Calf Feeding Research Articles

Effects of wheat straw particle size as a free-choice provision on growth performance and feeding behaviors of dairy calves

In the dairy calf feeding, supplementation of forage to the starter feed is commonly practiced. However, data are insufficient about how changes in particle size (PS) of forage affect calf performance and behavior in a free-choice forage provision system. This study aimed to assess the effects of supplementing wheat straw varying in PS on performance, skeletal growth characteristics, ruminal pH, nutritional behaviors, and blood metabolites of dairy calves. Forty-eight Holstein calves (43.8 ± 3.2 kg of BW) from d 15 of age were randomly assigned to one of the four treatments (n = 12/treatment; six males and six females): (1) starter without wheat straw supplementation (CON), (2) CON supplemented with wheat straw chopped at 1 mm geometrical mean particle length (GMPL) (fine PS), (3) CON supplemented with wheat straw at 4 mm GMPL (medium PS), and (4) CON supplemented with wheat straw at 7 mm GMPL (long PS). The calves were given ad libitum access to feed and water throughout the study. All calves were weaned on d 56 of age and continued the experiment until d 90. The starter, wheat straw, and total solid feed intakes were not affected by GMPL of wheat straw; however, CON calves had a lower solid feed-, total DM- and NDF-intake than calves offered wheat straw. Further, ADG, weaning, and final BWs as well as feed efficiency were similar between treatments. No difference was observed in growth rate of hip height, hip width, body barrel, wither height, and heart girth among treatments, however, wheat straw supplemented calves tended to have greater body length at weaning. Blood concentration of serum β-hydroxy butyrate was greater in wheat straw supplemented calves compared with CON calves on d 56 and 90. Calves supplemented with wheat straw spent more time eating starter and forage, lying and ruminating and less time for standing and non-nutritional behaviors compared with the CON calves on d 49 and 63 of the study. Moreover, calves offered wheat straw had greater ruminal pH than CON calves at 4 and 8 h after offering starter feed on d 35. In conclusion, supplementing wheat straw as a free-choice increased solid feed intake, rumen pH, and calves' welfare, however, PS of wheat straw had no effect.

Feeding behaviour and activity as early indicators of disease in pre-weaned dairy calves

Across the industry, there is large variation in health status of dairy calves and as a result, disease incidence and antibiotic use is high. This has significant implications for animal welfare, productivity and profitability of dairy and dairy-beef production systems. Technology-based early detection systems could alleviate these issues; however, methods of early detection of disease in dairy calves have not been widely explored. This study aimed to determine whether changes in activity and feeding behaviour can be used as early warning indicators of respiratory disease in calves. In total, 100 pre-weaned male Holstein calves (age: ~8−42 days) were used. Calves were group-housed and provided with starter diet, straw bedding and ad libitum water. Calves were fed milk replacer ad libitum through an automatic calf feeder, and each calf was fitted with a leg-mounted activity monitor. Daily activity and feeding behaviour variables were calculated for each calf. Each calf was assessed daily using a modified version of the Wisconsin Scoring System to assess respiratory disease status. Calves were classed as ‘Diseased’, ‘Intermediate’ or ‘Healthy’ based on their cumulative health score. The peak day of the most extreme illness event was identified for each calf. Data from Diseased and Healthy calves were paired for analysis based on age and BW. Data were compared for the day of peak illness, and for the 3 days previous and post. Compared to healthy calves, diseased calves lay for longer and tended to have longer lying bouts (daily lying: 17.6 ± 0.3 vs 16.7 ± 0.2 h, P < 0.01; bout length: 74.8 ± 10.6 vs 56.0 ± 3.7 min, P = 0.09 for diseased and healthy calves, respectively). Diseased calves fed for a shorter time and had fewer feeder visits (with intake) each day compared to healthy calves (feeding time (min): 19.3 ± 1.4 vs 22.8 ± 1.5; P < 0.05; visits: 2.1 ± 0.2 vs 3.2 ± 0.4; P < 0.05). Importantly, differences between diseased and healthy calves were evident in both activity and feeding behaviour on the days prior to the peak day of disease. Lying bout length was greater in diseased calves for the 2 days prior to the peak day (P < 0.05), lying time was longer on day −1 (P < 0.05) and feeder visits with milk intake were less frequent on day −3 (P < 0.05). Thus, measurement of feeding and activity using precision technology within early detection systems could facilitate early intervention and optimized treatment.

Metabolic and performance responses to the replacement of lactose by fat in milk replacer formulations for dairy calves

The recent trend in the dairy industry towards elevated planes of milk feeding of young calves requires reconsideration of calf milk replacer (CMR) formulations. The fat:lactose ratio in CMR is typically lower than that of whole milk and effects of increasing fat inclusion at the expense of lactose in CMR on nutrient metabolism and gut function of rearing calves are not sufficiently understood. Therefore, the current study aimed to determine the effect of increasing replacement of lactose by fat on growth performance, nutrient digestibility and metabolism, and glucose/insulin sensitivity. A total of 40 male calves (1.7 ± 0.10 days of age, 46.7 ± 0.76 kg BW) were blocked based on arrival date and randomly assigned to one of four treatments containing differing levels of fat and lactose (18F: 18.8% and 47.6%; 22F: 22.3% and 42.8%; 26F: 26.0% and 38.6%; 30F: 30.1% and 33.8%, fat and lactose DM, respectively). Calves were individually housed for the duration of the 11 week study and received their CMR (150 g/L) twice a day (0700 and 1600 h) from a teat bucket. The CMR feeding schedule consisted of 6 L/d from d 2 to 14, 7 L/d from d 15 to 56, and then 4 L/d during gradual weaning from 56 to 63 days. Pelleted starter, chopped straw, and water were available ad libitum throughout the study. Measurements included feed intake, growth, nutrient digestibility, fecal composition, and blood parameters. A glucose tolerance test (GTT) was performed between 28 and 32 days of age. By design, metabolizable energy intake from CMR increased linearly with fat level, but this did not result in a difference in BW, ADG, or concentrate intake. Fecal composition remained unaffected by treatment except for higher fat content in 22F compared to 26F. Also, plasma non-esterified fatty acids and total bilirubin differences were limited to 22F having the highest values whereas 26F had the lowest values. Regarding the GTT, total area under the curve (AUC) for glucose was highest in 22F and 26F and lowest in 18F whereas the AUC between 30 and 60 min for glucose was highest in 26F and lowest in 18F and 22F. Overall, altering the lactose:fat ratio in CMR did not affect growth performance while having minor effects on nutrient metabolism, but future investigation should focus on physiological consequences and effects in adult life to understand biological impact of fat and lactose levels in CMR for rearing calves.

Effect of milk allowance on the suitability of automated behavioural and physiological measures as early disease indicators in calves

This study investigated the effect of milk allowance on the suitability of behavioural and physiological responses, individually and in combination, as early disease indicators. A total of 120 heifer calves were assigned into a 5 L/d or 10 L/d milk allowance treatment group. Daily health checks were conducted to determine when calves presented clinical signs of neonatal calf diarrhoea (NCD). Automated calf feeders recorded milk feeding behaviour, and infrared cameras automatically recorded eye and cheek temperatures. Accelerometers recorded lying behaviour, and water drinking behaviour was recorded using an automated water system and video observations. Respiration rate was recorded once per day by counting flank movements. Calves were used as their own controls, with data analysed relative to the day of clinical identification (d 0). Based on changes which occurred over the 6 days prior to clinical signs of disease (across d -6 to 0), typically, feeding behaviours only changed significantly for calves on the 10 L/d milk allowance with an increase in total (P < 0.001) and rewarded visits to the feeder (P = 0.013), and a decrease in milk consumption (P = 0.011). Infrared temperatures only changed significantly prior to clinical signs for calves on the 5 L/d milk allowance, with a decrease in eye (P = 0.013) and cheek (P = 0.006) temperatures. Regardless of milk allowance, lying time (P = 0.028, 5- L/d; P = 0.011, 10 L/d), number of lying bouts (P < 0.001, 5 L/d; P = 0.007, 10 L/d), and average bout duration (P < 0.001, 5 L/d; P = 0.002, 10 L/d), changed significantly prior to clinical signs. The only significant change in water drinking behaviour prior to clinical signs was an increase in total trough visit duration for calves on the 5 L/d milk allowance (P = 0.029). Respiration rate showed no significant change prior to clinical signs regardless of milk allowance. For calves on the 10 L/d and 5 L/d milk allowances, the most suitable indicator of disease was the total number of visits to the feeder (P < 0.001) and the number of lying bouts (P < 0.001), respectively. Regardless of milk allowance, combinations of feeding and lying behaviours, and additionally infrared temperatures in the case of calves on the 5 L/d milk allowance, provided the strongest composite indicators of disease. Overall, results suggest milk allowance can influence the suitability of behavioural and physiological responses as early disease indicators. Milk allowance should be considered when determining which measures will act as the optimum indicator/s when developing and implementing algorithms into automated on-farm systems for disease detection.

Nevşehir İli Süt Sığırcılığı İşletmelerinin Yapısı ve Hayvan Besleme Uygulamaları Yönünden Değerlendirilmesi*

Bu araştırmanın amacı Nevşehir ili süt sığırcılığının genel durumu ve hayvan besleme alışkanlıklarını belirlemek-tir. Araştırma kapsamında Nevşehir ilinde süt sığırı yetiştiriciliği yapılan 105 işletme ziyaret edilerek anket çalışması yapılmıştır. Anket formunda işletmeye ve işletme sahibine ait genel bilgiler, buzağı büyütme ve besleme, düvelerin beslenmesi ve tohumlanması, sağmal ineklerin bakım, besleme, sağım, yemleme ve görülen hastalıklara yönelik soru-lar sorulmuştur. 105 işletmede toplam 9228 hayvan mevcuttur. Yetiştiricilerin %97’sinin ilkokul mezunu oldukları ve bunların %75’inin sigortalı oldukları belirlenmiştir. İşletmelerin %78.1’inde günde iki öğün yem verildiği ve verilen yem-lerin %97.1’inin sağım sonrası verildiği belirlenmiştir. Tüm işletmelerde doğan buzağılara kolostrum verildiği ancak verilme zamanlarının farklı olduğu görülmüştür. Düvelere, sağmal ineklere, kuru dönemdeki ineklere çoğu işletmelerin özel besleme yapmadığı belirlenmiştir. İşletmelerin %56.2’sinde yemlerin karışık verildiği (kaba yem + konsantre yem), yem miktarlarını ise ölçülmeden tecrübeye dayanarak verildiği belirlenmiştir. İşletmelerin çoğunda kaba yem üretimi yapıldığı belirlenmiştir. İşletmelerin %23.8’inde asidozis ve ketozis, %64.8’inde abomasum deplasmanı, %9.5’inde süt humması, %2.9’unda laminitis görüldüğü tespit edilmiştir. Sonuç olarak araştırma yapılan işletme sahiplerinin hayvan bakım ve besleme konusunda yeteri kadar bilgi sahibi olmadıkları, buzağı beslemede kolostrum ve süt içirme konusun-da dikkatli oldukları ancak kaba ve kesif yem verme hususuna dikkat etmedikleri için buzağı gelişiminde sıkıntılar oldu-ğu gözlenmiştir. İşletmede düve, gebe düve ve sağmal ineklerin beslenmesine dikkat edilmediği görülmüştür. Kaba yem üretimi bakımından da çoğunlukla dışa bağımlı oldukları anlaşılmıştır.

PSIX-21 Performance and health of dairy calves fed with acidified milk in tropical climates

Abstract The acidification of milk is used in mild climate countries as a way of conservation because it reduces the feed bacteriological load and consequently improves the animals’ performance. However, this management is hampered in hot climates. Thirty-tree males and female Holstein colostrum-fed newborn calves were used in a randomized block experimental design and fed different liquid feed: refrigerated whole milk (WM); acidified milk kept in room temperature (AM); or a commercial milk replacer (MR: 22.9% CP; 18.8% fat; 16% solids). The animals were housed in individual shelters with free access to water and starter concentrate since 2d of age. Calves were fed 6L of liquid diet divided in two meals until their gradual weaning at 56d of age. The milk was acidified to a pH of 4.5 with formic acid 12 hours prior to feeding and kept in ambient temperature (23.7°C). The pH was monitored and corrected to the target pH before each meal. Blood samples were weekly collected and health was evaluated daily. No effect on feed intake was observed (Table 1). Feeding AM decreased calves’ weight gain as compared to that for WM fed calves but with no difference from those fed MR. Fecal scores was higher for MR as compared to WM fed calves, but with no difference from AM. However, AM calves presented higher average rectal temperature than WM fed calves, but a lower number of days with fever. AM is an alternative for feeding calves in tropical climates with performance similar to that observed for MR but with lower days with fever.

Isolation and Characterization of Coronavirus and Rotavirus Associated with Calves in Central Part of Oromia, Ethiopia.

Background Coronavirus and rotavirus are most commonly associated etiologies for calves' diarrhoea, resulting in loss of productivity and economy of farmers. However, various facets of diarrheal disease caused by coronavirus and rotavirus in calves in Ethiopia are inadequately understood. A cross-sectional study was conducted with the aim of isolation and molecular characterization of coronavirus and rotavirus from calves in the central part of Oromia (Bishoftu, Sebata, Holeta, and Addis Ababa), Ethiopia, from November 2018 to May 2019. The four study areas were purposively selected and faecal samples were collected by simple random sampling for diagnosis of coronavirus and rotavirus infection by using the antigen detection enzyme-linked immunosorbent assay (Ag-ELISA) kit. In addition, this study was carried out to have insight in prevalence and associated risk factors of coronavirus and rotavirus infection in calves. Result During the study, 83 diarrheic and 162 nondiarrheic faecal samples collected from calves less than 4 weeks of age were screened for coronavirus and rotavirus. Of the 83 diarrheic samples, 1 sample (1.2%) was positive for coronavirus antigen and 6 samples (7.2%) were found to be positive for rotavirus antigen by Ag-ELISA. All the nondiarrheic samples were negative for both coronavirus and rotavirus Ag. The overall prevalence of coronavirus and rotavirus infection in calves was estimated at 0.4% (1/245) and 2.45% (6/245), respectively. All samples (7) of ELISA test positive of both coronavirus and rotavirus were propagated in Madin-Darby bovine kidney (MDBK) cells. After 3 subsequent passages, progressive cytopathic effect (CPE), i.e., rounding, detachment, and the destruction of monolayer cell of five samples (1 sample of coronavirus and 4 samples of rotavirus) (71.4%) were observed. At the molecular stage, reverse transcriptase polymerase chain reaction (RT-PCR) technique was used to determine the presence of coronavirus and rotavirus nucleic acid by using specific primers. The 5 samples that were coronavirus and rotavirus antigen positive by ELISA and develop CPE on cell culture were also positive on RT-PCR technique. The prevalence of infection peaked at 1st and 2nd weeks of age in male calves. Conclusion Diarrheal disease caused by coronavirus and rotavirus has a great health problem in calves that interrupts production benefits with reduced weight gain and increased mortality and its potential for zoonotic spread. So, the present findings show coronavirus and rotavirus infection in calves in Ethiopia that needs to be addressed by practising early colostrum feeding in newborn calves, using vaccine, or improving livestock management.

233 NaturSafe® supplementation mitigates some aspects of the acute phase immune response to a lipopolysaccharide (LPS) challenge in weaned beef calves

Abstract This study was conducted to determine if feeding calves NaturSafe would reduce the acute phase response (APR) to lipopolysaccharide (LPS) challenge. Crossbred steers (n=32; 274±2 kg) were randomly allotted to two treatment diets: 1) Control, fed a standard receiving ration, and 2) NaturSafe, fed the Control ration supplemented with NaturSafe at 12 g/hd/d (NaturSafe®, Diamond V). On d22, steers were fitted with indwelling jugular catheters and rectal temperature monitoring devices and placed in individual stalls. On d23, steers were challenged i.v. with 0.25 µg/kg BW LPS. Serum samples were collected and sickness behavior scores (SBS) recorded at 0.5-h intervals from -2 to 8h and at 24h relative to LPS challenge. Rectal temperatures were greater (P=0.01) in NaturSafe compared to Control steers for the following time intervals following LPS challenge: 6 to 11h, 13h, 15 to 20h, and 22 to 24h. Additionally, SBS were reduced (P&amp;lt; 0.01) in NaturSafe compared to Control steers. White blood cell concentrations were greater (P=0.05) in NaturSafe compared to Control steers prior to the LPS challenge, yet the response to LPS did not differ between treatments (P &amp;gt;0.05). A treatment × time interaction for serum cortisol concentrations (P&amp;lt; 0.01) showed an increase at 0.5 and 2h post-challenge but a reduction at 3h in NaturSafe compared to Control steers. Additionally, fibrinogen was greater (P&amp;lt; 0.01) in NaturSafe compared to Control steers. There was a treatment × time interaction (P&amp;lt; 0.01) for TNF-α where concentrations were reduced from 1 to 2h post-challenge in NaturSafe compared to Control steers. Serum IL-6 tended (P=0.09) to show a reduction in serum concentrations in NaturSafe compared to Control steers. There was a tendency (P=0.07) for a treatment × time interaction for IFN-γ. Overall these data suggest a priming effect of NaturSafe on the innate immune system of steers, resulting in an attenuated APR to the LPS challenge.

PSII-18 Effect of two different milk-feeding methods on performance and plasma glucose of dairy calves

Abstract The objective of this study was to evaluate two different methods of milk feeding calves and the effects on performance and plasma glucose. Thirty newborn Holsteins calves were individually housed with free access to water and starter concentrate and fed 6 L/d of whole milk divided in two meals (7h and 17h). A randomized blocks experimental design was used, with weight and day of birth as blocking effect, and calves were distributed in two methods of milk-feeding: (1) open bucket; (2) bucket with an artificial teat. Milk-feeding period started with 3 d of age, after colostrum feeding by bottle. The starter intake was monitored daily. Speed of milk intake, body weight and measures, and blood samples were taken weekly. Data were analyzed using the proc mixed of SAS for repeated measures, and the means were compared using the F test (P ≤ 0.05). Feeding milk using a bucket with an artificial teat decreased average daily starter intake (P &amp;lt; 0.03), probably because calves were more satisfied by the act of suckling. However, there were no effects on body weight gain, weight at weaning and average body measures. The bucket with artificial teat had a positive influence on blood glucose concentration, measure 2h after milk feeding (P &amp;lt; 0.01), as a response of lower speed for milk intake (P &amp;lt; 0.01). These results suggest that the speed for milk intake may interfere on blood glucose concentrations peak, however because the behavioral need of suckling is attended, it may decrease starter intake, but without decrease performance.

Predictive equations for early-life indicators of future body weight in Holstein dairy heifers

It takes an approximate 2-yr investment to raise a replacement heifer from birth to first calving, and selecting the most productive heifers earlier in life could reduce input costs. Daily milk consumption, serum total protein, pneumonia and scours incidences, body size composite, birth weights, and incremental body weights were collected on a commercial dairy farm from October 1, 2015, to January 1, 2019. Holstein calves (n = 5,180) were fed whole pasteurized nonsalable milk with a 30% protein and 5% fat enhancer added at 20 g/L of milk through an automated calf feeding system (feeders = 8) for 60 d on average. Calves were weighed at birth and several other times before calving. Average birth weight of calves was 40.6 ± 4.9 kg (mean ± standard deviation), serum total protein was 6.7 ± 0.63 mg/dL, and cumulative 60-d milk consumption was 508.1 ± 67.3 L with a range of 179.9 to 785.1 L. Daily body weights were predicted for individual animals using a third-order orthogonal polynomial to model body weight curves. The linear and quadratic effects of cumulative 60-d milk consumption, birth weight, feeder, year born, season born, respiratory incidence, scours incidence, and body size composite score were significant when predicting heifer body weight at 400 d (pBW400) of age. There was up to a 263-kg difference in pBW400 between the heaviest and lightest animal. Birth weight had a significant effect on predicted weights up to 400 d, and for every 1-kg increase in birth weight, there was a 2.5-kg increase in pBW400. Quadratic effect of cumulative 60-d milk consumption was significant up to 400 d. We divided 60-d milk consumption into quartiles, and heifers had the highest pBW400 in the third quartile when 60-d consumption was between 507.8 and 552.5 L. Body size composite score showed a 21.5-kg difference in pBW400 between the top and bottom 25th percentile of heifers. Heifers were 4.2 kg lighter at 400 d if treated for respiratory disease 3+ times during the first 60 d of life compared with heifers not treated for respiratory disease. Measurements that can be obtained in the early life of dairy calves continue to influence heifer growth up to 400 d of age.

The effects of manual and automated milk feeding methods on group-housed calf health, behaviour, growth and labour

It has been suggested that the integration of automatic feeding systems into calf rearing programmes has the potential to improve calf behaviour, growth and the associated labour. Thus, the objective of this study was to compare the effects of automatic and manual feeding systems on calf health, behaviour, growth and labour. A population of 60 dairy heifer calves was used: 44 Holstein-Friesian (HF) and 16 HF x Jersey (JE), balanced for birth weight (33 ± 4.1 kg), birth date (26 January ± 3.2 days) and breed. The experiment was a randomised block design including two treatments; i) automated calf feeding system (AFS) and ii) manual calf feeding system (MFS). Each treatment was replicated once, so a total of four balanced groups of 15 heifer calves were created. Milk replacer was offered at a rate of 6 L per calf/day (reconstitution rate 15%), with fresh water, ad-libitum concentrates and hay offered from three days old. Calves were weaned based on weight (90 kg for HF and 85 kg for HF x JE). Total labour input/day was consistently less for AFS compared to MFS (-00:01:06 per calf/day). Automatic feeding systems had a higher labour requirement for health inspections and training to the system (+00:00:15 per calf/day and +00:02:06 per calf/day, respectively), on a per calf basis, compared to MFS. The MFS-calves had an increased likelihood of experiencing faecal scores > 0 (Odds Ratio (OR) = 2.009; Confidence Interval (CI) = 1.463 – 2.759). The MFS-calves were also more likely to defecate and urinate (OR= 1.450; CI = 1.080-1.945), eat (OR= 1.281; CI = 1.140 – 1.439) and socially interact (OR= 1.300; CI = 1.111 – 1.521), compared to standing. There was no difference in number of days from birth to weaning (80.8 days) and weight at weaning (92.9 kg); average daily gain in both the pre (81 days) and post weaning (79 days) periods was similar between the two treatments (0.74 and 0.70 kg/day, respectively). Patterns for behaviours such as lying and playing were similar and low levels of abnormal behaviours were found in both treatments. Calves in both treatments exhibited good health and normal behavioural patterns as well as similar growth rates. Thus, when managed appropriately, the saving of labour is a distinct advantage automated feeding systems have over their manual counterparts when rearing group-housed calves.

Effect of crude protein level in high grain diets on calf growth and feed utilization

This study assessed the effect of crude protein level in the diet on animal performance, feed conversion ratio and N utilization, in early-weaned lot-fed calves. Four iso-energetic rations were formulated (ME: 12.0 MJ/kg dm) differing in the crude protein content (CP: 12%, 15%, 17% and 21%, DM basis), and offered in a random experimental design to 24 Hereford calves (107.2 ± 21.5 kg). Animals were individually housed and fed ad libitum twice a day for 84 days. Increasing CP levels in the diet promoted a quadratic response (P&lt;0.01) for dry matter intake (kg/d) and liveweight gain (LWG, kg/d), with maximum LWG of 1.36 kg/d for CP= 17.5%, without differences in subcutaneous back fat thickness (3.70 ± 0.73 mm, P = 0.25) or feed conversion ratio (4.44 ± 0.26, P&gt; 0.10). As CP increased in the diet, N consumption increased quadratically (P &lt;0.01), and an improvement was observed for CP (P = 0.053) and ndf (P = 0.020) apparent digestibility. Daily excretion of N in feces tended to decrease (P = 0.06), while urea-N concentration both in blood (P = 0.013) and urine (P = 0.046) increased. These results show that a level of 17% CP in the diet would optimize the performance of lot-fed early-weaned beef calves while controlling the excretion of N to the environment.

Milk production variations between rear and fore udder-halves in Barela dromedary camel

A number of twenty Barela camels were selected from herds present in Thal desert to study the variations from fore and rear part of the udder. The she-camels of 35 parity numbers in early to mid-stage lactation (1–12 months) were selected. All animals were milked twice daily on equal time intervals. The animals were allowed grazing/browsing daily for 10 hr while supplemented with gram straw when back to home. Twice watering was done. The fore and rear half measurements of udder include teat length, width, distance between teats, udder depth and side-wise distance. Regarding results the depth of rear quarters (cm) was found to be 29.36 ± 2.85 (P < 0.05) deep than fore quarters (25.85 ± 2.98). Teat length, width and distance between fore and rear teats were found significantly different (P < 0.05) while side-wise distance between teats (right & left) was found non-significant. The rear teats were found to be longer and thicker than the fore teats. The data regarding milk production and composition showed that rear-half produced significantly as 56.5% of total milk production and the fore-half 43.5%. The rear quarters produced more milk (P < 0.05) as 4.22 ± 0.85 than 3.27 ± 0.73 kg in fore quarters. The rear quarter milk was richer in fats, proteins and total solids percentage as 2.44 ± 0.22, 2.16 ± 0.26 and 2.16 ± 0.26 than 1.92 ± 0.26, 1.53 ± 0.22 and 6.02 ± 0.24 respectively in fore quarters. The fore quarter scored higher (P < 0.05) in lactose percentage as 2.83 ± 0.42 than 2.13 ± 0.31% in rear quarter. The nutrients from rear quarter milk were greater than fore quarter milk. The results could be used for future recommendations about calf feeding programs of camel husbandry in Pakistan.

The effectiveness of the use of extruded feed for calves with gastroenteric syndrome

The effectiveness of the use of extruded feed for calves with gastroenteric syndrome

Installations for defrosting and warming colostrum in continuous mode

The article is devoted to the development of microwave technology and installations for preparing frozen cow colostrum for calf feeding by exposure to an ultrahigh-frequency electromagnetic field in two volume resonators, which allow defrosting and heating of cow colostrum at different doses in a continuous mode. Two resonator microwave installations designed for farms have been developed and described. Effective modes of defrosting and warming up cow colostrum in an electromagnetic field of ultrahigh frequency: duration of exposure to ultra-high frequency electromagnetic field in a resonator is 12 min; power of microwave generators 3.5–3.65 kW; plant productivity 25–30 kg/h; energy costs for the process 0.12–0.18 kW-kg/h, heating temperature of raw materials to 38–40 °C. For cattle farms up to 600 heads, one microwave installation is enough to defrost and heat cow colostrum. The annual economic effect due to lower operating costs will be 153600 rubles. The profitability of the process will increase by 3.22%.

Effects of Housing System on Dairy Heifer Replacement Cost From Birth to Calving: Evaluating Costs of Confinement, Dry-Lot, and Pasture-Based Systems and Their Impact on Total Rearing Investment.

Replacement heifer rearing is critical for the future of dairy operations, to improve genetic merit and maintain herd size. A myriad of options exist on how to manage, feed, and ultimately raise replacement heifers. Pasture is perceived to offer optimal welfare and an economical housing system for replacement animals, but confinement systems are gaining popularity. This study investigates the costs associated with replacement heifer management decisions from birth to calving, considering the factors of housing systems, labor, feed, and health. The objective of this study was to develop an economic model to determine the cost of raising a replacement heifer managed in confinement, dry-lot, and pasture-based scenarios post-weaning. We accounted for variation in feed, labor, and health inputs and quantified the impact of these individual management decisions. An economic simulation with 10,000 iterations were completed for each situation using @Risk and PrecisionTree add-ons (Palisade Corporation, Ithaca, NY) where health incidence, commodity prices, and management variables were made stochastic. Published literature or sample farm data created parameters used in Pert distributions. Costs and biological responses were reflective of published surveys, literature, and market conditions. Management decision inputs had 3 main factors: housing type, ration composition, and labor utilization. Housing systems were calculated separately for confinement, dry-lot, and pasture scenarios. The mean total cost (min, max) to raise a replacement heifer from birth to calving, assuming the same pre-weaning strategy of group housing with an automatic calf feeder, was found to be $1,919.02 ($1,777.25, $2,100.57), $1,593.57 ($1,490.30, $1,737.26), and $1,335.84 ($1,266.69, $1,423.94) for confinement, dry-lot, and pasture, respectively. Total housing cost per replacement heifer was $423.05, $117.96, and $207.96 for confinement, dry-lot, and pasture management systems, respectively. When compared to total cost, housing contributed 21% for confinement, 7% for dry-lot, and 15% for pasture. Upon analysis of all scenarios, utilizing pasture to raise heifers resulted in a lower overall cost when compared to confinement housing options. Percentage breakdowns of feed, labor, housing, and fixed and variable costs provided more information on efficiency rather than total cost, which makes each situation different in relation to on-farm cost. This cost analysis is critical to assisting farms in making decisions in the utilization of their resources for replacement dairy heifers.

Effects of antimicrobial exposure on the antimicrobial resistance of Escherichia coli in the digestive flora of dairy calves

Veal calves are often identified as reservoirs for antimicrobial resistant Escherichia coli (E. coli). This production is closely linked with dairy production, as young calves — mostly males — are collected from dairy farms to enter the fattening process. The aim of this prospective study was to explore the factors on dairy farms that favour the selection of antimicrobial resistance (AMR) in the digestive E. coli strains of young calves and to assess whether the resistance levels and selection pressure were the same for males and females. The exposure of calves to antimicrobials was investigated through three factors: antimicrobial treatment of calves; feeding of calves with milk from cows treated with antimicrobials; and the consumption of colostrum from cows treated with antimicrobials at dry-off.The study design involved 100 dairy farms. A calf of each sex was selected from birth on each farm. Information on the calves’ exposure to antimicrobials was collected daily and calves were sampled (rectal swab) two weeks after birth, then seven weeks after birth for females only. Laboratory analyses included culture on two distinct media: a non-selective medium (identifying dominant flora) and a medium containing ceftiofur to select the extended-spectrum beta-lactamase (ESBL) phenotype. Susceptibility testing was performed on an E. coli strain from each medium. Generalised linear models were used to assess associations between the resistance of E. coli strains and antimicrobial exposure. A set of 280 swabs from healthy calves were analysed. In dominant flora, high levels of resistance (>60 %) were identified for streptomycin, tetracycline and amoxicillin but AMR levels were low (3 %) for critically important antimicrobials (3rd- and 4th-generation cephalosporins and fluoroquinolones). For females staying in dairy farms, a marked decrease in resistance was observed for almost all antimicrobials between the age of 15 days and 7 weeks. A selective medium revealed an ESBL phenotype for 20.7 % of the calves. Whether for AMR or antimicrobial exposure, no significant difference was found between male and female calves.The antimicrobial treatment of calves was associated with an increased resistance of E. coli from dominant flora for amoxicillin (OR = 2.9), gentamicin (OR = 4.6), florfenicol (OR = 5.0) and trimethoprim-sulfonamide (OR = 5.6). The consumption by calves of milk from cows treated with antimicrobials was also associated with an increased resistance to amoxicillin (OR = 2.6), gentamicin (OR = 4.0), tetracycline (2.6) and trimethoprim-sulfonamide (OR = 2.2). In contrast, the models did not reveal any association between AMR and consumption of colostrum from cows treated with antimicrobials at dry-off.

The occurrence and distribution of livestock-associated methicillin-resistant Staphylococcus aureus ST398 on German dairy farms

The objective of this study was to investigate the occurrence and distribution of methicillin-resistant Staphylococcus aureus (MRSA) on 20 German dairy farms. Farms were selected based on previous MRSA reports from phenotypic susceptibility testing of mastitis pathogens. Samples were collected from predefined groups of cows, young stock, farm personnel, and the environment. A high MRSA-positive test rate was detected in swab samples from milk-fed calves (22.7%; 46/203). In postweaning calves, the MRSA-positive test rate was 9.1% (17/187). From prefresh heifers, both nasal swabs and udder cleft swabs were collected if possible. Including both sample types, the MRSA-positive test rate in prefresh heifers was 13.0% (26/200). The positive test rate was 8.9% (17/191) in nasal swabs and 6.5% (11/170) in udder cleft swabs. In quarter milk samples (QMS), the MRSA-positive test rate was 2.9% (67/2347), and on cow level, 7.9% (47/597) of the dairy cows were affected. Among all cows included in this study, the geometric mean of somatic cell counts was higher in QMS that carried MRSA (345,000 cells/mL) in comparison to all QMS (114,000 cells/mL). No differences in parity or the affected mammary quarter position on the udder were observed among the 47 infected cows. Methicillin-resistant S. aureus was also detected in boot swab samples (dust), teat liners, and in suckers from automatic calf feeders. All isolates belonged to livestock-associated sequence type 398 and most common staphylococcal protein A (spa)-types were t011 and t034. Most isolates harbored the staphylococcal cassette chromosome mec (SCCmec)-type V, with the exception of some isolates with SCCmec-type IVa on 1 farm. Similar MRSA genotypes in samples from humans and dairy cows underline the possible zoonotic and reverse-zoonotic transmission of livestock-associated MRSA strains from dairy farms. Similar MRSA genotypes in pig and cattle barns were detected on only 1 of 5 farms that kept both cattle and pigs. Similar MRSA spa-types were detected in samples from different sources (dairy cows, young stock, environment, and humans), suggesting a possible contagious transmission on some of the farms. Sporadically, up to 3 different MRSA spa-types were detected in QMS from the respective farms. On MRSA-affected farms, improper milking hygiene procedures and elevated bulk-tank milk somatic cell counts (>250,000 cells/mL) were observed. The occurrence of livestock-associated MRSA ST398 in different samples from dairy farms, and especially in young calves, should be considered for future MRSA-monitoring programs and biosecurity guidelines.

Влияние опытного заменителя сухого обезжиренного молока на физиологическое состояние и продуктивность телят в возрасте 65-115 дней

Aim. To study the effect of experimental replacer of dry skimmed milk on physiological state and per-formance of calves of 65-115 days of age. Materials and Methods. Zootechnical, biochemical and mathematical methods of analysis were used in the course of research. The obtained digital material was processed using method of varia-tion statistics, considering the Student-t validation criteria, using the Microsoft Excel software package. Results. Studies helped to determine that feed intake in calves during the experiment on studying the efficiency of dry skimmed milk replacer used for feeding calves at the age of 65-115 days was nearly the same. Study of biochemical composition of blood of experimental animals indicates that inclu-sion of dry skimmed milk replacer and whole milk replacer in the diet instead of whole milk had no negative effect on physiological state of animals. During the experiment, blood indices were record-ed to be within physiological standards, which indicates the normal course of metabolic processes in calves of experimental groups. According to the results of blood analysis in young animals of the II and III experimental groups, an increase in concentration of total protein by 13.5 and 15.4%, glu-cose – by 6.5 and 7.3%, calcium – by 14.4 and 14.9%, phosphorus – by 16.5 and 17.3% had been determined in comparison with control analogues. The urea level in blood of young animals of the experimental groups was 3.5 and 4.5% lower compared to control. Study of growth dynamics showed that dry skimmed milk replacer and whole milk replacer used instead of whole milk in the di-et for calves aged 65-115 days had an insignificant effect on the average daily body weight. So, young animals consuming whole milk reached the average daily weight gain of 982 g, and their co-evals from II and III experimental groups 964 and 970 g, respectively. Feed costs per 1 kg of weight gain were recorded to be nearly at the same level. Cost of daily diet in experimental groups turned to be 10.3 and 5.8% cheaper compared to the control. Calculation of economic efficiency of use of dry skimmed milk replacer and whole milk replacer by animals in diet showed a decrease in price cost of weight gain by 8.5 and 4.8%. Conclusion. Based on the research conducted it has been determined that feeding 10-65 days of age calves with experimental milk replacer allowed to obtain 970 g of the average daily weight gain for the experiment period, or 1.2% lower than the control indicator. Feeding calves whole with milk re-placer helps reduce the cost of diet by 5.8% and price cost of weight gain by 4.8%, when feeding with skimmed milk replacer these indicators made 10.3 и 8.5 percent.

Effect of calfhood nutrition on metabolic hormones, gonadotropins, and estradiol concentrations and on reproductive organ development in beef heifer calves.

This study examined the effect of plane of nutrition on the endocrinological regulation of the hypothalamic-pituitary-ovarian (HPO) axis in beef heifer calves during a critical sexual developmental window early in calf hood. Forty Holstein-Friesian × Angus heifers (mean age 19 d, SEM = 0.63) were assigned to a high (HI; ADG 1.2 kg) or moderate (MOD; ADG 0.50 kg) nutritional level from 3 to 21 wk of life. Intake was recorded using an electronic calf feeding system, BW was recorded weekly, and blood samples were collected on the week of age 5, 10, 15, and 20 for metabolite, reproductive, and metabolic hormone determination. At 19 wk of age, on sequential days, an 8-h window bleed was carried out for luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol analysis. To characterize anterior pituitary gland function, an intravenous GnRH challenge was conducted (19 wk of age). Blood was collected via a jugular catheter every 15 min for 135 min for the analysis of LH, FSH, and estradiol. Calves were subsequently euthanized at 21 wk of age; the anterior pituitary, metabolic organs, and reproductive tract were weighed, and ovarian surface follicular numbers and oocytes recovered were recorded. Mean ADG was 1.18 and 0.50 kg for HI and MOD, respectively, resulting in a 76.6-kg difference in BW (P < 0.001). Blood insulin, glucose, and IGF-1 concentrations were greater (P < 0.001) for HI compared with MOD. There was a diet × time interaction for leptin (P < 0.01); concentrations were greater in HI compared with MOD at 20 wk of age with no difference between treatments before this. Dietary treatment did not alter the concentrations of adiponectin or anti-mullerian hormone. There was a diet × time interaction for FSH, whereby MOD had greater concentrations than HI at 10, 15, and 20, but not at 5 wk of age. Over the duration of an 8-h window bleed (19 wk of age), serum concentrations of LH, LH pulse frequency, and LH pulse amplitude were unaffected by treatment, whereas FSH (0.23 vs. 0.43 ng/mL) and estradiol (0.53 vs. 0.38 ng/mL) concentrations were less than and greater, respectively, for HI than MOD (P < 0.05). Likewise, following a GnRH challenge, the area under the curve analysis revealed greater (P < 0.01) estradiol and lesser (P < 0.01) FSH concentrations in calves on the HI relative to MOD diet, whereas concentrations of LH were unaffected (P = 0.26) between treatments. Ovarian surface follicle numbers were greater (P < 0.05) in HI compared with MOD. Total reproductive tract, uterus, and ovarian tissue expressed relative to BW were greater (P < 0.05) for HI compared with MOD. In conclusion, enhanced nutrition in early calfhood advances the ontogeny development of the HPO axis.