Pelleted Starter Research Articles

Feeding Essential Oils to Neonatal Holstein Dairy Calves Results in Increased Ruminal Prevotellaceae Abundance and Propionate Concentrations.

Since antibiotic use in animal production has become a public health concern, great efforts are being dedicated to find effective and viable alternatives. While essential oils (EO) have become attractive candidates for use in the livestock industry, their mode of action and microbial targets in food animals remain largely uncharacterized. To gain further insight, we investigated the rumen environment of neonatal calves fed calf starter pellets and milk replacer supplemented with a commercial blend of EO. Propionate concentrations were not only found to be higher in EO-fed calves compared to controls (P < 0.05), but ruminal bacterial communities also differed greatly. For instance, the abundance of Firmicutes was significantly lower in samples from EO-fed calves than in controls, which appeared to be mostly due to lower Lachnospiraceae levels (P < 0.05). In contrast, Bacteriodetes were more abundant in EO-fed calves compared to controls, which was primarily the result of higher Prevotellaceae (P < 0.05). Notably, two bacterial operational taxonomic units (OTUs) were significantly more abundant in EO-fed calves; SD_Bt-00966 was found to be a close relative of Prevotella ruminicola (97%), while SD_Bt-00978 likely corresponded to an uncharacterized species of Gammaproteobacteria. In addition, Pearson correlation and canonical correspondence analyses revealed potential associations between other ruminal bacterial OTUs and either short chain fatty acids (SCFA) parameters or metrics for calf growth. Together, these results support that EO supplementation in growing dairy calves can modulate rumen function through SCFA production and growth of specific rumen bacterial groups.

The Effect of Storage Time on the Total Lactic Acid Bacteria and Presence of Gram Positive and Negative Bacteria in Calf Starter Pellet Added with Fermented Cabbage Waste

The aim of this research was to examine the microbiological quality of calf starter pellet added with fermented cabbage waste after stored for 0, 4, and 6 weeks. The materials used in this research consisted of cornmeal, rice bran, soybean meal, molasses, mineral mix, and fermented cabbage waste. This research used Completely Randomized Design with 4 treatments and 3 replications. The mixed calf starter pellet consisted of 100% calf starter and 6% of fermented cabbage waste, and then stored for 0 weeks (P0), 2 weeks (P1), 4 weeks (P2) and 6 weeks (P3). The observed microbial qualities were the total lactic acid bacteria and the presence of gram positive and negative bacteria in the mixed calf starters. The total lactic acid bacteria were analyzed descriptively, while the presence of gram bacteria was analyzed with analysis of variance followed with Duncan’s test. The result of this research showed that an increase in storage time would result in lower lactic acid bacteria population, while the gram-positive and negative bacteria was not significantly affected. The research concluded that 6-weeks stored calf starter pellet added with 6% of fermented cabbage waste could maintain its lactic acid and gram-positive bacteria population, while also reducing its gram-negative bacteria population as well.

PSXV-27 Determination of the optimal canola meal inclusion rate in pelleted starters for Holstein calves.

PSXV-27 Determination of the optimal canola meal inclusion rate in pelleted starters for Holstein calves.

PSXI-25 Feeding a microbially-enhanced soy protein in starter pellets affects the fecal microbiome composition of growing dairy calves.

PSXI-25 Feeding a microbially-enhanced soy protein in starter pellets affects the fecal microbiome composition of growing dairy calves.

Growth performance and health of dairy calves given water treated with a reverse osmosis system compared with municipal city water

Our objective was to determine effects of drinking reverse osmosis water (RW) versus municipal city water (MW) on growth, nutrient utilization, and health scores of calves. Twenty-four Holstein calves (14 females, 10 males; 2 d old; 44.6 ± 6.10 kg of body weight), housed in individual hutches, were used in a 10-wk randomized complete block design study. Calves were blocked by birthdate and sex. Treatments were RW (Culligan Water Filtration System, Brookings, SD) versus MW (Brookings Municipal Utilities, Brookings, SD) that contained 13 and 387 mg/L of total dissolved solids, respectively. Milk replacer (28% crude protein; 18% fat) was fed twice daily during wk 1 through 5 and then once daily during wk 6. At each feeding, 0.45 kg of dry milk replacer was mixed with 2.83 L of the respective water type according to treatment. Calves were fed water, respective to treatment, and calf starter pellets ad libitum throughout the study. All intakes were recorded daily. Daily total respiratory scores (healthy ≤3, sick ≥5) were calculated from the sum of scores for rectal temperature, cough, and ocular and nasal discharges. Fecal consistency scores (0 = firm, 3 = watery) were also recorded daily. Body weights and frame growth were measured 2 d every 2 wk and jugular blood samples were collected 1 d every 2 wk at 3 h after the morning feeding. Fecal grab samples were collected 5 times per day for 3 d during wk 10 for analysis of apparent total-tract digestibility of nutrients. We found treatment by week interactions for dry matter intake and gain-to-feed ratio, and total dry matter intake increased more during the study for RW than MW. Gain-to-feed ratio was greater during the first few weeks of the feeding period for RW compared with MW and then comparable during the rest of study. Water intake was less in RW than MW, potentially indicating more efficient water use by calves. Frame growth, body weight, average daily gain, serum glucose, plasma urea nitrogen, β-hydroxybutyrate, total-tract digestibility of dry matter, and crude protein were similar. Fecal scores tended to be lower (firmer) in calves on RW, with an interaction by time. Respiratory scores decreased during the weaning period when calves drank RW. Results demonstrated calves drinking RW had similar growth and improved health scores with treatment by time interactions compared with MW.

Stress-related hormonal alterations, growth and pelleted starter intake in pre-weaning Holstein calves in response to thermal stress.

This study aimed to investigate the effect of heat stress and month of birth on growth performance, pelleted starter intake, and stress-related hormones in Holstein calves. Birth weight and growth records, representing 4735 Holstein calves from a large commercial dairy herd in northern Mexico (25° N; 22.3°C mean annual temperature) from 2013 to 2015, were analyzed. Temperature-humidity index (THI) at calving, season of birth, and month of birth were the independent variables, whereas growth traits were the dependent variables. Increased THI at birth from <65 to >85units was associated with a decrease in birth weight from 39.3 to 38.7kg. Calves subjected to high THI (>75units) at calving showed lesser (P<0.01) pre-weaning gains (405±97g/calf/day), whereas those calves born with THI<70units presented the highest gains (466±112g/calf/day). Birth during the fall months reduced (P<0.01) weaning weight by about 5kg compared with winter months. Also, the pre-weaning average daily gain for calves born in the fall was about 70g less (P<0.01) than calves delivered in winter months. Plasma triiodothyronine and tetraiodothyronine levels were lower (1.02±0.21 and 48±7.9ng/mL, respectively; P<0.01) in summer and highest in winter (1.64±0.48 and 66±11ng/mL, respectively). Mean plasma cortisol concentration was higher in heat-stressed calves born in summer (59±40ng/mL) than calves born in winter (20±28ng/mL). Pelleted starter intake 1week before weaning was lowest (P<0.01) in the fall (0.82±0.26kg/calf/day; mean±SD) and highest in spring (1.26±0.43kg/calf/day). It was concluded that in this particular environment, heat stress affects birth weight and growth rate of Holstein calves. Thus, environmental management of the newborn calf during hot spring and summer months is warranted to optimize pelleted starter intake and calf growth rates.

Case Study: Concentrations of biotin in blood of Holstein bull calves supplemented with biotin and pantothenic acid

<h2>ABSTRACT</h2> Pantothenic acid interferes with biotin absorption in nonruminants. The objective of this study was to determine whether pantothenic acid affects the concentration of biotin in the blood of young calves. Weaned bull calves (n = 16) were fed ad libitum a pelleted starter including no supplemental B-vitamins and hay for 2 wk before the beginning and until the end of the experiment. Water was available ad libitum at all times. Two wk after weaning, calves were blocked by age and randomly assigned to 4 treatments according to a randomized complete block design. Treatments consisted of administering, for 14 d, a daily gelatin capsule containing no B-vitamins, 10 mg of biotin, 240 mg of pantothenic acid, and 10 mg of biotin + 240 mg of pantothenic acid. Expeller soybean meal was used as a carrier of the vitamins in the capsules. Blood samples were collected by venipuncture of the jugular vein at d 0 and 14. Concentrations of avidin-binding substances (ABS) in plasma were determined by a single-step competitive enzyme-binding assay. The concentrations of ABS in plasma were similar for all treatments (<i>P</i> > 0.24) and did not change after dosing vitamins over time (3.47 and 3.07 ng/mL for d 0 and 14, respectively; SEM=1.5 ng/mL; <i>P</i> > 0.63). Plasma concentrations of ABS were substantially greater than those previously reported for lactating dairy cows (0.7–2.1 ng/mL). Based on these data, we cannot conclude whether or not an interaction exists between biotin and pantothenic acid in regards to biotin absorption.

Biological bases for whitebait culture Galaxias maculatus (Jenyns, 1842): a review

Galaxias maculatus (Jenyns, 1842), is a gourmet fish of great commercial importance with overexploited fisheries. So, studies of its biology are essential in order to develop a technology for its cultivation (galaxiculture), which is at a pilot stage. The goals of this work are: 1) to provide a synthesis of the literature information on the biology of the species, and 2) to identify the lack of scientific knowledge and critical points for the development of a technology for mass commercial culture. G. maculatus is a small carnivorous fish with euryhaline populations differentiated between diadromic and freshwater. Diadromic populations spawn in the estuaries, and then the larvae migrates to the sea, returning aged 6 months and metamorphosing into adults. Studies of their systematic, populations and larvae stage in Chilean waters are scarce, but studies on feeding, reproduction and diseases are more numerous. One year old females lay about 1,200 adhesive eggs and an important number of them die after the first spawning (40%). G. maculatus has rapid growth (1.1% day-1) and a high metabolism, with an average life of 2 years. They can be cultivated in captivity, spawn and incubate their eggs to obtain larvae; adults eat salmon starter pellets and grow in tanks. The ciliate protozoa Ichtyophthirius multifilis (ich) produces high mortality in larvae and adults in confinement; mortality can be controlled with salt bath. The problems to be solved by research for future commercial fish farming are: recognising and selecting suitable populations for cultivation; increasing the number of eggs spawned by females; develop suitable diets for larvae and broodstock; and controlling ectoparasitic diseases. The critical point is achieving mass production by improving the techniques of reproduction and larviculture.

The effect of different physical forms of starter feed on rumen fermentation indicators and weight gain in calves after weaning

The aim of the study was to determine the effect of different physical forms of starter feed on rumen fermentation indicators of calves after weaning and their weight gain. The experiment was performed with Czech Fleckvieh calves after weaning. The calves were fed ad libitum completely pelleted starter feed or texturized starter feed with chopped straw. The rumen fluid samples were collected after a month of feeding the starter feeds. The calves were weighed monthly. The pH, total acidity, total volatile fatty acids, acetate, propionate, butyrate, lactic acid, ammonia and the number of rumen ciliate protozoa were determined in the rumen fluid samples. The calves receiving the starter feed with straw showed significantly higher rumen pH (6.24 ± 0.51 vs. 5.58 ± 0.30), total volatile fatty acids (98.02 ± 20.46 vs. 61.40 ± 26.51 mmol/l), molar proportion of acetate (61.20 ± 4.87 vs. 50.53 ± 4.66%), and the acetate:propionate ratio (2.38 ± 0.53 vs. 1.34 ± 0.18) and lower molar proportion of propionate (26.55 ± 4.48 vs. 37.92 ± 3.58%) compared with the calves receiving pelleted starter feed. Average daily gain of the calves did not differ significantly. The feeding of starter feed with chopped straw compared with the pelleted starter feed led to better development of the rumen fermentation evaluated by rumen pH, by total volatile fatty acids production, and by the proportion and ratio of acetic and propionic acids. The feeding of starter feed with chopped straw reduced the occurrence of subacute ruminal acidosis in the weaned calves.

Growth performance of calves fed microbially enhanced soy protein in pelleted starters

Our objective was to determine effects of feeding calves pelleted starters with microbially enhanced (fungi-treated) soy protein (MSP) in replacement of soybean meal (SBM) with different milk replacers (MR). Thirty-six Holstein calves (2 d old; 24 females, 12 males) in individual hutches were used in a 12-wk randomized complete block design study. Treatments were (1) MSP pellets with MR formulated for accelerated growth (28% crude protein, 18% fat; MSPA), (2) SBM pellets with MR formulated for accelerated growth (SBMA), and (3) MSP pellets with conventional MR (20% crude protein, 20% fat; MSPC). Pellets were similar except for 23% MSP or 23% SBM (dry matter basis). Pellets and water were fed ad libitum throughout the study. Feeding rates of MR on a dry matter basis were 0.37kg twice daily during wk 1, 0.45kg twice daily during wk 2 to 5, and 0.45kg once daily during wk 6. Intakes were recorded daily. Body weights, frame size measurements, and jugular blood samples were collected 2 d every 2 wk at 3 h after the morning feeding. Fecal grab samples were collected 5 times per d for 3 d during wk 12 and then composited by calf for analysis of apparent total-tract digestibility of nutrients using acid detergent insoluble ash as an internal marker. Total and starter pellet dry matter intake were greatest for calves fed SBMA and least for MSPC. Calves had similar average daily gain among treatments, but there was a treatment by week interaction and during the last few weeks of the study calves on MSPC had less body weight compared with MSPA or SBMA. Gain-to-feed ratio was similar among treatments; however, there was a treatment by week interaction. Serum glucose was similar among treatments. Plasma urea nitrogen was greatest for calves fed MSPA and least for MSPC. Plasma concentrations of IGF-1 were greatest for calves fed SBMA. Plasma concentrations of triglycerides were greatest for calves fed MSPC. Plasma concentrations of β-hydroxybutyrate had a treatment by time interaction. Treatments had similar total-tract dry matter digestibility, but calves fed MSPC had greater crude protein digestibility than SBMA, with MSPA similar to both. Results demonstrated calves fed pelleted starters with MSP had maintained growth performance with less starter intake compared with SBM.

1468 Comparison of two calf-rearing programs on the performance and cost–benefit ratio

There is a deep interest in assessing different kinds of calf rearing programs based on greater rates of liquid feeding to increase ADG and to decrease age at first calving. In a complete randomized design with repeated measures, two milk feeding plans (treatments) were evaluated in 57 Holstein female dairy calves (37.3 ± 3.7 kg BW and 3 d old) during 10 wk. Treatment 1 (T1) consisted of feeding 12% of weight at 3 d in whole milk and treatment 2 (T2) a consisted of a step-down program of 20 (from 0 d to 2 wk), 15 (3–4 wk), and 10% (5–10 wk) of weight at 3 d in whole milk. Calves were fed colostrum (IgG; 100 mg/mL) at 30 min of life and after that, they were left with the cow suckling ad libitum until 3 d of life without access to solid feed. Calves were housed in individual hutches with ad libitum access to T1 (n = 28) and T2 (n = 29). From the third day, calves were offered pelleted starter feed (173.1 g CP, 460.1 g NSC, and 201 g NDF per kilogram DM) in the morning at 0700 h. Water was offered ad libitum. The calves were weaned when the intake of the starter feed was over 1.000 g/d during three consecutive days, from Day 1 to 4 after weaning half of the milk amount was given and since 5 d without milk. Body weight, DMI, ADG, days to weaning (DW), feed:gain ratio, total protein and energy intake, chest girth (CG), height at withers (HW), height at sacrum (HS), and total cost of production were measured. No differences were found (P > 0.05) on BW, CG, and HW and HS changes during the 10 wk among treatments. At the end of the trial, no differences were detected (P > 0.05) in BW, ADG, DW, concentrate DMI and feed:gain ratio, CG, and HW and HS. Calves fed T2 tended (P = 0.11) to have greater total DMI and protein DMI (79.6 and 19 kg) than calves fed T1 (73.7 kg and 17.6 kg). Calves fed T2 had greater (P < 0.05) milk DMI, ME of DMI, and cost of production (33.3 kg, 341.5 Mcal, and 105.4 USD) than calves fed T1 (28.7 kg, 312.2 Mcal, and 93 USD). Feeding with a step-down program having more milk does not support improvements of performance and increases the average cost of production.

Effect of probiotic Bacillus amyloliquefaciens strain H57 on productivity and the incidence of diarrhoea in dairy calves

A spore-forming probiotic, Bacillus amyloliquefaciens strain H57 (H57), was administered to dairy calves in starter pellets to determine effects on liveweight gain, feed conversion efficiency and animal health under summer feeding conditions, without antibiotics. Twenty-four male and female calves were allocated into two groups and from 4 weeks of age individually offered 6 L/day of whole milk and ad libitum starter pellets impregnated with H57 (3.16 × 108 cfu per kg DM) or without (Control) until 12 weeks of age. The calves were housed in a non-air-conditioned animal house, with deep-straw bedding over concrete, under typically challenging subtropical summer conditions. After 12 weeks the calves were released into a grazing paddock as one group and were supplemented ad libitum with control pellets and hay, until 19 weeks of age. From Weeks 4 to 12, liveweight and feed intakes were measured weekly and health status was monitored daily. Rumen fluid and blood were collected at Weeks 4 and 12, and to test for persistence after cessation of feeding H57, each were measured again at Week 19. From Weeks 4 to 12, the H57 calves grew faster (767 vs 551 g/day, P = 0.01), tended to consume more pellets (1013 vs 740 g DM/day, P = 0.07) and were 19% more feed conversion efficiency (2.43 vs 2.90 kg milk + starter DM/kg weight gain, P = 0.01) compared with the Control calves. The mean duration of each diarrhoea event was 2 days less for the H57 calves than the Control (P = 0.01). The H57 calves weaned 9 days earlier (P = 0.02) and were heavier at Week 19 (155 vs 139 kg, P = 0.03) than the Control calves. The only effect of H57 on rumen volatile fatty acid concentrations was an elevation in valerate at Week 12 (4.10 vs 2.47 mmol/L, P = 0.03). Plasma β-hydroxy butyrate was also elevated in the H57 calves at Week 19 (0.24 vs 0.20 mmol/L), indicating the potential of H57 to improve rumen development. H57 can be used to improve the nutritional performance and reduce the risk of diarrhoea in dairy calves as they transition from milk to dry feed.

356 Feeding microbially-enhanced soy protein in starter pellets to dairy calves

356 Feeding microbially-enhanced soy protein in starter pellets to dairy calves

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.

Digestive development in neonatal dairy calves with either whole or ground oats in the calf starter

A series of 3 trials was conducted to determine effects of whole or ground oats in starter grain on reticulorumen fermentation and digestive system development of preweaned calves. Male Holstein calves (43.1±2.3kg at birth; n=8, 9, and 7 for trials 1, 2, and 3, respectively) were housed in individual pens in a heated facility; bedding was covered with landscape fabric to prevent consumption of bedding by the calves. In trials 1 and 2 only, calves were fitted with rumen cannulas by wk 2 of life. In all trials, a fixed amount of starter (containing 25% oats either ground and in the pellet or whole) was offered daily; orts were fed through the cannula in trials 1 and 2. Calves were randomly assigned to an all-pelleted starter or pellets plus whole oats. Rumen contents (trials 1 and 2) were sampled weekly at −8, −4, 0, 2, 4, 8, and 12 h after grain feeding for determination of pH and volatile fatty acids. Calves were killed 3 wk (trial 1) or 4 wk (trials 2 and 3) after grain was offered; organs were harvested, emptied, rinsed, and weighed to gauge digestive organ development. Starter intake was not different between treatments. Weekly measurements of rumen digesta pH did not change and only subtle changes were observed in molar proportions of individual volatile fatty acids. Molar proportion of butyrate and pH linearly decreased with age, whereas acetate proportion increased. Reticulorumen weight and papillae length tended to be greater for calves fed pelleted starter, whereas abomasum weight was greater for calves fed pellets plus whole oats. Fecal particle size and starch content were greater for calves fed pellets plus whole oats. Under the conditions of this study, physical form of oats in starter grain did not affect rumen fermentation measurements; greater rumen weight and papillae length in calves fed pelleted starter may be the result of greater nutrient availability of ground oats. Under the conditions of this study with young calves on treatments for <4 wk, increasing particle size of the starter by feeding whole oats did not affect rumen fermentation nor did it improve digestive system development.

Interaction between the physical form of the starter feed and straw provision on growth performance of Holstein calves

Two experiments were conducted to assess the effect of physical form of a starter feed with or without straw supplementation on growth performance of Holstein calves. In experiment 1, a total of 32 calves were randomly assigned at 7 d of age to texturized starter feed (containing rolled barley, corn, and oats) without straw, texturized starter feed with chopped straw, and pelleted starter feed with chopped straw. All calves were offered 4 L of pasteurized whole milk twice daily from 7 to 35 d of age, 2 L of milk twice daily from 36 to 42 d of age, and 2 L of milk from 43 to 49 d of age. Animals were weaned at 50 d of age, and the study finished when calves were 63 d old. In experiment 2, a total of 60 calves (8 d of age) were randomly assigned to texturized starter feed (containing whole corn) without straw, pelleted starter feed without straw, and pelleted starter feed with chopped straw. All calves were offered the same milk replacer (MR; 23% crude protein and 19.5 fat) at 11% dry matter concentration, 4 L/d of MR until 14 d of age, 6 L/d of MR from 14 to 37 d, 3 L/d of MR from 38 to 44 d, and 1.5 L/d of MR from 45 to 52 d of age. The experiment finished when calves were 58 d old (1 wk after weaning). Rumen liquid pH was measured after weaning. In both studies, calves were individually housed in pens on sawdust bedding and starter feed and chopped straw were offered free choice in separate buckets. In experiment 1, starter feed and straw intake and growth did not differ among treatments. However, calves receiving straw showed a greater rumen pH compared with those not receiving straw. In experiment 2, pelleted started feed supplemented with straw fostered an increase in solid feed intake (as percentage of body weight) compared with a pelleted or texturized starter feed without straw supplementation. However, calves that received the texturized starter feed containing whole corn had rumen pH similar to those fed a pelleted starter feed with straw. Feeding a texturized starter feed containing rolled barley, corn, and oats (with or without straw provision) was not able to maintain rumen pH or promote growth and intake compared with offering a pelleted starter feed with chopped straw. However, when whole corn was used in the texturized starter feed, rumen pH was equivalent to that obtained with a pelleted starter feed and straw supplementation.

Effect of milk intake and weaning strategy on measures of calf performance and feed utilization in group-housed Jersey calves

Increased milk intake in the preweaning period has been associated with improved rate of gain, improved health, reduced age at first calving and improved first lactation milk production. However, feeding higher levels of milk may slow starter pellet intake, delaying rumen adaptation, which can result in reduced rate of gain and impaired health in the post-weaning period. The study objective was to describe the effect of milk feeding rate and weaning strategy on measures of growth, health, feed intake, feed efficiency and economics in group-housed preweaned Jersey calves.

The effect of palatability of protein source on dietary selection in dairy calves

Evidence has shown that soybean meal is perceived as more palatable than canola meal by dairy calves in short-term preference tests. This study evaluated the effect of protein source on longer-term dietary selection of dairy calves. In experiment 1, 40 Holstein bull calves (11.4±4.3d of age) were randomly assigned to 1 of 2 choice diets for 6wk: base starter pellet (S; 12% crude protein; CP) and high-protein pellet (40% CP) containing either (1) soybean meal (SB) or (2) canola meal (CM). In wk 7 to 8, all calves were offered a single pelleted diet containing the protein source to which they were previously exposed. In experiment 2, 22 Holstein bull calves (9.9±4.6d of age) were offered, for 6wk, a choice of 2 mixed pelleted diets: (1) 70% S and 30% SB (SB mix), or (2) 70% S and 30% CM (CM mix). In wk 7 to 8, calves were randomly assigned to 1 of 2 choice diets, as in experiment 1: (1) SB + S, or (2) CM + S. All feeds were provided ad libitum. Calves received 6 L/d of milk replacer [0.75kg/d of dry matter (DM)] for the duration of both experiments. Feed intake was recorded daily and calves were weighed every 14d. Feeds were sampled weekly to analyze DM and nutrient intake. Mixed diets in experiment 2 were analyzed for CP in wk 4 and 6 to assess feed sorting (calculated as actual CP intake as a percentage of predicted intake). In experiment 1, calves offered SB + S in wk 1 to 6 consumed more high-protein pellet than calves offered CM + S [73 vs. 42% of DM intake (DMI)] and, consequently, more CP (168 vs. 117g/d). Solid feed DMI and average daily gain were similar between treatments. When offered a single diet in wk 7 to 8, calves offered starter containing soybean meal increased intake to a greater extent than calves offered the starter containing canola meal. In experiment 2, calves preferred the SB mix to CM mix (preference ratio: 0.7). Calves consumed more CP than predicted from SB mix in wk 4 and 6 (108±2.0%), indicating that they were sorting in favor of SB. In contrast, calves consumed less CP than predicted from CM mix in wk 4 (81.48±4.1%), indicating that they were sorting against CM. When assigned to choice treatments in wk 7 to 8 of experiment 2, calves offered SB + S consumed more protein pellet than calves offered CM + S (81 vs. 31% DMI) and consumed more CP (378 vs. 196g/d). Average daily gain was greater for calves offered SB + S but DMI was similar. Overall, these results suggest that dietary selection was influenced by innate feed preferences, and milk-fed calves may not be sensitive to protein imbalances in their diet.

Dietary preference in dairy calves for feed ingredients high in energy and protein

In 3 experiments, we assessed preference of recently weaned dairy calves for (1) 8 high-energy feed types [barley meal, corn meal, corn gluten feed (CGF), oat meal, rice meal, sorghum meal, wheat meal, and wheat middlings meal]; (2) 6 high-protein feed types [corn gluten meal (CGM), wheat distillers dried grains, rapeseed meal, soybean meal (SBM), sunflower meal, and pea meal]; and (3) 4 mixtures (50:50) of the highest- and lowest-ranked high-energy and high-protein feeds, to assess whether calves maintain preference for feed ingredients that are included in a mixture. In all experiments, pairwise preference tests were conducted between all feed types (28 different pairwise preference tests in experiment 1, 15 tests in experiment 2, and 6 tests in experiment 3). Each pairwise preference test was conducted by offering ad libitum access to both feed types for 6h. All tests were repeated with 20 Holstein calves. Before this study, calves were offered milk replacer at a rate of 4L/d and a pelleted starter feed ad libitum. After weaning at 62d of age, each calf was involved in a pairwise preference test at 3 and 5d postweaning. A preference ratio was calculated for each calf in each test as (intake of feed type A)/(intake of feed type A + intake of feed type B). Preference for feed types was ranked across tests in each experiment using pairwise comparison charts. In experiment 1, the highest-ranked high-energy feed type was wheat meal and the lowest ranked were rice meal and CGF. In experiment 2, the highest-ranked high-protein feed type was SBM and the lowest ranked was CGM. According to the preference rankings from experiments 1 and 2, experiment 3 evaluated (50:50) mixtures of SBM + wheat meal, SBM + CGF, CGM + wheat meal, and CGM + CGF. The mixture of SBM + wheat meal was highest ranked, CGM + CGF was lowest ranked, and the mixtures containing one high-ranked and one low-ranked feed ingredient (SBM + CGF and CGM + wheat meal) were ranked equally. The results of this study indicate that young calves exhibit clear preferences for certain high-energy and high-protein feeds that may be considered highly palatable. Further, preference ranking of feed types provided as 50:50 mixtures was consistent with ranking of individual feed types, suggesting that palatability of mixed starter rations can be improved by inclusion of a preferred feed type.

What do preweaned and weaned calves need in the diet: A high fiber content or a forage source?

The objective of this study was to determine whether the improvement of performance of young calves associated with the supplementation of chopped grass hay reported in some studies is due to an increase in the total neutral detergent fiber (NDF) content of the consumed diet or to the provision of chopped grass hay. Sixty-three Holstein calves [9±4.4 d old; mean ± standard deviation (SD)] were randomly distributed in 4 treatments resulting from the combination of 2 levels of NDF content of a pelleted starter and the supply or absence of forage provision: low-NDF starter (18%) with or without chopped oat hay, and high-NDF starter (27%) with or without chopped oat hay. All animals were fed the same milk replacer (21% crude protein and 19.2% fat) at the rate of 4 L/d at 15% dry matter from d 1 to 34, and 2 L/d at 15% dry matter from d 35 to 42 (weaning). The study finished 2 wk after weaning. Body weight was measured weekly and individual calf starter and hay intake was recorded daily. On d 50, blood samples were drawn 2h after the morning concentrate offer to determine serum glucose and insulin concentrations. On d 52, samples of ruminal fluid were obtained via an esophageal tube, and pH was measured immediately. During the preweaning period, pelleted starter intake was similar among treatments, but average daily gain tended to be greater in low- than in high-NDF treatments (0.69 vs. 0.63±0.020kg/d, respectively; mean ± SD). However, during the 2 wk after weaning, supplementation of forage improved pelleted starter intake and average daily gain without affecting the gain-to-feed ratio. Probably, the greater pelleted starter intake observed in forage-supplemented calves was mainly due to the greater ruminal pH found in forage-supplemented calves compared with forage-deprived calves (5.81 vs. 5.05±0.063, respectively). Blood insulin-to-glucose ratio was greater in forage-supplemented compared with unsupplemented calves [mean ± SD; 6.53 vs. 4.24±0.125 insulin (ng/L)-to-glucose (mg/dL) ratio, respectively]. In conclusion, a low-NDF pelleted starter is recommended during the preweaning period, and the provision of chopped hay is necessary right after weaning to improve calf performance.