Different milk feeding intensities during the first 4 weeks of rearing dairy calves: Part 2: Effects on the metabolic and endocrine status during calfhood and around the first lactation

Feeding dairy calves at high intensity has been demonstrated to increase milk yield in later life. We investigated the effect of 3 different feeding regimens in the preweaning period on the metabolic and endocrine status during calfhood and in heifers at the onset of the first lactation. In trial 1, 57 German Holstein calves were allocated to 3 different feeding groups: milk replacer restricted to 6.78 kg/calf per day, 11.5% solids (MR-res, n = 20), milk replacer 13.8% solids, ad libitum (MR-ad lib, n = 17), and whole milk ad libitum (WM-ad lib, n = 20). All calves received ad libitum colostrum for 3 d postnatal (p.n.). From d 4 to 27, all calves were fed according to their respective feeding regimen, resulting in average intakes of 6.38, 9.25, and 9.47 kg/d in MR-res, MR-ad lib, and WM-ad lib, respectively. Thereafter, all calves were fed according to the MR-res regimen until weaning at d 55 (gradually until d 69 p.n.). Blood samples were collected on d 0 before colostrum intake and on d 1, 3, 11, 22, 34, 43, 52, 70, 90, and 108 p.n. Liver biopsies were taken on d 19 and 100, and on d 22, 52, and 108 p.n. intravenous glucose tolerance tests were performed. The male calves (n = 8 to 10 per group) underwent also an insulin tolerance test on d 24, 54, and 110 p.n. The females (n = 28) from trial 1 were further reared and bred as common practice, and were enrolled in trial 2 when beginning the last trimester of pregnancy. Blood samples were collected monthly antepartum starting 91 d before calving and weekly (0–70 d) postpartum. Trial 1 was subdivided into 4 phases (P): P0 (d 0–1), P1 (d 2–27), P2 (d 28–69), and P3 (d 70–110 p.n.). In trial 1, the leptin and adiponectin concentrations increased with colostrum intake. Differences in fatty acids, insulin, adiponectin, revised quantitative insulin sensitivity check index (RQUICKI), and variables from the glucose tolerance tests were largely limited to P1. The MR-res group had greater RQUICKI and fatty acid values, and lower insulin and, as a trend, adiponectin concentrations than in 1 or both ad lib groups. These differences were partly sustained in P2 (fatty acids, adiponectin, and RQUICKI) and in P3 (adiponectin). The hepatic mRNA abundance of the gluconeogenic enzymes phosphoenolpyruvate carboxykinase and pyruvatcarboxylase increased from d 19 to 100. None of the blood variables were different between the groups when tested in pregnancy and lactation. Our results do not support a sustained deflection of metabolic regulation by rearing at different feeding intensities; nevertheless, the differences observed during rearing might influence nutrient utilization in later life or the cellular development of organs, such as the mammary gland, and thereby affect milk yield. Further studies involving greater animal numbers and, thus, improved power will help to sort out the mechanisms of programming body function in later life via nutrition in early life.     

Effects of ad libitum milk intake on dairy calves

Conventional milk feeding for calves (by bucket twice daily at a total of 10% of body weight) was compared with feeding milk for ad libitum consumption from a nipple. Calves were weaned gradually between d 37 and 42 by diluting the milk with water, and body weight and feed consumption were followed until d 63. Calves fed ad libitum drank 89% more milk than calves fed conventionally during the preweaning period, but the ad libitum-fed calves ate only 16% as much calf starter and 17% as much hay. Consumption of starter and hay increased rapidly after weaning, and treatment differences disappeared. Probably as a result of the much higher intake of milk, the ad libitum-fed calves gained 63% more weight than the conventionally fed calves before weaning, resulting in a 10.5-kg weight advantage on d 35. During and immediately after weaning, the rate of weight gain slowed for both treatment groups, but recovered by approximaely d 49. There were no treatment differences in weight gains over the weaning or postweaning periods, and at the end of the experiment on d 63, the calves fed ad libitum maintained an advantage in mean (+/- SEM) body weight (89.07 +/- 2.47 kg vs 81.07 +/- 2.47 kg for the conventionally fed calves). Incidence of diarrhea was low and did not differ between treatment groups. We conclude that ad libitum nipple feeding of milk to dairy calves can allow for increased milk intake and weight gain with no detrimental effects on intake of solid food after weaning.     

Effects of ad libitum milk replacer feeding and butyrate supplementation on behavior,immune status,and health of Holstein calves in the postnatal period

Animal welfare in dairy calf husbandry depends on calf rearing and is probably improved by intensive milk feeding programs. In addition, butyrate supplementation in milk replacer (MR) stimulates postnatal growth and may affect the immune system in calves. We have investigated the combined effects of ad libitum MR feeding and butyrate supplementation on feeding behavior, health, and the immune responses in calves. Holstein calves (n = 64) were examined from birth until wk 11 of age. Calves received MR either ad libitum (Adl) or restrictively (Res) with (AdlB+, ResB+) or without (AdlB?, ResB?) 0.24% butyrate supplementation starting on d 4. From wk 9 to 10, all calves were gradually weaned and were fed 2 L/d until the end of the trial. Concentrate, hay, and water were freely available. Calves were housed in straw-bedded group pens with automatic MR feeders, where feed intake and feeding behavior were documented. Blood was drawn on d 1 before the first colostrum intake; on d 2, 4, and 7; and weekly thereafter until the end of the study to measure plasma concentrations of total protein, albumin, the immunoglobulins IgG₁, IgG₂, and IgM, and the acute phase proteins fibrinogen, serum amyloid A, and haptoglobin. Liver samples were taken on d 50 and 80 to determine gene expression related to acute phase proteins. Body temperature was measured daily for the first 3 wk, and clinical traits were scored daily. Ad libitum MR feeding resulted in greater MR intake, greater MR intake per meal, slower sucking rate, and greater body weight, but in a lower number of unrewarded visits and lower concentrate intake when compared with Res. Butyrate reduced the sucking rate but increased MR intake per meal. Immunoglobulins in the blood plasma increased after colostrum intake in all calves, with only minor differences among groups throughout the study. Plasma fibrinogen and serum amyloid A increased in the first week of life in all calves, and fibrinogen was greater in Res than in Adl on d 21, 49, and 63. Hepatic gene expression of fibrinogen on d 80 was greater in Adl than in Res. Gene expression of SAA2 was greater on d 50 in Adl than in Res and on d 80 was greater in ResB+ than in ResB?. Body temperature was greater in Adl than in Res during the first 2 wk, but neither MR feeding nor butyrate affected the health status. An improved animal welfare in Adl calves is supported by fewer signs of hunger, but intensive milk feeding and butyrate did not affect the health and immune status of the calves in a consistent manner.     

Limit-feeding a high-energy diet to meet energy requirements in the dry period alters plasma metabolite concentrations but does not affect intake or milk production in early lactation

Limit-feeding dry cows a high-energy diet may enable adequate energy intake to be sustained as parturition approaches, thus reducing the extent of negative energy balance after parturition. Our objective was to evaluate the effect of dry period feeding strategy on plasma concentrations of hormones and metabolites that reflect energy status. Multiparous Holstein cows (n = 18) were dried off 45 d before expected parturition, paired by expected calving date, parity, and previous lactation milk yield, and randomly assigned to 1 of 2 dry-period diets formulated to meet nutrient requirements at ad libitum or limited intakes. All cows were fed the same diet for ad libitum intake after parturition. Prepartum dry matter intake (DMI) for limit-fed cows was 9.4 kg/d vs. 13.7 kg/d for cows fed ad libitum. During the dry period, limit-fed cows consumed enough feed to meet calculated energy requirements, and ad libitum-fed cows were in positive calculated net energy for lactation (NE_L) balance (0.02 vs. 6.37 Mcal/d, respectively). After parturition, milk yield, milk protein concentration, DMI, body condition score, and body weight were not affected by the prepartum treatments. Cows limit fed during the dry period had a less-negative calculated energy balance during wk 1 postpartum. Milk fat concentration and yield were greater for the ad libitum treatment during wk 1 but were lower in wk 2 and 3 postpartum. Plasma insulin and glucose concentrations decreased after calving. Plasma insulin concentration was greater in ad libitum-fed cows on d −2 relative to calving, but did not differ by dietary treatment at other times. Plasma glucose concentrations were lower before and after parturition for cows limit-fed during the dry period. Plasma nonesterified fatty acid concentrations peaked after parturition on d 1 and 4 for the limit-fed and ad libitum treatments, respectively, and were greater for limit-fed cows on d −18, −9, −5, and −2. Plasma tumor necrosis factor-α concentrations did not differ by treatment in either the pre- or postpartum period, but tended to decrease after parturition. Apart from a reduction in body energy loss in the first week after calving, limit feeding a higher NE_L diet during the dry period had little effect on intake and milk production during the first month of lactation.     

Ad libitum milk replacer feeding,but not butyrate supplementation,affects growth performance as well as metabolic and endocrine traits in Holstein calves

The enhanced growth performance of calves fed a higher plane of nutrition pre-weaning is well documented, and the effect of butyrate on the development of the gastrointestinal tract in calves has been evaluated. The aim of this study was to examine the synergistic effects of ad libitum milk replacer (MR) feeding and butyrate supplementation on growth performance and energy metabolism in calves. Sixty-four (32 male, 32 female) Holstein calves were examined from birth until wk 11 of life. Calves received MR either ad libitum (Adl) or restrictively (Res) with (AdlB+, ResB+) or without (AdlB?, ResB?) 0.24% butyrate supplementation. Colostrum and transition milk were fed in predefined amounts (Res or Adl) for the first 3 d postpartum. Ad libitum and restrictive MR feeding with or without butyrate was performed from d 4 until wk 8 of age. From wk 9 to 10, all calves were gradually weaned and were fed 2 L/d until the end of the trial. Concentrate (CON), hay, and water were freely available. Intakes of MR and CON were measured daily. Calves were weighed at birth and weekly thereafter. Blood was drawn on d 1 before the first colostrum intake; on d 2, 4, and 7; and weekly thereafter until the end of the study to measure plasma concentrations of metabolites and hormones. Liver samples were taken at d 50 and at the end of the study to determine gene expression related to glucose metabolism. Milk, MR, and total nutrient intake were greater, but CON intake was lower in Adl than in Res calves, resulting in a greater body weight, but partially lower gain to feed ratio in Adl than in Res. Plasma concentrations of glucose and insulin were higher during the ad libitum milk-feeding period, whereas plasma β-hydroxybutyrate was lower in Adl than in Res. Plasma concentrations of nonesterified fatty acids, lactate, total bilirubin, and cortisol were lower, but triglyceride and cholesterol concentrations were higher in Adl than in Res at specific time points. Feed intake, growth performance, and metabolic and endocrine changes were insignificantly affected by butyrate, and hepatic gene expression of enzymes related to endogenous glucose production was barely influenced by ad libitum MR feeding and butyrate supplementation. Intensive MR feeding indicated greater stimulation of growth and anabolic metabolism, but butyrate supplementation did not further improve postnatal growth or anabolic processes either in intensive or restrictive MR-fed calves.     

Effects of rearing diet, age at freshening, and lactation feeding system on performance

This two-phase trial involved 83 Holstein heifers. The rearing phase consisted of two diets (alfalfa silage plus corn grain for ad libitum intake vs. corn silage plus urea for ad libitum intake) and two breeding age groups (13 vs. 16 mo). The lactation phase compared the above treatments plus two lactation feeding systems: concentrate fed individually to production versus a TMR. The heifers were assigned randomly to the rearing phase at 7 wk of age and fed their respective diets until 14 d prepartum. They were placed on preassigned lactation diets 14 d prepartum and remained on the lactation phase for 550 consecutive d. Daily gains and height at the withers were similar between forage groups during the first half of the rearing phase; in the second half, the heifers fed alfalfa silage were taller at the withers. Those fed corn silage consumed less DM and CP throughout the rearing phase and gained more BW than the heifers fed alfalfa in the latter half. There were no differences in daily gain or DMI between the breeding age groups. In the lactation phase, the group fed alfalfa for ad libitum intake consumed more DM and gave more milk during the first 90 d of lactation than heifers fed corn silage. However, after 90 d the difference in cumulative milk production was not significant. There were no differences in milk production. FCM, or DMI between breeding age groups. The cows fed concentrate consumed more DM and gave more milk during the first 90 d of lactation. By 550 d, there were no differences. Feeding high levels of corn silage can cause heifers to have lower DMI in early lactation. These differences tend to disappear during the second lactation.     

Influence of ad libitum milk replacer feeding and butyrate supplementation on the systemic and hepatic insulin-like growth factor I and its binding proteins in Holstein calves

Ad libitum milk feeding and butyrate (B) supplementation have the potential to stimulate postnatal growth and development in calves. The somatotropic axis is the main endocrine regulator of postnatal growth and may be affected by both ad libitum milk replacer (MR) feeding and B supplementation in calves. We hypothesized that ad libitum MR feeding and B supplementation stimulate systemic and hepatic insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBP) in preweaning calves. Sixty-four (32 male, 32 female) Holstein calves were examined from birth until wk 11 of life. Calves received MR either ad libitum (Adl) or restrictively (6 L/d; Res). In each feeding group half of the calves received a MR with 0.24% butyrate and the other half received same MR without butyrate. Ad libitum MR feeding was performed from d 4 until wk 8 of age. From wk 9 to 10, Adl and Res calves were gradually weaned and were fed 2 L/d until the end of the trial. Concentrate, hay, and water were freely available. Feed intake was measured daily and body weight weekly. Blood samples for analyzing plasma concentrations of glucose, insulin, IGF-I, and IGFBP-2, -3, and -4 were taken on d 1, 2, 4, and 7, then weekly or every other week (IGFBP) until wk 11 of life. Liver samples were taken on d 50 and at the end of the study (d 80) to measure gene expression of the growth hormone receptor 1A (GHR1A), IGF1, IGFBP1 to 4, and of the IGF Type 1 and insulin receptor in the liver. Intake of MR and body weight were greater, but concentrate intake was lower in Adl than in Res. Plasma concentrations of IGF-I and IGFBP-3 were greater and plasma concentration of IGFBP-2 was lower in Adl than in Res during the ad libitum milk feeding period. After reduction of MR in both groups to 2 L/d plasma concentrations of IGF-I and IGFBP-4 were lower and plasma concentration of IGFBP-2 was higher in Adl than in Res. Supplementation of B depressed plasma IGF-I from wk 1 to 4 and in wk 9. On d 50, mRNA abundance of the GHR1A and IGF1 was greater and of IGFBP2 mRNA was lower in Adl than in Res. At d 80, IGFBP2 mRNA was greater in Adl than in Res, and IGFBP2 mRNA increased with B supplementation. Ad libitum MR feeding stimulated the systemic and hepatic IGF system and mirrored the greater growth rate during the ad libitum MR feeding, whereas butyrate supplementation partly reduced the systemic and hepatic IGF system.     

Comparison of red clover and ryegrass silage for dry cows and influence on subsequent lactation performance

The objective of this study was to investigate the use of red clover (RC) silage as a forage for dry dairy cows, primarily relative to its impact on tissue mobilization and repletion during the transition period and performance during the first 10 wk of lactation. Forty multiparous lactating Holstein-Friesian dairy cows were divided into 2 paired groups at 70 d before predicted calving dates; a subset (n = 8) of the cows were used for N and P balance measurements twice during the study. From the start of the experiment until 4 wk before predicted calving date all cows were offered ad libitum access to a ryegrass (RG) silage with no concentrate. At 4 wk before predicted calving date, one group of cows remained on the same diet, and the other group was changed to a diet of ad libitum access to RC silage. There was no difference in feed intakes, but CP intake was higher in cows fed RC silage, whereas ME intake was higher in cows fed RG silage. Cows fed RG silage gained more weight over the last 4 wk of the dry period (DP) than those fed RC silage, but there was no treatment effect on BCS. During the DP fecal N excretion was higher for cows fed RC silage, and there were no treatment differences in urine N excretion or overall N balance. At birth, calves from cows fed the RC silage were heavier. After calving, all cows were offered the same diet of ad libitum access to the same RG silage and a standard lactation concentrate. During the first 10 wk of lactation there was no difference in feed intake between the 2 previous treatment groups, and feed intake reached a maximum at approximately 4 wk of lactation. Cows on the RG treatment during the DP gained more longissimus dorsi muscle depth during the DP and retained it during early lactation. Mobilization of this muscle occurred before calving, indicating repartitioning of amino acids to other body tissues. There were no carryover effects of DP treatment on apparent partitioning of N from diet to milk, urine, or feces at wk 3 of lactation. Feeding RC silage during the DP had almost no impact on subsequent performance of dairy cows in early lactation, probably because the 2 silages were nutritionally very similar.     

Effects of photoperiod and pair-feeding on lactation of cows fed corn or barley grain in total mixed rations

Effects of photoperiod and type of grain were assessed using 47 cows (wk 1; 59.5 d of lactation) exposed daily to 16 h of light (long day) and fed randomly one of two diets containing an equal amount of cracked corn or rolled barley. During wk 5, cows were assigned within each diet to long day and ad libitum feeding, short day (8 h of light: 2 h of dark: 2 h of light: 12 h of dark) and ad libitum feeding, or long day and ad libitum feeding (wk 5 to 8) followed by pair feeding with short day cows between wk 9 and 16. Milk composition was not affected by treatments. Between wk 9 and 16, long day cows fed for ad libitum consumption or pair fed produced 5 to 11% more milk than cows exposed to short day; feed intake of long day cows fed for ad libitum consumption was greater than short short day and long day cows pair fed cows. Milk yield and total feed intake were not affected by type of grain in the diet. In conclusion, long day photoperiod increased milk yield and feed intake.     

Performance and fecal flora of calves fed a Bacillus subtilis concentrate

Eighty-four Holstein calves were assigned at 2 d of age to one of three treatments: 1) control with no additives; 2) 10 g of a mixed microbial concentrate containing Lactobacillus acidophilus, Lactobacillus lactis, and Bacillus subtilis; or 3) 10 g of a B. subtilis concentrate. The microbial concentrates were mixed with milk replacer during the a.m. feeding. The milk replacer was offered twice daily at 5% BW per feeding; the reconstituted replacer contained 12.5% DM. Volume of replacer fed was based on initial weight of calf and held constant until weaning. Water and starter ration were offered for ad libitum intake throughout the trial. Calves were weaned abruptly at 30 d of age and received only water and starter from d 31 to 44. General health and performance of all calves were good. Although differences in weight gain and feed efficiency were not significant, the B. subtilis concentrate tended to have a positive effect on feed efficiency during wk 1 to 4 and on immediate postweaning gain. A higher fecal bacilli count at 6 wk in calves fed the microbial concentrates may be related to their tendency for improved gain during d 31 to 44, the immediate postweaning period.     

Influence of feeding different amounts of milk on performance, health, and absorption capability of baby calves

The influence of feeding high milk on performance, health, and absorption capability of the small intestine was studied in Holstein calves (eight males and eight females). Animals were kept in outdoor hutches bedded with straw. Treatments consisted of two quantities of milk: 1) 4.1 kg of whole milk from 3 to 48 days of age when calves were weaned and 2) gradually increasing milk from 4.1 to 7.0 kg during the first 2 wk of treatment and feeding 7.6 kg per day thereafter until day 42. Milk was reduced gradually during the 7th wk. Intake of milk averaged 4.1 and 6.7 kg per animal per day. Commercial starter, alfalfa hay, and water were offered ad libitum to all calves. Higher milk resulted in larger weight gains (615 versus 538 g/day) and less starter intake. Total dry matter intake, feed efficiency, and scour scores were not different between treatments, but rectal temperatures were greater on high milk. Female calves fed high milk showed less xylose absorption and more days medicated than females fed less milk.     

Different milk feeding intensities during the first 4 weeks of rearing dairy calves: Part 3: Plasma metabolomics analysis reveals long-term metabolic imprinting in Holstein heifers

Adequate nutrition of calves is a fundamental requirement for efficient production in later life. Suboptimal nutrition before weaning could have detrimental long-term effects on metabolic health and could thereby decrease production efficiency. In this study, the metabolomic profiles of German Holstein calves reared on whole milk ad libitum (n = 10), milk replacer ad libitum (n = 9), and milk replacer in restricted amounts (n = 9) were compared. Furthermore, this profiling approach was extended to the first lactation in the same animals for characterizing the long-term effect of quantitative and qualitative dietary manipulations affecting calves during development in a period that is sensitive to metabolic imprinting. Blood plasma samples were collected on d 3, 22, and 52 of life as well as during wk 4 before and wk 3 and 8 after the first calving. Samples were subjected to a targeted metabolomics analysis using the AbsoluteIDQ p180 kit of Biocrates Life Science AG (Innsbruck, Austria). Profiling of metabolomics data was performed by principal component analysis and heatmap visualization of the metabolome, as well as by comparing fold changes and t-test statistics of metabolites. A quantitative identification of 180 plasma metabolites was possible, belonging to the metabolite classes of acyl-carnitines, AA, biogenic amines, phosphatidylcholines, lysophosphatidylcholines, sphingomyelins, and hexoses. Comparing metabolite concentrations between ad libitum-reared and restrictively reared animals revealed significant differences both during calfhood as well as during first lactation. Most dominantly, acylcarnitines of both short- and long-chain length were more abundant in ad libitum reared animals in the long-term, suggesting alterations in mitochondrial function, most likely indicating adaptive mechanisms of energy expenditure. Furthermore, plasma sphingomyelin concentrations were affected by ad libitum versus restricted milk replacer feeding, which can imply long-term modulatory mechanisms affecting insulin sensitivity. The functional characterization of the identified metabolic patterns, particularly the alterations of single lipid species, is required for further improving our understanding of the links between early nutrition shaping metabolic development and a healthy productive life of Holstein dairy cows.     

Effects of providing water from a bucket or a nipple on the performance and behavior of calves fed ad libitum volumes of acidified milk replacer

Little information is available on how much water ad libitum milk-fed calves consume during the milk-feeding stage and during weaning to solid feed. Further, no information exists on the effects on calf behavior and performance of different water delivery systems during these stages. Therefore, the objectives of this study were first, to examine the water intake of calves fed acidified milk replacer ad libitum during the milk-feeding and weaning stages, and second, to determine whether the method of water delivery affected water and feed intake and growth during these periods or oral behavior during weaning. To evaluate this, we registered feed and water intake, growth, and oral behaviors of 24 dairy calves before and after abrupt weaning from a 7-wk ad libitum acidified milk replacer feeding regimen. Two water sources (open bucket and nipple) were compared. During the 7-wk milk-feeding period, the calves drank, on average, 12.9 ± 0.7 L/d of acidified milk replacer but very little water. However, after abrupt removal of milk, the 2-mo-old calves rapidly increased their water intake. Moreover, no differences in water intake between the 2 water sources were noted either before or after abrupt weaning. Calves were observed to have some difficulties in using the water nipple. Calves provided water through the nipples consumed less water at each drinking bout but visited the water nipple more frequently compared with calves provided access to water from the bucket. We observed no differences in all other behaviors observed. Overall, the calves rapidly increased their feed intake, rumination time, frequency of cross-sucking, and vocalization after weaning. In conclusion, despite the calves’ consuming very little water when provided ad libitum access to acidified milk replacer, they dramatically increased their water consumption after abrupt weaning from milk. Calves did experience some difficulties in using the water nipples.     

Effect of extra energy as fat or milk replacer solids in diets of young dairy calves on growth during cold weather.

The effects of feeding two levels of supplemental fat and extra milk replacer solids on Holstein calves housed in hutches during the winter were investigated. Fifty calves (10 per treatment) were assigned to the following dietary treatments: 1) milk replacer (control) reconstituted to 12.5% DM fed at 10% of BW (adjusted weekly), 2) same as treatment 1 plus 113 g/d of supplemental fat, 3) milk replacer reconstituted to 15% DM and fed at 10% of BW (adjusted weekly), 4) same as treatment 1 plus 226 g/d of supplemental fat, and 5) milk replacer reconstituted to 15% DM fed at 14% of BW (adjusted weekly). Half the amount of milk replacer consumed during wk 4 was fed during wk 5, and calves were weaned to dry feed at 35 d of age. A pelleted starter was offered for ad libitum intake throughout the 42-d trial. Gains in BW were greater for calves fed 226 than 113 or 0 g/d of supplemental fat (d 3 to 28). Calves fed milk replacer reconstituted to 15% DM at 14% of BW had greater BW gains during d 3 to 28 than control. Starter consumption was similar between groups receiving 113 and 0 g/d of fat supplement but lower in the group fed 226 g/d. Extra milk replacer solids in diets increased fecal scores to levels greater than those of calves in other groups. The benefit of fat supplementation of milk replacers was manifested as increased BW gain during the 1st mo of life.     

Abomasal pH, nutrient digestibility, and growth of Holstein bull calves fed acidified milk replacer

Our objective was to compare nutrient digestion and utilization, amount and pattern of intake, and pH profile over time of abomasal contents in calves offered acidified milk replacer ad libitum or regular (sweet) milk replacer twice daily at 10% of body weight per day. Ten Holstein bull calves were fed replacers reconstituted to 13% dry matter for 4 wk. Daily milk replacer and water consumption and weekly body weight were recorded. Other variables were measured during the 2nd and 4th wk. Calves offered acidified replacer consumed more dry matter and gained more body weight than did calves fed sweet replacer; however, there was no difference in feed conversion ratio. Apparent digestibility of dry matter, ether extract, nitrogen, and retention of absorbed nitrogen were not affected by treatment. Acidified milk replacer offered ad libitum lowered the pH of abomasal contents and feces compared to regular replacer offered at 10% of body weight per day. Feeding patterns of calves offered acidified replacer ad libitum were variable. No adverse effects of feeding acidified milk replacer were noted.     

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.     

Ad Libitum or Twice Daily Feeding of Acidified Milk Replacer to Calves Housed Individually in Warm and Cold Environments

Forty-two Holstein calves were assigned randomly to treatments in a 2 × 2 factorial arrangement of two milk replacer feeding systems (ad libitum vs. twice daily feeding of cold acidified milk replacer) and two housing types (warm vs. cold). The objectives were to compare the cold ad libitum system with a twice daily regimen and to evaluate its use under two housing types. For wk 1 to 5, calves fed ad libitum consumed more dry milk replacer (.86 vs. .65 kg/d), less calf starter (.07 vs. .15 kg/d), and less free choice water (.50 vs. 1.29 kg/d) than calves fed twice daily. Gains for ad libitum vs. twice daily were not different, but were significantly higher for cold than warm housing possibly due to respiratory problems in the barn. Calves did not increase consumption of replacer in response to cold housing. For wk 6 to 8, no differences in intake were observed, but daily gains were higher for calves in warm housing (.74 vs. .49 kg). There were no differences in weights or daily gain at 24, 36, or 52 wk of age. Plasma glucose was higher for calves fed ad libitum (127.1 vs. 110.6 mg/dl). All calves showed two distinct plasma glucose peaks during a day, indicating that calves fed ad libitum may consume two meals per day instead of small frequent meals.Ad libitum feeding of acidified replacer did not result in improved growth despite higher replacer intakes. There were no differences in response to ad libitum feeding in warm or cold housing.     

Competition during the milk-feeding stage influences the development of feeding behavior of pair-housed dairy calves

This study investigated how the feeding behavior of pair-housed calves develops in response to reduced teat and feed place availability. Twenty Holstein bull calves were pair housed and provided with milk replacer (MR) and grain concentrate ad libitum via either (1) 1 teat and feed bucket/pen, such that calves could not feed simultaneously [competitive feeding (CF)] or (2) 2 teats and feed buckets/pen [noncompetitive feeding (NCF)]. The calves were weaned during wk 7 of life by incrementally diluting the MR. Postweaning, all pens were managed identically and offered a complete pelleted diet ad libitum via 2 feed buckets/pen (NCF) in period 1 (wk 8 and 9) and period 3 (wk 12 and 13) and exposed to a competitive challenge with CF in period 2 (wk 10 and 11). Feeding times and competitive interactions were recorded from video for 3 d/wk in wk 2, 4, and 6 and 2 d/wk in wk 8 to 13. Meal criteria were used to calculate daily meal frequency, meal time, and synchronized meal time (the percentage of meal time when calves within the pen were engaged in simultaneous meals). Milk replacer intake was subject to a treatment × week interaction, with calves in CF pens having lower MR intake (wk 2: 8.3 vs. 10.0 L/calf per day for CF vs. NCF), but compensating by increasing intake to a greater extent over time (wk 4–5: 13.3 vs. 11.7 L/d for CF vs. NCF). Corresponding to MR intake, meal frequencies and feeding times evolved differently over this period, increasing in CF pens and decreasing in NCF pens (wk 2: 5.8 vs. 11.1 and wk 4–6: 6.2 vs. 5.1 meals/d for CF vs. NCF). Calves in CF pens also spent less time engaged in synchronized meals (28 vs. 51% of meal time; standard error = 7.1) and displaced each other 5 times more frequently during synchronized eating. Postweaning, calves in previously CF pens maintained 5 times greater displacement frequencies and had fewer overlapping meals than calves in previously NCF pens (34.5 vs. 40.7% of meals, respectively). Postweaning, when calves were all fed noncompetitively (2 buckets/pen in periods 1 and 3), calves previously fed CF had greater intakes in period 3 (4.87 vs. 4.44 kg/d) and a tendency for greater intake in period 1 (2.80 vs. 2.63 kg/d), greater rates of intake in period 3 (87.8 vs. 72.0 g/min) and a tendency for greater rates of intake in period 1 (44.3 vs. 38.9 g/min), and greater meal frequencies in both periods (11.1 vs. 9.9 meals/d). In the competitive challenge period (1 bucket/pen in period 2), intake, rates of intake, and meal frequencies were subject to treatment × week interactions: calves in NCF pens had lower intake and meal frequencies, but increased meal frequency, intake, and rate of intake over time to a greater extent than calves previously in CF pens. These results indicate that calves are able to adapt to moderate competition by increasing meal frequency and that behavioral responses to competition persist postweaning.     

Evaluating effects of providing hay on behavioral development and performance of group-housed dairy calves

Providing access to forage has been shown to influence feeding behavior and non-nutritive oral behavior in individually housed calves, and these effects may be enhanced or altered in calves reared in social housing. We evaluated the effect of hay provision on the behavioral development and performance of group-housed dairy calves. Holstein calves (n = 32) were group-housed (4 calves per group) at 17 ± 3 (mean ± SD) d of age. All calves were provided milk replacer (8 L/d) via an automated milk feeder and pelleted starter and water ad libitum. Pens were randomly assigned to receive either chopped coastal Bermuda grass in buckets adjacent to the starter trough (starter and hay, STH; n = 4 pens), or no additional feed (starter only, ST; n = 4 pens). Calves were weaned through a 10-d stepdown program beginning at 46 d of age. Intake of solid feed and hay were recorded daily, and body weights were measured weekly. The behavior of 2 focal calves per pen was recorded continuously from video for 12 h on 2 consecutive days during each of wk 4, 6, and 7 of life, to measure solid feed intake time, grooming, and pen-directed sucking. Hay provision influenced total feed intake, with calves provided hay having greater total solid feed intake in the week before weaning (0.79 vs. 0.55 kg/d, STH vs. ST, respectively; SE = 0.19). Average daily gain (ADG) was similar during the pre-weaning period but tended to be greater for STH calves during weaning. Calves in pens provided hay also had fewer unrewarded visits to the milk feeder during weaning (12.5 vs. 21.1 visits per 12 h, STH vs. ST, respectively; SE = 3.59) and performed less pen-directed sucking (9.11 vs. 19.3 min per 12 h, STH vs. ST, respectively; SE = 2.86). Self-grooming time and bout characteristics evolved differently between treatments over time, with pens of calves provided hay having a greater increase in frequency and duration of self-grooming bouts during weaning. Overall, we found that providing hay to pre-weaned calves resulted in behavioral and performance benefits, including greater total feed intake and reductions in pen-directed sucking, suggesting that access to hay may improve calf welfare.     

Sodium bicarbonate and yeast culture effects on ruminal fermentation, growth, and intake in dairy calves.

Sodium bicarbonate and yeast culture effects on ruminal fermentation, intake, and growth were evaluated in young calves. In trail 1, nine ruminally cannulated Holstein calves averaging 12 wk of age were fed control starter (17% CP) or starters containing 3% sodium bicarbonate or .2% yeast (Saccharomyces cerevisiae) culture in a 3 x 3 Latin square. Calves were fed for ad libitum consumption for 10 d and then at 85% of ad libitum intake to d 14. Ruminal fluid taken at 0 h postfeeding tended to have higher pH and a greater proportion of acetate when calves were fed sodium bicarbonate, but other ruminal and blood parameters did not differ among treatments. By 4 h after feeding, ruminal VFA had increased to 120.7 mM, molar proportions of individual acids were altered, and blood ketones and VFA increased in treated calves. In trial 2, 42 Jersey calves were fed experimental starters for ad libitum consumption during a 12-wk study. Calves began the study at 3 to 5 d of age. There were no significant effects of yeast culture or sodium bicarbonate on DMI or intake of starter, rates of gain, or feed efficiency. Plasma urea N was reduced when sodium bicarbonate was fed. Both sodium bicarbonate and yeast culture affected blood and ruminal metabolites when calves were limit-fed but did not influence intake or daily gain when calves were fed for ad libitum consumption.