Mean Average Daily Gain Research Articles

Investigating genotype by environment interaction for beef cattle fertility traits in commercial herds in northern Australia with multi-trait analysis

BackgroundGenotype by environment interactions (GxE) affect a range of production traits in beef cattle. Quantifying the effect of GxE in commercial and multi-breed herds is challenging due to unknown genetic linkage between animals across environment levels. The primary aim of this study was to use multi-trait models to investigate GxE for three heifer fertility traits, corpus luteum (CL) presence, first pregnancy and second pregnancy, in a large tropical beef multibreed dataset (n = 21,037). Environmental levels were defined by two different descriptors, burden of heat load (temperature humidity index, THI) and nutritional availability (based on mean average daily gain for the herd, ADWG). To separate the effects of genetic linkage and real GxE across the environments, 1000 replicates of a simulated phenotype were generated by simulating QTL effects with no GxE onto real marker genotypes from the population, to determine the genetic correlations that could be expected across environments due to the existing genetic linkage only. Correlations from the real phenotypes were then compared to the empirical distribution under the null hypothesis from the simulated data. By adopting this approach, this study attempted to establish if low genetic correlations between environmental levels were due to GxE or insufficient genetic linkage between animals in each environmental level.ResultsThe correlations (being less than <0.8) for the real phenotypes were indicative of GxE for CL presence between ADWG environmental levels and in pregnancy traits. However, none of the correlations for CL presence or first pregnancy between ADWG levels were below the 5th percentile value for the empirical distribution under the null hypothesis from the simulated data. Only one statistically significant (P < 0.05) indication of GxE for first pregnancy was found between THI environmental levels, where rg = 0.28 and 5th percentile value = 0.29, and this result was marginal.ConclusionsOnly one case of statistically significant GxE for fertility traits was detected for first pregnancy between THI environmental levels 2 and 3. Other initial indications of GxE that were observed from the real phenotypes did not prove significant when compared to an empirical null distribution from simulated phenotypes. The lack of compelling evidence of GxE indicates that direct selection for fertility traits can be made accurately, using a single evaluation, regardless of environment.

The impact of rainfall on beef cattle growth across diverse climate zones

Genetics, animal husbandry and the feedbase all impact cattle growth. Australia’s cattle feedbase covers 40% of the continent and encompasses diverse climates and landscapes, making stocking rate decisions challenging. Of the factors contributing to climate change, rainfall is a primary determinant of feedbase growth and, with this, cattle growth. Understanding the interplay between rainfall and cattle growth across the diverse Australian landscape is thus critical to aid farmer decision-making. However, revealing such interactions between landscape and rainfall for cattle growth for such decision-making has until now been infeasible due to a lack of sufficient temporal and spatial cattle growth data. The Optiweigh (OW) system has been deployed across Australia’s extensive beef production systems as a voluntary weighing unit, opportunistically monitoring cattle liveweight (LW). This study determined the impact of rainfall on the temporal and spatial variability of beef cattle growth across three of Australia’s agro-climatic zones (grassland, subtropical and temperate), aiming to describe the diverse feedbase through patterns of LW variability. A total of 1.3 million cattle LW observations were collected from 82 026 cattle over 2 years (2020–2022). Rainfall data from the Australian Bureau of Meteorology were also collated for the closest meteorological station to each OW unit. Cattle LW average daily gain (ADG) was clustered by season and zone. A series of linear mixed models were used to examine ADG for each zone-season combination, with random effects for individual animals and farms, and fixed effects for climate zone and current and lagged rainfall. The overall mean ADG for the dataset was 0.68 kg/day, with greater growth variability between farms within a zone (SD: 0.349 ± 0.021 kg/day, estimate ± SE) than between cattle within a farm (SD: 0.229 ± 0.004 kg/day). This ADG variability can be partly attributed to the timing and amount of rainfall, with agro-climatic zones showing unique interactions between rainfall and ADG. Seasonal lagged rainfall effects were present in the grassland and temperate zones, while rainfall in the temperate zone had a year-round effect on cattle growth. Further, season-wise lagged rainfall had mixed effects on ADG, whereas rain occurring in a season reduced growth in the same season across zones (P < 0.001). These findings provide valuable initial insights into the variability of ADG across the landscape over time and markedly improve our understanding of the interplay between climate and Australia’s diverse feedbase, contributing to improved management strategies.

Enhancing early life nutrition alters the hepatic transcriptome of Angus × Holstein-Friesian heifer calves

Early life nutrition has a major influence on subsequent lifetime performance in cattle. The aim of this experiment was to investigate the effect of plane of nutrition from 3 to 21 weeks of age on the liver transcriptome. Holstein-Friesian × Angus heifer calves with a mean (±SD) age and BW of 19 (±5) days and 51.2 (±7.8) kg, respectively, were assigned to either a high-energy diet to support a mean average daily gain (ADG) of 1.2 kg/day (HI; n = 15) or a moderate diet (MOD; n = 15) to support a mean ADG of 0.5 kg/day. At 145 ± 3 days of age, all calves were euthanised, liver tissue samples collected and flash-frozen in liquid nitrogen. Following RNA sequence analysis, the total number of differentially expressed genes (DEGs) (at false discovery rate (FDR) > 0.05) was 537; 308 upregulated and 229 downregulated in HI compared to MOD. The number of DEGs mapped to IPA (at FDR > 0.05) was 460; 264 upregulated and 196 downregulated. There was greater expression of genes associated with cellular development and metabolism in heifers on the HI compared to the MOD diet. The genes (fold change) of the somatotrophic axis; IGF1 (3.7), IGFALS (2.6) and GHR (1.5) were upregulated in the HI compared to MOD diet. The cytokine receptor genes, IL17RB (1.7) and IL20RA (3.3), were upregulated in the HI heifers, which were detected in a network interacting with metabolically regulated genes. The potential enhanced cell-to-cell communication evident from DEGs would increase the calves’ ability to combat health challenges. The findings of this study indicate that enhancing the early life plane of nutrition in heifer calves results in the upregulation of genes that are associated with increased metabolic activity and thus metabolic capacity. Moreover, the interaction between metabolic and immune communication genes indicates that enhanced nutrition has the potential to improve the immune response in the liver which will play a central role in ensuring optimal lifetime performance.

Cangpu Oral Liquid as a Possible Alternative to Antibiotics for the Control of Undifferentiated Calf Diarrhea.

Antibiotics are essential in the prevention of calf diarrhea epidemics. As more antibiotics become ineffective due to drug-resistant bacteria, attention must be directed toward alternative treatments for calf diarrhea. Natural antibiotic alternatives, such as Chinese herbal medicine, have become a research hotspot in the clinical treatment of diseases such as calf diarrhea due to their characteristics of fewer side effects, low cost, little residue, and no drug resistance. The Cangpu Oral Liquid (CP) was modified from a traditional herbal formula that had been widely used in ancient China to treat gastrointestinal diseases in animals. In order to evaluate the treatment effect of CP on neonatal calf diarrhea, a randomized controlled field trial was performed. Two hundred and forty-six diarrheal Holstein calves of 2–15 days old were selected and randomly divided into two treatment groups receiving either apramycin or CP. 101 out of 123 calves recovered from diarrhea in the CP group, whereas 77 out of 123 calves showed recovery after antibiotic therapy. There were no differences in initial weight between both groups, while the final weight was significantly different (P = 0.892, P = 0.025, respectively). The mean average daily gain (ADG) of calves (211.45 gram/day) in the CP group was significantly higher compared to the antibiotic group (164.56 gram/day) (P = 0.001). The CP group also showed a shorter recovery time from diarrhea (3.90 days vs. 6.62 days, P = 0.001). The current results indicate that the CP has a beneficial clinical effect on the treatment of diarrhea in neonatal calves and is an effective alternative treatment option.

Porcine ear necrosis in weaned piglets: prevalence and impact on daily weight gain

BackgroundPorcine ear necrosis (PEN) in pigs is characterized by a blue to black discoloration of the tip or margin of the ear followed by necrosis. The present study investigated the prevalence of PEN in a Belgian pig farm with PEN problems in nursery pigs, the effect of a mycotoxin detoxifier added to the feed on PEN prevalence, and the impact of PEN on the piglets’ growth. Six consecutive batches of weaned piglets [565–751 piglets per batch, (n = 3898)] were included. For each weaning batch, the presence and severity of PEN during the nursery period (3–10 weeks of age) were recorded weekly. Average daily gain (ADG) was calculated by weighing 597 individual piglets divided over the six batches. Additionally different mycotoxins were measured in the feed using LC–MS/MS analysis, and to three randomly selected batches, a mycotoxin detoxifier (Mycofix® Plus 5E, Biomin) was added to the feed.ResultsAt the end of the nursery period, 11.0–32.0% of the piglets in each batch were affected. The prevalence increased with the number of weeks post-weaning, especially from week 4 after weaning onwards. Mild, moderate, severe and very severe lesions represented 84.6%, 14.0%, 1.3% and 0.1% of all lesions, respectively. Different mycotoxins were present in the feed, but all at low concentrations. The mean ADG (± SD) for pigs without (n = 243) and with (n = 158) lesions was 391 g (± 71 g) and 394 g (± 65 g), respectively (P > 0.05). The ADG for mildly affected (387 g ± 68 g) and moderately affected piglets (420 g ± 44 g) was not significantly different (P > 0.05). The PEN prevalence in the batches without or with the mycotoxin detoxifier was 25% and 22%, respectively (P > 0.05).ConclusionsTwenty-three percent of animals showed lesions at the end of the nursery. Affected pigs did not have a lower ADG compared to non-affected animals, which might be explained by the fact that most affected piglets only had mild lesions. The addition of a mycotoxin detoxifier did not influence the prevalence of PEN, possibly because of the low levels of mycotoxin contamination. Further research is warranted to assess the impact of more severe PEN lesions and the effect of control measures.

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.

Feed efficiency and maternal productivity of Bos indicus beefcows.

This study evaluated 53 primiparous cows (36.8±1.23 months old and 484±40.9 kg of body weight) performance tested (GrowSafe® System) from 22±5 to 190±13 days of lactation in order to obtain daily dry matter intake (DMI). The animals received a high-forage diet (forage-to-concentrate ratio of 90:10). Milk production of the cows was evaluated three times by mechanical milking and the energy-corrected milk yield (ECMY) was calculated. Energy status (through the indicators glucose, cholesterol, triglycerides, and β-hydroxybutyrate), protein status (indicators albumin, urea, and creatinine), mineral status (indicators calcium, phosphorus, and magnesium), and hormonal status (indicators insulin and cortisol) were estimated four times throughout lactation. The residual feed intake (RFI) of cows was calculated considering DMI, average daily gain (ADG) and mid-test metabolic weight (BW0.75) obtained in early lactation (from 22±5 to 102±7 days), and the animals were classified as negative (most efficient) or positive RFI (least efficient). The RFI model explained 53% of the variation in DMI. The mean DMI, ADG, ECMY, and calf weight as a percentage of cow weight were 12.47±2.70 kg DM/day, 0.632±0.323 kg/day, 10.47±3.23 kg/day, and 36.6±5.39%, respectively. Negative RFI cows consumed 11.5% less DM than positive RFI cows, with performance and metabolic profile being similar to those of positive RFI cows, except for a lower milk protein content and higher blood cholesterol concentration. In conclusion, negative (most efficient) and positive RFI (least efficient) Nellore cows, fed an ad libitum high-forage diet, produced similar amounts of milk, fat and lactose and had similar subcutaneous fat thickness, weight, calf weight as a percentage of cow weight, and blood metabolite concentrations (except for cholesterol). Therefore, there are economic benefits to utilizing RFI in a cow herd since cattle had decreased DMI with similar overall performance, making them more profitable due to lower input costs.

Genetic (co)variation between resistance to Aeromonas hydrophila and growth in tambaqui (Colossoma macropomum)

Tambaqui (Colossoma macropomum) is the main native fish farmed in South American continental aquaculture. One of the major pathogens affecting world fresh water aquaculture is the bacterium Aeromonas hydrophila, which generates several disease outbreaks and production losses in farmed tambaqui stocks. Up to date, there are no studies focusing on understanding the quantitative basis for the genetic improvement for disease resistance in tambaqui. Thus, the objective of this study was to determine the genetic parameters for resistance to A. hydrophila and the genetic correlation with average daily gain in juveniles of tambaqui, to determine whether these traits can be included in selective breeding programs. Estimation of genetic parameters was performed using data from an experimental challenge performed in 18 full-sib families, using a total of 576 individuals. Before bacterial challenge, all animals were evaluated for average daily gain (ADG) in the juvenile phase during 30 days. The challenge spanned 120 h (5 days) and disease resistance traits were defined as: i) binary survival (BS) and, ii) time of death (TD) of fish presenting clinical signs of A. hydrophila infection. The mean ADG was 0.49 g/day (SD = 0.21) in the population and heritability for this trait was moderate (h2 = 0.37 ± 0.13). BS and TD varied considerably among families (26% to 89% and 10.7 h to 69.2 h, respectively), which indicated a significant genetic variation related to resistance to A. hydrophila infection. Low to moderate values for heritability were found for BS and TD (0.17 ± 0.06 and 0.23 ± 0.09, respectively). The genetic correlations between resistance to A. hydrophila and ADG in juveniles of tambaqui were not significantly different from zero. The significant genetic variation found for A. hydrophila resistance in tambaqui indicates that selecting superior genotypes is a viable approach to reducing the impact of diseases outbreaks in aquaculture.

Zinc amino acid complex in association with chromium methionine improves the feed efficiency of finished Nellore cattle in the feedlot

Trace minerals are vital to the metabolism and performance of beef cattle and may improve meat quality. The objective of this study was to evaluate the effects of a Zn amino acid complex (ZnAA) fed alone or in association with a Cr methionine complex (CrMet) on the performance and meat quality of Nellore cattle finished in a feedlot. Three hundred thirty-six Nellore bulls were blocked by body weight (BW; 342 ± 24.5 kg) and assigned to one of the following three dietary treatments: a control diet containing 54 mg/kg of Zn from an inorganic source of minerals (CON); a diet providing 21.6 mg/kg of Zn from an inorganic source with 32.4 mg/kg of a Zn amino acid complex (ZnAA); and a diet providing 21.6 mg/kg of Zn from an inorganic source with 32.4 mg/kg of a Zn amino acid complex combined with 0.36 mg/kg of a CrMet complex (ZnCr). The total number of days on the diets was 130 days, with an initial 35-d period for dietary acclimation to the finishing diet. Statistical analysis was performed using the MIXED procedure of SAS with the pen as the experimental unit (36 pens). Blood parameters and meat quality were analyzed as repeated measures (from 72 animals; 2 animals/pen). The final BW, dry matter intake (DMI), and average daily gain (ADG) was similar among the treatments (P ≥ 0.261). The overall mean DMI, final BW, and ADG were 9.15 kg/d, 535 kg, and 1.49 kg/d, respectively. Feeding ZnCr improved efficiency (P = 0.011) compared with the ZnAA and CON bulls. Leucocytes, aminotransferase, β-hydroxybutyric acid, cholesterol, glucose, and cortisol were affected (P ≤ 0.038) by time but not by dietary treatment. Flight speed and serum cortisol level were unaffected (P ≥ 0.518) by dietary treatment. No significant treatment effects (P ≥ 0.169) were detected for hot carcass weight, fat, pH, temperature, liver, kidney, or KPH. Treatment tended to alter the area of the Longissimus muscle (P = 0.081). The Longissimus muscle area was greater for bulls fed ZnCr than for bulls fed ZnAA or CON (80.6 vs. 77.5 cm2). There was a tendency (P = 0.073) for decreased Warner-Bratzler shear force in animals fed ZnCr. Tenderness was improved by 12.3 % compared with CON. Individual fatty acids (P ≥ 0.171) and total fatty acids (saturated and unsaturated; P ≥ 0.392) did not differ among the treatments. These data suggest that finishing Nellore bulls fed ZnCr in a feedlot setting exhibited greater efficiency and tended to exhibit improved meat tenderness compared with bulls fed ZnAA.

Mitochondrial abundance and function in skeletal muscle and liver from Simmental beef cattle divergent for residual feed intake

Cellular mitochondrial function has been suggested to contribute to variation in feed efficiency (FE) among animals. The objective of this study was to determine mitochondrial abundance and activities of various mitochondrial respiratory chain complexes (complex I (CI) to complex IV (CIV)) in liver and muscle tissue from beef cattle phenotypically divergent for residual feed intake (RFI), a measure of FE. Individual DM intake (DMI) and growth were measured in purebred Simmental heifers (n = 24) and bulls (n = 28) with an initial mean BW (SD) of 372 kg (39.6) and 387 kg (50.6), respectively. All animals were offered concentrates ad libitum and 3 kg of grass silage daily, and feed intake was recorded for 70 days. Residuals of the regression of DMI on average daily gain (ADG), mid-test BW0.75 and backfat (BF), using all animals, were used to compute individual RFI coefficients. Animals were ranked within sex, by RFI into high (inefficient; top third of the population), medium (middle third of population) and low (efficient; bottom third of the population) terciles. Statistical analysis was carried out using the MIXED procedure of SAS v 9.3. Overall mean ADG (SD) and daily DMI (SD) for heifers were 1.2 (0.4) and 9.1 (0.5) kg, respectively, and for bulls were 1.8 (0.3) and 9.5 (1.02) kg, respectively. Heifers and bulls ranked as high RFI consumed 10% and 15% more (P < 0.05), respectively, than their low RFI counterparts. There was no effect of RFI on mitochondrial abundance in either liver or muscle (P > 0.05). An RFI × sex interaction was apparent for CI activity in muscle. High RFI animals had an increased activity (P < 0.05) of CIV in liver tissue compared to their low RFI counterparts; however, the relevance of that observation is not clear. Our data provide no clear evidence that cellular mitochondrial function within either skeletal muscle or hepatic tissue has an appreciable contributory role to overall variation in FE among beef cattle.

Short communication: Risk factors identified at arrival associated with average daily gain at a grain-fed veal facility: A prospective single cohort study

The primary objective of this prospective cohort study was to identify factors evaluated upon arrival at a grain-fed veal facility that were associated with increased growth. A secondary objective was to determine if the factors associated with average daily gain (ADG) varied between the pre- and postweaning periods. Calves were visually assessed and scored using a standardized health scoring system immediately upon arrival. They were also weighed and vaccinated, and had blood drawn from their jugular vein to determine their serum total protein level. Weights were taken on d 49 and 78 after arrival and were used to calculate ADG. Three mixed linear regression models were created to determine factors associated with ADG from 0 to 49 d after arrival, 0 to 78 d after arrival, and 49 to 78 d after arrival. A total of 998 calves were evaluated and weighed upon arrival; 636 and 915 of those calves were weighed at d 49 and d 78, respectively. Mean ADG were 610 g/d from 0 to 49 d after arrival, 860 g/d from 0 to 78 d after arrival, and 1,240 g/d from 49 to 78 d after arrival. In the model evaluating growth from 0 to 49 d, calves arriving at the facility with a higher body mass index (BMI) gained more weight per day than calves that arrived with a lower BMI. If calves arrived in the spring, they gained 201 g/d more than calves that arrived in the winter. For the period following weaning (d 49 to 78), BMI was also associated with growth. For every additional 1 g/cm2 increase in BMI at arrival, calves gained an additional 1.55 g/d from d 49 to 78. Growth from arrival to d 78 was affected solely by BMI. For every 1 g/cm2 increase in BMI at arrival, calves gained 1.23 g/d more during the entire observation period. Body mass index and season at arrival affected growth through the initial period at a grain-fed veal facility. Producers should consider these factors, especially BMI, when purchasing calves to maximize the calves' growth potential.

The effect of birth type on quantitative characteristics in pre-weaned Bligon goats

This study aimed to determine the effect of birth type on growth performance in Bligon goats. In total, 88 female Bligon kids kept on a farmer group in Yogyakarta were appraised for quantitative traits. The goat does were divided into two birth types, single and twin. The traits observed were birth weight (BW), weaning weight (WW), ADG (average daily gain), body length (BL), heart girth (HG), withers height (WH) and hip height (HH). Data were analyzed using T-test. The results indicated that birth type had a significant effect (p<0.05) on BW, BL, HG and WH at birth (mean values 2.65±0.36 kg, 32.12±3.92 cm, 34.17±3.1 cm and 34.73±2.75 cm in single born and 2.03±0.35 kg, 29.43±3.08 cm, 32.29±2.59 cm and 32.88±2.64 cm in twins respectively). Birth type also had a significant effect (p<0.05) on WW, HG, WH, and HH at weaning age (mean values 10.27±2.05 kg, 43.97±3.7 cm, 51.05.±4.65 cm, 49.41±4.50 cm and 51.65±4.54 cm in single born and 8.45±2.47 kg, 41.02±3.5.55 cm, 44.70±5.48 cm, 43.27±5.09 cm and 44.82±4.97 cm in twins respectively). The mean ADG in single born (71.31±26.09 g) was significantly (P<0.05) higher than that in twins (88.73±22.07 g). In conclusion, birth type affects quantitative characteristics in Bligon goats.

Assessment of selenium supplementation by systemic injection at birth on pre-weaning calf health

The objective of this randomized clinical trial was to evaluate the effect of selenium and vitamin E supplementation by systemic injection on dairy calf health and growth during the pre-weaning period. The study was conducted at 39 dairy farms in Ontario, selected through a convenience sample of farms in close proximity to either Guelph or Kemptville. A total of 835 Holstein heifer calves were enrolled in this study. At birth, calves were randomly allocated to receive selenium and vitamin E supplementation by injection (3 mg sodium selenite and 136 IU dl-a-tocopherol acetate) or a placebo solution. At enrollment, producers recorded time of birth, calving ease, and colostrum feeding status. At weekly visits to the individual dairy farms, trained technicians collected measurements and samples from enrolled calves. Blood was collected from calves that were up to 8 d of age to assess the concentration of serum total protein and selenium. Between 8 and 15 d of age, fecal samples were collected to identify the presence of rotavirus and Cryptosporidium parvum (C. parvum) using a commercially +available lateral immuno-chromatography antigen detection kit. Each enrolled calf was also weighed and assessed for health scores during the first, second, and seventh weeks of life. The average serum selenium concentration (SD) in treated calves was 0.08 μg/mL (0.02), versus 0.06 μg/mL (0.01) in control calves. The incidence of failure of passive transfer (FPT) among study calves was 21%, and did not differ between treatment groups. The mean average daily gain (ADG) for the study period was 1.43 lb (0.65 kg)/day and was not associated with selenium and vitamin E supplement injection. Of the 761 fecal samples tested, 272 (36%) and 118 (16%) tested positive for C. parvum and rotavirus antigen, respectively. Selenium and vitamin E treatment had a protective effect against rotavirus infection. However, there was no effect of experimental treatment on C. parvum infection status. Reduced odds of treatment for diarrhea was also seen in the selenium and vitamin E treatment group. This study suggests that selenium and vitamin E injection at birth could improve pre-weaning health by reducing rotavirus infection and diarrhea.

In the search for low-cost year-round feeds: Pen-level growth performance of local and crossbred Ugandan pigs fed forage- or silage-based diets versus commercial diet

Smallholder pig farmers in East Africa report that lack of feed, seasonal feed shortages, quality and cost are key constraints to pig rearing. Commercially prepared pig diets are too expensive and people and pigs compete for food. Smallholder farmers typically feed nutritionally unbalanced diets, resulting in low average daily gain (ADG) and poor farmer profits. Our objective was to compare the ADG of Ugandan pigs fed forage- or silage-based or commercial diets. Ugandan weaner-grower pigs were randomly assigned to forage- or silage-based diets or commercial diet. Pigs were weighed every 3 weeks from 9 to 32 weeks of age. Pen-level ADG and feed conversion were compared across diets using multiple linear regression. The ADG of pigs fed forage- or silage-based diets was lower than those fed commercial diets between 9 and 24 weeks of age ( p < 0.05). Between 28 and 32 weeks, pigs fed forage-based diets had lower ADG than those on other diets ( p < 0.05). Least squares mean ADG (g/pig/day) for pigs fed forage- or silage-based diets or commercial diet were 36, and 52, and 294 respectively at 9–15 weeks; 163, 212, 329 at 15–19 weeks; 112, 362, 574 at 20–24 weeks and 694, 994, and 1233 at 28 to 32 weeks of age. It was concluded that forage- and silage-based diets are unsuitable for small, newly weaned pigs. Feeding forage- or silage-based diets to finishing pigs is more suitable. Forage- and silage based diets are year-round low-cost pig-feeding strategies that will improve the growth performance of East African pigs, thereby increasing pig farmer income and food security.

Effects of Nickel Supplementation on Antioxidant Status, Immune Characteristics, and Energy and Lipid Metabolism in Growing Cattle.

Nickel (Ni) has not been elucidated as an essential mineral in dairy animals, though in plants and lower organisms, its role in activation of urease enzyme is well known. This study was conducted to evaluate the effect of Ni supplementation on intake, growth performance, urease activity, antioxidant and immune status, and energy and lipid metabolism in growing cattle. Eighteen growing Hariana heifers were randomly allocated into three groups on body weight (125 ± 3.0kg) and age basis (10 ± 2.0months). Feeding regimen was similar in all the groups except that treatment groups were supplemented with 0.0 (Ni0.0), 1.5 (Ni1.5), and 3.0 (Ni3.0) mg of Ni/kg dry matter (DM) in three respective groups. DM intake (DMI), average daily gain (ADG), feed efficiency, plasma urease activity, biomarkers of antioxidant and immune status, energy and lipid metabolism, and plasma Ni levels were observed during the 90-day experimental period. There was linear increase (p< 0.05) in mean DMI and ADG without affecting feed efficiency was observed in 3.0mg of Ni/kg DM supplemented heifers. Dietary Ni supplementation showed linear increase (p < 0.05) in mean plasma urease activity. No effects of (p > 0.05) of Ni supplementation were observed on superoxide dismutase (SOD) and catalase (CAT) activity and plasma lipid peroxide (LPO) concentration; whereas, mean plasma total antioxidant status (TAS) showed linear decrease (p < 0.001) in Ni-supplemented groups. Adding Ni up to 3.0mg of Ni/kg DM did not exert (p > 0.05) any effect on plasma total immunoglobulin and immunoglobulin G (IgG) concentrations. Mean plasma cortisol level showed negative association with supplemental Ni levels and concentration was found lowest (p < 0.05) in 3.0mg of Ni/kg DM-added group. Dietary Ni supplementation did not affect mean plasma concentrations of glucose, cholesterol, triglyceride, and non-esterified fatty acids (NEFA). There was a linear increase (p< 0.001) in plasma Ni concentrations as the Ni concentrations increased in the diet. The results of present study indicated that dietary supplementation of 3.0mg of Ni/kg DM improved performance of growing cattle by increasing urease activity.

Preweaned heifer management on US dairy operations: Part I. Descriptive characteristics of preweaned heifer raising practices

The objective of this study was to describe preweaned dairy heifer calf management practices on dairy operations across the United States that were used to analyze factors associated with colostrum quality and passive transfer, Cryptosporidium and Giardia, morbidity and mortality, and average daily gain. This study included 104 dairy operations in 13 states that participated in the National Animal Health Monitoring System's Dairy 2014 calf component study. This 18-mo longitudinal study focused on dairy heifer calves from birth to weaning, and data were collected on 2,545 heifer calves. Descriptive statistics were generated regarding colostrum feeding, preweaning housing, milk feeding and consumption, growth, morbidity and mortality, and weaning practices. The majority of calves enrolled were Holsteins (89.4%). Over half the calves (63.2%) enrolled in the study received the majority of their colostrum via bottle; however, 22.1% of calves from 51.0% of operations received colostrum via suckling from their dams. For all calves, the mean time to the first colostrum feeding was 2.8 h, and the average amount of colostrum at the first feeding was 2.9 L, with 4.5 L provided in the first 24 h. The mean serum IgG of all calves was 21.7 g/L; however, 76.0% of operations had at least 1 calf with failure of passive transfer of immunity with a serum IgG below 10 g/L. The majority of calves in the study were housed individually (86.6%). Nonetheless, 20.2% of operations housed some calves in groups, representing 13.4% of all calves. Approximately one-half of the calves in the study (52.3%) were dehorned or disbudded during the preweaning period, with only 27.8% of these calves receiving analgesics or anesthetics during the procedure. Whole or waste milk was the liquid diet type fed to 40.1% of calves, and milk replacer was fed to 34.8% of calves. A combination of milk and milk replacer was fed to 25.1% of calves. Calves, on average, were fed 2.6 L per feeding and fed 2.6 times/d, resulting in a total of 5.6 L of liquid diet fed per day. The mean average daily gain for all calves enrolled in the study was 0.7 kg/d. Fecal samples were collected and almost all operations had at least 1 calf positive for Cryptosporidium (94.2%) or Giardia (99.0%), and 84.6% of operations had calves that tested positive for both Cryptosporidium and Giardia. Over one-third of calves (38.1%) had at least one morbidity event during the preweaning period and the mortality rate was 5.0%. The mean age at weaning was 65.7 d. This study provides an update on dairy heifer raising practices in the United States.

Preweaned heifer management on US dairy operations: Part VI. Factors associated with average daily gain in preweaned dairy heifer calves

The study objective was to evaluate average daily gain (ADG) in dairy heifer calves based on health, feeding, management practices, and environmental factors. This study included 102 operations in 13 states that participated in the calf component of the National Animal Health Monitoring System's Dairy 2014 study. This 18-mo longitudinal study included 1,410 Holstein heifer calves monitored from birth to weaning. The mean ADG from birth to final weight was 0.74 kg/d. Backward elimination model selection in Proc Mixed after univariate screening determined factors that significantly affected ADG. The final model included dam lactation number, singleton versus twin birth, bedding type, Giardia and Cryptosporidium fecal shedding, disease events, a categorized average temperature-humidity index for the preweaning period (pTHI), amount of protein in the liquid diet (kg/d), milk pasteurization, direct-fed microbials, and the interaction between milk pasteurization and direct-fed microbials. After controlling for other independent variables in the model, calves born to first-lactation dams gained less (0.60 kg/d) than calves from second- (0.65 kg/d) or third- or greater-lactation (0.64 kg/d) dams. Singleton calves gained 0.07 kg/d more than twins. Calves bedded with sand or no bedding gained less (0.49 kg/d) than calves on all other bedding types. Calves negative for Cryptosporidium or Giardia at the time of sampling gained 0.03 or 0.02 kg/d more, respectively, than calves that were positive for Cryptosporidium or Giardia. Calves with no disease events gained 0.07 kg/d more than calves with one or more disease events. Calves experiencing an average pTHI <50 gained more (0.67 kg/d) than calves experiencing an average pTHI from 50 to 69 (0.62 kg/d), or ≥70 (0.59 kg/d). Within the range of observed kilograms of protein fed per day in the liquid diet, every additional 0.1 kg of protein fed per day equated to 0.02 kg/d of gain. Calves fed milk replacer with a direct-fed microbial gained less (0.44 kg/d) than calves fed milk replacer without a direct-fed microbial (0.60 kg/d) and calves fed pasteurized or unpasteurized milk regardless of direct-fed microbial use. These results highlight the importance of feeding a quantity and quality of a liquid diet to achieve optimal growth, keeping calves free of disease, the type or status of bedding, and mitigating the effects of temperature and humidity on preweaning ADG.

Dose–response evaluation of the standardized ileal digestible tryptophan : lysine ratio to maximize growth performance of growing-finishing gilts under commercial conditions

Environmental regulations as well as economic incentives have resulted in greater use of synthetic amino acids in swine diets. Tryptophan is typically the second limiting amino acid in corn-soybean meal-based diets. However, using corn-based co-products emphasizes the need to evaluate the pig’s response to increasing Trp concentrations. Therefore, the objective of these studies was to evaluate the dose–response to increasing standardized ileal digestible (SID) Trp : Lys on growth performance of growing-finishing gilts housed under large-scale commercial conditions. Dietary treatments consisted of SID Trp : Lys of 14.5%, 16.5%, 18.0%, 19.5%, 21.0%, 22.5% and 24.5%. The study was conducted in four experiments of 21 days of duration each, and used corn-soybean meal-based diets with 30% distillers dried grains with solubles. A total of 1166, 1099, 1132 and 975 gilts (PIC 337×1050, initially 29.9±2.0 kg, 55.5±4.8 kg, 71.2±3.4 kg and 106.2±3.1 kg BW, mean±SD) were used. Within each experiment, pens of gilts were blocked by BW and assigned to one of the seven dietary treatments and six pens per treatment with 20 to 28 gilts/pen. First, generalized linear mixed models were fit to data from each experiment to characterize performance. Next, data were modeled across experiments and fit competing dose–response linear and non-linear models and estimate SID Trp : Lys break points or maximums for performance. Competing models included broken-line linear (BLL), broken-line quadratic and quadratic polynomial (QP). For average daily gain (ADG), increasing the SID Trp : Lys increased growth rate in a quadratic manner (P<0.02) in all experiments except for Exp 2, for which the increase was linear (P<0.001). Increasing SID Trp : Lys increased (P<0.05) feed efficiency (G : F) quadratically in Exp 1, 3 and 4. For, ADG the QP was the best fitting dose–response model and the estimated maximum mean ADG was obtained at a 23.5% (95% confidence interval (CI): [22.7, 24.3%]) SID Trp : Lys. For maximum G : F, the BLL dose–response models had the best fit and estimated the SID Trp : Lys minimum to maximize G : F at 16.9 (95% CI: [16.0, 17.8%]). Thus, the estimated SID Trp : Lys for 30 to 125 kg gilts ranged from a minimum of 16.9% for maximum G : F to 23.5% for maximum ADG.

Effect of a Buttiauxella phytase on production performance in growing/finishing pigs fed a European-type diet without inclusion of inorganic phosphorus

SummaryThe effect of a Buttiauxella phytase, in a dose range of 0-1000 FTU/kg in feed, on production performance in growing/finishing pigs fed European type wheat, corn, barley and SBM based diet was determined. Five dietary treatments were tested including a positive control (PC), a negative control (NC) without inorganic P and with reduced Ca (–0.12%) and metabolisable energy content (–0.14 MJ ME/kg) or NC supplemented with Buttiauxella phytase (Axtra® PHY, Danisco Animal Nutrition, DuPont Industrial Biosciences, Marlborough, UK) at 250, 500 or 1000 FTU/kg respectively. A total of 100 pigs (mean initial BW of 30 kg, Topig x Pi, 10 weeks of age) were used, with 20 replicates per treatment (50% gilts and 50% barrows). Pigs were individually housed in pens and randomly allocated on the basis of body weight (BW) and gender to the five treatments. Feed, in mash form, and water were offered ad libitum. Basal diets had an intrinsic phytase level of approximately 300 and 440 FTU/kg in NC grower and NC finisher diets respectively. Mean average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated for the feeding phases of 30–85 kg (grower), 85–125 kg (finisher) on trial and for overall period. During the grower phase, increasing phytase dose resulted in a linear increase in ADG. Phytase inclusion at 250, 500 and 1000 FTU/kg improved ADG by 3.5, 7.2 and 8.1% respectively compared to NC and by 0.8, 4.5 and 5.3% respectively compared to those fed the PC. Performance in the finisher phase, overall period and slaughter parameters were not different between dietary treatments. The data showed that it was beneficial to increase phytase dose up to 1000 FTU/kg in grower pigs up to 85 kg BW. In the finisher phase, in pigs with BW above 85 kg, 500 FTU/kg was sufficient to replace inorganic P and maintain performance and carcass characteristics comparable to pigs fed the PC.

Influence of early weaning on the behavioural patterns and growth performance in large white Yorkshire (LWY) piglets

The behavioural pattern and growth performance of three groups of LWY piglets weaned at different ages was studied for six months. The first, second and third groups were weaned at 25, 40 and 56 days, respectively. The playing and huddling behavior was more in group 1 piglets. While fighting, standing, locomotion and tail biting behavior was more in group 2 piglets. Whereas the lying behavior was more in group 3 piglets. There was a significant difference (P is less than 0.01) among the three groups of piglets for all behavioral patterns. The post weaning weight (kg) gains reached 56.63 ± 0.41, 65.03 ± 0.36 and 63.09 ± 0.38 Kg for group 1, group 2 and group 3 respectively, at the end of study period. A significant difference (P is less than 0.01) was observed among the three groups for all the fortnightly interval body weights. The mean average daily gain for group 1, 2 and 3 was 0.33, 0.38 and 0.36 respectively. Significant difference (P is less than 0.01) had been observed between the groups for average daily gain. The present study had suggested that early weaning at 40days age was more advantageous than 25 days age and conventional 56days weaning age.