Reconstituted versus dry alfalfa hay in starter feed diets of Holstein dairy calves: Effects on feed intake, feeding and chewing behavior, feed preference, and health criteria

Transition milk or milk replacer powder as waste milk supplements to cold-stressed neonatal Holstein dairy calves: Effects on performance, feeding behavior, and health

Young calves are more susceptible to cold than older animals due to their limited ability to regulate body temperature and lack of fat reserves and may have difficulty consuming the energy needed to cope with the cold by maintaining body temperature and meeting their metabolic needs, especially when fed constant levels of waste milk (WM) with less solids, which can be detrimental to health and future performance. An alternative to overcome this problem is increasing the milk's solids content to the existing volume by using different sources [milk replacer powder (MR) or transition milk (TM)]. Thus, we aimed to evaluate the effects of increasing the total solids of WM via MR (WM+MR) or TM (WM+TM) on the performance, feeding behavior, and health-related variables of cold-stressed dairy calves during pre- and post-weaning. We hypothesized that feeding WM supplemented with MR or TM as potential liquid feed enhancers would improve milk dry matter and energy intake of the calves with a positive impact on body development and have no negative impact on feeding behavior and health. Additionally, we hypothesized that MR would not differ from TM. As a sample size calculation at 80% power using power analysis (PROC POWER) in SAS 9.4, a total of 51 Holstein-Friesian vigorous male calves [vigor score 21-27; 17 per treatment; 4-d old; body weight (BW) = 40.0 ± 0.63 kg (mean ± SD)] were selected, assigned randomly to treatments, and housed in individual pens in an outdoor barn. Irrespective of the type of treatment, all calves were fed 6 kg/d liquid feed from d 1 to d 53 of the experiment. In a step-down weaning program, calves received 0.5 kg liquid feed from d 54 to d 60. All calves were weaned on d 61 and remained in the study until d 101 as post-weaning evaluation. The calves had ad libitum access to starter feed and fresh drinking water across the experiment. Intake, growth, and behavior data were analyzed using a general linear mixed model and health data were analyzed using mixed logistic regression, mixed linear regression, and survival analysis models in SAS. We found that supplementation was responsible for a greater dry matter intake (DMI; P = 0.004), superior average BW (P = 0.037), and increased crude protein (CP; P = 0.001) and crude fat (CF; P = 0.001) intakes, with the most favorable outcomes observed for the WM+TM group when compared with WM+MR. Animals fed WM (control group; CON) showed a smaller average daily gain during the first 40-d of life (P = 0.026), showing slight changes during the whole period of evaluation when compared with the supplemented groups (SUP; WM+MR and WM+TM). No difference between MR- and TM-SUP groups, probability of having abnormal appearance (P = 0.032) and pneumonia occurrence (P = 0.022) was reduced in the SUP than in CON animals, with no effect on diarrhea among treatment groups (P = 0.461). Using milk supplements added to WM is an alternative to improve the intake, performance, and health of young calves under cold stress. Our findings showed that SUP animals outperformed the CON group in terms of DMI, average BW, and intake of CP and CF, with the TM-SUP group displaying the most favorable outcomes. Moreover, the SUP groups demonstrated reduced odds of experiencing abnormal appearance and pneumonia, highlighting the positive impact of supplementation on calf health.

Forage sources in total mixed rations early in life influence performance, metabolites, and behavior of dairy calves

The objective of this study was to evaluate effects of forage inclusion and sources on performance, metabolism, and feeding behavior of dairy calves. Forty-eight Holstein calves were blocked and randomly assigned to 1 of 4 dietary treatments according to sex and BW at 28 d of life to determine the effects of feeding forage sources (ensiled and dry), with different quality on performance, metabolites, and behavior. Treatments consisted of a no-forage coarsely ground starter (CON); or total mixed ration (TMR) containing 7.5% on a dry matter (DM) basis of Tifton hay of either medium quality (MH) or low quality (LH); or 10% on a DM basis of corn silage (CS). During the first 28 d of life, all calves received 3 L of whole milk twice daily, a commercial pelleted starter and no forage, and water ad libitum. After that, the solid diet was changed to the respective dietary treatments. Calves were gradually weaned from 52 to 56 d of age, and followed for 14 d postweaning. Individual solid feed and milk intakes were recorded daily, and BW and metabolic indicators of intermediate metabolism were recorded weekly. Behavior was recorded, and the analysis was conducted on wk 7 (preweaning) and 10 (postweaning). Solid feed intake increased at wk 7 and 8 when MH, LH, and CS were included in TMR; the same results were observed postweaning. The diets did not affect the average daily gain and BW, but the feed efficiency increased with the CON diet. The β-hydroxybutyrate concentration was greater in calves receiving TMR-containing forage than CON diet. Furthermore, calves supplemented with forage had a greater rumination time. In conclusion, all forage sources included in the TMR showed feed intake and behavior benefits, reinforcing the need for fiber from forage in pre- and postweaning diets.

Initial diet shapes resistance-gene composition and fecal microbiome dynamics in young ruminants during nursing

This study was conducted to examine how colostrum pasteurization affects resistance genes and microbial communities in calf feces. Forty female Holstein calves were randomly assigned to either the control (CON) group, which received unheated colostrum, or the pasteurized colostrum (PAT) group. The calves body weight was measured weekly before morning feeding. Calf starter intake were measured and recorded daily before morning feeding. Samples of colostrum were collected before feeding. Blood was collected on d 1 and 70 before morning feeding. Ten calves were randomly selected from each group (n = 20 calves total) for fecal sampling on d 3, 28, 56 and 70 for subsequent DNA extraction and metagenomic sequencing. Total bacterial counts in the colostrum were markedly higher in the CON group than in the PAT group. Pasteurized colostrum administration substantially reduced the ARO diversity and diminishes the abundance of Enterobacteriaceae, thereby decreasing their contribution to resistance genes. Pasteurization also reduced glucoside hydrolase-66 activity in 3-day-old calves which led to an increase in the activity of aminoglycoside antibiotics, resulting in 52.63 % of PAT-enriched bacteria acquiring aminoglycoside resistance genes. However, from the perspective of overall microbial community, the proportion of aminoglycoside, beta-lactam and tetracycline resistance genes carried by microbial community in PAT group was lower than CON group (P < 0.05). Fecal samples from the PAT group contained greater abundances of Subdoligranulum (P < 0.05) and Lachnospiraceae_NK4A136_group (P < 0.05) on days 28 and 70 compared to CON. Network analysis and abundance variations of the different bacteria obtained by linear discriminant analysis effect size analysis showed that pasteurized colostrum feeding reduced the interactions among related bacteria and maintained stability of the hind-gut microbiome. In conclusion, these findings underscore the intricate interactions between early diet, calf resistance-gene transmission and microbial dynamics, which should be carefully considered in calf-rearing practices.

Growth performance, blood metabolites, ruminal fermentation, and bacterial community in preweaning dairy calves fed corn silage-included starter and total mixed ration

The objective of this study was to evaluate the effects of the inclusion of whole-plant corn silage (WPCS) in a starter or total mixed ration (TMR) on growth, blood metabolites, ruminal fermentation, and microbial community in preweaning dairy calves. A total of 45 healthy dairy calves were blocked by date of birth and randomly assigned to 1 of 3 treatments: 100% calf starter (CONS), a mix of 85% calf starter and 15% WPCS [dry matter (DM) basis; CSCS], or 100% WPCS-based lactation TMR (CTMR). Pasteurized normal milk was fed to all the animals under the same regimen. The experiment ran from when the calves were 2 d old to weaning at 63 d. Milk and feed intakes were recorded daily. Growth performance data and blood samples were collected on wk 3, 5, 7, and 9 of the experiment. Rumen fluid was sampled at 40 and 60 d. The 3 treatments had different particle size fractions. The CSCS group had greater medium fraction (<19 mm, >8 mm) and particles retained on 8-mm sieves than the other 2 groups, whereas the CTMR group had the greatest long (>19 mm) and fine (<4 mm) fractions and physically effective neutral detergent fiber (NDF) on 8- and 4-mm sieves, but had the smallest short fraction (<8 mm, >4 mm) and particles retained on 4-mm sieves. The 24-h in vitro digestibility of DM, crude protein (CP), NDF, and acid detergent fiber (ADF) were decreased in order by the CONS, CSCS, and CTMR groups. Compared with the CONS group, the digestibility of ether extract (EE) was lower in the CSCS and CTMR groups, whereas the digestibility of starch was similar among treatments. During the experimental period, the DM, CP, and metabolizable energy intakes from milk, solid feed, and total feed were not affected by treatments. The NDF, ADF, and EE intakes and potentially digestible intakes were greater in the CTMR group than in the other 2 groups. With the exception that body barrel was greater for calves fed CSCS, growth parameters and blood metabolites were similar among treatments. Compared with the CSCS group, the CTMR group had greater rumen pH and total volatile fatty acids, propionate, and isovalerate concentrations, but a lower acetate:propionate ratio. The CTMR group had greater relative abundances of some cellulolytic bacteria (Rikenellaceae RC9 gut group, Christensenellaceae R7, Ruminococcaceae NK4A214, Ruminococcaceae UCG, Ruminococcus, and Erysipelotrichaceae UCG) in the rumen, which may be beneficial for the early acquisition of specific adult-associated microorganisms. In summary, a WPCS-based lactation TMR, but not the WPCS-included starter, had the potential to be an alternative starter in preweaning calves without having significant adverse effects. These findings provide theoretical and practical implications for the rational application of TMR in the early life of dairy calves.

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

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

Development of ruminating behavior in Holstein calves between birth and 30 days of age

Ruminating behavior accompanies the development of the rumen and the intake of solid feed in calves. However, few studies have reported on the emergence and development of rumination. In this study, we observed ruminating behavior changes of 56 Holstein calves (body weight at birth = 40.1 ± 3.96 kg; mean ± standard deviation) from birth to 30 d of age under the feeding management of suckling calves that were only fed pelleted concentrate feed and milk. All calves were housed in individual pens equipped with infrared cameras. We explored feed intake within 30 d of age, body weight on 61 d of age, and other apparent indicators, including the age of first eating the bedding, duration of non-nutritive oral behavior at 25 and 30 d of age, total starter feed intake within 30 d of age, average daily starter feed intake within 30 d of age, and duration of ruminating behavior at 25 and 30 d of age for all calves, to further explore the effects of the age of first ruminating behavior (AFR). The AFR fitted the normal distribution and ranged from 15 to 20 d of age for 50% of the experimental population. The AFR was positively correlated with the age of first eating the bedding and duration of non-nutritive oral behavior at 30 d of age. Total starter feed intake within 30 d of age, average daily starter feed intake within 30 d of age, duration of ruminating behavior at 25 and 30 d of age, and duration of eating the bedding at 25 and 30 d of age were negatively correlated with AFR. Overall, to the best of our knowledge, this is the first study that has analyzed the correlation between AFR and other indicators. We found that earlier AFR was associated with shorter duration of non-nutritive oral behavior, longer durations of rumination and eating the bedding, and higher feed intake by 30 d of age.

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

Simple Summary

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

Abstract

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

Substituting corn silage with reconstituted forage or nonforage fiber sources in the starter diets of Holstein calves: effects on performance, ruminal fermentation, and blood metabolites

We examined the effects of replacing corn silage (CS) with reconstituted alfalfa hay (AH) or beet pulp (BP) in the starter diet on the nutrient intake and digestibility, growth performance, rumen fermentation characteristics, selected blood metabolites, and health status in Holstein dairy calves. Newborn female calves (n = 54; 3 d of age; 39.8 ± 1.36 kg BW) were assigned randomly to 3 groups receiving starter diets containing CS [10% dry matter (DM) basis; CS diet) and reconstituted AH (10% DM, RAH diet) or BP (10% DM; RBP diet). The starter diets had the same nutrient composition and DM content. The calves were weaned on day 50 and the study continued until day 70. Nutrient intake, body weight (at weaning and at the end of the study), daily weight gain, feed efficiency, and body measurements (including heart girth, withers height, body length, body barrel, hip height, and hip width) were not affected by the diet (P > 0.05). Health-related variables including rectal temperature, fecal score, and general appearance score were not influenced by the diets (P > 0.05). During the postweaning period, apparent total tract digestibility of DM, organic matter, and crude protein were higher for RBP (P = 0.001); however, digestibility of neutral detergent fiber was lower in RAH compared with CS or RBP (P = 0.001). Daily amount of nutrient digestibility did not change across the diets (P > 0.05). Rumen fluid pH and total volatile fatty acid concentration and profile were not different across the diets after weaning (P > 0.05). Calves fed RAH or RBP had higher blood concentration of β-hydroxy butyric acid compared with CS only before weaning (P = 0.03). Blood albumin concentration was higher for RBP compared with CS or RAH during the preweaning (P = 0.006) and overall (P = 0.005) periods; however, it was lower for CS compared with RBP after weaning (P = 0.03). Concentration of other blood variables including glucose, blood urea N, total protein, and globulin did not change across the diets (P > 0.05). Calves, in general, were healthy, and replacing CS with RAH or RBP in the starter diet had no beneficial effect on their feed intake or growth performance indicating that CS and reconstituted AH or BP can be used interchangeably in dairy calf starter diets until 70 d of age, allowing dairy producers more choices in selecting the feed ingredients.

Grain source and chromium supplementation: Effects on health, metabolic status, and glucose-insulin kinetics in Holstein heifer calves

Carbohydrate-rich diets may increase urinary excretion of chromium (Cr) and the need to supplement the diet with Cr to meet animal requirements. The present study was performed to examine the effect of the type of grain (corn vs. barley) and Cr-methionine supplementation on health-related variables, blood levels of metabolites and hormones related to energy metabolism, and insulin sensitivity in Holstein calves. Forty-eight newborn heifers (3 d of age) were assigned randomly to 4 diets in a 2 × 2 factorial arrangement. Experimental diets were either corn-based (CBD) or barley-based (BBD) diets supplemented with 0 or 0.05 mg/kg of metabolic body weight. Chromium was provided in milk before weaning (d 3-73 of age) and in prewarmed water after weaning (d 74-94 of age). There was no interaction between the type of grain and Cr on the health-related variables and blood metabolites and hormones. Type of grain did not affect fecal score, respiration rate, and rectal temperature; however, there were tendencies for higher diarrhea occurrence (odds ratio = 1.69) and lower chance of having pneumonia (odds ratio = 0.49) in calves fed BBD versus CBD despite longer duration of diarrhea (0.54 d) and shorter days with pneumonia (0.63 d) in calves fed BBD. Calves supplemented with Cr had lower fecal score during the preweaning and overall periods and respiration rate throughout the study. Supplemental Cr decreased the duration (0.63 d) and chance of having pneumonia (odds ratio = 2.01). Calves fed BBD had lower blood levels of urea N during the postweaning period, with no changes in other blood variables between CBD and BBD. Tendencies were detected for lower blood levels of β-hydroxybutyric acid during the preweaning and overall periods and higher cortisol in Cr-supplemented calves. Chromium supplementation increased insulin clearance rate and decreased the time to half-maximal concentration and the area under the curve in BBD but not CBD calves. The calves were generally healthy, and the type of grain did not affect the health and blood variables related to energy metabolism. However, Cr supplementation increased fecal consistency, decreased respiration rate and days with pneumonia, and increased insulin sensitivity when added to BBD.

Substituting corn silage with reconstituted forage or nonforage fiber sources in the starter feed diets of Holstein calves: Effects on intake, meal pattern, sorting, and health

We examined the effect of replacing corn silage (CS) with reconstituted alfalfa hay (RAH) or reconstituted beet pulp (RBP) in the starter diets on feeding behavior, sorting, and health criteria using 54 neonatal female Holstein calves that were assigned randomly to 3 groups receiving starter diets containing CS (10% on a dry matter basis), RAH, or RBP. The starter diets had the same nutrient composition and moisture level but differed in particle size distribution. Calves fed CS tended to have a lower intermeal interval compared with calves fed RAH before weaning; however, meal frequency and duration, eating rate, and meal size were not affected by treatment before and after weaning, which resulted in no changes in feed intake and time spent eating. Rumination frequency was higher for calves fed CS than for calves fed RAH or RBP after weaning. Feeding RBP decreased rumination duration compared with CS and RAH after weaning; however, calves fed RBP had a higher rumination bout interval compared with calves fed CS. Calves fed CS spent more time ruminating compared with calves fed RAH or RBP after weaning. Feeding CS tended to decrease and decreased time devoted to standing and lying, respectively, compared with calves fed RBP; however, calves fed RBP tended to spend more time on nonnutritive oral behaviors compared with calves fed RAH. Calves fed CS sorted against particles retained on the 8-mm sieve of the Penn State Particle Separator (PSPS) and for particles retained on the 1.18-mm sieve of the PSPS. Feeding RAH increased sorting for particles retained on the 8- and 1.18-mm sieves of the PSPS. Calves fed RBP sorted only for particles retained on the 1.18-mm sieve of the PSPS. Calves fed RBP tended to be more susceptible to developing pneumonia compared with calves fed CS or RAH; however, frequency and duration of diarrhea and pneumonia or number of days needed to medicate the diseases were unchanged across treatment groups. Initial (d 3) blood total protein concentration was similar (6.51 g/dL) across treatment groups. Overall, replacing CS with RAH or RBP did not affect time devoted to eating and feed intake due to no significant changes in meal size or intermeal interval before and after weaning. Calves showed feed sorting at the extent to which they balanced intake of nutrients and met their nutritional needs. Calves in general were healthy; therefore, CS, RAH, or RBP can be used interchangeably based on availability and competitive feed price.