Calf Growth Research Articles

Management of phosphorus nutrition of beef cattle grazing seasonally dry rangelands: a review

This review examines the effects of phosphorus (P) deficiency as a major constraint to productivity of cattle grazing rangelands with low-P soils. Nutritional deficiency of P may severely reduce liveweight (LW) gain of growing cattle (e.g. by 20–60 kg/annum) and the productivity of breeder cow herds as weaning rate, mortality and calf growth. In seasonally dry tropical environments, the production responses to supplementary P occur primarily during the rainy season when the nutritional quality of pasture as metabolisable energy (ME) and protein is high and pasture P concentration is limiting, even though the P concentrations are higher than during dry season. When ME and nitrogen of rainy-season pasture are adequate, then P-deficient cattle typically continue to gain LW slowly, but with reduced bone mineralisation (i.e. osteomalacia). In beef breeder herds when diet P is insufficient, cows with high bone P reserves can mobilise bone P reserves during late pregnancy and early lactation. Mobilisation may contribute up to the equivalent of ~7 g diet P/day (one-third of the P requirements) in early lactation, and, thus, allow acutely P-deficient breeders to maintain calf growth for at least several months until depletion of cow body P reserves. However, severe P deficiency in cattle is usually associated with reduced voluntary intake (e.g. by 20–30% per kg LW), severe LW loss and poor reconception rates. When P intake is greater than immediate requirements, breeders can replenish bone P. Replenishment in mature cows occurs slowly when ME intake is sufficient only for slow LW gain, but rapidly at ME intakes sufficient for rapid LW gain. Bone P replenishment also occurs in late-pregnant heifers even when losing maternal LW. Intervals of mobilisation and replenishment of body P reserves will often be important for P nutrition of beef breeder cows through annual cycles. Diagnosis of P deficiency in grazing cattle is difficult and must encompass estimation of both diet P intake and availability of P from body reserves. Cattle behaviour (e.g. pica, osteophagea), low soil P concentrations and low herd productivity provide valuable indicators. Some constituents of blood (plasma inorganic P, calcium, plasma inorganic P:calcium ratios and endocrine markers) are valuable indicators, but the threshold values indicative of P deficiency at various ME intakes are not well established. It is evident that knowledge of both the nutritional physiology and requirements for P provide opportunities to better manage P nutrition to alleviate production losses in low-input systems with beef cattle grazing rangelands.

Age-related functional changes of total thyroid hormones and glycosaminoglycans in growing calves.

Background and Aim:During the physiological growing, thyroid and proteoglycan glycosaminoglycan (GAG) changes dynamically occur, according to genetic and non-genetic factors. The purpose of this research was to compare the effects of early postnatal development (10 days) until 210 days of life on the triiodothyronine (T3), thyroxine (T4), the relative T4:T3 ratio, and GAGs profile, and to define the different reference intervals of the calf’s development through the various growing phases.Materials and Methods:The effect of growing on total thyroid hormones and GAG profiles was studied from 10 days to 210days of age in 64 clinically healthy Brown calves, 30males and 34females. Blood samples were collected at 10, 20, 30, 60, 90, 120, 150, 180, and 210days of age.Results:The results showed a significant effect of a calf’s growth on T3, T4, and GAG values (p<0.0001). Significant correlations between T3 and T4 were observed. Compared to the previous time point, T3 showed a significant decrease at 20days and at 60days (p<0.01), while a significant increase was observed at 90days and 210days (p<0.05); T4 showed a significant decrease at 20days (p<0.01), while significant increases were observed at both 180days and 210days (p<0.05); GAGs showed a significant increase at 120days and 210days (p<0.05). Positive and significant correlations between BW and GAGs in both males (p<0.0057) and females (p<0.0059) were observed.Conclusion:It can be concluded that the highest T3 and T4 concentrations have been associated with the early growing process (10days), with an increasing trend also at 210days, it is possible to hypothesize a probable metabolic effect of thyroid function in anabolic and/or catabolic directions during the calves’ development. Likewise, it can be reasonably inferred that the highest plasma GAGs at 210days may be due to their metabolic role during the development of growing calves. Taken together, these findings suggest the potential and relative contribution made by thyroid and GAGs effects on the dynamics of growing calves.

The influence of "Stimix Zoostim" and "Normosil" probiotics on fecal microflora, hematologic indicators, nutrient digestibility, and growth of mother-bonded calves.

Aim:This paper presents the results of the studies on “Stimix Zoostim” and “Normosil” probiotics and their influence on fecal microflora, hematologic indicators, immunoresistance, nutrient digestibility, and growth intensity of mother-bonded calves.Materials and Methods:The calves of the control group were fed with their basic diet (BD) without “Stimix Zoostim” or “Normosil,” whereas the calves of the experimental group were fed with their BD supplemented with “Stimix Zoostim” and Normosil.” For 10-20-day-old calves, the daily dose was 10 mL per head, whereas 21-90-day-old calves received 15 mL of probiotics per head per day. The calves of the experimental group were administered probiotics every day. Calves aged 10 to 60 days received probiotics with milk, and then at the age of 61 to 90 days, received probiotics with water. (This is a sequential process. At 60 days old, calf rearing with milk stops, and after that, we use probiotics added to water to rear them). Both groups were administered probiotics twice a day, specifically 50% of the daily dose at each feeding time.Results:The results in this study proved that “Stimix Zoostim” and “Normosil” probiotics exhibit high probiotic activity and have a positive effect on the calves’ fecal microflora. Feeding the calves with probiotics resulted in a significant increase in the number of normal flora, such as lactic acid bacteria and bifidobacteria, and a decrease in the amount of Escherichia. It also resulted in an increase in red blood cells, hemoglobin, and γ-globulins within the physiological range. In our study, we found that the phagocytic reaction in the blood serum of the experimental group was slightly enhanced, suggesting a high response of the body to infectious agents.Conclusion:Thus, the group of calves receiving probiotic “Stimix Zoostim” exhibited an exceedance of phagocytic activity by 4.8% and the group receiving “Normosil” by 4.4%, in comparison with the control group. The daily dose of 10 mL of probiotics per head for 10-20-day-old calves and 15 mL per head for 21-90-day-old calves also had a positive effect on nutrient digestibility, growth, and forage consumption. The economic benefit per animal was 149.23 and 157.0 rubles, respectively.

Exposure to blue LED light before the onset of darkness under a long-day photoperiod alters melatonin secretion, feeding behaviour and growth in female dairy calves.

The effect of blue LED on melatonin secretion, feeding behaviour and growth was addressed in Holstein female dairy calves. In Exp.1, six animals (8weeks old, 97±4.1kg BW) were exposed to yellow or blue LED for 2hr before darkness over 7days under a long-day photoperiod (LDPP). In Exp. 2, six animals (8weeks old, 88.5±4.8kg BW) were exposed to blue light from a white LED all daytime or a yellow LED for 2hr before the darkness of LDPP (blue light cut) over 3weeks. In Exp. 1, blue light mildly suppressed melatonin secretion during the 2-hr treatment but did not affect the timing of the nightly melatonin rise. However, the rise in nighty melatonin levels was higher with yellow than blue LED. In Exp. 2, white LED completely suppressed melatonin secretion during the 2-hr treatment, but plasma melatonin concentrations were similar during the darkness. Grass hay intake, rumination time, frequency of water intake and body weight gain were higher in animals exposed to the yellow rather than the white LED. Overall results indicate that exposure to blue light from white LEDs under an LDPP suppresses melatonin secretion and might negatively impact the development of female dairy calves.

Branched-chain volatile fatty acids and folic acid accelerated the growth of Holstein dairy calves by stimulating nutrient digestion and rumen metabolism

The combined addition of branched-chain volatile fatty acids (BCVFAs) and folic acid (FA) could improve growth performance and nutrient utilization by stimulating ruminal microbial growth and enzyme activity. This study was conducted to evaluate the effects of BCVFA and FA addition on growth performance, ruminal fermentation, nutrient digestibility, microbial enzyme activity, microflora and excretion of urinary purine derivatives (PDs) in calves. Thirty-six Chinese Holstein weaned calves (60 ± 5.4 days of age and 107 ± 4.7 kg of BW) were assigned to one of four groups in a randomized block design. Treatments were control (without additives), FA (with 10 mg FA/kg dietary DM), BCVFA (with 5 g BCVFA/kg dietary DM) and the combined addition of FA and BCVFA (10 mg/kg DM of FA and 5 g/kg DM of BCVFA). Supplements were hand-mixed into the top one-third of total mixed ration. Dietary concentrate to maize silage ratio was 50 : 50 on a DM basis. Dietary BCVFA or FA addition did not affect dry matter intake but increased average daily gain (ADG) and feed conversion efficiency. Ruminal pH and ammonia N were lower, and total volatile fatty acids (VFAs) concentration was higher for BCVFA or FA addition than for control. Dietary BCVFA or FA addition did not affect acetate proportion but decreased propionate proportion and increased acetate to propionate ratio. Total tract digestibility of DM, organic matter, CP and NDF was higher for BCVFA or FA addition than for control. Dietary BCVFA or FA addition increased activity of carboxymethyl cellulase and cellobiase, population of total bacteria, fungi, Ruminococcus albus, R. flavefaciens, Fibrobacter succinogenes and Prevotella ruminicola as well as total PD excretion. Ruminal xylanase, pectinase and protease activity and Butyrivibrio fibrisolvens population were increased by BCVFA addition, whereas population of protozoa and methanogens was increased by FA addition. The BCVFA × FA interaction was significant for acetate to propionate ratio, cellobiase activity and total PD excretion, and these variables increased more with FA addition in diet without BCVFA than in diet with BCVFA. The data indicated that supplementation with BCVFA or FA increased ADG, nutrient digestibility, ruminal total VFA concentration and microbial protein synthesis by stimulating ruminal microbial growth and enzyme activity in calves.

Kraft Pulp: A Nobel Wood-based Supplementary Feed to Promote Growth of Calves

Kraft Pulp: A Nobel Wood-based Supplementary Feed to Promote Growth of Calves

Can fenbendazole-medicated molasses blocks control Toxocara vitulorum in smallholder cattle and buffalo calves in developing countries? Studies from upland Lao PDR

Context Anthelmintic treatments are not widely adopted by smallholder farmers in Laos (Lao People’s Democratic Republic) to treat bovid Toxocara vitulorum, resulting in high calf morbidity and mortality. Aims Field trials were conducted to provide baseline efficacy data on an alternative, easy-to-use treatment by provision of fenbendazole-medicated molasses blocks (FMB) in situ. Methods Participating villages were randomly allocated to the following treatments: (1) conventional orally administered pyrantel, (2) access to FMB, (3) access to non-medicated molasses blocks (MB), and (4) no blocks (control). Faecal eggs per gram (EPG) and weight were monitored in cattle (n = 171) and buffalo calves (n = 44) under field conditions for 48–56 days. Key results In 2016, the MB treatment was associated with the fastest reduction in predicted average EPG at 2% per day, while FMB and pyrantel had an equivalent reduction of 1% per day, relative to the control (P = 0.062). Predicted average weight also differed significantly among treatments, with pyrantel and MB having the greatest average daily gain at 230 g and FMB at 200 g, which was higher than for control calves at 170 g (P = 0.002). In buffalo calves, treatment was not significantly associated with EPG or weight. The 2018 trial corroborated that FMB and MB treatments were associated with increased EPG reductions in cattle at 3% per day, relative to control calves (P = 0.007). Again, the MB treatment had the greatest predicted average daily gain at 200 g, compared with FMB calves at 160 g and control calves at 150 g (P = 0.005). Conclusions The field trials provided baseline evidence that FMB and MB have potential applications in reducing environmental contamination of T. vitulorum eggs and may improve calf growth in low-input systems. However, further testing ex situ is required to control for variability in calf weight and T. vitulorum burdens, so as to optimise anthelmintic doses, assess the addition of urea to the block formula and assess product marketability. Implications If successful, medicated nutrient blocks may be a simple method to reduce calf mortality and morbidity, enhancing the reproductive efficiency of large ruminant production in smallholder farms in developing countries.

Short communication: administering an appeasing substance to Bos indicus-influenced beef cattle at weaning and feedlot entry

The bovine appeasing substance (BAS) is expected to have calming effects in cattle experiencing stressful situations. Therefore, this study investigated the impacts of BAS administration during two of the most stressful events within beef production systems: weaning and feedlot entry. In experiment 1, 186 Bos indicus-influenced calves (73 heifers, 113 bulls) were weaned at 211 ± 1 days of age (day 0). At weaning, calves were ranked by sex and BW, and assigned to receive BAS (Nutricorp, Araras, SP, Brazil; n = 94) or water (CON; n = 92). Treatments (5 ml) were topically applied to the nuchal skin area of each animal. Calf BW was recorded and samples of blood and tail-switch hair were collected on days 0, 15 and 45. Calves that received BAS had greater (P < 0.01) BW gain from day 0 to 15 compared with CON. Overall BW gain (days 0 to 45) and BW on days 15 and 45 were also greater (P ≤ 0.03) in BAS v. CON. Plasma haptoglobin concentration was less (P < 0.01) in BAS v. CON on day 15, whereas cortisol concentrations in plasma and tail-switch hair did not differ between treatments (P ≥ 0.13). In experiment 2, 140 B. indicus-influenced bulls (∼27 months of age) from 2 different pasture-based systems (70 bulls/origin) were transported to a commercial feedlot (≤ 200-km transport; day -1). On day 0, bulls were ranked by source and BW, and assigned to receive BAS (n = 70) or CON (n = 70) and the same sampling procedures as in experiment 1. Bulls receiving BAS had greater (P = 0.04) BW gain from day 0 to 15, but less (P < 0.01) BW gain from day 15 to 45 compared to CON. No other treatment effects were detected (P > 0.14). Therefore, BAS administration to beef calves alleviated the haptoglobin response associated with weaning, and improved calf growth during the subsequent 45 days. Administration of BAS to beef bulls at feedlot entry improved BW gain during the initial 15 days, but these benefits were not sustained throughout the 45-day experiment.

Breeding objectives and practices in three local cattle breed production systems in Burkina Faso with implication for the design of breeding programs

Understanding characteristics of production systems and identification of specific preferred traits related to breeding objectives is a first important step to the successful implementation of any breeding program. This study was conducted in the South West of Burkina Faso, the traditional habitat of trypanotolerant Baoulé cattle, to identify farmers’ trait preferences and breeding practices. Following a synthesis of information from stakeholders, a structural questionnaire was designed and administered to 194 heads of households. Cattle herd structure was investigated via herd survey on 101 farms to record breed, age, status, weight and linear body measurements of animals. Own herd ranking method was used in addition to identify the most important criteria for selecting breeding cows. The importance of each criterion was estimated by computing the index of ranking. Regarding breeds and herd mobility, sedentary pure Baoulé, sedentary mixed breed, and transhumant Zebu and crossbred systems were defined. Average cattle herd size was 51.23±55.72 heads and was significantly (P˂0.05) highest in the transhumant Zebu and crossbred system. Herd structure showed that cows were the most frequent age-sex-class in all the production systems. A high proportion of all farmers reported purposefully selecting their breeding animals but only 36.67% of them in pure Baoulé system select their breeding females. Breeding bulls were selected from young males in the own herd and they were selected significantly (P˂0.05) later in pure Baoulé system. The majority of transhumant farmers reported castration of not selected males while only 33% of farmers in pure Baoulé system reported that. The most important common criteria for selection among the production systems were adult size for both males and females, including calf growth for females. Production systems were heterogeneous on the other preferred traits. Based on these findings, implementation of breeding programs involving farmers and their specific characteristics and practices can contribute to improve and conserve local cattle breeds in this area. Community-based breeding programs for pure Baoulé and crossbreds aiming to improve body size and trypanotolerance are being implemented.

Technical note: Estimating body weight of dairy calves with a partial-weight scale attached to an automated milk feeder

Monitoring early growth in neonatal dairy calves provides insight into the effectiveness of a producer's nutrition program and helps monitor for sickness. The objective of this study was to validate whether a partial-weight scale attached to an automated milk feeder (Combi; DeLaval, Tumba, Sweden) could precisely and accurately estimate calf weights compared with twice-weekly weights of a calibrated electronic scale (gold standard; Brecknell PS1000; Avery Weigh-Tronix LLC, Fairmont, MN). Holstein heifers (n = 20) were enrolled in this study from birth until 84 d of age. All heifers were eligible to receive 10 L of milk replacer/d for 56 d and were subsequently weaned using a step-down strategy across 14 d. The automated milk feeder had a radio frequency identification panel placed directly above the scale such that calves had to stand with both front hooves on the scale platform to access milk from the nipple. An algorithm was created to summarize and clean the scale measurements of any non-biologically relevant data points. The relationship between the daily weight average from the partial scale and the electronic scale was analyzed using Pearson correlations, linear regressions, and Bland-Altman plots. Data from the partial weight scale were considered precise if the correlation coefficient and coefficient of determination were very high (>0.90) and the mean bias from the Bland-Altman plots included zero with the 95% interval of agreement. The partial-weight scale was considered accurate if the slope from the linear regression did not differ significantly from 1. We found a very high Pearson correlation coefficient (0.99) and coefficient of determination (0.99). Bland-Altman plots were deemed acceptable and nonbiased; the Bland-Altman difference (feeder weight - scale weight) was 0.45 ± 2.33 kg (mean ± standard deviation). The slope of the linear regression was not different from 1 (slope = 1.01; 95% confidence interval = 1.00-1.03), suggesting that the partial-weight scale was accurate. In summary, the partial-weight scale was validated, with a high precision and accurate estimate of weight in calves compared with the gold standard electronic scale. The partial-weight scale may be a useful tool for producers to estimate calf weight if a data cleaning algorithm is used.

Weaning Holstein Calves at 17 Weeks of Age Enables Smooth Transition from Liquid to Solid Feed.

Simple SummaryWeaning calves from liquid to solid feed can be a stressful event in their life and can affect growth, development and welfare. It is commonly done at the age of 7 to 8 weeks on dairy farms, but weaning at a greater age could potentially reduce the associated stress. Therefore, it might improve growth rates and enable a smooth transition to an adult liver metabolism. To confirm this hypothesis this study evaluated the effect of two different weaning ages (7 vs. 17 weeks of age) on female Holstein calves. Furthermore, the effect of mothers’ parity was analyzed (primiparous vs. multiparouos). Primiparous cows were often immature and still developing during their first pregnancy. This can lead to negative intrauterine conditions and result in long-term changes in the calf’s metabolism. Late-weaned calves consumed high amounts of concentrate feed before weaning despite their high milk replacer intake, indicating the maturation of their rumen. In addition, they experienced a smooth transition to an adult liver metabolism as reflected by steady plasma glucose and cholesterol concentrations. Later weaning corrected the reduced growth of calves born to primiparous cows as well, indicating that those particularly benefitted from late weaning. All benefits were indicated by slower changes of blood metabolites and higher growth rates, which might lead to better health and productivity in their subsequent lifetime. Development of calves depends on prenatal and postnatal conditions. Primiparous cows were still maturing during pregnancy, which can lead to negative intrauterine conditions and affect the calf’s metabolism. It is hypothesized that weaning calves at higher maturity has positive effects due to reduced metabolic stress. We aimed to evaluate effects of mothers’ parity and calves’ weaning age on growth performance and blood metabolites. Fifty-nine female Holstein calves (38.8 ± 5.3 kg birth weight, about 8 days old) were used in a 2 × 2 factorial experiment with factors weaning age (7 vs. 17 weeks) and parity of mother (primiparous vs. multiparous cows). Calves were randomly assigned one of these four groups. Live weight, live weight gain and morphometry increased over time and were greater in calves weaned later. Metabolic indicators except total protein were interactively affected by time and weaning age. Leptin remained low in early-weaned calves born to primiparous cows, while it increased in the other groups. The results suggest that weaning more mature calves has a positive effect on body growth, and calves born to primiparous cows particularly benefit from this weaning regimen. It also enables a smooth transition from liquid to solid feed, which might reduce the associated stress of weaning.

307 A social facilitator can reduce calf walking behavior at weaning

Abstract Common industry practice is to wean beef calves prior to natural weaning with the objectives of improving cow body weight and preparing calves for the subsequent receiving, growing, and finishing phases of production. Discontinuing the cow-calf social and nutritional bond before natural weaning, however, causes atypical walking and vocalizing behaviors by calves that are detrimental to calf growth and health. A proposed alternative weaning method is the addition of a social facilitator cow at weaning to reduce calf stress. Utilizing global positioning system (GPS) technology, we were able to determine total distance walked, total time devoted to walking, and area of the pasture utilized by the calf. Thus, the objective of the present study was to evaluate the effects of a social facilitator on calf growth during weaning and more specifically, walking behaviors, utilizing a Garmin® product. Angus x Simmental heifer calves (n = 80) were used in this study, and in all four replications calves were randomly allotted to each treatment group (n = 10), social facilitator (SF) or control (CON) on the day of weaning (day 0). Calves in the SF group were placed on pasture at weaning with a social facilitator, and CON calves were placed in a similar sized pasture without a social facilitator. All calves were allocated their own GPS tracking device on days 0 (weaning), 7, and 14 for a full 24 hours before removal. Data were analyzed as a randomized complete block design with repeated measurements (SAS 9.4). Placing calves with a social facilitator decreased the distance walked (P = 0.001), and the amount of time calves devoted to walking (P = 0.001). Placing a social facilitator with calves at weaning, therefore, has an effect on walking distance and amount of time calves devote to walking.

PSVIII-28 The effect of adaptogen on the growth and development of dairy calves

Abstract For the harmonious development, intensive growth and preservation of young animals in the diet it is necessary to include various feed additives, complexes, adaptogens that enhance the metabolic processes in the body. The purpose of the study is to study the feasibility and effectiveness of the use of adaptogen in calves rations. To achieve this goal in industrial conditions, 30 calves of Holstein breed at the age of 5–7 days were selected and divided into two groups of 15 animals each. The duration of the experiment was 90 days. Calves of the experimental group in milk, and then in concentrates included adaptogen “Energy” in the amount of 250 mg / kg body weight. The control animals were fed according to the standard scheme in the farm. The feeding mode for all calves was in accordance with the growing technology. The adaptogen includes: succinic, citric acid, inulin, oligofructose, methionine, lactic acid bacteria immobilized on aluminosilicate (patent RU 2493725). The results of the experiment (table 1) showed that the inclusion of an adaptogen provided a high growth rate throughout the entire period. At the end of the experiment, the body weight of calves of the experimental group was 6.52% (P &amp;gt; 0.05) higher compared to the control.

32 Nutritional management of forage-based cow-calf operations

Abstract The beef cattle industry in the Southeastern United States relies primarily on forages that not always meet the cowherd nutritional requirements, resulting in reduced performance if supplemental nutrients are not provided. Although precalving nutrition modulates postnatal offspring performance, most studies did not utilize Bos indicus-influenced cows consuming low-quality, warm-season forages. Hence, 3 studies evaluated the impact of different supplementation strategies during gestation on subsequent cow and calf performance.Study 1focused on timing of dried distillers grains (DDG) supplementation during late-gestation. Treatments initiated 84 d before calving and consisted of no supplementation, 1 kg/d of DDG from d 0 to 84, or 2 kg/d of DDG from d 0 to 42. Timing of prepartum DDG supplementation did not impact cow reproduction, but calf pre-weaning growth was enhanced only when cows received longer vs. shorter or no periods of prepartum supplementation. Study 2evaluated the use of prepartum supplementation of sugarcane molasses/urea added or not with DL-methionine hydroxyl analog. At 56 d before calving, Brangus heifers received no supplementation or molasses/urea (7.2 kg DM/wk) with or without methionine (105 g/wk; Alimet, Novus) until calving. Sugarcane molasses/urea supplementation improved cow BCS at calving and calf postnatal growth compared to no supplementation. However, supplemental methionine did not further enhance cow and calf growth performance. Study 3 compared winter vs. annual supplementation of sugarcane molasses/urea or range cubes. Starting on d 0 (pregnancy diagnosis; May), Brangus cows were assigned to receive molasses/urea supplementation during winter only (calving until end of breeding season) or year-round supplementation of molasses/urea or range cubes. Treatments had similar annual supplement DM amount (272 kg/yr). Year-round supplementation of molasses/urea and range cubes enhanced cow BCS at calving but did not impact pregnancy rate of cows and calf weaning weights than winter molasses/urea supplementation.

Effects of Low-Stress Weaning on Calf Growth Performance and Carcass Characteristics

ObjectivesThe objective of this study was to compare the influence of two low stress weaning methods with conventional weaning on post-weaning performance and carcass characteristics of beef steers.Materials and MethodsAngus × Simmental crossbred steer calves (n = 90) from a single source were stratified by body weight and dam age into three groups; one treatment was randomly assigned to each group: ABRUPT (calves isolated from dams on the day of weaning), FENCE (calves separated from dams via a barbed wire fence for 7 d prior to completely weaning), and NOSE (nose-flap inserted and calves remained with dams for 7 d prior to completely weaning). At d +7 post-weaning calves were transported to a commercial feedlot where they received standard step-up and finishing rations typical for a Northern Plains feedlot. To understand the influence of each weaning method on haptoglobin (an acute-phase protein), blood samples were collected via coccygeal venipuncture at d –7 (PreTreat), 0 (Weaning), and +7 (PostWean) from a subsample of calves (n = 10 per treatment) and analyzed using a bovine haptoglobin ELISA kit. Body weights (BW) were recorded on study d –34 (PreWean), –7 (PreTreat), 0 (Weaning), 7 (PostWean), 32 (Receiving), 175 (Ultrasound), and 253 (Final) and average daily gains (ADG) were calculated between each time period. On d 175 post-weaning BW were recorded, and ultrasound fat thickness and intramuscular fat were determined and utilized to project marketing dates. Carcass measurements were recorded at the time of harvest and included hot carcass weight, 12th rib backfat, ribeye area, USDA Yield Grade and Quality Grade, and marbling score. Haptoglobin, BW, and ADG data were analyzed as repeated measures using the ante-dependence covariance structure in the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) for effects of weaning treatment, day, and their interaction; birth weight was included as a covariate for ADG and BW. Carcass traits were analyzed for the effect of weaning treatment using the MIXED procedure. Separation of least-squares means was performed using LSD with a Tukey’s adjustment and assuming an α level of 0.05.ResultsWeaning method interacted (P &lt; 0.0001) with time period for ADG and BW. Calf BW increased in all treatments until the PostWean period, wherein BW decreased (P &lt; 0.0001) in ABRUPT and NOSE and was maintained (P &gt; 0.05) in FENCE. From the Receiving to Final time periods BW increased similarly (P &gt; 0.05) for all treatments. Calf ADG was greater (P &lt; 0.01) in calves in the NOSE treatment at Weaning than ABRUPT or FENCE. In the PostWean period, the FENCE calves had ADG that was not different (P &gt; 0.05) than zero but was greater (P &lt; 0.0001) than the negative ADG of ABRUPT and NOSE calves. During the Receiving period ADG was greater (P &lt; 0.05) for ABRUPT compared to NOSE and FENCE. Time influenced (P &lt; 0.001) haptoglobin concentration. No difference in haptoglobin was observed between the PreTreat and Weaning or PostWean periods; however, haptoglobin concentration was greater (P &lt; 0.001) at PostWean compared to Weaning. Weaning method did not influence (P &gt; 0.05) carcass measurements.ConclusionCollectively these data suggest low stress weaning methods do not significantly improve post-weaning growth performance or carcass merit compared to calves weaned using conventional methods.

Evaluation of Saccharomyces cerevisiae boulardii CNCM I-1079 fed before weaning on health and growth of male dairy calves

ABSTRACT Objective The objective of this study was to evaluate the efficacy of Saccharomyces cerevisiae boulardii CNCM I-1079 (SCB; Lallemand Animal Nutrition, Milwaukee, WI) in improving growth and fecal consistency in young dairy calves. Materials and Methods Male Holstein calves that arrived at a commercial rearing facility were randomly assigned to 1 of 3 treatment groups: control (no active dry yeast supplement); 5.0 g per head per day of ProTernative Milk containing 10 × 109 cfu of SCB (SCB5); or 10.0 g per head per day of ProTernative Milk containing 20 × 109 cfu of SCB (SCB10). These treatments were administered in the daily allotment of milk replacer. Fecal scores, bovine respiratory disease scores, and treatments administered were recorded on a daily basis. Body weight was measured at arrival and d 42 and 56 following arrival. Results and Discussion A total of 240 male Holstein calves were enrolled in the trial, with 80 calves in each respective treatment group. No differences among the groups were found with respect to mortality, fecal scores, or bovine respiratory disease scores. A growth advantage was found, especially in the postweaning period, with the SCB10 group having a 0.17 kg/d increase in ADG from d 42 to 56 after arrival when compared with the control. No difference in growth, however, was observed in the group fed SCB5. Implications and Applications This study demonstrates that supplementation of SCB before weaning is associated with a growth advantage, despite almost 30 and 7% of the calves experiencing diarrhea and pneumonia, respectively.

A negative energy balance during the peri-implantational period reduces dam IGF-1 but does not alter progesterone or pregnancy-specific protein B (PSPB) or fertility in suckled cows

The aim of this study was to evaluate the effect of a negative energy balance during the first third of gestation on metabolic, endocrine, and pregnancy recognition parameters in 2 beef cattle breeds adapted to semiextensive conditions. Seventy-five lactating Parda de Montaña and 40 Pirenaica multiparous cows rearing calves were synchronized and timed artificial inseminated (TAI) on day 76 postpartum. Cows were assigned to one of 2 diets (CONTROL or SUBNUT; 100% or 65% of their requirements supplied) until day 82 of gestation. Pregnancy was diagnosed 37 d post-TAI using ultrasound. Blood samples were obtained to determine metabolic (glucose, NEFA, β-hydroxybutyrate, cholesterol, and urea) and endocrine (IGF-1) status throughout the first third of gestation and to determine the concentrations of progesterone and pregnancy-specific protein B (PSPB) in the peri-implantational period. Undernutrition affected both cow and calf performance. The CONTROL cows maintained BCS and BW, whereas SUBNUT cows had negative daily gains. The CONTROL lactating calves had higher BW gains than SUBNUT. These negative effects were more evident in the Pirenaica breed, which was more sensitive to undernutrition. The negative energy balance was reflected in the cows’ metabolic profiles, with higher NEFA values and lower IGF-1 concentrations in SUBNUT cows. However, undernutrition did not affect dam pregnancy/TAI or pregnancy recognition and maintenance, confirming that during periods of undernourishment pregnant dams prioritize the allocation of dietary energy toward reproductive functions. Progesterone concentration on day 21 post-TAI (with a 4.8 ng/mL cut-off value) and PSPB on day 26 post-TAI (with a 0.57 ng/mL cut-off value) were determined as the earliest indicators to accurately establish dam pregnancy status, regardless of breed or nutrition treatment. In summary, early undernutrition affected cow performance and metabolic profiles and impaired lactating calf growth, but did not affect progesterone or PSPB concentrations or the pregnancy/TAI rate in suckled cows.

Effects of milk replacer feeding levels on performance and metabolism of preweaned dairy calves during summer

The objective of this study was to evaluate the effect of milk replacer (MR) feeding programs on performance and metabolism during summer. At 3 d of age (DOA), calves were randomly assigned to 1 of 4 dietary treatments: control [CON; 0.55 kg dry matter (DM) of a 20% crude protein (CP) and 20% fat MR per day], intermediate (IL; 0.66 kg DM of a 26% CP and 17% fat MR per day), high (HL; 0.77 kg DM of a 26% CP and 17% fat MR per day), or aggressive (AL; 0.87 kg DM of a 26% CP and 17% fat MR per day). Calves were managed similarly and housed in individual polyethylene hutches using sand as a bedding material. Because 3 calves fed the AL diet developed abomasum bloating during the first 30 DOA, the AL treatment was terminated. Milk replacer (12.5% solids) was offered twice daily until 42 DOA, when MR was fed once daily to reduce its intake by 50%. Calves were weaned at 49 DOA and remained in hutches until 56 DOA. Calf starter and water were offered ad libitum. Ambient temperature and relative humidity in and outside the hutches were assessed hourly. Starter and MR intakes were recorded daily. Respiration rate and rectal temperature were determined 3 times each week. Body weight was measured at 3, 14, 28, 42, and 56 DOA. Plasma was collected at 5, 10, 14, 28, 42, 43, 45, 47, 49, 51, and 56 DOA for analysis of glucose, β-hydroxybutyrate, triglycerides, nonesterified fatty acids, urea nitrogen, and insulin concentrations. There were no treatment effects on starter intake, rectal temperature, or respiration rate. By 7 DOA, calves fed the IL and HL diets consumed the same amount of MR and a higher amount of MR than the CON calves. At wk 2, calves from all treatments had similar MR consumption before returning to the projected intake by design at wk 4. Calves fed the IL and HL treatments had similar body weight but were heavier than those fed the CON diet at wk 6, 7, and 8. Calves fed the IL and HL diets had similar average daily gain, which was higher than that of calves fed the CON diet. There was no difference in plasma metabolites among treatments, but insulin concentration increased as milk allowance increased. In summary, feeding an intermediate level of MR during summer improved calf growth compared with the CON diet, but a higher MR allowance did not support further improvements in calf performance.

Changed Caecal Microbiota and Fermentation Contribute to the Beneficial Effects of Early Weaning with Alfalfa Hay, Starter Feed, and Milk Replacer on the Growth and Organ Development of Yak Calves.

Simple SummaryYak calves during the pre-weaning period are mainly fed by maternal grazing and nursing, which is beneficial to the oestrus and mating of female yaks or the survival and growth of calves. Barn feeding and early weaning with mixed rations of available roughage and grains was presented as an alternative to maternal grazing and was supposed to be beneficial to the tremendous ruminal and intestinal development and growth of yak calves. The caecum is also the primary site of microbial fermentation, but the limited research has focused on the role of caecal microbiota in regulating the growth of yaks. The findings of the current study indicated that early weaning by supplying calves with milk replacer, alfalfa hay, and starter feed improves yak calf growth performance compared with maternal grazing and nursing, in part through alterations of caecal microbiota and caecal volatile fatty acid (VFA) production induced by supplementation with alfalfa hay and starter feed.This study aimed to investigate the effect of early weaning by supplying calves with alfalfa hay, starter feed, and milk replacer on caecal bacterial communities and on the growth of pre-weaned yak calves. Ten 30-day-old male yak calves were randomly assigned to 2 groups. The maternal grazing (MG) group was maternally nursed and grazed, and the early weaning (EW) group was supplied milk replacer, starter feed, and alfalfa hay twice per day. Compared with the yak calves in the MG group, the yak calves in the EW group showed significantly increased body weight, body height, body length, and chest girth. When suffering to the potential mechanism of improved growth of yak calves, except for the enhanced ruminal fermentation, the significantly increased total volatile fatty acids, propionate, butyrate, isobutyrate, and valerate in the caecum in the EW group could also serve to promote the growth of calves. By using 16S rDNA sequencing, some significantly increased caecal phylum and genera, which were all related to the enhanced caecal fermentation by utilizing both the fibrous and non-fibrous carbohydrates, were identified in the EW group. In conclusion, early weaning of yak calves by supplying them with alfalfa hay, starter feed, and milk replacer is more beneficial to the growth of yak calves when compared with maternal grazing and nursing, in part due to alterations in caecal microbiota and fermentation.

Behavioural development in southern right whale calves

ABSTRACT: Most baleen whales migrate to low-latitude breeding grounds during winter to give birth and nurse their calves during the early stages of growth and development. While mothers invest a large amount of energy into the early development of their calves, the time allocated to important behaviours associated with maternal care (e.g. nursing) as well as the energetics related to the rapid growth of calves are important to quantify and understand to inform conservation measures. To investigate this, we conducted behavioural focal follows of southern right whale Eubalaena australis mother-calf pairs on a breeding ground in South Australia using unmanned aerial vehicles. Over the breeding season, we conducted behavioural focal follows of 51 mother-calf pairs for a total of 58 h across 75 d. Our observations showed that the proportion of time calves spent in nursing position and the duration of potential nursing bouts increased with increasing calf size throughout the breeding season, suggesting that calves seek to maximise energy acquisition. With increasing body size, the absolute metabolic expenditure of calves increased, underlining the importance of mothers being able to maintain low energy expenditure to ensure sufficient energy available for their calves during the nursing season. Our findings from this undisturbed population (1) demonstrate the considerable changes that calves undergo during the ~3 mo they spend on the breeding ground and (2) highlight the importance of these areas to be protected from anthropogenic disturbances that could disrupt the crucial maternal care, energy transfer and rapid early development of calves.