starter feed and oat hay fed as free-choice provision in different buckets). The calves were weaned on day 56, and then the study continued until day 84. Intakes of starter feed and oat hay were recorded daily, whereas BW and hip height (HH) on day 3 and then every 14 days. Samples of blood were collected on the initiation of experiment and then every 14 days, and rumen contents on day 28, 56 and 84. No treatment effects were found for starter, starch, CP, total DM intake, average daily gain, feeding efficiency, change in HH, ruminal fluid pH, concentrations of ruminal propionate and NH3-N, concentrations of urea nitrogen and non-esterified fatty acids in the blood. There were differences between treatments in terms of ruminal total volatile fatty acids and molar concentrations of acetate, butyrate and acetate to propionate ratio; highest in OH and OH-FC groups, especially during the postweaning period. On the other hand, lower concentrations of iso-valerate were found in OH and OH-FC groups on day 56 and 84. The concentrations of IGF-I throughout the experiment and β-hydroxybutyrate during the postweaning period in the blood were influenced by treatment, with the greatest values observed in OH and OH-FC calves. Results of this study indicate that starter feed containing chopped oat hay improves rumen fermentation parameters, which might allow successful transition from preruminant to mature ruminant state. Also, providing chopped oat hay with pelleted starter feed seems to be a better method than free-choice supplementation.

Review: How Forage Feeding Early in Life Influences the Growth Rate, Ruminal Environment, and the Establishment of Feeding Behavior in Pre-Weaned Calves

Simple Summary

Under natural grazing systems, calves are likely to consume forage in early life. However, forage inclusion in the diet of pre-weaned calves has long been a controversial issue due to it possibly being associated with negative calf performance. Recent published literature seems to confound previous research. This review aims to understand the factors that may influence forage inclusion in the ration of pre-weaned calves. We have explored research related to the effect of feeding forage on rumen and behavioral development to better understand whether forage should be fed to the young calf. Based on the findings, it is concluded that a small amount of good quality forage is recommended for calves to improve their behavioral expression and rumen environment, which may further improve calf performance.

Abstract

The provision of forage to pre-weaned calves has been continuously researched and discussed by scientists, though results associated with calf growth and performance have remained inconsistent. Multiple factors, including forage type, intake level, physical form, and feeding method of both solid and liquid feed, can influence the outcomes of forage inclusion on calf performance. In the current review, we summarized published literature in order to get a comprehensive understanding of how early forage inclusion in diets affects calf growth performance, rumen fermentation, microbiota composition, and the development of feeding behavior. A small amount of good quality forage, such as alfalfa hay, supplemented in the diet, is likely to improve calf feed intake and growth rate. Provision of forage early in life may result in greater chewing (eating and ruminating) activity. Moreover, forage supplementation decreases non-nutritive oral and feed sorting behaviors, which can help to maintain rumen fluid pH and increase the number of cellulolytic bacteria in the rumen. This review argues that forage provision early in life has the potential to affect the rumen environment and the development of feeding behavior in dairy calves. Continued research is required to further understand the long-term effects of forage supplementation in pre-weaned calves, because animal-related factors, such as feed selection and sorting, early in life may persist until later in adult life.

Effects of Physical Forms of Total Mixed Rations on Intake, Weaning Age, Growth Performance, and Blood Metabolites of Crossbred Dairy Calves

Simple Summary

Weaning the calf earlier has been found to reduce the milk feeding and labor cost through higher solid feed intake and early rumen development. Forages, when included in calf starter diet, have been found to be beneficial in this regard. This experiment was planned to evaluate the effects of adding 15% oat hay to calf starter and feeding the same as pelleted or un-pelleted total mix ration. Three groups of calves were given four liters of milk daily during the first week and then six liters daily with free access to water and the respective starter diet. The quantity of milk was gradually reduced until the calf started consuming 800 grams of starter for three days. Feed intake, health scores, and shed temperature/humidity were recorded daily. Body weight, body measurements, and blood sample collections were carried out weekly. Feed intake and body measurement gains were similar in all groups. Blood metabolite concentrations and rumen development parameters were also not affected. Average daily weight gain and feed efficiency were numerically higher for calves given pelleted total mix ration followed by unpelleted total mix ration and only concentrate starter feed. On average, calves fed pelleted total mix ration were weaned 5.4 days earlier than those fed only concentrate. No negative effect was observed on any health or growth parameter with addition of oat hay. Expenditure per kg of weight gain was numerically lowest in the pellet fed group, followed by hay mix starter and only starter fed calves. Oat hay may be safely included in calf starter ration as pelleted mixture with economic benefits.

Abstract

This study evaluated the effects of hay-based total mix ration (TMR) in pelleted or unpelleted form on intake, weaning age, performance parameters, blood metabolites, and cost-effectiveness in crossbred dairy calves during the preweaning period under hot climatic conditions. Thirty calves (4 ± 1 days (d) old), were assigned to one of the three dietary treatments in a randomized complete block design. Treatments assigned were: (1) conventional calf starter (CCS); without hay (2) TMR containing 85% calf starter and 15% chopped oat hay (OH) and (3) pelleted TMR (PTMR) containing 85% calf starter and 15% OH. Colostrum-fed calves were offered four liters (L) of whole milk each, during the first week, followed by six L daily. Calves were weaned off milk gradually on the basis of targeted starter intake of 200, 600, and 800 grams, after which they were considered weaned. Environmental temperature, feed intake, and health scores were recorded daily. The calves experienced heat stress with an average temperature-humidity index (THI) of 80.06 ± 3.42. Results revealed that average daily dry matter intake (DMI), average daily gain (ADG), and feed efficiency (FE) were not different (P > 0.05) among the treatments. Changes in body measurements, rumen development parameters, and blood metabolites were also not affected by the treatments (P > 0.05). Average weaning age in PTMR was 5.4 d earlier as compared to CCS. Feed cost per unit gain tended to be lower for PTMR compared with CCS-fed (86%) calves. Feeding pelleted TMR containing 15% OH tended to reduce the weaning age and feed cost per unit gain without affecting growth performance, intake, FE, and health parameters in crossbred calves under heat stress conditions.

Effects of forage type and age at which forage provision is started on growth performance, rumen fermentation, blood metabolites and intestinal enzymes in Holstein calves

The aim of this study was to determine the effects of two forage sources supplemented either from Day 3 or Day 15 of age on growth performance, rumen fermentation, blood metabolites, intestinal enzymes and incidence of diarrhoea in Holstein bull calves. Forty neonatal male Holstein calves (40.6 ± 5.8 kg BW) were randomly assigned to five treatments, with eight replicates each, including calves fed starter feed without any forage provision (Control; CON), and the same starter plus either chopped alfalfa hay started fed from Day 3 (AE) or Day 15 of age (AL) or chopped oat hay fed from Day 3 (OE) or Day 15 of age (OL). The study finished when all calves were weaned at 56 days of age. During the experimental period average daily gain, starter intake and total dry matter intake were similar among calves fed either of five dietary treatments (P > 0.05). Empty rumen weight (proportional to bodyweight) was greater in CON calves than in OL calves (P < 0.05). The AL calves had a lighter small intestine compared with CON, OL and AE calves, but similar to OE. Frequency of diarrhoea was not affected by dietary treatment (P > 0.05). Rumen concentration of total volatile fatty acids and pH were similar among dietary treatments (P > 0.05). Control calves had a lower molar proportion of acetate compared with OL calves, but similar to the other calves (P < 0.05). Forage-fed calves had similar molar proportion of butyrate to CON calves. Acetate to propionate ratio was higher in OL-fed calves than in those fed CON and AE diets (P < 0.05). Rumen concentration of NH3-N tended to be higher (P = 0.059) in CON calves than in forage-fed calves. During experimental period, serum concentrations of globulin, total protein, glucose and total cholesterol were similar among dietary treatments. Calves fed OE had lower serum concentration of albumin than those fed other diets (P < 0.01). Serum concentration of triglycerides (P < 0.05) was greater in calves fed AE followed by those fed AL and then those fed CON, OL and OE. The AL-fed calves had a higher serum lactate dehydrogenase compared with AE and OE fed calves, but similar to calves fed OL and CON. Duodenum amylase concentration was greater (P < 0.05) in AE-fed calves compared with CON-fed calves, but similar to calves fed AL, OL and OE. Calves fed OL had greater (P < 0.05) ileum lipase concentration than those fed OE, but similar to calves fed AL, AE and CON. In conclusion, provision of chopped alfalfa or oat hay to calves either from Day 3 or Day 15 of age resulted in similar starter intake and total dry matter intake and feed efficiency and physical development of the reticulorumen compared with calves fed the CON diet, which justifies the supply of forage to young calves, even at an early age, as forages are generally cheaper than starter concentrates.

Effect of fermented total mixed rations on the growth performance, carcass and meat quality characteristics of Hanwoo steers

This study was conducted to assess the effects of fermented total mixed ration (FTMR) on the growth performance, carcass and meat quality traits of Hanwoo steers. The present study evidenced that the FTMR had a strong effect on dry matter intake, body weight, daily gain, slaughter weight and carcass characteristics compared with control animals. The results showed that the dry matter intake (7.17 ± 0.13 kg), average body weight (615.20 ± 112.82 kg), and daily gain (0.56 ± 0.16 kg) were greater in animals receiving FTMR than in control animals (P < 0.05). The meat quality characteristics indicated that cooking loss and the pH values did not vary between control and FTMR treated animals; however, animals in the treated groups (FTMR) had higher meat quality grades, carcass weight (396.13 ± 18.35), fat thickness (13.25 ± 1.75), marbling score (5.63 ± 0.56), meat color (40.06 ± 1.23), crude fat (18.39 ± 1.32) and sensory characteristics (flavor 5.03 ± 0.17; tenderness 4.42 ± 0.33; juiciness 5.10 ± 0.16). Nevertheless, the shear force values decreased significantly in FTMR-treated animals compared with control group steers. Overall, FTMR may not only improve the growth performance, biochemical metabolites, and fatty and acetic acid profiles of steers, but may also enhance the carcass and meat quality characteristics of Hanwoo steers. Regarding economics, our research findings suggest that FTMR-based feeds may enhance Hanwoo steer meat quality at a low cost.

Early supplementation of starter pellets with alfalfa improves the performance of pre- and postweaning Hu lambs

This study aims to determine the effects of alfalfa supplementation on the pre- and postweaning performance, rumen development, and feed transition in starter diet-fed lambs. Six of 66 male Hu lambs were slaughtered at the age of 10 d to serve as a control. The other 60 lambs were randomly allocated to 2 dietary treatments: milk replacer and starter pellets without (STA) or with free-choice chopped alfalfa (S-ALF). The animals were offered 300 g/d of the concentrate mixture and had free access to alfalfa after weaning at the end of wk 4 (age 38 d). The alfalfa inclusion in the S-ALF group tended to increase the starter intake before weaning, significantly increased the concentrate intake soon after weaning ( < 0.05), and increased the BW ( < 0.01) and ADG ( < 0.10) in pre- and postweaning lambs. The S-ALF group had heavier carcasses ( < 0.05), rumens ( < 0.05), reticula ( < 0.05), omasums ( < 0.10), abomasums ( < 0.05), and visceral organs ( < 0.10) than the STA lambs after weaning. Alfalfa supplementation increased ( < 0.05) the rumen papillae length and the ratio of the duodenal villus height to the crypt depth; it also decreased ( < 0.05) the concentration and molar proportion of propionate in wk 1 and 5. The STA lambs had higher ( < 0.01) blood concentrations of globulin and blood urea nitrogen and lower β-hydroxybutyrate after weaning. The STA group also had a higher incidence of feed plaque. From the above results, we infer that the free-choice addition of chopped alfalfa to starter diets is beneficial to rumen development, relieves weaning stress, and improves the performance of lambs.

Effects of corn straw or mixed forage diet on rumen fermentation parameters of lactating cows using a wireless data logger

The objective of this study was to evaluate the effect of two different forage types on rumen fermentation parameters and profiles using a wireless data logger. Eight lactating cows were randomly assigned to one of two dietary treatments with a low forage diet with corn straw (CS) or a high forage diet with mixed forage (MF) as the forage source, respectively. Dietary physically effective neutral detergent fiber (peNDF) content was 11.3% greater in CS. Dry matter intake and milk fatty acid content decreased upon CS (P < 0.05). Ruminal pH, temperature and oxidation reduction potential (ORP) were monitored for 14 weeks. The CS group had significantly higher pH but lower temperature and ORP compared to MF (P < 0.01). With the CS diet regime, pH at the time before morning feeding, rumination and post-ingestion were significantly higher than those in the MF group (P < 0.05). However, times with the ruminal pH below 6.0 and 5.8 were significantly reduced (P < 0.05), whereas ruminal pH below 5.6 tended to be lower (P = 0.07). The results indicated that rumen fermentation parameters were affected by forage types and dietary peNDF content might be predominant in ruminal pH regulation.

Characteristics of rumen in Naemi lamb: Morphological changes in response to altered feeding regimen

This study sought to chart the ontogenesis of rumen in Naemi lambs through histomorphometeric evaluation subjected to alfalfa hay in total mixed rations (TMR). A total of 40 growing healthy Naemi male lambs (28.85±1.09kg), at weaning (90±3days) was randomly distributed into four groups. One group was fed on TMR (control) only, while others were supplemented with restricted amount of alfalfa hay at the rate of 100g per day (T1), 200g once per two days (T2) and 300g once per three days (T3) in addition to ad libitum TMR. The results indicated that body weight and dry matter intake increased significantly in treated groups. Significantly higher (P<0.05) pH was recorded in all the treated groups after 8h of feeding. Similarly, the brightness (L*), redness (a*) and yellowness ((b*) of rumen was significantly higher (P<0.05) in treated groups. The papillary length, width and surface area of rumen were significantly (P<0.05) high in alfalfa supplemented groups. Iron (Fe) concentration in rumen tissue decreased significantly (P<0.05) in treated groups. We concluded that a dietary plan based on ad libitum TMR with the addition of alfalfa at the rate of aforementioned protocol not only enhanced feed intake and growth rate of the growing Naemi lambs but also improved the structural characteristics of the rumen.

Effects of physical form of starter and forage provision to young calves on blood metabolites, liver composition and intestinal morphology

This study evaluated the effects of physical form of starter feed and forage provision on the performance, blood metabolites, liver composition and intestinal morphology of dairy calves. Individually housed calves (n = 52; body weight = 41.5 ± 2.5 kg) were randomly allocated (n = 13 per treatment) to one of the following four treatments: (i) ground starter feed (GS; mean particle size = 0.72 mm in diameter), (ii) textured starter feed (TS; mean particle size = 3.61 mm in diameter, including steam-flaked corn and barley), (iii) pelleted starter feed (PS; mean particle size = 4.53 mm in diameter) and (iv) ground starter feed with chopped alfalfa hay (GS + AH; mean particle size = 1.02 mm in diameter). The calves fed GS + AH diets had greater (p < 0.01) starter intake, final body weight and average daily gain compared with the other groups, while GS and TS groups both had greater (p < 0.01) starter intake than the PS group. Feed efficiency was found to be better (p < 0.05) in the TS group than in the GS or PS group, but not different from the GS + AH one. Compared with the other groups, the GS + AH group had the highest (p < 0.01), while the PS one had the lowest (p < 0.01) concentrations of blood glucose and triglyceride. The calves fed GS + AH had the highest blood concentrations of total protein, globulin, triiodothyronine (T3), thyroxin (T4), T3 : T4 ratio (p < 0.05) and levels of fat and glycogen in the liver (p < 0.01) compared with the other groups. The highest (p < 0.05) liver glycogen contents were observed in the GS + AH and TS groups. The duodenum, ileum and jejunum in the calves fed GS + AH exhibited a greater muscle layer thickness (p < 0.05) compared with the other groups. Based on the results obtained, the addition of dietary forage to starter diets positively influenced performance, liver composition and intestinal morphology in developing calves.

Invited review: Transitioning from milk to solid feed in dairy heifers

Calves are born with a physically and metabolically underdeveloped rumen and initially rely on milk to meet nutrient demands for maintenance and growth. Initiation of solid feed consumption, acquisition of anaerobic microbes, establishment of rumen fermentation, expansion of rumen in volume, differentiation and growth of papillae, development of absorption and metabolic pathways, maturation of salivary apparatus and development of rumination behavior are all needed as the calf shifts from dependence on milk to solid feed. In nature and some production systems (e.g., most beef calves), young ruminants obtain nutrients from milk and fresh forages. In intensive dairying, calves are typically fed restricted amounts of milk and weaned onto starter feeds. Here we review the empirical work on the role of feeding and management during the transition from milk to solid feed in establishing the rumen ecosystem, rumen fermentation, rumen development, rumination behavior, and growth of dairy calves. In recent years, several studies have illustrated the benefits of feeding more milk and group rearing of dairy calves to take advantage of social facilitation (e.g., housing with peers or dam), and this review also examines the role of solid feed on rumen development and growth of calves fed large quantities of milk and reared under different housing situations. We conclude that the provision of high-starch and low-fiber starter feeds may negatively affect rumen development and that forage supplementation is beneficial for promoting development of the gut and rumination behavior in young calves. It is important to note that both the physical form of starter diets and their nutritional composition affect various aspects of development in calves. Further research is warranted to identify an optimal balance between physically effective fiber and readily degradable carbohydrates in starter diets to support development of a healthy gut and rumen, rumination behavior, and growth in young calves.

Determining optimum age of Holstein dairy calves when adding chopped alfalfa hay to meal starter diets based on measures of growth and performance

The present study was conducted to determine the optimum age of Holstein dairy calves for an effective inclusion of alfalfa hay (AH) in starter feed on performance, apparent digestibility and feeding behavior. A total of 40 Holstein dairy calves (20 female and 20 male) were used in a completely randomized design in which calves were randomly assigned to one of four different dietary treatments including control (CON) calves fed starter feed without any forage and three treatments consisting of the same starter feed plus 15% chopped AH fed when calves were at the 2nd (AH2), 4th (AH4) or 6th (AH6) week of age. Calves were individually housed and bedded with sand that was replaced every other day. Feed and water were available ad libitum throughout the experiment. Calves were fed milk at 10% of birth BW twice daily until d 57. The study concluded when calves were 73 days old. Starter intake was recorded daily and BW was measured weekly. Data were analyzed as a complete randomized design by MIXED procedures of SAS. Results demonstrate that calves receiving AH treatments numerically consumed more starter feed (0.62 v. 0.78, 0.71 and 0.65 kg/day for CON, AH2, AH4 and AH6, respectively) and had greater average daily gain (ADG) compared with CON (0.48 v. 0.57, 0.49 and 0.49 kg/day for CON, AH2, AH4 and AH6), although the significant difference was observed only between AH2 and CON. Among AH treatments, calves in AH2 had better performance than AH6 in several cases including starter intake, ADG. No detectable differences were observed, however, in apparent dry matter, organic matter or CP digestibility among treatments. Ruminal pH and NH3 concentrations, measured on weeks 4, 6, 8 and 10, were lower for calves fed CON compared with other treatments, with ammonia concentrations decreasing over time. Calves in the AH treatments spent more time eating and ruminating compared with CON. Calves fed CON, however, spent more time on laying down compared with other treatments. Overall, results from the present study illustrated that inclusion of alfalfa in starter feed for calves at 2 weeks of age may improve feed intake, ADG and stimulate rumination in young Holstein dairy calves. Results, however, should be viewed with caution as the number of calves per treatment was small and large calf-to-calf variation may have affected the results reported.

Postweaning performance of heifers fed starter with and without hay during the milk-feeding period

This study assessed the carryover effects of providing forage during the milk-feeding period on postweaning feed intake and growth of heifers. At 11 wk of age, heifers previously (3 to 77 d of age) reared on starter (n=8) or starter plus grass hay (n=8) were switched to a single diet consisting of restricted amounts of concentrate [60% of the starter required to support daily body weight (BW) gain of 800 g] with ad libitum access to coarsely chopped orchardgrass hay. Feed intake and growth were measured from 11 to 18 wk of age. Starter dry matter (DM) intake averaged 2.14 ± 0.15 kg/d for both treatments. Forage consumption and total (starter plus hay) DM, neutral detergent fiber, crude protein, and metabolizable energy intakes were greater in heifers previously fed forage compared with those provided no forage. Initial and final BW were similar for the 2 treatments (108.2 ± 9.1 and 149.6 ± 9.3 kg, respectively). Overall average daily gain in heifers previously fed starter alone (0.92 ± 0.05,kg/d) tended to be greater than those previously fed starter plus hay (0.79 ± 0.06,kg/d). Total DM intake (starter plus hay) was lower in heifers previously fed starter alone than those fed starter plus hay (3.55 ± 0.13 vs. 4.08 ± 0.15 kg/d, respectively). Feed efficiency (BW gain/DM intake) after switching to a common diet was greater in calves previously fed starter alone than in those previously fed starter plus hay (0.26 ± 0.01 vs. 0.19 ± 0.01, respectively). However, heifers provided access to hay had a smaller body barrel (an indicator of gut fill) at 15 wk (127.7 ± 1.7 vs. 134.3 ± 2.7 cm) and 17 wk (132.4 ± 1.9 vs. 141.0 ± 2.2 cm) of age and had greater blood β-hydroxybutyrate (0.22 ± 0.04 vs. 0.32 ± 0.04 mmol/L) compared with heifers that did not have access to hay earlier in life. These results indicate that provision of hay early in life promotes forage intake when heifers are switched to a high forage diet. However, greater feed consumption did not translate into live BW gain. Higher feed efficiency after switching to a common diet in heifers previously fed starter alone compared with those fed starter plus hay must be viewed with caution because intestinal content likely varied between treatment groups.

Hay intake improves performance and rumen development of calves fed higher quantities of milk

Research to date has suggested that access to forage before weaning can limit rumen development in calves, but no research has yet addressed the role of forage for calves fed higher quantities of milk. This study compared performance and rumen development of calves provided high volumes (equivalent to approximately 20% of calf birth weight) of milk with and without access to hay. At d 3 of age, individually housed calves were randomly assigned to treatment (either ad libitum access to chopped grass hay or no forage; n=15 calves per treatment, 10 heifers, and 5 bulls). All calves were provided ad libitum access to water and starter throughout the study. All calves were offered 8L of milk/d from a nipple bottle from d 3 to 35, 4 L/d from d 36 to 53, and 2L/d until weaning at d 56. Solid feed intake and growth parameters were monitored from d 3 to 70. At d 70, males from both treatments were slaughtered to measure rumen development parameters. Overall dry matter (DM) intake from solid feed did not differ between treatments before wk 5. However, during wk 6 to 10, calves fed forage consumed more total DM (starter plus hay) than did calves fed no forage. Hip and wither height, heart girth, and body barrel at d 3, 56, and 70 did not differ between treatments. Reticulorumen weight was heavier in calves fed hay versus those fed only starter (12.77±1.29 vs. 7.99±0.69 kg with digesta; 1.89±0.05 vs.1.60±0.09 kg without digesta). Body weight without digesta was similar in calves fed forage or no forage. Mean rumen pH was higher in calves fed hay compared with those fed no forage (5.49±0.08 vs. 5.06±0.04). In conclusion, provision of chopped hay to calves fed high volumes of milk can promote solid feed DM intake and rumen development without affecting BW gain.