Growth Performance Of Dairy Calves Research Articles

Effects of pre-weaning supplementation with fennel seed powder in two terms on growth performance, health status, and blood metabolites of Holstein dairy calves

This study investigated the effects of fennel seed powder (FSP) supplementation in liquid feed on growth performance, health, and blood parameters of preweaning dairy calves. In a 2 × 2 factorial design, 56 one-day-old female Holstein calves (n = 14/treatment) received liquid diet [colostrum (4.5 kg/d for the first 2 d), waste milk (6 kg/d from d 3 to 43, 5 kg/d from d 44 to 45, 4 kg/d from d 46 to 47, 3 kg/d from d 48 to 49)] supplemented with either of 3 or 6 g FSP (FSP3 or FSP6) in two terms (T: 25 or 50 d). Biometric and health traits were recorded daily, and blood metabolites were analyzed at d 25 and 50. The experiment was conducted under mild heat stress. The FSP6 group showed significant increase in starter dry matter intake (g/d and % of BW), starter crude protein (g/d), starter ether extract (g/d), starter ME (Mcal/d), total dry matter intake (g/d and % of BW), and total crude protein intake (g/d) during the last ten days of the experiment. The FSP6 group also had a significantly higher average daily gain (g/d), overall body weight (d 1–51), final weight (d 51), and total hip width compared with the FSP3 group. Feed conversion was higher in the FSP6–25 T or − 50 T groups than in the FSP3–25 T (but not −50 T) group. Calves receiving 3 g of FSP had a higher likelihood of experiencing elevated rectal temperature [≥ 39.4 ºC, odds ratio (OR) = 1.583 and confidence interval (CI) = 1.25 to 2.00], poor general appearance [(1 = normal and alert; 2 = ears drooped; 3 = head and ears drooped, dull eyes, slightly lethargic; 4 = head and ears drooped, dull eyes, lethargic; and 5 = severely lethargic); ≥ 2, OR = 1.47 and CI = 1.14 to 1.91)], and diarrhea [(1 = normal; 2 = soft to loose; 3 = loose to watery; 4 = watery, mucous, slightly bloody; and 5 = watery, mucous, and bloody); ≥ 3 (OR = 1.36 and CI = 1.04 to 1.76)] compared to those in the FSP6 group. Conversely, calves in the FSP6 group had fewer days of increased rectal temperature (4.75 vs. 7.11 d), poor general appearance (3.93 vs. 5.75 d), and diarrhea (3.85 vs. 5.11 d) than those in the FSP3 group. In addition, serum levels of alanine transferase (15.90 vs. 16.98 U/L for FSP6 vs. FSP3) and malondialdehyde (1.24 vs. 1.43 nmol/mL for FSP6 vs. FSP3) were significantly lower in the FSP6 group than in the FSP3 group. In addition, longer feeding of FSP was more effective than shorter feeding in lowering both traits. A triglyceride-lowering effect was observed in the FSP3 group compared with the FSP6 group (27.45 vs. 30.90 mg/dL). Overall, supplementation of liquid feed with 6 g FSP for 25 or 50 d improved growth performance in dairy calves.

Optimizing amla (Phyllanthus emblica) fruit powder supplementation in liquid feed fed to Holstein dairy calves: Insights from growth performance and health events

Despite efforts at improvement, calf diarrhea remains one of the main problems in calf rearing. Amla (Phyllanthus emblica) fruit could be a good candidate to improve gut health due to its antimicrobial, gastro-protective, and immunomodulatory effects. This study aimed to evaluate the effect of amla fruit powder supplementation on frequency of diarrhea and growth performance of dairy calves. One hundred male Holstein calves [2-days (d)-old; 42.6 ± 1.7 kg body weight (BW)] were randomly assigned into five treatments, CON, PEF5, PEF10, PEF20, and PEF40, with 0, 5, 10, 20, and 40 g/d amla fruit powder (PEF) supplementation, respectively, and housed in individual hutches (n = 20 calves per treatment). The experiment lasted from 2 to 75 d of age (weaning) and calves were fed milk (2–7 d), milk replacer (8–75 d), and calf starter (2–75 d). The PEF supplementations were fed in two meals a day, equal amount each time, by mixing into milk or milk replacer. Feed intake and fecal score data were collected daily; BW and body frame measurements at 2, 14, 28, 42, and 75 d; and rumen fluid samples at 14, 28, 42, and 75 d. Starter and total dry matter intakes (DMI) differed among treatments during 22–75 with the highest in CON and linearly decreased with increasing PEF doses. Liquid feed DMI tended to decrease with increasing PEF doses. PEF supplementation had quadratic effect on body weight (BW), average daily gain (ADG), feed efficiency, body length, heart girth, and withers height. The BW and ADG differed among treatments during 29–75 and 15–75 d, respectively, with the highest in PEF5 followed by CON and lowest in PEF40. However, PEF did not improve BW and ADG compared to the CON. The overall feed efficiency in PEF5 was higher than in PEF20 and PEF40. PEF5 decreased the frequency of fecal score “3” (P = 0.02) while PEF5 (P < 0.01) and PEF10 (P = 0.03) increased the frequency of fecal score “1”, compared to the CON. Frequency of diarrhea in the PEF5 group (7.9%) was lower (P < 0.05) than all groups (11.1%, 14.3%, 22.6%, and 24.2% for PEF10, PEF20, and PEF40, respectively). Rumen fermentation (pH, ammonia-N, and volatile fatty acids) was not affected by PEF supplementation. However, ammonia-N showed a decreasing trend with increasing PEF levels. The results suggested that PEF could be fed at 5 g/d to reduce diarrhea in preweaning dairy calves.

The Influence of Feeding with Colostrum and Colostrum Replacer on Major Blood Biomarkers and Growth Performance in Dairy Calves.

Bovine colostrum (BC) is the first milk produced by lactating cows after parturition. BC is rich in various amino acids, proteins, and fats essential for the nutrition of the neonate calves. Despite the evident beneficial effect of BC on calves, the effect of BC on blood biomarkers is poorly understood. Calves that received BC showed significantly higher body mass at days 7 and 30 (38.54 kg and 43.42 kg, respectively) compared to the colostrum replacer group (p = 0.0064). BC induced greater quantities of blood neutrophils (0.27 × 109/L) and monocytes (4.76 × 109/L) in comparison to the colostrum replacer (0.08 and 0.06 × 109/L, respectively) (p = 0.0001). Animals that received BC showed higher levels of total serum protein (59.16 g/L) and albumin (29.96 g/L) in comparison to the colostrum replacer group (44.34 g/L and 31.58 g/L, respectively). In addition, BC induced greater intestinal mucus production in the Wistar rat model. Collectively, these results demonstrate that BC is important for the growth of calves and that it provides a significant beneficial effect on morphological and biochemical blood parameters.

Comparative evaluation of different bedding materials on growth performance of Murrah buffalo calves

Ideal bedding management is essential for optimal health, welfare, and growth performance of dairy calves. The study was conducted in order to compare the effect of different bedding materials on growth performance of Murrah buffalo calves. Murrah buffalo calves (n=20) of less than 4 months of age were selected and divided into four groups (5 animals/group), viz. T1: Concrete floor, T2: Concrete floor bedded with sand, T3: Concrete floor bedded with wheat straw and T4: Concrete floor bedded with rubber mat. Body weight and body measurement (body length, height of wither and heart girth) were taken at fortnightly and monthly intervals, respectively. There was no significant difference in body weight between treatment groups. However, average weight gain (kg) and ADG was significantly high in calves reared on T3 as compared to other treatment groups, though no significant difference was observed between T1, T2 and T4. Body length was significantly lower in T2 as compared to T3, however, difference in body length among T1, T2 and T4 groups was relatively non-significant. Moreover, body height and heart girth were significantly higher in calves reared on wheat straw floor as compared to concrete and sand bedded floor. Estimation of net profit per calf after reducing the bedding cost revealed that it was highest for wheat straw bedding followed by rubber mat, concrete and least for sand bedding. It can be concluded that wheat straw followed by rubber mat could be used effectively as bedding over concrete floor during winter season for rearing of calves.

Forage for Pre-weaning Calves: An Update

Forage nutrition for pre-weaning calves hosts numerous practical questions and on-farm challenges. The present review article aimed to update and address the biological consequences of forage provision to pre-weaned dairy calves. Health, nutrient intake (milk plus solid feed), and rumen development are the most important factors related to calf growth in pre- and post-weaning periods. A growing body of evidence suggests that the health and growth performance of dairy calves in the pre-weaning period are associated with their later performance as dairy cows. It seems that starter feeding strategies, including grain type, processing method, feed texture, and forage inclusion during the critical pre-weaning period may have profound effects on rumen function and calf performance. It is well understood that grain fermentation by-products are essential for increased growth and absorptive capacity of the rumen papillae. Forage provision as a part of a starter diet has been a topic of recent research. The rumen pH is the main factor altering the fate of fermentation and eventually animal health. In the pre-weaned calf, two major hypotheses exist regarding forage feeding. The first hypothesis describes that the rumen is not completely developed in pre-weaned calves and forage provision during this period might increase gut fill, and hence, decrease starter intake. It is believed that depressed starter intake may limit energy intake and finally suppress calf growth rate. The second hypothesis indicates that the rumen pH may decline as calves age and starter intake increases. Accordingly, forage inclusion in calf starter diets could prevent further rumen pH decline and subsequent negative consequences while improving starter intake and calf growth. Research data regarding these hypotheses are controversial. Many factors, such as milk feeding method, grain, forage type, and experimental conditions could affect calf responses to dietary forage. The current review focused on the biological consequence of forage provision to young calves to provide a practical framework for better use of forages in pre-weaned calves feeding programs. Keywords: Forage, Growth, Pre-weaned calf, Rumen development

Effects of group housing and incremental hay supplementation in calf starters at different ages on growth performance, behavior, and health

The present study examined the effects of age at group housing and age at incremental hay supplementation in calf starters from 7.5 to 15% (dry matter, DM) and their interaction on growth performance, behavior, health of dairy calves, and development of heifers through first breeding. A total of 64 calves (n = 16 calves/treatment, 8 male and 8 female) were randomly assigned to 4 treatments in a 2 × 2 factorial arrangement, with age at group housing (early = d 28 ± 2, EG vs. late = d 70 ± 2, LG; 4 calves per group) and age at incremental hay supplementation of calf starters from 7.5 to 15% of DM (early = d 42 ± 2 d, EH vs. late = d 77 ± 2, LH) as the main factors. All calves (female and male) were weaned at 63 days of age and observed until 90 days of age. Heifer calves were managed uniformly from 90 days of age until first calving to evaluate the long-term effects of treatment. No interactions were observed between age at group housing and age at incremental hay to calves on starter feed intake, performance, calf health and behavior, and heifer development through first breeding, which was contrary to our hypothesis. The age at which incremental hay supplementation was administered had no effect on starter feed intake, growth performance, or heifer development until first calving. When EG calves were compared with LG calves, nutrient intake (starter, total dry matter, metabolizable energy, neutral detergent fiber, starch, and crude protein), average daily gain, and final body weight increased. In addition, frequency of standing decreased and time and frequency of eating increased in EG calves compared to LG calves. Overall, early group housing leads to improved growth performance in dairy calves with no negative effects on calf health compared to late group housing.

The Effects of Amino Acid Supplementations during Weaning on Starter Intake and Growth of Dairy Calves

Supplementationof L-glutamine (Gln) at 1.0% of DMI has shown to enhance immune function,alleviate stress and promote growth in weaned piglets. Branched-chain aminoacids (BCAA) particularly leucine are known to promote muscle growth. Thoseenhancements are critical for calves undergoing weaning particularly from ahigh volume of milk at an early age. In the present study we examined theeffects of a Gln supplement (1.0% of DMI) with or without BCAA on starterintake and growth performance of dairy calves weaned early (35 d of age) from ahigh milk volume (9.0 L/d). &amp;nbsp;A separategroup of calves not receiving any amino acid supplement served as the control(CTL). &amp;nbsp;All calves were partially weaned restrictingthe milk volume to 3.0 L/d at 35 d of age. The amino acids were fed mixing inmilk during the first week of weaning (35 to 42 d). While having 9.0 L of milk,calves consumed zero grain but had average daily gain (ADG) close to 0.9 kg/d. Eventhough milk volume restriction significantly increased starter intake, it wasassociated with a significant growth depression that was not alleviated by Glnor Gln plus BCAA during the first week of weaning. During the second week ofweaning, calves had ADG that was comparable to pre-weaning growth rates.Regardless of treatments, calves achieved 1.0 kg/d starter intake within 16 dafter partial weaning and thus weaned completely at 51 d of age.&amp;nbsp; Calves supplemented with Gln or Gln plus BCAAwas related to significantly lower starter intake and body weight than CTL postweaning (49 to 70 d).&amp;nbsp; In conclusion, supplementationof Gln (1% of DMI) alone or with BCAA was not successful in mitigating growthdepression associated with weaning. On the other hand, they negatively affectedstarter intake post-weaning suggesting a lasting impact on mechanisms governingfeed intake. The present study demonstrated that 1.0 kg/d starterintake can be achieved at 7 week of age by employing a step-wise weaning schemefor dairy calves fed a high volume of milk.

Effects of replacing steam-flaked corn with shredded sugar beet pulp on feed sorting, behavior, blood metabolites, and growth performance of dairy calves.

This experiment was conducted to investigate the effects of partial replacement of steam-flaked corn (SFC) with shredded sugar beet pulp (SBP) in the starter diet on selective intake (sorting), feeding and chewing behavior, blood biochemical parameters, and growth in newborn female Holstein dairy calves. A total of 48 calves (3 d old; 40.1 ± 0.84 kg body weight; mean ± SE) were randomly assigned to 1 of 2 feeding treatments containing 0 or 25% SBP (percentage of dry matter [DM]) in the starter diet. Calves were weaned on d 61 and remained in the study until d 81. Intake of starter feed and total intake of DM (milk DM + starter feed DM), crude protein, and neutral detergent fiber were increased (P < 0.05) by feeding SBP; however, intake of starch (P < 0.01) and total intake of ether extract (P = 0.03) were decreased with no apparent effect on total intake of ME. Average daily gain, feed efficiency, final weight, and skeletal growth also showed no significant changes. Circulating concentrations of glucose, total protein, and albumin were not affected by partial replacement of SBP with SFC; however, higher concentrations of blood urea-N (P = 0.01) and a lower albumin-to-globulin ratio (P = 0.03) were observed in SBP- vs. SFC-fed calves. Calves fed SBP sorted more for particles retained on the 4.75-mm sieve (P = 0.02) and against particles retained on the 0.6-mm sieve and bottom pan (P < 0.01). Intake of neutral detergent fibers and starch from particles retained on all sieve fractions was increased and decreased (P < 0.01), respectively, by replacing SFC with SBP. Replacement of SBP with SFC was associated with increased meal length and meal size and increased rumination frequency and length, but decreased intervals between rumination (P ≤ 0.01). Calves fed SBP spent more time eating, rumination, and standing and less time lying and non-nutritive oral behaviors (P < 0.01). In general, 25% replacement of SFC with SBP did not affect calf performance but increased time spent rumination and eating and decreased non-nutritive oral behaviors.

Review: Effects of different forms of calf starters on feed intake and growth rate: A systematic review and Bayesian meta-analysis of studies from 1938 to 2021

ABSTRACT Purpose This study aimed to conduct a comprehensive review with meta-analysis to determine the effects of different forms of calf starters (ground, pelleted, textured, ground diets blended with hay, and textured diets blended with hay) on starter feed intake and growth rate of dairy calves during preweaning and postweaning periods. Sources The main sources for information and data included in this review were peer-reviewed literature from 1938 to 2021. The search engines Web of Science, PubMed, and Google Scholar were used. Findings of 37 full-text articles and 60 studies were Bayesian meta-analyzed for pooled estimates. Synthesis Newborn calves are not functional ruminants. Thus, this function must be developed, and that largely occurs due to the chemical composition of their diet and its fermentation in their rumens. There is ongoing discussion regarding what kinds of processing or form of calf starters should be used to improve growth performance of dairy calves. Conclusions and Applications This review article attempted to review all the literature related to different forms of starter feed (i.e., ground, pelleted, textured). It appears that considerable changes have occurred between 1938 and 2020 in the calf starter manufacturing process. Results of this meta-analysis showed that greater starter intake occurred when hay was supplemented to the finely ground starter (125 g/d) or when calves received textured starters compared with pelleted diets (107 g/d). Because variation is great in calf studies, there was not sufficient evidence for a recommended starter physical form for improving the growth rates of dairy calves. Processing of calf starter diets requires further investigation according to the guidelines for measuring and reporting calf and heifer experimental data.

Soybean oil supplementation and starter protein content: Effects on growth performance, digestibility, ruminal fermentation, and urinary purine derivatives of Holstein dairy calves

This study investigated the effects of feeding dairy calves starter diets containing 19% or 22% crude protein (CP) content on a dry matter basis and either supplemented or not with soybean oil (SBO, 0 vs. 3%, dry matter basis) on growth performance, digestibility, urinary nitrogen, and purine derivatives (PD) excretion. A total of 48 female Holstein dairy calves (mean 39.8 kg of body weight) were randomly distributed to experimental diets in a 2 × 2 factorial arrangement of treatments. The 4 dietary treatments were (1) starter diet without SBO supplement and 19% CP (NSBO-19CP), (2) starter diet without SBO supplement and 22% CP (NSBO-22CP), (3) starter diet with 3% SBO and 19% CP (SBO-19CP), and (4) starter diet with 3% SBO and 22% CP (SBO-22CP). Milk feeding value was similarly based on a constant protocol across experimental treatments and calves had ad libitum access to water and starter diets throughout the study. All calves were weaned on d 63 of age and remained in the study until d 83 of age. Calves supplemented with SBO had lower starter feed intake and average daily gain (ADG) and lower feed efficiency (FE) but had a higher fecal score indicating a higher likelihood of diarrhea occurrence compared with unsupplemented calves. Wither heights, digestibilities of organic matter, CP, and neutral detergent fiber were decreased, and ruminal volatile fatty acids tended to be reduced, and the molar proportion of ruminal butyrate (preweaning) and acetate (postweaning) reduced by supplemental SBO. The urinary allantoin and total PD excretion were reduced; however, urinary nitrogen excretion was increased when calves were supplemented with SBO. The CP amount did not affect starter feed intake, FE, or diarrhea occurrence rate, whereas the 22CP diets increased neutral detergent fiber digestibility, improved ADG (tendency), and increased allantoin and urinary PD excretion compared with the 19CP diets. The starter feed intake, ADG, FE, diarrhea occurrence rate, nutrient digestibility, and ruminal fermentation were not affected by the interaction between starter SBO and CP level; however, hip height and total PD in calves that received the SBO-22CP diets were higher than those fed the SBO-19CP diets. In conclusion, based on our experimental conditions, supplemental SBO could not be recommended for dairy calves. Furthermore, our findings indicate that SBO has negative effects on performance more attributed to reducing starter intake, digestibility, and ruminal volatile fatty acid concentration rather than because of a limitation of starter metabolizable protein supply and intestinal amino acid availability. Therefore, our results indicate that feeding the higher starter CP content is not a viable strategy to compensate for the negative effects of SBO supplementation on the growth performance of dairy calves.

Effect of calf starter on the growth performance of dairy calves

Dairy calves must be fed appropriately to meet their nutritional needs, supporting optimal growth and development to achieve the recommended target age at first calving (AFC) of 24 months. Traditional restricted milk feeding practices suppress growth, contribute to negative welfare states and may result in malnutrition and immunosuppression. In this study a total of eight high yielding calves (four Holstein Friesian and four Sahiwal breed) whose average body weight was 44.8 kg and 58 kg respectively. The supplied calf starter was composed of maize crushed, rice polish, wheat bran, gram broken, mustard oil cake, vitamin mineral premix, molasses and common salt. Calf starter was supplied initially 0.25 kg/day/calf in equal halves to the experimental calves twice a day i.e. at 7.00 AM and 12.30 PM and gradually increase upto 1 kg/d/calf. Average body weight gain, wither height gain, body length gain, barrel height gain, and hip height gain in Sahiwal and Holstein Friesian calves were 65.97±1.04 Kg, 31.04±1.13 inch, 32.34±1.46 inch, 12.80±0.71 inch, 35.05±1.27 inch, and 53.61±2.41 Kg, 29.78±1.17 inch, 30.93±1.66 inch 11.78±0.66 inch, 33.44±1.41 inch respectively. Our study concluded to establish a consensus on calf feeding standards which support physiological function, facilitate weaning, support growth targets and ensure calf health and welfare is protected.&#x0D; Asian Australas. J. Biosci. Biotechnol. 2020, 5 (2), 60-64

Effects of conditioner retention time during pelleting of starter feed on nutrient digestibility, ruminal fermentation, blood metabolites, and performance of Holstein female dairy calves

This study evaluated the effects of conditioner retention time during the pelleting process of starter feed on intake, nutrient digestibility, ruminal fermentation, blood metabolites, and growth performance of dairy calves. A total of 30 Holstein female dairy calves [40 ± 1.93 kg of body weight (BW)] were randomly assigned to 1 of 3 treatments: (1) pelleted starter conditioned for 0 min (CON), (2) pelleted starter conditioned for 2 min, and (3) pelleted starter conditioned for 4 min. Three pelleted starter feeds had similar nutritional composition, and the starters were blended with 3% chopped wheat straw and fed to individually housed calves from d 3 to 70 of age. All calves were fed 4 L/d of pasteurized whole milk twice daily at 0800 and 1600 h from d 3 to 50 of calf age, followed by 2 L/d of morning feeding from 51 to 56 d of age. All calves were weaned on d 56 of age and remained in the study until d 70 of age. With the increase of conditioner retention time during pellet processing for 0, 2, and 4 min, the gelatinized starch content of pelleted starter feed linearly increased from 14, 30, and 45%, respectively. Additionally, the pellet durability and hardness also linearly increased with increasing conditioner retention time during pelleting. Feeding pelleted feed prepared using different conditioner retention time did not affect feed dry matter intake, metabolizable energy intake, weaning BW, final BW, or feed efficiency during the study. We observed no differences in the total-tract apparent digestibility of organic matter, neutral detergent fiber, and crude protein around weaning (d 49 to 56 of age) and after weaning (d 63 to 70 of calf cage); however, the digestibility of dry matter and starch after weaning was increased with increasing conditioner retention time during pelleting of starter feed. No difference was found in overall average daily gain (ADG) or growth rates of hip height, withers height, and heart girth. Ruminal volatile fatty acid profile was not affected by pelleting under different conditioner retention times. The ruminal ammonia concentration tended to be lower for calves fed the 4-min diet compared with those fed the CON diet during the postweaning period. The postweaning (d 57-70 of age) ADG was greater for calves fed the 4-min diet compared with those fed the CON diet. In conclusion, the conditioning time during the pelleting process of starter feed increased the gelatinization of starch, durability, and hardness of the pellets but did not influence feed intake, feed efficiency, and skeletal growth during the first 70 d of age. Increasing conditioning time during the pelleting process improved postweaning ADG; however, the final BW of calves was similar among treatments.

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

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

Effects of linseed oil and rumen undegradable protein:rumen degradable protein ratio on performance of Holstein dairy calves.

The present study evaluated the interaction effects of n-3 fatty acids (from linseed oil (LSO), 0 v. 2·5, % DM basis) with rumen undegradable:degradable protein (RUP:RDP) ratios (low ratio (LR) 27:73; high ratio (HR) 38:62 based on crude protein %) in dairy calves' starter diet. Forty-eight 3-d-old female Holstein dairy calves (41·5 kg of body weight (BW)) were allocated in a 2 × 2 factorial arrangements in the following treatments (n 12 calves/each): (1) no supplementation of LSO with LR (NLSO-LR); (2) no supplementation of LSO with HR (NLSO-HR); (3) supplementation of LSO with LR (LSO-LR) and (4) supplementation of LSO with HR (LSO-HR). The calves were weaned on day 53 of the experiment and remained in the study until day 73. Intake was not affected by LSO and RUP:RDP ratio. However, average daily gain (ADG) was improved with LSO supplementation. Feeding the HR diet increased ADG compared with the LR diet during the entire period. Final BW was greater in calves fed on the LSO than those fed the NLSO diet. Microbial protein production did not differ among treatments. Calves fed on LSO diets had greater feed efficiency than those which were not fed on LSO diets. The calves supplemented with LSO had greater wither and hip heights compared with the unsupplemented calves. The glucose, cholesterol, HDL and insulin concentrations increased in calves supplemented with LSO. In conclusion, the HR diet improved calves' performance post-weaning; however, LSO could enhance growth performance of dairy calves during the pre-weaning period.

Prevalence and species composition of major internal and external parasites of calves in selected dairy farms of Bahir Dar milk-shade

This study was carried out from October 2013 to November 2014 in selected dairy farms of Bahir Dar milk-shade to estimate the prevalence and species composition of major internal and external parasites and to examine the associated risk factors in dairy calves. A total of 168 and 77 dairy calves less than 9 month old were used to study the prevalence of calf internal and external parasites, respectively. Type of internal and external parasites, degree of nematode infection (EPG) and packed cell volume (PCV) were determined by using standard parasitological and hematological procedures. The overall prevalence of internal and external parasites was 65.5% and 45%, respectively. The prevalence of Coccidia, Strongyle spp, Ascaris, Monezia, Paramphistomum, Trichuris, Schistosoma and Fasciola spp. was 25.6%, 20.8%, 17.1%, 14.3%, 6.0%, 3.0%, 1.8% and 0.6%, respectively. A significant difference (p&lt;0.05) was observed in strongyle and coccidia infection across season and dairy production system. Major external parasites of calves were ticks (23.4%), flea (16.9%) and lice (7.8%). Boophilus decoloratus (17.1%), Amblyoma varigatum (2.6%) and Rhipicephalus evertsi-evertsi, (2.6%) were the prevailed tick species found in the study area. The prevalence of B. decoloratus was significantly (p&lt;0.05) higher in peri-urban (26.8%) than urban (5.6%) dairy. Ctenocephalidae flea (18.4%) and two species of lice, L. vitulli (6.6%) and D. bovis (1.3%) were also recovered from dairy calves. In conclusion, the overall prevalence of calf internal and external parasites reported in the present study area was considerably high. This could affect the health and growth performance of dairy calves in the study ares. Therefore, as poorly managed calves are susceptible to most endo and ectoparasites, strategic deworming and acaricide application with subsequent implementation of improved calf management practices is warranted.Keywords: Dairy calf; External parasites; Internal parasites; Prevalence; Species composition

Interaction between the physical forms of starter and forage source on growth performance and blood metabolites of Holstein dairy calves

The objective of this study was to investigate the effects of the physical forms of starter and forage sources on feed intake, growth performance, rumen pH, and blood metabolites of dairy calves. Forty male Holstein calves (41.3 ± 3.5 kg of body weight) were used (n = 10 calves per treatment) in a 2 × 2 factorial arrangement of treatments with the factors being physical forms of starter (coarse mash and texturized) and forage source [alfalfa hay (AH) and wheat straw (WS)]. Individually housed calves were randomly assigned to 1 of the 4 dietary treatments, including (1) coarsely mashed (CM; coarse ground grains combined with a mash supplement) starter feed with AH (CM-AH), (2) coarsely mashed starter feed with WS (CM-WS), (3) texturized feed starter (TF; includes steam-flaked corn, steam-rolled barley combined with a pelleted supplement) with AH (TF-AH), and (4) TF with WS (TF-WS). Both starters had the same ingredients and nutrient compositions but differed in their physical forms. Calves were weaned on d 56 and remained in the study until d 70. All calves had free access to drinking water and the starter feeding at all times. No interaction was detected between the physical forms of starter feeds and forage source concerning starter intake, dry matter intake, metabolizable energy (ME) intake, average daily gain (ADG)/ME intake, ADG, and feed efficiency (FE). The preweaning and overall starter feed intake, dry matter intake, and ME intake were greater for calves fed TF starter diets than those fed CM starter diets. The ADG/ME intake was greater for calves fed TF starter diets than that fed CM starter. The FE was greater for calves fed TF starter diets compared with those fed CM starter during the preweaning, postweaning, and overall periods. The WS improved FE during the postweaning period compared with AH. The physical form of starter, forage source, and their interaction did not affect plasma glucose, triglycerides, and very low-density lipoprotein concentrations. Ruminal pH was greater for calves fed TF starter diets than those fed CM starter on d 30 of life. An interaction was observed between the physical forms of starter diets and forage source for β-hydroxybutyrate on d 28. These results showed that when starter diets contained similar ingredients and nutrient contents, processing calf starters to reduce the number of fine particles can improve the growth performance in dairy calves. Furthermore, the provision of WS improved FE and ADG of calves during the postweaning period.

Nutrient intake, rumen fermentation and growth performance of dairy calves fed extruded full-fat soybean as a replacement for soybean meal

The objective of this study was to investigate the effects of extruded full-fat soybean (ESB) as a replacement for soybean meal (SBM) on nutrient intake, rumen fermentation, and growth performance of dairy calves. A total of 45 male Holstein dairy calves (42.0±0.5 kg of BW) were randomly assigned to one of three experimental diets: (1) 0% ESB (Control): 35.3% SBM no ESB; (2) 25% ESB: 27.0% SBM+9.0% ESB; and (3) 50% ESB: 19.0% SBM+19.0% ESB. All calves were weaned on day 56 of age and remained in the study until day 70 of age. During the pre-weaning and overall periods, substituting of SBM with ESB had no effect on intake of starter feed, metabolizable energy (ME), CP and non-fiber carbohydrate (NFC). Compared with the control, 50% ESB resulted in a decrease in starter feed intake, and intakes of other nutrients including CP, NFC and ME during the post-weaning period. Substituting SBM with ESB decreased intake of C16 : 0 and increased intakes of n-9 C18 : 1, n-6 C18 : 2 and n-3 C18 : 3 during the pre-weaning, post-weaning and overall periods. Using ESB as a replacement for SBM did not affect average daily gain, feed efficiency, rectal temperature and fecal score over the trial periods. Compared with control, the rumen concentration of NH3-N decreased for 50% ESB on days 35 and 56 of age but not when compared with 25% ESB. Rumen pH, total volatile fatty acids concentrations, and the molar proportions of ruminal acetate, propionate and butyrate were not different among treatments. Body measurements were not affected by the treatments. In conclusion, substitution of SBM with ESB may improve nitrogen utilization efficiency in dairy calves but slightly reduce post-weaning starter intake with no negative outcomes on growth performance and rumen fermentation.

Rumen fermentation, blood metabolites, and growth performance of calves during transition from liquid to solid feed: Effects of dietary level and particle size of alfalfa hay

This study evaluated the effects of particle size (PS) and dietary level of alfalfa hay (AH) on rumen fermentation parameters, blood metabolites, eating behavior, and growth performance in dairy calves during transition from liquid to solid feed. Sixty newborn dairy calves (41±2.5,kg of body weight) were used in a 2×2 factorial arrangement with the factors dietary AH level (medium, 12.5%, or high, 25%, on DM basis) and PS (fine=1mm or medium=3mm, as geometric means) of AH. Hence, the dietary treatments were (1) medium level of AH with fine PS (M-FPS), (2) medium level of AH with medium PS (M-MPS), (3) high level of AH with fine PS (H-FPS), and (4) high level of AH with medium PS (H-MPS). Particle size of AH did not affect total DMI (TDMI) during the preweaning period, although TDMI was greater for calves fed MPS than in those fed FPS during the postweaning and overall periods. Calves fed MPS spent more time eating solid feed and ruminating and less time on nonnutritive oral behaviors compared with FPS calves. The dietary level of AH did not affect behavioral parameters. Average daily gain of calves was not affected by dietary treatment before weaning. During the postweaning and overall periods, average daily gain was greater in calves fed MPS than in those fed FPS at the 25% AH level, but this effect was absent with 12.5% AH. Furthermore, the rumen pH values on d 35 and 70 of the study were greater for MPS than for FPS, regardless of the dietary level of AH. Effects of AH level, PS, and their interaction did not affect blood glucose concentrations in developing calves. These results indicate that feed intake, feeding behavior, rumen fermentation parameters, and blood β-hydroxybutyrate concentration may be affected by rations differing in forage PS; thus, providing calves with MPS can improve calf performance and reduce their nonnutritive oral behaviors.

Effects of supplementation level and particle size of alfalfa hay on growth characteristics and rumen development in dairy calves.

The aim of this study was to assess the effects of particle size (PS) of alfalfa hay on growth characteristics and rumen development in dairy calves at two levels of alfalfa supplementation. Fifty newborn dairy calves (42.7±2.2kg BW) were used in a 2×2 factorial arrangement with the factors supplementation level (low, 8%; or high, 16% on DM basis) and PS (medium, 2.92mm; or long, 5.04mm as geometrical means) of alfalfa hay. In addition, a control group without alfalfa hay was used. Hence, treatments were: control (C); low level with medium PS (LM); low level with long PS (LL); high level with medium PS (HM) or high level with long PS (HL). Growth performance of alfalfa-fed calves did not differ from control calves, but alfalfa supplementation decreased corneum thickness of the rumen wall. In alfalfa-fed calves, post-weaning starter intake was greater for LL calves than for LM calves. During the entire rearing period, starter intake was 26-32% higher for LL and HM calves than for LM calves. Pre-weaning average daily gain was higher for LL and HM calves than for HL calves, but this effect was not persistent over the entire rearing period. Final body weight decreased from 86 to 79kg when the level of long PS alfalfa hay increased from 8 to 16%, but increased from 78 to 87kg when the level of medium PS alfalfa increased from 8 to 16%. Regardless of PS and level, morphometric characteristics of rumen wall were generally similar among alfalfa feeding groups, but corneum thickness decreased from 8.7 to 6.1μm with greater PS at the low level. These results indicate that adequate, but not excessive, physical stimulation is required for appropriate rumen development and growth performance of dairy calves.

Effects of barley grain processing method (steam-processed vs. dry-rolled) on intake and growth performance of dairy calves

This study was conducted to determine the effects of barley processing method on the performance of pre-weaned dairy calves. The experiment comprised 12 bull calves which were offered either dry-rolled (DR) or dry-rolled plus steam-processed (DRSP) barley. During the pre-weaning period (from 14 to 56 days of age) the dry matter and energy intakes of the DRSP calves were higher than those of the DR calves (p<0.1). During weaning (56–70 days) and on average over the whole experiment (14–70 days) there were no differences in intake. The weight gain of the DRSP calves was 32% higher than that of the DR calves during the pre-weaning period (p<0.05). During weaning the DR calves grew 33% faster than the DRSP calves (p<0.1). There was no difference in gain on average over the whole experiment. This study indicates no need for steam-processing of barley offered to dairy calves.