Association of morbidity, mortality, and average daily gain with transfer of passive immunity in dairy-beef crossbred calves up to 60 d of life.

Adequate transfer of passive immunity (TPI) is a cornerstone for a proper health status of calves. In the literature, there is limited information on the prevalence of failure of TPI in dairy-beef crossbred calves and its impact on morbidity, mortality, and average daily gain (ADG) during the preweaning period. Therefore, this study aimed to evaluate the association between TPI with morbidity, mortality, and ADG in pre-weaned dairy-beef crossbred calves. A total of 1,055 newborn dairy-beef crossbred calves were enrolled upon arrival at a calf-raising facility in California from January to August 2021. Farm of origin, genetic breed group, sex, and body weight were recorded upon arrival. Blood was collected at 24 ± 1 h post-arrival to evaluate serum IgG concentration, serum total protein (TP), and packed cell volume. Morbidity (diarrhea and respiratory treatment records) and mortality were recorded daily until 60 d of life. Calves were grouped into 2 genetic breed groups: Holstein x Beef (Ho x Be, 49.6%) and Jersey × Beef crossbred calves (Je × Be, 50.4%). Descriptive statistics and Cox proportional hazard models were created to evaluate the association of TPI categories for serum IgG (TPI-IgG: poor: < 10.0 g/L, fair: 10.0 - 17.9 g/L, good: 18.0 - 24.9 g/L, and excellent: ≥ 25.0 g/L) and TP (TPI-TP: poor: < 5.1 g/dL, fair: 5.1 - 5.7 g/dL, good: 5.8 - 6.1 g/dL, and excellent: ≥ 6.2 g/dL), sex, and genetic breed group with morbidity and mortality. Additionally, a mixed linear regression was performed to evaluate the association of sex, genetic breed group, and TPI categories with ADG. Overall morbidity and mortality were 84.8% (n = 895) and 2.5% (n = 26). Calves classified as TPI-IgG excellent were associated with the lowest (43.2% less) hazard of being treated compared with TPI-IgG poor calves. For mortality, dairy-beef crossbred calves with TPI-IgG excellent were associated with a reduction of 82.0% in the hazard of dying compared with TPI-IgG poor. The TPI-IgG poor and TPI-IgG fair calves were associated with a decreased ADG of 101.0 and 98.8 g/d, respectively, in comparison with TPI-IgG good calves. Average daily gain of TPI-IgG good and TPI-IgG excellent calves were not different. In our study, dairy-beef crossbred calves enrolled may have endured challenging conditions that increased morbidity. This reinforces the importance of high IgG levels to decrease morbidity and mortality and maximize ADG in dairy-beef crossbred calves raising systems. Further research should evaluate the long-term effects of TPI categories on the health and performance of dairy-beef crossbred calves.

Strategies to alleviate heat stress on performance and physiological parameters in feedlot-finished cattle under heat stress conditions. A systematic review-meta-analysis.

Strategies to alleviate heat stress on live performance - dry matter intake (DMI), average daily gain (ADG), and feed conversion efficiency (FCE) - and on physiological parameters - respiratory rate (RR) and panting score (PS) - of feedlot-finished cattle were evaluated by systematic review-meta-analysis. Using the PICO framework were identified 3813 records, with 31 publications and 6729 cattle being considered in the meta-analysis (MA). The comparison most reported was sun vs. shade (n = 24 publications), followed by shade vs. shade (area per animal and effectivity in reduce solar load) (n = 7 publications) and sun vs. sprinkling (n = 4 publications). Cattle with access to shade with total reduction in solar load improved ADG (p = 0.008) and FCE (p = 0.024), and reduced RR (p < 0.001) compared to unshaded animals. Cattle with access to shade with a height between 3 and 4 m increased ADG (p < 0.001), tended to improve FCE (p = 0.054), and reduced RR (p < 0.001) compared to unshaded animals. An area of shade from 2 to 4 m2/animal increased ADG (p = 0.002), and higher than 4 m2/animal reduced RR (p < 0.001) compared to unshaded animals. Animals that received sprinkling volume below 1 L/animal/min improved ADG (p = 0.008) compared to unshaded animals. Cattle with access to shade with a high area per animal improved DMI (p = 0.023) and ADG (p < 0.001) compared to animals with a low area. In univariate meta-regression, it was observed that the variables significantly (P < 0.05) influencing DMI were THI category; influencing ADG were cattle gender, THI category, and coat color; influencing FCE were cattle age and hemisphere; and influencing RR were country, THI category and climate. Performance and physiological parameters of feedlot-finished cattle under heat stress depend on animal and environmental characteristics.

Effect of ultrasonographic lung consolidation on health and growth in dairy calves: A longitudinal study.

Bovine respiratory disease (BRD) is a common and complex disease process in calves. Subclinical disease exists and early detection can be challenging due to inconsistent or nonexistent clinical signs. Thoracic ultrasonography (TUS) is often used and has the potential to improve the identification of respiratory diseases. Combining systematic TUS with clinical examination allows distinguishing BRD, including upper respiratory tract disease (clinical signs of respiratory disease, but no significant lung consolidation), clinical pneumonia (clinical signs of respiratory disease along with lung consolidations), and subclinical pneumonia (no clinical signs, but lung consolidations). Data on subclinical pneumonia are scarce, particularly outside of the North American or European contexts similar to Iran in west Asia with a dry and semi-arid climate and intensive breeding systems similar to North America which breeding calves begin in individual boxes, then moving to group pens, and finally to free stall or open shed housing systems. The first objective of this longitudinal study was to use weekly ultrasonography to monitor calves from birth until weaning in an Iranian dairy herd. The second objective was to look for any association between individual lung consolidation episode or cumulative consolidation episodes on preweaning growth. Thoracic ultrasonography was performed on calves (n = 221) weekly from birth to weaning (8 wk), and scanning occasions for each calf were equally distributed with 1-wk intervals (using consolidation threshold ≥3 cm as a specific lung consolidation definition, and ≥1 cm as a more sensitive threshold). Calf body weights were recorded using a weight tape. Other information recorded were transfer of passive immunity (TPI) using serum Brix (%) ≥8.4% as adequate TPI within the first week after birth and the treatment history of the calves. The main strategy for modeling was to determine how long-term lung consolidation affects average daily gain (ADG) during the preweaning period. A linear model was used to determine the effect of the number of weeks with consolidation on ADG. Using consolidation threshold of ≥3 cm, the mean (±SD) of total ADG for calves with no consolidation episode, 1 consolidation episode, and 2 or more consolidation episodes were 0.45 (±0.10), 0.39 (±0.10), and 0.38 (±0.11) kg/d, respectively. In the final multivariable regression analysis model and based on consolidation threshold of ≥3 cm, calves with 1 and 2 or more consolidation episodes had significantly lower ADG ± standard error (SE) of 0.04 ± 0.02 kg/d, and 0.06 ± 0.02 kg/d, respectively compared with animals with no consolidation episode. A total of 20% of calves (46/229 calves that entered the study) were treated for respiratory disease based on clinical signs (based on farmer examination). The final model also included specific confounders related to ADG and their interactions with lung consolidation (TPI and BRD treatment). An overall of 86% of adequate TPI was obtained. Bovine respiratory disease treatment based on farmer diagnosis had a larger negative effect on preweaning ADG than ultrasonography-diagnosed consolidation episodes (lower ADG ± SE of 0.10 ± 0.03 kg/d). When using a more sensitive consolidation threshold (≥1 cm as consolidation), the number of weeks with consolidation was also negatively associated with the ADG in the multivariable linear regression model with significant difference of 0.05 ± 0.02 kg/d for nonconsolidated calves versus calves consolidated for 2 or more weeks and insignificant difference of 0.01 ± 0.02 kg/d for nonconsolidated calves versus calves with 1 consolidation episode.

Performance evaluation of Marwari lambs for growth traits and impact of inbreeding.

This study aimed at the performance evaluation of a closed flock of Marwari sheep and also to study the effect of accumulated inbreeding on the growth traits using a linear mixed model methodology. The data generated for 39 years (1981 to 2020) on Marwari sheep maintained at ICAR-Central Sheep & Wool Research Institute, Arid Region Campus (CSWRI, ARC), Bikaner, Rajasthan, India were used for analysis on growth traits. The overall least-squares means (LSM) of live weights at birth (BWT), weaning (3MWT), 6 months (6MWT), 9 months (9MWT) and 12 months (12MWT) were observed to be 3.02 ± 0.01, 14.30 ± 0.04, 20.12 ± 0.05, 23.68 ± 0.06 and 26.39 ± 0.07 kg, respectively. Overall LSM for average daily gain from birth to 3 months (ADG1), 3 to 6 months (ADG2) and 6 to 12 months (ADG3) were 125.44 ± 0.40, 67.37 ± 0.40 and 35.83 ± 0.29 g/day, respectively. Kleiber ratio (KR) from birth to 3 months (KR1), 3 to 6 months (KR2), and 6 to 12 months (KR3) were 16.78 ± 0.02, 6.58 ± 0.04 and 3.05 ± 0.02, respectively. Results revealed a 4.36, 25.83, 36.33, 31.50 and 28.99% improvement in the live weights since the inception of the improvement programme. This is also reflected by a significant effect of sire on all the growth traits. The estimate of inbreeding in the flock was 1.55%. Highly inbred animals were 5.13% (>5% Fi). The study revealed the non-significant effect of inbreeding level on all growth traits except for BWT and KR3. For BWT, inbreeding classes had variation; however, a negative effect was not seen. The inbreeding class (>5% Fi) was reduced by 0.05 units for KR3 as against its preceding class. Dam's age at lambing and weight influenced the birth weight and subsequent weights. The study concluded that the selection programme of Marwari sheep is in the right direction; however, regular monitoring of inbreeding is necessary and factors affecting growth must be monitored to attain better growth rates in the nucleus.

Pharmacokinetics and effect on renal function and average daily gain in lambs after castration and tail docking, of firocoxib and meloxicam.

AIMS: To evaluate and compare the pharmacokinetics of IM and oral firocoxib, and IM meloxicam, and detect their effect on renal function and average daily gain (ADG) in lambs undergoing tail docking and castration. METHODS: Seventy-five male Romney lambs, aged 3-6 weeks, were randomised into five treatment groups (n = 15 per group): IM firocoxib (1 mg/kg); oral firocoxib (1 mg/kg); IM meloxicam (1 mg/kg); normal saline (approximately 2 mL, oral); or sham. Following the treatment administration, hot-iron tail docking and rubber ring castration were performed in all groups except the sham group, which did not undergo the procedures, but the animals were handled in the same manner as castrated and tail docked lambs. Blood samples were collected before and 1, 2, 4, 6, 8, 24, 48, 72, 96 and 120 hours after treatment administration, and drug concentrations in plasma were quantified by liquid chromatography and mass spectrometry. Plasma urea and creatinine concentrations were determined at a commercial laboratory. Lamb body weights were recorded before and 2, 4 and 8 weeks after tail docking and castration. The pharmacokinetic analysis was carried out using a non-compartmental approach. Between-group and between-time-point differences were compared using mixed model analyses. RESULTS: There was no evidence for a difference in plasma elimination half-life between firocoxib given IM (LSM 18.6 (SE 1.4) hours), firocoxib given orally (LSM 18.2 (SE 1.4) hours), and meloxicam given IM (LSM 17. 0 (SE 1.4) hours). Firocoxib (IM) had a significantly greater volume of distribution (LSM 3.7 (SE 0.2) L/kg) than IM meloxicam (LSM 0.2 (SE 0.2) L/kg). Lambs in the meloxicam group had higher (p < 0.05) plasma urea and creatinine concentrations than those in the firocoxib, saline and sham groups. Lambs' ADG was decreased (p < 0.01) compared to the other treatment groups in the 0-2 week period following meloxicam administration. CONCLUSIONS AND CLINICAL RELEVANCE: Both formulations of firocoxib had a long plasma elimination half-life and large volume of distribution. There was a transient reduction in ADG in the meloxicam group, possibly due to mild renal toxicity. Comparative studies on dose-response effects of firocoxib and meloxicam in lambs following the procedures are required.Abbreviations: ADG: Average daily gain; Cmax: Maximum concentration; COX: Cyclooxygenase; LOD: Limit of detection; NSAID: Non-steroidal anti-inflammatory drugs; CL: Plasma clearance; T1/2el: Plasma elimination half-life; Tmax: Time to achieve Cmax; Vd: Volume of distribution.

Effects of the breeding season, birth type and sex on growth and reproductive performances of sheep breeds.

The study aimed at determining the effects of breed type, breeding season, sex and type of birth on the growth and reproductive traits of lambs. Two ewe breed types (Gellaper and Swakara) and four ram breed types (Damara, Dorper, GeDo and Swakara) were used. Two lambing seasons, spring (March-May) and autumn (September-November), were considered. Gellaper-based lambs born in autumn had higher (P < 0.05) mean birth weight (4.58 kg) compared to spring-born lambs (3.43 kg). Ram lambs were heavier (P < 0.05) than ewe lambs at weaning and post-weaning age. Singletons were heavier than twins (P < 0.05) at birth, weaning and breeding. Single and autumn-born lambs had a higher average daily gain (ADG) than spring-born lambs (P < 0.05). Ram lambs had a higher pre-weaning and overall ADG (P < 0.05) compared with ewe lambs. Swakara-based lambs gained more from weaning to mating compared to Gellaper-based lambs (P < 0.05). The conception, lambing and annual reproductive rate were all influenced by breed type and season (P < 0.05). Swakara-based lambs had higher reproductive capabilities, while Gellaper-based lambs grew faster but take longer to breed type; autumn lambing gave rise to low birth weights but heavier lambs at weaning and post-weaning, hence suitable for mutton production.

Stocking density, ambient temperature, and group size affectsocial behavior, productivity and reproductivity of goats- A review.

The stocking density (animal/area, SD) is one of the significant factors that influence the welfare and performance of animals. However, there are discrepancies in the recommended SD for fiber, meat, and dairy goats, which means farming practices and welfare standards for goats should be better defined. Therefore, this review article sheds light on 1) some differences between goats and sheep. 2) the geographical distribution of fiber, meat type, and dairy goat populations. 3) effects of interaction between SD and group size on social, feeding, and aggressive behaviors. 4) the effects of SD on meat and milk production. 5) the relationship between SD and reproductive performance. In conclusion, the larger space allowance with access to an outdoor yard can improve species-specific behaviors and meat and milk yield. Moreover, goats are more sensitive to high SD (less than 3 m2/ goat), especially during the last stage of the gestation period. Allowing optimal floor space for each breed is important to avoid the undesired behavioral response. Conclusively, improving the housing aspects, including floor space and enrichment tools, would assist in implementing welfare-economic production standards for goats.

The effect of environmental temperature on average daily gain in preweaned calves: A randomized controlled trial and Bayesian analysis.

Neonatal calves are relatively susceptible to heat loss, and previous research suggests that reduced environmental temperatures are associated with reduced average daily gain (ADG) during the preweaning phase. Current methods of mitigating negative effects of colder environmental conditions include the use of calf jackets and the provision of supplementary heat sources; however, previous research is limited. The aim of this study was to evaluate the effect of calf jackets and 1-kW heat lamps on the growth rates of preweaning calves and evaluate associations between environmental temperature and ADG using a Bayesian approach to incorporate both current and previous data. Seventy-nine calves from a single British dairy farm were randomly allocated at birth to 1 of the following 4 groups: no jacket and no heat lamp, heat lamp but no jacket, jacket but no heat lamp, or both heat lamp and jacket between January and April of 2021. Calves were weighed at both birth and at approximately 21 d of age. Temperature was recorded both inside and outside of the calf building, and in pens both with and without heat lamps using data loggers. To explore the effect of treatment group and environmental temperature on ADG, a fixed effects model was fitted over 1,000 bootstrap samples. The effect of environmental temperature on ADG was further explored within a Bayesian framework that used temperature and ADG data for 484 calves from 16 farms available from a previous trial as prior information. Calves housed under a 1-kW heat lamp had an increased ADG of 0.09 kg/d (95% bootstrap confidence interval: -0.02 to 0.20 kg/d), and no effect of jacket or interactions between jacket and heat lamp were found. A significant positive association was identified between the mean environmental temperature of the calf building and ADG, with a 1°C increase in temperature being associated with a 0.03 kg/d increase in ADG (95% bootstrap confidence interval: 0.01 to 0.04 kg/d). Associations between environmental temperature and ADG were further evaluated within a Bayesian framework, and posterior estimates were 0.014 kg/d of ADG per 1°C increase (95% credible interval: 0.009 to 0.021 kg/d). This study demonstrated that a 1-kW heat lamp was effective in increasing ADG in calves, and no significant effect of calf jacket on ADG was found. A significant, positive effect of increased pen temperature on calf ADG was identified in this study and was reinforced when including prior information from previous research within a Bayesian framework.

Feeding rumen-protected lysine to dairy cows prepartum improves performance and health of their calves.

Providing adequate concentrations of AA in the prepartum diet is pivotal for the cow's health and performance. However, less is known about the potential in utero effects of particular AA on early-life performance of calves. This experiment was conducted to determine the effects on dairy calves when their dams were fed rumen-protected lysine (RPL; AjiPro-L Generation 3, Ajinomoto Heartland Inc.; 0.54% dry matter of total mixed ration as top dress) from 26 ± 4.6 d (mean ± standard deviation) before calving until calving. Seventy-eight male (M) and female (F) Holstein calves were assigned to 2 treatments based on their dams' prepartum treatment, RPL supplementation (PRE-L) or without RPL (CON). At the time of birth (0.5-2 h after calving), before colostrum was fed, blood samples were collected. An initial body weight was obtained at 1 to 3 h after birth. Calves were fed 470 g of colostrum replacer (Land O'Lakes Bovine IgG Colostrum Replacer, Land O'Lakes, Inc.) diluted in 3.8 L of water. Calves were provided water ad libitum and fed milk replacer (Advance Excelerate, Milk Specialties Global Animal Nutrition; 28.5% crude protein, 15% fat) at 0600 h and 1700 h until 42 d of age. Calves were measured weekly, at weaning (d 42), and at the end of the experimental period (d 56). Plasma concentrations of AA were measured on d 0, 7, and 14 d using ultra-performance liquid chromatography-mass spectrometry (Waters) with a derivatization method (AccQ-Tag Derivatization). Final body weight was greater for M (87 ± 11 kg) than F (79 ± 7 kg). Calves in PRE-L tended to have greater dry matter (814 ± 3 g/d) and crude protein (234 ± 6 g/d) intakes than those in CON (793 ± 9 g/d and 228 ± 11 g/d, respectively). Calves in PRE-L had greater average daily gain (0.96 ± 0.04 kg/d) than calves in CON (0.85 ± 0.03 kg/d) during wk 6 to 8. Calves in PRE-L tended to be medicated fewer days than CON (4.7 ± 1.2 d vs. 6.2 ± 3.4 d, respectively). Calves in PRE-L-M and CON-F (2,916 ± 112 µM and 2,848 ± 112 µM, respectively) had greater total AA concentration in plasma than calves in PRE-L-F and CON-M (2,684 ± 112 µM and 2,582 ± 112 µM, respectively). Calves in PRE-L-F and CON-M (4.09 ± 0.11% and 4.16 ± 0.11%, respectively) had greater concentration of Lys as a percentage of total AA compared with calves in CON-F and PRE-L-M (3.91 ± 0.11% and 3.90 ± 0.11%, respectively). Calves in PRE-L tended to have greater percentage of phagocytic neutrophils (39.6 ± 1.59%) than calves in CON (35.9 ± 1.59%). In conclusion, increasing the metabolizable lysine provided to prepartum dairy cows had modest effect over offspring performance, with the major result being a greater average daily gain for calves in PRE-L during the preweaning phase (wk 6-8).

Improving growth rates in preweaning calves on dairy farms: A randomized controlled trial.

Previous research has identified key factors associated with improved average daily gain (ADG) in preweaning dairy calves and these factors have been combined to create a web app-based calf health plan (www.nottingham.ac.uk/herdhealthtoolkit). A randomized controlled trial was conducted to determine the effect of implementing this evidence-based calf health plan on both productivity and health outcomes for calves reared on British dairy farms. Sixty dairy farms were randomized by location (North, South, and Midlands) to either receive the plan at the beginning (INT) or after the end of the trial (CON) and recorded birth and weaning weights by weigh tape, and cases of morbidity and mortality. Calf records were returned for 3,593 calves from 45 farms (21 CON, 24 INT), with 1,760 calves from 43 farms having 2 weights recorded >40 d apart for ADG calculations, with 1,871 calves from 43 farms born >90 d before the end of the trial for morbidity and mortality calculations. Associations between both intervention group and the number of interventions in place with ADG were analyzed using linear regression models. Morbidity and mortality rates were analyzed using beta regression models. Mean ADG was 0.78 kg/d, ranging from 0.33 to 1.13 kg/d, with mean rates of 20.12% (0-96.55%), 16.40% (0-95.24%), and 4.28% (0-18.75%) for diarrhea, pneumonia, and mortality. The INT farms were undertaking a greater number of interventions (9.9) by the end of the trial than CON farms (7.6). Mean farm ADG was higher for calves on INT farms than CON farms for both male beef (MB, +0.22 kg/d) and dairy heifer (DH, +0.03 kg/d) calves. The MB calves on INT farms had significantly increased mean ADG (0.12 kg/d, 95% confidence interval: 0.02-0.22) compared with CON farms. No significant differences were observed between intervention groups for morbidity or mortality. Implementing one additional intervention from the plan, regardless of intervention group, was associated with improvements in mean ADG for DH calves of 0.01 kg/d (0.01, 0-0.03) and MB calves of 0.02 kg/d (0.00-0.04). Model predictions suggest that a farm with the highest number of interventions in place (15) compared with farms with the lowest number of interventions in place (4) would expect an improvement in growth rates from 0.65 to 0.81 kg/d for MB, from 0.73 to 0.88 kg/d for DH, a decrease in mortality rates from 10.9% to 2.8% in MB, and a decrease in diarrhea rates from 42.1% to 15.1% in DH. The calf health plan tested in this study represents a useful tool to aid veterinarians and farmers in the implementation of effective management interventions likely to improve the growth rates, health, and welfare of preweaning calves on dairy farms.

Growth performances, nutrient digestibility, ruminal fermentation and energy partition of Thai native steers fed exclusive rice straw and fermented sugarcane bagasse with Lactobacillus, cellulase and molasses.

The study aimed to evaluate the effect of sugarcane bagasse feeding treated with Lactobacillus casei TH14 (L. casei TH14), cellulase and molasses (BG) on nutrient digestibility, ruminal fermentation, energy partition and growth performances of Thai native steers compared to conventional feeding of rice straw (RS). Eight Thai native steers (144 ± 19.5 kg of initial body weight) were randomly allocated to two roughage sources in a completed randomized design: RS (n = 4) and BG (n = 4). The feeding trial lasted for 90 days plus 21 days for treatment adaptation. The results showed that the BG group showed (p < 0.05) greater intake (2.34 vs 2.02 kg/day), total intake (3.90 vs 3.55 kg/day) and average daily gain (0.27 vs 0.23 kg/day) while feed conversion ratio was lower compared to RS group. The BG group had a greater (p < 0.05) organic matter and acid detergent fibre intake than the RS group as well as dry matter and neutral detergent fibre digestibility. The steers fed RS and BG were significantly (p < 0.05) different for total volatile fatty acids and propionic acid at 4 h after offering the diet. The intake of nitrogen (g/day) and apparent nitrogen absorption was significantly (p < 0.05) higher for BG than the RS group while nitrogen excretion in faeces was significantly lower in RS than the BG group. BG group showed significantly (p < 0.05) greater gross energy intake and digestible energy partition when compared to the RS group. In conclusion, feeding BG enhanced feed utilization, growth performance, ruminal fermentation, nitrogen utilization and energy utilization.

The impact of milk suckling protocol and schedule on body weight and some morphometric measurements of Holstein heifers.

Having a successful heifer raising operation is not only relevant financially, but also influential for the future of the dairy herds. Milk feeding has a significant role on the health and growth of calves before weaning, in addition to the direct progressive effects on future performance post-weaning. Therefore, the aim of this study was to compare the effects of constants amount of milk (CMS) versus step-up/step-down (SUSD) on calf performance in two different suckling schedules of suckling milk gradually till 9th weeks of calf age, then decreasing it till weaning. For this study, forty Holstein heifers calves utilized between birth and 8 months of age were randomly divided into four groups of 10 calves each. Grouping was performed according to suckling protocol (constant versus variable) and suckling schedule (2 versus 3 times/day). Each calf suckled 600 kg of milk in a suckling period of 120 days. Body weight (BW), in addition to five body measurements: chest girth (CG), height at wither (HW), height at rump (HR), body length (BL), and diagonal length (DL), were recorded weekly. The heaviest BW was observed on SUSD calves suckling twice/day which had also the highest HW at weaning. Similarly, were BW, HW, and CG at 6 months of age. Also, the same group achieved the largest daily BW (0.902 kg/day), BL (0.246 cm), and CG (0.338 cm/day) gains during the pre-weaning phase. However, CMS suckled 3 times/day calves had the largest daily BW gain between birth and 6 or 8 months of age. CMS twice/day calves had the largest daily gain in CG from weaning to 6 months and from weaning to 8 months of age followed by SUSD suckling 3 times/day calves. Also, CMS twice/day calves had the largest daily gain in rump height from birth to 8 months of age compared to other groups. It can be concluded that when equal amounts of milk were fed during the suckling period, suckling protocol affected growth rate before weaning but that effect diminished as calf age increased after weaning.

Influences of maternal factors on the estimate of genetic parameters for goat feed efficiency traits.

The objective of the present study was to estimate the genetic parameters for the feed efficiency traits in Barbari goats. The data records of 9332 progenies born to 413 sires and 2580 dams were collected with respect to the average daily weight gain (ADG), i.e., ADG1 (birth to weaning), ADG2 (weaning to 6 months), ADG3 (6 to 12 months), as well as derived trait Kleiber ratio (KR), i.e., KR1 (ADG1/3MW0.75), KR2 (ADG2/6MW0.75), and KR3 (ADG3/12MW0.75). The data were corrected for fixed covariates like period of kidding, the season of birth, sex, type of birth, and parity. Univariate and multivariate animal models with an average information function of restricted maximum likelihood (REML) were used to estimate genetic factors for these traits. The best model was evaluated based on the likelihood ratio test. The direct heritability estimates were 0.21 ± 0.03, 0.17 ± 0.03, 0.23 ± 0.04, 0.22 ± 0.04, 0.16 ± 0.04, and 0.26 ± 0.04 for ADG1, ADG2, ADG3, KR1, KR2, and KR3, respectively. However, they were inflated due to high and negative estimates of covariance between direct animal and maternal genetic effects. Moderate estimates of heritability augur the scope for improvement for feed efficiency traits. The maternal genetic effects (m2) significantly contributed to 3-12% of the total phenotypic variance. The realized heritability of mass selection, which takes into account direct and maternal genetic variance together, shows a low to moderate estimate of genetic variance for ADG and KR. The genetic correlation ranged from - 0.48 ± 0.11 (ADG1-KR3) to 0.95 ± 0.00 (ADG1-KR1), phenotypic correlation ranged from - 0.28 ± 0.01 (ADG2-KR3) to 0.94 ± 0.01 (ADG1-KR1), maternal genetic correlation ranged from - 0.22 (KR2-KR3) to 0.96 (ADG1-KR1) and - 0.69 (ADG1-KR3) to 0.95 (ADG1-KR1) for the maternal permanent environment, respectively. Kids can be indirectly chosen for higher feed efficiency since ADG and their associated KR have substantial genetic correlations. It is suggested that the KR should be used as a selection criterion for Barbari goats for improving feed efficiency.

Space allowance: a tool for improving behavior, milk and meat production, and reproduction performance of buffalo in different housing systems-a review.

Buffalo population has dramatically increased during the last two decades, especially in tropical and subtropical regions. Although buffalo are important milk and meat-producing animal, still practices of buffalo farming and welfare aspects are not well established. Housing system and stocking density are significant factors that affect the welfare and production of animals; however, no space allowance standards have been demonstrated for buffalo at different ages. This review article presents the following: (1) an overview of buffalo subtypes and their geographical distribution of buffalo populations and their production; (2) the effect of housing systems and space allowance on the social behavior and welfare indices; (3) the effects of space allowance on milk production and growth performance of buffalo; and (4) the relationship between space allowance and reproductive performance. Although the limited data in this area of research, it can be driven that a larger space allowance with access to a pool, especially during the hot season, maintains buffalo production at optimal levels. Moreover, optimal floor space improves the welfare and social indices of buffalo; however, there are discrepancies in aggressive and agonistic behavior results. Surprisingly, the reproductive performance of buffalo was not affected by space allowance. Therefore, further research is needed to identify the impact of the housing aspects, including space allowance and enrichment tools. on the productive performance, and welfare indices of buffalo. This would assist in implementing welfare-economic standards for buffalo production and reveal the potentiality of this eco-friendly animal.

A meta-analysis of genome-wide association studies for average daily gain and lean meat percentage in two Duroc pig populations.

BACKGROUND: Average daily gain (ADG) and lean meat percentage (LMP) are the main production performance indicators of pigs. Nevertheless, the genetic architecture of ADG and LMP is still elusive. Here, we conducted genome-wide association studies (GWAS) and meta-analysis for ADG and LMP in 3770 American and 2090 Canadian Duroc pigs. RESULTS: In the American Duroc pigs, one novel pleiotropic quantitative trait locus (QTL) on Sus scrofa chromosome 1 (SSC1) was identified to be associated with ADG and LMP, which spans 2.53 Mb (from 159.66 to 162.19 Mb). In the Canadian Duroc pigs, two novel QTLs on SSC1 were detected for LMP, which were situated in 3.86 Mb (from 157.99 to 161.85 Mb) and 555 kb (from 37.63 to 38.19 Mb) regions. The meta-analysis identified ten and 20 additional SNPs for ADG and LMP, respectively. Finally, four genes (PHLPP1, STC1, DYRK1B, and PIK3C2A) were detected to be associated with ADG and/or LMP. Further bioinformatics analysis showed that the candidate genes for ADG are mainly involved in bone growth and development, whereas the candidate genes for LMP mainly participated in adipose tissue and muscle tissue growth and development. CONCLUSIONS: We performed GWAS and meta-analysis for ADG and LMP based on a large sample size consisting of two Duroc pig populations. One pleiotropic QTL that shared a 2.19 Mb haplotype block from 159.66 to 161.85 Mb on SSC1 was found to affect ADG and LMP in the two Duroc pig populations. Furthermore, the combination of single-population and meta-analysis of GWAS improved the efficiency of detecting additional SNPs for the analyzed traits. Our results provide new insights into the genetic architecture of ADG and LMP traits in pigs. Moreover, some significant SNPs associated with ADG and/or LMP in this study may be useful for marker-assisted selection in pig breeding.

Effects of calfhood respiratory disease on health and performance of dairy cattle: A systematic review and meta-analysis.

Bovine respiratory disease (BRD) is one of the most common calfhood diseases in dairy cattle. Unfortunately, published data on the short- and long-term effects of calfhood BRD on health and performance are scarce and, when available, often conflicting and uncertain. The objective of this study was therefore to review the scientific literature on the effects of calfhood BRD on health and performance of dairy cattle and summarize the research findings using a meta-analysis approach. The systematic review and meta-analysis were performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed and CAB Abstract databases were screened for relevant studies that were published in English (until February 3, 2020). Only studies reporting naturally occurring BRD cases from birth to 12 mo of age in dairy calves in Europe and North America were considered eligible. Both observational studies and randomized controlled trials were included. Random-effect meta-analysis models were used to quantify the effect of BRD on outcomes for which at least 5 studies reported a numeric estimation of the effect of BRD. From an initial pool of 525 references, 27 full-text articles with original data were included in the manuscript. Meta-analysis models were prepared for 4 outcomes: odds of mortality (n = 7 studies), odds of herd removal before first calving (n = 5 studies), average daily gain (n = 10 studies), and milk production during first lactation (n = 5 studies). In these models, heifers diagnosed with BRD during calfhood had 2.85 times higher odds of dying (95% confidence interval: 1.22 to 6.69) and 2.30 times higher odds of herd removal (i.e., dead, culled, or sold) before the first calving (95% confidence interval: 1.75 to 3.03) compared with heifers not diagnosed with this condition. Heifers experiencing calfhood BRD also had an average daily gain reduced by 0.067 kg/d (95% confidence interval: -0.099 to -0.034) and they produced 121.2 kg (95% confidence interval: -184.9 to -57.5) less milk during their first lactation. Other health and performance outcomes, such as age at first calving and odds of not finishing the first lactation, were also investigated but not summarized using a meta-analysis approach. Pooled estimates obtained in the present study may provide more accurate estimates of the overall economic losses associated with calfhood BRD in dairy cattle.

Diagnosis of respiratory disease in preweaned dairy calves using sequential thoracic ultrasonography and clinical respiratory scoring: Temporal transitions and association with growth rates.

Bovine respiratory disease (BRD) in dairy calves is a multifactorial condition, involving environmental, host, and pathogen factors. Thoracic ultrasound scoring (TUS) has recently been validated as an accurate method of detecting BRD-related lung pathology in dairy calves. Previous studies investigating the use of TUS in preweaned dairy calves have largely been based on cross-sectional data from all-year production systems. The objectives of this longitudinal observational study were to characterize the temporal transitions in TUS scores in dairy calves from pasture-based, seasonal-calving herds using sequential examinations during the preweaning period, and to investigate the relationship between the presence and temporal pattern of BRD, diagnosed by TUS or clinical respiratory scoring (CRS), and average daily gain (ADG). In spring of 2019, 317 preweaned calves from 7 commercial dairy farms were recruited at less than 4 wk old (ranging from 1-27 d of age). Each farm was examined on at least 3 occasions at 20- to 28-d intervals and housed indoors in group or individual pens. At each visit TUS scores, CRS scores based on the University of Wisconsin Calf Respiratory Score Chart (https://www.vetmed.wisc.edu/fapm/wp-content/uploads/2020/01/calf_respiratory_scoring_chart.pdf), and live weight using a dairy breed-specific weigh band were recorded. All data were recorded by the same 2 veterinarians over the course of the study. The final data set consisted of 966 TUS and CRS scores collected from 317 calves over a period of approximately 6 wk from 7 farms. The data were analyzed in multivariable, mixed effects, linear regression models, with separate models constructed for TUS and CRS scores. Random effects (intercepts) were included for calf, farm, and visit week. Additionally, a random slope was included for age at sampling by farm. Median farm TUS score ranged from 0 to 2.5 over the 3 visits (possible range: 0-5). The percentage of calves with a TUS score ≥3 (consolidation of the full thickness of 1 lung lobe), on each farm ranged from 0 to 50%. The median CRS in calves on individual farms ranged from 1 to 3 over the 3 visits (possible range: 0-12). The percentage of calves on each farm with a CRS score ≥5 (possible range: 0-12) ranged from 0 to 26%. The TUS and CRS scores were weakly correlated. The TUS was associated with reduced ADG. Calves with TUS scores ≥3 grew at 126 g/d less than unaffected calves over the 3-wk period before examination. The predicted effect on ADG was dependent on the age and duration over which the animal was affected. Calves affected later (i.e., between visits 2 and 3) had lower predicted weights at 63 d compared with calves with increased TUS scores earlier in the study period. Calves with a TUS score ≥3 at each of the 3 sampling points had the lowest weight at 63 d of age. There was no association of CRS with ADG. This study showed that in contrast to CRS, higher TUS scores are associated with lower ADG, with weight loss being more pronounced in chronic cases.

Astragalus root extract improved average daily gain, immunity, antioxidant status and ruminal microbiota of early weaned yak calves.

BACKGROUND: Early weaning in yak calves is being attempted to improve yak reproduction rate. However, this has to be done with caution because of the high mortality rate of calves due to the lack of nutrients and the harsh environmental conditions. Twenty-four weaned male yak calves were used in a 60 day feeding trial in which astragalus root extract (ARE) was supplemented. They were assigned randomly to one of four dietary treatments (n = six per treatment) that differed in ARE level: 0 g kg-1 (control), ARE0 ; 20 g kg-1 , ARE20 ; 50 g kg-1 , ARE50; and 80 g kg-1 dry matter intake (DMI), ARE80 . RESULTS: Final bodyweight and average daily gain (ADG) were significantly higher and the DMI/ADG ratio was significantly lower in calves with ARE supplementation than control (ARE0 ) calves. Ruminal concentrations of acetate and propionate and serum concentration of superoxide dismutase in ARE80 calves were higher than in the other groups and serum concentration of insulin was higher in ARE80 calves than in ARE20 calves. Serum immunoglobulin G (IgG) and interleukin-2 (IL-2) concentrations in ARE-fed calves were higher than in controls. Serum tumor necrosis factor (TNF-α) concentration was higher in ARE50 and ARE80 groups than ARE0 calves and serum interleukin-6 (IL-6) concentration was higher in ARE80 than in ARE0 calves. Serum immunoglobulin A (IgA), IgG and immunoglobulin M (IgM) concentrations increased with age in ARE-fed calves. ARE supplementation increased the abundance of fiber degrading bacteria. CONCLUSION: ARE at a dosage of 5% to 8% DMI can be supplemented to early weaned yak calves to improve growth performance, antioxidant capacity and immunity. © 2020 Society of Chemical Industry.

Effect of different blend levels of spineless cactus and Mombasa hay as roughage on intake, digestibility, ingestive behavior, and performance of lambs.

This study aimed to determine the best level of the blend of spineless cactus (Nopalea cochenillifera) and Mombasa (Panicum maximum) hay as roughage in the diet of lambs based on intake, digestibility, ingestive behavior, and lamb performance. Forty-eight uncastrated crossbred Santa Ines breed lambs with an average age of 4 months old and an average initial BW of 20.5 kg ± 2.8 kg were distributed in two experiments using a completely randomized design: experiment 1: 16 lambs (four treatments and four replicates) for in vivo digestibility trial in metabolic cage; experiment 2: 32 lambs (four treatments and eight replicates) in feedlot to determine intake, ingestive behavior, and performance. As the amount of cactus in the roughage increased, there was a linear reduction (P <0.001) on intake (g/day) of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), non-fibrous carbohydrates (NFC) digestibility, time spent ruminating, feeding efficiency of NDF (P = 0.0153), NDF rumination efficiency rate (P = 0.032), final BW, TWG, and ADG of lamb. However, there was a linear increase (P <0.001) on the intake of the NFC and TDN, digestibility coefficient of DM, CP, total carbohydrates (TC) and NDF gross energy, metabolizable energy, and time spent idling when spineless cactus increased in the roughage blend. The least amount of cactus in the roughage (112-637 g/kg DM) promoted higher intake of DM and CP, improving lamb performance. However, the blend up to 450-300 g/kg DM improved digestibility and energy production as well as it did not affect the feed efficiency.

Enteric methane emissions by young Brahman bulls grazing tropical pastures at different rainfall seasons in the Peruvian jungle.

The aim of this research was to measure enteric methane (CH4) emissions by young Brahman bulls grazing tropical pastures at different rainfall seasons in the Peruvian jungle. Fourteen 1.5-year-old, young bulls (280 kg ± 18 kg BW) were grazed on tropical grasses and legumes dominated by German grass [Echinochloa polystachya (Kunth) Hitch.] and minor proportion of Torourco grass [Paspalum conjugatum (P.J. Bergius) Roxb] and Leguminous Calopo (Calopogonium mucunoides Desv.) and Kudzú [Pueraria phaseoloides (Roxb.) Benth]. Enteric CH4 emission was measured by the sulfur hexafluoride (SF6) tracer-gas technique. Organic matter intake (OMI) was determined from organic matter digestibility (OMD) using a fecal protein crude index and fecal output estimated by the dosage of external markers. There was a difference in OMD between seasons (68 and 66% for the dry and rainy seasons, respectively; P < 0.0001). The OMI (6.7 and 7.4 kg/day) and CH4 (178.7 and 298 g/day) were higher (P < 0.05) in the dry season than in the rainy season, respectively. The yield of CH4 was lower (P < 0.0001) during rainy season (7.1%) than at the dry season (10.6%). The CH4 emission (g/day) was correlated with OMD (%) (r = 0.74, P < 0.0001). Enteric CH4 emissions of young bulls grazing mixtures of tropical pastures were significantly lower in animals grazing on the rainy-season, expressed either through unit of absolute emission, intake or as percentage of the GEI. Likewise, OMD of consumed pasture was the most important factor determining CH4 emission.