Solid Feed Consumption Research Articles

335 Use of Feed Additives Added to the Milk Replacer and Concentrate Or Only to the Concentrate in Unweaned Dairy Beef Calves After Transportation and Its Effects on Performance

Abstract Previous studies have shown that the use of additives to enhance intake and immunity at farm arrival could be a strategy to minimize the negative effects of stress and feed restriction during transportation in unweaned calves. Unweaned dairy beef calves are fed low liquid feeding programs to avoid mechanical diarrheas and to enhance the consumption of solid feed to increase growth. A total of 78 dairy beef calves (57.8 ± 1.64 kg) coming from auction market were used to evaluate the effect of various feed additives [FA; comprising palatability enhancers (PE), standardized olive pomace extract (OE), and tributyrin (TB)] added to the milk replacer (MR) and concentrate or only to the concentrate on performance until 1 week after weaning. Calves were distributed in 6 treatments: calves fed MR and concentrate without FA (CTR-CTR; n = 13); calves fed MR without FA and concentrate with PE (CTR-PE; n = 13); calves fed MR without FA and concentrate with complete mixture OE + TB + PE (CTR-COM; n = 13); calves fed MR and concentrate with PE (PEPE; n = 13); calves fed MR with PE and concentrate with complete mixture OE + TB + PE (PE-COM; n = 13); calves were fed MR with complete mixture OE + TB + PE and concentrate with PE (COM-PE; n = 13). At arrival calves were only fed 2 L of MR twice daily at 12.5% and concentrate feed ad libitum. On day 35 of the study, animals were submitted to a social stress challenge, calves within one treatment were mixed for 24 h, and on day 36, calves returned to their home pens and the afternoon milk was removed. On day 42, all calves were weaned, and they were followed until day 49. Data were analyzed with a mixed-effects model. No differences were observed in concentrate intake the first week after transportation. However, an interaction between treatment and time (P < 0.01) was observed among treatments in concentrate intake from day 35 until day 49 when calves were already weaned. The PE-PE and PE-COM calves had a greater (P < 0.10) concentrate intake from day 28 to day 42 than CTR-CTR or CTR-PE calves, while from day 42 to day 49 the CTR-COM was the group of calves with the greatest concentrate intake. Although no differences were observed on final BW among treatments, the CTR-COM calves had numerically greater ADG than the rest of the treatments. In unweaned dairy beef calves with liquid feeding restriction, the mixture of palatability enhancers, standardized olive pomace extract, and tributyrin potentially increases concentrate intake and growth when added in the concentrate feed.

Milk plane of nutrition and alfalfa hay provision in neonatal Holstein calves: growth performance, ruminal fermentation characteristics, and blood biochemical attributes

Greater nutrient supply through an increased amount of milk and addition of forage to starter may improve the growth rate, rumen development, average daily gain (ADG), and dry matter intake (DMI) of dairy calves. This experiment aimed to study the effect of interaction between milk plane feeding and inclusion of alfalfa hay in starter on the performance, skeletal characteristics, ruminal fermentation and plasma metabolites of dairy calves. Thirty-two 3-d-old Holstein female calves (36.43 ± 2.1 initial BW) were individually housed (n = 8 calves per treatment) and, assigned to 1 of 4 experimental treatment groups in a completely randomized design with a 2 × 2 factorial arrangement. Experimental treatment groups were (1) conventional (COV) milk feeding without forage provision (COV-NF); (2) COV milk feeding with forage provision (COV-F); (3) high milk feeding without forage provision (HM-NF); and (4) high milk feeding with forage provision (HM-F). Calves in the COV and high milk methods received 4 or 8 L/d milk, respectively. Forage-supplemented calves received 15% alfalfa hay mixed with the thoroughly ground starter as a total mixed ration. Calves had ad libitum access to water and starter throughout the study. All calves were weaned at 56 d of age and, the experiment was fulfilled two weeks following the weaning. Individual milk intake and solid feed consumption were recorded daily. The interaction of milk plane nutrition and alfalfa provision was significant for the starter and DM intake, with the greatest starter intake for COV-F treatment and DMI for COV-F and HM-NF treatments during the overall period. The greatest ADG during the pre-weaning and overall period and BW at weaning were observed in HM-NF treatment calves. Calves in the HM-NF treatment had the highest final heart girth; however, other skeletal measurements were not influenced by milk plane feeding and alfalfa provision interaction. No interaction was detected between the milk plane feeding and alfalfa provision for plasma glucose, BUN, BHBA, albumin, total protein, AST and ALT concentrations and rumen fermentation attributes. Regardless of alfalfa provision, pre-weaning starter intake, ADG, feed efficiency (FE), post-weaning starter intake, overall starter intake, FE, weaning BW, body length and hip height, and acetate concentration were increased; whereas, total VFA and valerate concentrations were decreased as milk plane increased. Milk plane feeding and forage inclusion had no effect on diarrhea incidence. It is concluded that independent of alfalfa provision, feeding a higher milk plane improved the performance of dairy calves.

Impact of feeding management strategy on overall weight gain, growth dynamics of selected organs and growth rate and development of the mammary gland in Preweaned heifers

The aim of the study was to analyse the influence of feeding management, favouring a reduction in the intake of liquid feed and an increase in the consumption of solid feed, in preweaning heifers on their growth performance and the growth rate of gastrointestinal organs and mammary gland (MG) and MG structural components mammary parenchyma (PAR) and mammary fat pad (MFP). Eighteen heifers (Polish Holstein-Friesian), after a 6-day adaptation, at age 14 days were randomly assigned to one of three treatment groups (n = 6): I (initial), R (restricted) or AL (ad libitum). The heifers of I group were euthanized immediately and the R and AL calves at 62 days of age, after a feeding treatment period lasting 48 days. The R and AL heifers, had free access to a starter concentrate (SC) and were fed milk replacer (MR) three times daily, according to the following schedules: for the R treatment, the daily ration was calculated according to Nutrient Requirement of Dairy Cattle (NRC, 2001) to maintain an average daily weight gain of 500 g, and the AL group was given unlimited access to MR for 30 min, at each feeding. In the R treatment heifers the daily intake from MR of crude protein (CP) was 129 g and metabolizable energy (ME) 2.9 Mcal were 1.9 times lower and from SC of CP was 90 g and ME 1.56 Mcal were 2.9 times higher compared with those nutrients intake in the AL treatment. The feeding management protocol for the R group, despite the unlimited availability of SC, did not cover the energy demand during the preweaning period in heifers as indicated by the lower concentration of glucose and the higher concentration of non-esterified fatty acids and urea, compared with AL treatment. The R diet slowed body weight gain and reduced the weights of the liver and kidneys at 62 days of age. Also, most critically, the R diet inhibited the growth of MG, PAR and MFP, as well as CP content of MG structural components, compared to the calves fed the AL diet. The proposed alternative feeding management with MR offered 3-times a day with free access for 30 min, enhances the body weight gain and the growth of the MG and its structural components. The results indicate that 1) the proposed alternative feeding management with MR offered 3-times a day with free access for 30 min, enhances the rate of body and MG and its structural components weight gain, and 2) that despite the increasing intake of starter concentrate, milk replacer is the main source of nutrients in preweaning heifers and in terms of body and organ growth gain, compensatory increased starter concentrate intake is insufficient.

Predicting the Feed Intake of Artificially Reared Pre-Weaned Lambs from Faecal and Dietary Chemical Composition

Predicting feed intake in suckling lambs consuming both milk and pasture can be challenging, and thus intake values are often derived from solely milk or solid feed consumption. The present study investigated if dry matter (DM), organic matter (OM), and metabolisable energy (ME) intakes of lambs given a combination of milk and pellets under controlled conditions could be predicted with enough precision using dietary and faecal chemical composition. A total of 34 pre-weaned lambs bottle-fed milk replacer with or without access to pellets and kept in metabolic cages for four days were used. To develop the prediction equations, 54 faecal samples with detailed information on their chemical compositions, and the feed consumed by the lambs, were used. Pellet DMI was predicted from neutral detergent fibre concentration in faeces and pellets, pellets %DM, and live weight (LW) of lambs. Milk DMI was predicted from faecal Nitrogen concentration and LW. Milk and pellet DMI and their ME content were combined to predict DMI/d and ME intake/d. The equations developed were validated against 40 spot faecal samples randomly selected from the lambs. DM, OM, and ME intakes were predicted with high accuracy and precision. The results showed that the developed equations can be used with enough accuracy to predict ME, OM, and DM intakes in pre-weaned lambs ingesting milk and pellets concurrently, thus the results revealed that the established equations may be used to predict ME, OM, and DM intakes in pre-weaned lambs drinking milk and pellets at the same time, allowing feeding regimens for young lambs to be developed.

Impact of supplemental liquid feed pre-weaning and piglet weaning age on feed intake post-weaning

The impact of weaning age and/or supplemental liquid feed in the farrowing pen on pre- and post-weaning feed intake was investigated. The supplemental feed systems consisted of a milk replacer from day 2, changed to a cereal-based liquid feed 12 days after birth. By continuing with the same feed post-weaning, but in dry form, we hypothesised that the feed change would be less abrupt and would increase feed intake post-weaning. The study consisted of 24 sows and their litters in a 2 × 2 factorial design. The design factors were weaning age (WeaningAge) at either 24 days (D24) or 35 days (D35) and with or without access to supplementary liquid milk replacer/feed (+SupFeed/-SupFeed). Individual eating behaviour pre- and post-weaning was observed on video recordings. Results of this study showed that the transition from milk replacer to liquid feed during lactation (on day 12) caused a drop in number of bouts observed per piglet of ingesting supplemental feed (day 11 compared to days 12 and 13) (p < 0.05). Independent of WeaningAge, more bouts of ingesting supplemental feed per piglet were seen the day before weaning in piglets with lower suckling success (p < 0.05). WeaningAge D35 compared to D24 shortened the latency to the first observation of solid feed consumption and drinking water, and litters weaned at D35 had more eating and drinking bouts per piglet the first 12 h post-weaning (p < 0.05). WeaningAge D35 also increased eating bouts the day after weaning (24 to 36 h post-weaning) (p < 0.05), 6 days after weaning (p < 0.05) and the daily amount of feed consumed per pen the first week post-weaning. Access to supplemental feed shortened the latency to the first feed consumption but increased the latency to water consumption within 12 h of weaning (p < 0.05). Access to supplemental feed and the mean frequency of feed intake pre-weaning (days 11-13) did not affect the frequency of feed or water consumption per piglet post-weaning (p > 0.1). Nor did access to supplemental feed affect the daily amount of feed consumed per pen from weaning to 6 days after (p > 0.1). The results of the present study show that later weaning, to a greater extent than supplemental feed pre-weaning, could increase feed intake post-weaning. However, the effect on gut health and diarrhoea needs to be investigated to evaluate whether it is an effective alternative to antibiotics and medical zinc.

Feeding fennel (Foeniculum vulgare) seed as potential appetite stimulant to newborn Holstein dairy calves: Effects on meal pattern, ingestive behavior, oro-sensorial preference, and feed sorting

This trial was performed to investigate the effects of feeding graded levels of fennel seed powder (FSP) on nutrient intake, meal and rumination patterns, chewing and sorting behaviors in newborn Holstein dairy calves. Forty-eight calves (27 males and 21 females; n = 16 per treatment group; 3 d of age; 36.3 ± 1.06 kg of BW; mean ± SE) were assigned randomly to receive incremental levels of FSP at 0.0 (FSP0), 1.5 (FSP1.5) or 3.0 g/d (FSP3) in milk (morning feeding; during the first month of study period) and then in the starter feed (as top-dressed; from d 31 until weaning). Calves were weaned on d 71 and remained in the study until d 81. Starter feed dry matter (DM) intake increased linearly with increasing amount of FSP and increased and tended to increase in FSP3 and FSP1.5 as compared with FSP0, respectively. Growth rate increased linearly with increasing amount of FSP and was greater in FSP supplemented calves than in control calves. Overall body weight but not feed conversion ratio was greater in FSP supplemented calves compared with FSP0. Oro-sensorial preferences were greater in FSP supplemented calves and it was also greater in FSP3 compared with FSP1.5. Sorting index decreased linearly with increasing amount of FSP and decreased in FSP3 compared with FSP0 for particles retained on the 2.36, 1.18, and 0.6 mm sieves and tended to decrease in FSP1.5 compared to FSP0 for particles retained on the 2.36 and 1.18 mm sieves with significant difference for particles retained on the 0.6 mm sieve. Sorting index increased linearly with increasing amount of FSP and increased and tended to increase in FSP3 and FSP1.5 compared with FSP0 for feed materials retained on the bottom pan, respectively. Irrespective of the amount of FSP fed, all calves sorted for particles retained on all studied sieves and against feed materials on the bottom pan. Starter feed DM intake from particles retained on all studied sieves (except for 4.75 mm sieve) and feed materials retained on the bottom pan increased linearly with increasing amount of FSP and increased in FSP supplemented calves compared with control calves. Calves fed FSP initiated to eat their first solid feed in a shorter timeframe after starter feed provision with no changes in first meal duration among treatment groups. Despite of linear increase in eating rate and meal size in FSP supplemented calves, meal and rumination patterns and time devoted to eating, ruminating, resting, drinking, standing, and lying were not affected by treatment; however, non-nutritive oral behaviors were linearly decreased with increasing amount of FSP and decreased and tended to decrease in FSP3 and FSP1.5 compared with FSP0, respectively. In general, feeding FSP shortened time-delay to initiate first solid feed consumption by increasing oro-sensorial preference of the feed, increased feed intake through increases in the rate of eating and thereby the meal size, decreased non-nutritive oral behaviors without affecting chewing behavior, and improved growth performance.

Investigation of weaning strategy and solid feed location for dairy calves individually fed with an automated milk feeding system

The objective of this study was to investigate the effect of 2 gradual weaning programs and 2 locations of solid feed within individual calf pens on feed intake, growth, and behavior of calves fed milk by an automated milk feeder. Using a 2 × 2 factorial design, 60 female calves were randomly assigned to 1 of 2 weaning treatments and 1 of 2 solid feed placement treatments. Calves were assigned to a continuous gradual weaning program (CG) or a multi-step gradual weaning program (MG). Calves assigned to the CG treatment had their milk allocation reduced in small, equal increments from 12.5 L/d on d 43 to 2 L/d on d 56. Calves assigned to the MG treatment were offered 10 L/d on d 43 to 45, 8 L/d on d 46 to 49, 6 L/d on d 50 to 52, and 3 L/d on d 53 to 56. Solid feed was placed either at the front of the pen adjacent (ADJ) to where the automated milk feeder offered milk or at the back of the pen on the opposite (OPP) side from where the milk was offered. All calves were offered 12.5 L/d of milk replacer from d 2 to 42, fresh solid feed (5% chopped wheat straw mixed with 95% calf starter pellet) from d 5 onward, and ad libitum water starting d 0. Calves were weaned from d 43 to 56 and additionally monitored from d 57 to 70. No interactions of effects of weaning and feed location treatment were detected. Both MG and CG calves had similar water and solid feed consumption, blood β-hydroxybutyrate concentrations, and behavior. By design, calves on the CG treatment consumed greater amounts of milk during the weaning phase than MG treatment calves (6.7 vs. 6.3 L/d), which resulted in milk drinking behavior differing between the treatments during the weaning phase. Although average daily gain and body weights were similar between treatments, MG calves had greater middle girth gain during wk 7 compared with CG calves (0.6 vs. 0.3 cm/d). Calves on the ADJ treatment consumed 16.7% more solid feed and 0.55 L/d more milk during the preweaning phase compared with OPP treatment calves. In all 3 phases, ADJ treatment calves consumed more water than OPP treatment calves. The ADJ calves spent more time consuming solid feed during the 10-wk period. The ADJ treatment calves had 10% greater average daily gain compared with OPP treatment calves during the preweaning phase. Overall, the results indicate that both gradual weaning treatments resulted in similar performance and behavior. However, placement of solid feed next to the milk source was demonstrated to increase feed, water, and milk intake during the preweaning stage, contributing to greater growth.

Effects of exchanging lactose for fat in milk replacer on ad libitum feed intake and growth performance in dairy calves

The recent trend in the dairy industry toward ad libitum feeding of young calves merits reconsideration of calf milk replacer (CMR) formulations. Additionally, feed intake regulation in young calves provided with ad libitum milk and solid feeds is insufficiently understood. This study was designed to determine the effect of exchanging lactose for fat in CMR on voluntary feed intake and growth performance. Lactose was exchanged for fat on a weight/weight basis, resulting in different energy contents per kilogram of CMR. Thirty-two male calves (1.7 ± 0.12 d of age, 47.6 ± 0.83 kg of body weight) were assigned to 1 of 16 blocks based on arrival date. Within each block, calves were randomly assigned to 1 of 2 treatments. The experimental period was divided into 4 periods. In period 1, until 14 ± 1.7 d of age, calves were individually housed, restricted-fed their assigned CMR treatments at 2.5 to 3 L twice daily, and provided with unlimited access to water, chopped straw, and starter. In period 2, calves were group-housed with 8 calves per pen and received ad libitum access to their assigned CMR treatments, starter feed, chopped wheat straw, and water. During period 3, from 43 until 63 d of age, calves were weaned by restricting CMR allowance in 2 steps, maintaining access to all other feeds. All calves were completely weaned at d 64 of age and were monitored until 77 d of age (period 4). Measurements included the intake of all dietary components, body weight gain, and a selection of blood traits. Increasing fat content at the expense of lactose decreased CMR intake by 10%, whereas total calculated metabolizable energy intake and growth remained equal between treatments. Total solid feed (starter and straw) consumption was not affected by CMR composition. These data indicate that calves fed ad libitum regulate their CMR intake based on energy content. High-fat CMR increased plasma phosphate, nonesterified fatty acids, triglycerides, and bilirubin, whereas plasma glucose remained unchanged. Despite the limited animal numbers in the present experiment, there was a significant decrease in the total number of health events (mainly respiratory) requiring therapeutic intervention and in the total number of therapeutic interventions in calves fed high-fat CMR. Calves appeared to consume CMR based on energy content, with a difference in ad libitum intake proportional to the difference in energy content of the CMR, maintaining equal body weight gain and solid feed intake.

Effect of weaning age on growth, mammary gland development, and immune function in Holstein Friesian calves fed conserved alfalfa (FiberStart)

This study aimed to evaluate intake, body growth, and the development of the rumen, mammary gland, and immune system in Holstein Friesian calves reared for 100 d on the commercially available feed FiberStart (conserved alfalfa, Medicago sativa; Fiber Fresh Feeds Ltd., Reporoa, New Zealand) and fed calf milk replacer (CMR) for either 56 or 91 d. Eighty calves (40 bulls and 40 heifer calves) were reared indoors in groups (n = 5 of the same sex/pen). All calves were fed 4 L of CMR/d (175 g/L of CMR) in 2 feeds/d for the first 10 d and then 1 feed/d until d 49 or 84. The calves were gradually weaned by d 56 (earlier weaned; n = 8 pens) and d 91 (later weaned; n = 8 pens). All calves were fed FiberStart ad libitum as the only solid feed source from d 1 to 100 of the study. Irrespective of treatment, all calves had similar body weights at d 0 (40.9 ± 3.0 kg) and d 49 (74.2 ± 5.1 kg) of the study. Calf sex had no effect on intake, growth, blood, and immune system parameters. Earlier-weaned calves consumed 18% more solid feed dry matter but had 16% lower body weight gain (28.9 vs. 38.5 kg, respectively) from d 56 to 100 relative to later-weaned calves, resulting in different body weight at 100 d (104 vs. 121 ± 1.3 kg). Although earlier-weaned calves could compensate for the loss of CMR dry matter and crude protein intake from d 56 to 100 by increasing forage intake, they were unable to compensate for the loss of energy from the CMR by increasing solid feed consumption. Plasma β-hydroxybutyrate concentrations were 52% greater in earlier-weaned calves than in later-weaned calves at d 84, indicating greater metabolic activity of the rumen wall. The duration of CMR feeding had no influence on humoral or cell-mediated immune functions of the calves, as evidenced by a lack of effect on antivaccine antibody responses as well as on immune gene expression. Earlier- versus later-weaned heifer calves had 5% lower mammary gland mass, indicating that greater energy supply increased mammary mass. The results of this experiment demonstrate the ability to artificially rear dairy calves on a conserved alfalfa as the only solid feed. Furthermore, earlier weaning off CMR promotes solid feed intake and an associated increase in blood β-hydroxybutyrate, an indicator of rumen development, but increasing the duration of CMR feeding improves growth and mammary gland mass by d 100. The implications of these findings on lifetime growth, health, and milk production in dairy heifers warrant further investigation.

Space allowance influences individually housed Holstein male calves' age at feed consumption, standing behaviors, and measures of immune resilience before and after step-down weaning

Many dairy calves in the southwestern regions of the United States are raised in wooden hutches with 1.23 m2 of free space that house 3 calves individually. Producers claim that calves in hutch systems are not ready to wean and be placed in groups at the country-average age of 6 wk. Calves may remain in this individual housing system until as late as 10 wk of age. The objective of this study was to modify space allowance of hutches and evaluate weaning readiness using age at solid feed consumption, standing behaviors, and measures of immunity. Calves were randomly assigned at 4 d of age to conventional (CONV; 1.23 m2 of space; n = 18), moderate (MOD; 1.85 m2 of space; n = 17), or maximized (MAX; 3.71 m2 of space; n = 19) space allowance in hutches. These modifications also changed the number of calves housed per hutch from 3 (CONV) to 2 (MOD) and 1 (MAX). Calves were fed milk replacer via bottle twice daily until weaning and offered ad libitum feed throughout the experiment. Step-down weaning was initiated (Wi) at age 53 or 54 d by withdrawal of the p.m. bottle and was completed (Wc) 11 d later by removal of the a.m. milk replacer. Accelerometer data for standing behaviors were collected relative to Wi (3 consecutive days to represent -4 wk, -3 d, 3 d, and 3 and 5 wk). Blood samples were collected in the a.m. just before Wi (d 0) and at d 3, 11, 14, and 18 after Wi. Calves provided with more space (MOD and MAX) compared with CONV calves consumed feed at an earlier age and had slightly healthier erythrocytes, greater circulating glucose, and fewer circulating eosinophils. The CONV calves had haptoglobin (Hp) responses to the stressors of both Wi and Wc and had more IFN-γ from whole blood stimulated with phytohemagglutinin-P. The MAX calves had the least active neutrophils (phagocytosis and oxidative burst), but MOD calves' leukocytes secreted the most TNF-α from whole blood stimulated with lipopolysaccharide. Just before and after weaning, MAX calves spent more time per day in the standing position than CONV and MOD calves and had an Hp response to Wc, but MOD calves did not have an Hp response to Wi or Wc. Based on these results, MOD calves were the most ready for weaning; therefore, they potentially can be moved to group housing at an earlier age than CONV calves, thus improving animal welfare concerns over space allowance and individual housing.

Social housing influences the behavior and feed intake of dairy calves during weaning

We investigated the effect of social housing on the behavioral, intake, and physiological changes that occur at weaning for dairy calves fed milk ad libitum. These changes were evaluated during the weaning (d 40 to 48 of age) and postweaning (d 49 to 56 of age) stages. Twenty male Holstein calves were fed milk replacer ad libitum and weaned gradually by dilution over 9 d starting at d 40 of age. Calves were housed in pairs (10 calves) or individually (10 calves) from birth until the beginning of the postweaning phase, when all calves were paired. Feed and water intake were monitored daily. Feeding time was video-recorded, and blood β-hydroxybutyrate concentration was measured on alternate days beginning on d 40 and ending on d 56 of age. Electronic accelerometers continuously recorded standing and lying behavior for the 17-d study. Solid feed consumption increased by more than 5-fold over the weaning phase in all calves; during this phase pair-housed calves consumed more than twice (0.96 vs. 0.50 kg/d on d 48) that of the individually housed calves. Postweaning all calves rapidly increased their solid feed intake, and to a greater extent for previously individually housed calves, such that intake was similar between treatments by d 56. Free water intake was stable during weaning; however, a decrease (of 6.6 L) occurred in the constituent milk replacer water intake across this phase. As result, total water intake (free water + milk replacer water content) decreased (by 6.0 L) over the weaning phase between d 40 (14.9 L/d) and d 48 (8.9 L/d). On the first day postweaning (d 49), total water intake for all calves increased sharply (to 19.0 L/d) and then returned to a lower baseline (13.2 L/d) the next day (d 50), and slowly increased over the following week. During the weaning phase, feeding time and feeding rate increased with time for all calves, whereas pair-housed calves had greater feeding rates than individually housed calves (13.4 vs. 6.6 g of DM/min). After weaning, calves previously housed individually spent more time feeding in the early hours of the day than calves housed in pairs. Lying time and lying bout frequency decreased with calf age during the weaning period across treatments, and pair-housed calves tended to spend less time lying than individually housed calves (1,015 vs. 1,039 min/d) during this time period. Blood β-hydroxybutyrate increased across treatments over the weaning period, with the largest increase occurring between d 48 (0.05 mmol/L) and d 50 (0.2 mmol/L). These results show that calves alter their behavioral patterns during weaning and that housing calves in pairs may ease the transition from milk to solid feed.

Evaluation of an accelerated growth program for pre-weaned Shall lambs

In order to evaluate the effect of source and amount of milk delivered to lambs on their performance, thirty newborn Shall male lambs (4.76±0.31kg) were randomly assigned to one of three treatments: 1) conventional whole milk feeding program at 10% of body weight (CWM); 2) conventional milk replacer feeding at 10% of body weight and 17.1% milk solid (MRC); 3) accelerated milk replacer feeding program at 20% of body weight and 21% milk solid (MRA). Lambs were weaned at 56 d of age and the experiment finished 2 week after weaning. Milk and solid feed intakes were individually recorded on a daily basis. As the experiment advanced, the solid feed consumption (P<0.01) and average daily gain (ADG; P<0.01) increased, but MRC fed lambs had a decreased ADG compared to CWM or MRA groups in the pre-weaning (94g/day vs. 140 and 155g/day, respectively), but not in post-weaning, phase. The accelerated program led to decreased solid feed intake in the MRA group while the other lambs had similar starter intake, though total dry matter intake was greater in MRA compared with others. The CWM group had the best gain:feed ratio, resulting in similar final body weights as the MRA group and greater body weights compared with MRC lambs. Circulating β-hydroxy butyric acid was decreased (P<0.01) in MRA lambs compared with lambs on the traditional program during pre-weaning, but not post-, weaning period. In conclusion, it appears that lambs can be artificially reared on very low fat MRA program with greatly improved ADG during the first month of life, but, without altering final performance.

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.

Effects of alfalfa hay and its physical form (chopped versus pelleted) on performance of Holstein calves

Inclusion of forage and its physical form in starter may affect rumen development, average daily gain (ADG), and dry matter intake (DMI) of dairy calves. To evaluate the effects of forage and its physical form (chopped vs. pelleted) on growth of calves under a high milk feeding regimen, 32 Holstein calves (38.8±1.1kg) were assigned at birth to 1 of 3 treatments in a completely randomized block design. Dietary treatments (% of dry matter) were (1) 100% semi-texturized starter (CON); (2) 90% semi-texturized starter + 10% chopped alfalfa hay (mean particle size=5.4mm) as a total mixed ration (TMR; CH); and (3) 90% semi-texturized starter + 10% pelleted alfalfa (mean=5.8mm) hay as a TMR (PH). Data were subjected to mixed model analysis with contrasts used to evaluate effect of forage inclusion. Calves were weaned at 76 d of age and the experiment finished 2 wk after weaning. Individual milk and solid feed consumption were recorded daily. Solid feed consumption and ADG increased as age increased (effect of week), but neither forage inclusion nor physical form of forage affected these variables pre- or postweaning. Plasma urea N was affected by treatments such that the CON group had a lower concentration than forage-fed groups. Forage inclusion, but not physical form, resulted in increased total protein in plasma. Although days with elevated rectal temperature, fecal score, and general appearance were not affected by dietary treatments, calves fed alfalfa hay during the first month of life had fewer days with respiratory issues, regardless of physical form of hay. We concluded that provision of forage does have some beneficial effects in calves fed large amounts of milk replacer, but pelleted alfalfa hay did not result in any improvement in calf performance or health.

Performance and health responses of dairy calves offered different milk replacer allowances

Eighty female Holstein calves (12±4.1d of age and 42±4.3kg of BW) were collected from different herds, brought to the study site, and blocked by age and assigned to either a 6L/d maximum daily milk replacer (MR) allowance (LMR) or a maximum MR allowance of 8L/d (HMR). Calves were kept in individual hutches until 52d of age and then moved into pens, forming groups of 10. All calves had ad libitum access to a mash starter feed. Calves in both treatments received the MR distributed in 3 separate allotments between 1wk after the beginning of the study and 52d of age. Then, all calves were moved to group pens and preweaned by offering 2L/calf of the same MR twice daily in a trough until the age of 59d, when MR offer was further reduced to a single dose of 2L until the age of 73d, when all calves were completely weaned. Individual starter feed and MR consumption was recorded on a daily basis until 52d of age, and on a group basis until weaning time. Body weight was measured at the beginning of the study and at 52 (preweaning), 73 (weaning), and 110, 160, and 228d of age. Solid feed consumption (mean ± SE) was greater in LMR (821±42.1g/d) than in HMR calves (462±42.1g/d) between 42d of age and 52d (preweaning). As expected, as age increased, solid feed consumption increased, and LMR showed a more marked increase than HMR calves. Despite the greater solid feed intake of LMR calves, HMR grew faster than LMR calves until preweaning time, but from preweaning to weaning, LMR calves grew more than HMR calves (977 vs. 857±30.7g/d, respectively; mean ± SE). No differences in feed efficiency were observed. While calves were individually housed, no differences were observed in the incidence of bovine respiratory disease or diarrhea between treatment groups. We concluded that, under the milk regimen, age range of calves, and weaning method used in the current study, before preweaning, HMR calves grow more than LMR calves, but between preweaning and weaning, LMR grow more than HMR calves, overcoming the difference in BW at preweaning. As a result, with the weaning scheme followed herein, providing more milk does not ensure greater performance; no differences are obtained in BW at weaning and at 228d of life. Also, based on solid feed consumption patterns seen in this study, we determined that the optimum age to reduce MR allowances and foster solid feed intake is around 45d of age.

Effect of calf starter feeding on gut microbial diversity and expression of genes involved in host immune responses and tight junctions in dairy calves during weaning transition

Calf starters are usually offered to dairy calves to facilitate the weaning process, however, the effect of solid feed consumption on gut health has not been well studied. This study aimed to investigate the effect of calf starter feeding on the gut bacterial community and mucosal immune functions in dairy calves during weaning transition. Mucosal tissue and digesta samples were collected from rumen, jejunum, ileum, cecum, and colon upon slaughtering of calves (n=8) after feeding the experimental diets [milk replacer (MR) or milk replacer + calf starter (MR+S)] for 6 wk. Expression of toll-like receptor (TLR) 10 was downregulated along the gut, whereas TLR2 in colon and TLR6 along the gut were upregulated in MR+S-fed calves compared with MR-fed calves. Ileal TLR9 and TLR10 showed higher expression compared with the other regions regardless of the diet. Peptidoglycan recognition protein 1 demonstrated a diet- and gut-regional dependent expression pattern, whereas β-defensin did not. The diet and gut region also affected the expression of tight junction–regulating genes claudin 4 and occludin. Bacterial diversity tended to be different between the 2 diets, whereas the bacterial density was different among gut regions and sample type. The present study revealed that changes in bacterial diversity, expression of genes encoding host mucosal immune responses, and barrier functions were associated with the MR+S diet, and suggests that solid feed consumption may alter gut microbiome and host mucosal functions during weaning transition.

Changes in body content of iron, copper and zinc in Iberian suckling piglets under different nutritional managements

Thirty-eight purebred Iberian sows were used in two consecutive trials to determine the influence of different nutritional strategies applied to the litters on body composition and retention of some trace minerals in the body of suckling piglets weaned at 35d of age. Exclusively milk feeding (M), conventional suckling (CS) and intermittent suckling (IS) were studied. Only litters on CS and IS treatments had free access to creep feed from day 15 onwards. Those of the CS group had continuous access to their dams. Piglets on the IS treatment were progressively separated from the sow during 6h, 8h and 10h on days 29–30, 31–32 and 33–34, respectively. Eight piglets at birth (4 per trial replicate) and one piglet per litter on day 35 of age were slaughtered and used to study whole-body content of Fe, Cu and Zn, and its distribution in the different body compartments. Mineral retention was calculated following the comparative slaughter procedure. Average contents of these trace elements in Iberian sows’ milk were Fe 1.65, Cu 1.46 and Zn 11.10mg/kg, whereas those analyzed in creep feed were Fe 240, Cu 170 and Zn 2900mg/kg (as fed). The body concentration of Fe at weaning was unchanged between groups, although Fe stored in liver tended to be higher in IS piglets (32.3, 30.5 and 50.0mg/kg for M, CS and IS piglets respectively, P=0.101). No differences (P>0.05) were observed in whole-body or liver concentration of Cu between groups, although Cu concentration was increased (P<0.01) in some body compartments (blood and head/feet/tail) in CS and IS compared to M piglets. Significant effect of the feeding regimen was found in body levels of Zn in weaned piglets, as retention and body content resulted progressively increased as follows: IS>CS>M groups (P<0.001), with significant differences for all body parts. Zn liver concentration increased around 3-fold in creep fed piglets compared to milk fed piglets (53, 149 and 157mg/kg for M, CS and IS piglets, respectively, P=0.029). It may be concluded that stimulation of consumption of solid feed containing pharmacological levels of these trace elements in the suckling piglet may lead to some changes in body content of Fe and Cu at weaning, and increases greatly Zn body levels. Beneficial consequences of these nutritional practices warrant to be evaluated, as they cause substantial increase in environmental contamination.

Effect of Dietary Supplementation of Glutathione on Blood Biochemical Changes and Growth Performances of Holstein Calves

The objective of this experiment was to evaluate the effect of dietary supplementation of glutathione (GSH) on health, solid feed consumption, nutrient intake, body weight gain (BWG), feed efficiency, blood metabolites and the occurrence of diarrhea in Holstein neonatal calves. The calves were fed plain milk as a control (CON) or milk with GSH supplementation. Sixteen calves were separated from their mothers immediately after birth, moved into individual cages and fed colostrum for the first three days. For GSH supplementation, three grams of GSH powder were mixed in 1.8 L of heat-treated milk and placed in a plastic bottle with a rubber nipple. The calves were fed GSH-supplemented milk only once out of four daily feedings. For the first 25 d, calves were fed 1.8 L of milk four times per day. Milk feeding frequency was reduced to three times per day from days 26 to 30, followed by twice a day from days 31 to 44, and once a day from days 45 to 49, after which they were weaned at day 50. Body weight gain (BWG), feed consumption, and growth performance were monitored until day 70. The dietary supplementation of GSH had no effect on daily feed intake and growth performance in growing calves. Hematological results revealed red blood cell distribution width (RDW) was lower, and mean corpuscular volume (MCV) was significantly higher in calves fed GSH. Serum lactate dehydrogenase (LDH) concentrations were lower in calves fed GSH. Rectal temperature at day 70 was higher in calves that did not receive GSH, while mean frequency of diarrhea and enteritis was less in calves fed GSH. It is concluded from the present study that BW gain, total dry matter intake (DMI), feed efficiency, and breathing rate did not differ between groups. However, there were some positive blood parameters and the mean frequency of diarrhea and enteritis was less in calves fed GSH compared to CON which did not receive GSH. With the results obtained, supplementation of GSH is highly recommended. (Key Words : Glutathione, Hematology, Neonatal Calves)

Rumen development and growth of Balouchi lambs offered alfalfa hay pre- and post-weaning

The consumption of solid feed is essential for successful transition from a pre-ruminant to a functional digestive tract. Lambs fed starter rations containing highly fermentable carbohydrates often experience dramatic changes in concentrations of rumen and blood metabolites. The optimal amount of roughage required in the diet of pre-ruminant animals is still unclear. The objective of this study was to determine the effect of feeding alfalfa hay on performance and rumen development in young Balouchi lambs. In a completely randomized design, 30 lambs were fed one of three experimental diets consisting of a control, without alfalfa hay (C), a diet containing 7.5% alfalfa hay (A1), and a diet containing 15% alfalfa hay (A2). Lambs fed A1 and A2 diets had lower dry matter intake during the pre-weaning period (P < 0.01) and overall (P = 0.02), but feed conversion ratio and average daily gain were not affected by feeding alfalfa hay. Concentration of beta-hydroxybutyric acid was higher in C compared with the A1 and A2 groups (P < 0.01). Concentrations of glucose and non-esterified fatty acids did not differ among the groups of animals. Feeding alfalfa hay reduced thickness of the rumen epithelial keratinized layer (P = 0.04) and increased thickness of muscular layer (P = 0.05). We concluded that including 15% alfalfa hay in the starter diet could reduce thickness of the keratinization layer and increase muscularity of rumen wall without adverse effects on growth and performance of newborn lambs.

Effect of flavoring a starter in a same manner as a milk replacer on intake and performance of calves

The effects of including the same flavor additive in a milk replacer (MR) and a starter to facilitate a sensorial association between the flavor of starter and that of the MR were explored in an attempt to encouraging calves to increase solid feed consumption around weaning. Twenty-two male Holstein calves (initial body weight = 51.2 ± 0.82 kg; age = 22 ± 1.6 d) participated in this study. All calves consumed the same starter during the first 34 d of study and were weaned at 42 d of study (65 d of age). The study finished 14 d after weaning. All calves received the same flavored MR and during the 7 d preceding weaning until the end of the study, half of the calves were fed a pelleted starter with the same flavor as that of the MR around weaning, whereas the remaining calves were offered the same starter without flavor. Starter and MR consumptions were registered daily, and BW recorded weekly. Overall, starter intake was not affected by flavor addition. However, calves with the lowest solid feed consumption before weaning (days 28–34 of study), numerically (P=0.11) consumed more starter following weaning when the starter was flavored compared with calves receiving plain starter. These calves also tended (P=0.06) to have a greater average daily gain during the 14 d following weaning compared with calves within the same low level of solid feed consumption but that consumed the unflavored starter. Flavoring calf starters in the same manner as MR might improve solid feed consumption and performance of calves with a low appetence for solid feed before weaning.