Pre-weaning Phase Research Articles

Effect of an Ultra-Diluted Complex on Health, Growth Performance, and Blood Parameters of Pre-Weaned Dairy Calves

This study aimed to evaluate the effects of an ultra-diluted complex on the health status, growth performance, and blood parameters of dairy calves during the preweaning phase in a double-blind, placebo-controlled trial. During a 75-period trial, thirty-four Holstein newborn calves at the second day of life were completely randomized individually into two treatments: (1) control (CON), oral saline supplementation (5 mL/d); and (2) oral supplementation with 5 mL/d of a ultra-diluted complex (UD): Sulfur: 1060 + Viola tricolor: 1014 + Caladium seguinum: 1030 + Zincum oxydatum: 1030 + Phosphorus: 1060 + Cardus marianus: 1060 + Colibacillinum: 1030 + Podophyllum: 1030 + Vehicle: alcohol. Free access to water and a starter was ensured during the trial period. Feed intake and fecal and health scores were monitored daily. Calves were weighed and measured weekly. Blood samples were collected at enrollment on the first day and every 21 days until the 75th day, 2 h after morning milk feeding, and tested for hematology, blood urea nitrogen, aspartate aminotransferase, gamma-glutamyl transferase, total protein albumin, globulin, and creatinine. At 70 days of age, calves were disbudded following the standard management practices of the farm. The inflammatory profile, including Immunoglobulin A, Immunoglobulin G, ceruloplasmin, transferrin, albumin, and haptoglobin, was quantified in serum samples. The ultra-diluted complex was ineffective in reducing the incidence of diseases, starter feed intake, daily weight gain, and body measurements and inflammatory profile. Blood parameters were also not affected. Thus, the ultra-diluted complex was inefficient in reducing the incidence of diseases and did not affect the performance and metabolites of pre-weaned Holstein calves.

Early Life Nutrition and its Effects on the Developing Heifer: Growth, nutritive intakes, and metabolism.

We aimed to assess the effects of preweaning nutrition and postweaning growth rates on the metabolic characteristics of replacement dairy heifers until 20 mo of age. At birth heifers, were allocated to one of 4 treatment groups which were a combination of preweaning (high or low preweaning nutritional treatment), and postweaning treatments (high or low postweaning growth rate). In the preweaning phase (birth until weaning at 10 weeks of age) heifers were subject to either a High (8 L/day) or Low (4 L/day) milk feeding strategy, then at weaning either a high or low postweaning growth rate. Heifers in the high preweaning treatment groups recorded greater growth rates until weaning compared with heifers in the low preweaning treatment groups. Heifers in the high preweaning groups consumed approximately twice the amount of milk and half the amount of concentrate. Blood samples taken at 6 weeks of age had lower BHB and higher glucose and IGF-1 concentrations in the high preweaning treatment in the preweaning phase; these differences disappeared postweaning. Additionally, insulin levels were also higher, and QUICKI index results were lower for heifers on the high preweaning treatment and for those on the high postweaning treatment, at 6 weeks and 13 mo of age. No differences between treatments were detected at 8 mo of age. Results indicate a positive effect of accelerated preweaning nutrition and post weaning growth rate (at 13 mo of age) on these metabolic biomarkers, however these treatment effects were independent of one another and reflected the nutritional input at the time.

Performance, nutrient digestibilities, and metabolic profiles of Holstein calves fed whole milk or milk replacer at two feeding levels.

The macronutrient composition of common milk replacers (MR) largely differs from bovine whole milk (WM). These differences are more nutritionally relevant when calves receive higher milk allowances. Therefore, the present study compared fresh WM with a conventional MR fed at 2 level of feeding allowances evaluating growth performance, apparent total-tract nutrient digestibilities, nitrogen (N) balance, and serum metabolite profiles in calves. Forty-eight newborn Holstein male calves (1.96 ± 0.99 d of age; 45.0 ± 4.37 kg BW) were blocked by arrival date and age. Calves in each block were then randomly assigned to the 4 treatments (n = 12/treatment): MR or WM at a high (9.0 L/d) or low feeding allowance (4.5 L/d) fed 3 times daily. Calves were weaned between wk 6 and 10 following the introduction of the starter feed in wk 6. The study ended 13 wk after the arrival at the facility. Blood and body weights were collected on arrival, and weekly thereafter. Total 24h-collection periods of feces and urine was performed at wk 2, 4, 5, 7, 9, 11, and 13. Remarkably, no interactions were observed between liquid feed and level of supply. Calves fed MR had higher ADG during the pre-weaning phase than to calves fed WM. However, calves fed WM had an increased growth rate post-weaning, resulting in no difference in BW at the end of the study. Calves fed WM had a higher apparent crude fat digestibility during the weaning period. Metabolic N efficiency, expressed as N balance relative to digestible N supply, was higher during the pre-weaning phase, but tended to be lower during the post-weaning phase for calves fed MR as compared with calves fed WM. In the pre-weaning period, serum glucose, BHB, nonesterified fatty acids (NEFA), total protein (TP), urea, albumin, globulin, triglyceride (TG), and cholesterol were influenced by liquid feed source. Carry-over effects of milk source on TG and TP were observed during the post-weaning period. As expected, calves fed a high-milk allowance showed better ADG at pre-weaning and were consistently heavier throughout the study than calves fed a low-milk allowance. Feeding a high-milk allowance did not negatively affect nutrient digestibility during the post-weaning phase. In the pre-weaning phase, milk allowance affected glucose and cholesterol metabolism, whereas TG, TP, albumin, and NEFA concentrations were affected during the post-weaning period. From a single oral dose of indigestible markers (Cr-EDTA, lactulose, and D-mannitol), calves fed a high-milk allowance showed greater urinary recovery of all markers after 6h of collection, but not after 24h. Calves fed a high-milk allowance had a higher proportion of days with lower fecal scores during the pre-weaning phase. In conclusion, the serum metabolite profiles of calves throughout the study were highly influenced by milk source. Higher milk allowance increased growth performance and had no adverse effects on starter feed intake or nutrient digestibility in the post-weaning phase. The multiple effects described for milk source and level of supply were overall independent, presenting no relevant interactions.

PSVIII-9 Effects of growth implants and timing of vaccination on calf immunity and growth performance

Abstract This study assessed calf growth performance and blood parameters of beef calves under different growth implants and timing of vaccination protocols. Crossbreed beef calves (n = 59) were stratified by birth body weight (BW) and age (41 ± 5.2 kg of BW and 70 ± 8 d of age) and randomly assigned in a split-plot design with implant strategy as the main plot and timing of vaccination as the subplot. The main plot (treatment) consisted of 3 implant strategies: 1) Synovex C (SC; n = 20; 100 mg progesterone/10 mg estradiol benzoate, or 2) Synovex One Grower (SG; n = 19; 150 mg trenbolone acetate and 21 mg estradiol benzoate; or 3) no implant (CON; n = 20). Subplot treatments were the timing of vaccination booster against bovine respiratory disease pathogens on 1) weaning (WV; n = 29) or 2) 7-d post-weaning (PWV; n = 30). Cow-calf pairs were treated alike in a single pasture during the pre-weaning phase, receiving the same vaccine (Bovi-Shield Gold One Shot and Ultrabac 7) on d 0 (implantation day) and booster time (WV or PWV). After weaning (approximately 187 d of age), calves were allocated in a single pen receiving ad libitum hay until d 60 post-weaning. Body weight and blood were collected on d 0, weaning, d 0 and 28 relative to vaccination booster, and d 60 post-weaning. Blood was collected to determine insulin-like growth factor (IGF-1), cortisol, and leptin concentrations and to perform a complete blood cell count. WV calves had decreased cortisol concentrations on booster day and 28 d post-vaccine (P = 0.01). Regardless of implant treatment, calves tended to have decreased IGF-1 concentrations 28-d post-vaccine booster (P = 0.09). An effect of treatment (P < 0.01) was detected for lymphocyte counts, with CON having greater concentrations vs. SG and SC calves. A treatment × timing of vaccination (P < 0.01) interaction was detected for monocyte counts, where SG-PWV calves had the greatest concentrations. A treatment effect (P < 0.02) was observed for eosinophil percentage, where SG had reduced percentages than CON, while SC was intermediate. An effect of treatment was detected for leptin (P < 0.01), with SG calves having the least, CON being intermediate, and SC the greatest concentrations. From d 0 to 60 d post-weaning, SG tended to have greater ADG (P ≤ 0.07) compared with CON, while SC was intermediate. On d 28 and d 35 post-weaning, calves implanted with SG were heavier (P ≤ 0.04) than the CON but not than SC. In summary, this study demonstrates that growth implants and timing of vaccination significantly affect both physiological parameters and growth performance in beef calves. Implanting calves with Synovex One Grower resulted in improved growth performance.

The effects of Bacillus subtilis spores and yeast cell wall supplementation on growth and health in Holstein dairy calves

The study aimed to assess the impact of Bacillus subtilis spores and yeast cell wall (YCW) on the performance and health of dairy calves during the milk-feeding period. Thirty female Holstein calves (birth body weight [BW] of 36.7 ± 4.81 kg) were randomly assigned to three treatments: Control (CTL, no additives), T1 (Bacillus subtilis spores), and T2 (Bacillus subtilis + YCW). Animals were individually housed with free access to water and commercial pellet starter. Calves received 8 L/d of pasteurized waste milk and were weaned at 63 d of age. The treatments (T1 and T2) were mixed into milk and administered daily from 3 to 63 d of age. Dry matter (DM) intake (from liquid and starter feed), fecal score, and rectal temperature were recorded daily. Additionally, heart girth was measured at 0, 15, 30, 45, and 60 d of age, and BW was measured at 0 and 60 d of age. Blood was sampled from the jugular vein at 0, 20, and 60 d of age for analysis of serum immunoglobulin G (IgG). There was treatment × time interaction (P = 0.04) for fecal consistency scores. Calves supplemented with Bacillus subtilis tended (χ2 test, P = 0.07) to have lower cases of diarrhea than other groups. T1 or T2 supplementations did not affect milk DM intake, starter DM intake, or total DM intake. Growth performance (BW at weaning and average daily gain) was similar between treatments. Dairy calves fed Bacillus subtilis plus YCW tended to have (P = 0.09) higher rectal temperature and had higher frequency (χ2 test, P < 0.01) of rectal temperature >39.1°C compared to the CTL and Bacillus subtilis groups. However, treatments had similar levels of serum IgG (CTL = 18.3, T1 = 16.7, and T2 = 18.6 mg/mL; P = 0.58). Our results suggest that Bacillus subtills and YCW may interact in the digestive tract of young calves as evidenced by the increased rectal temperature in T2. While the cause of this interaction remains uncertain, there was no negative effect on the animal health or growth performance. The use of Bacillus subtilis spores shows promise in improving fecal consistency scoring in dairy calves fed pasteurized waste milk during the pre-weaning phase.

A randomized trial on the effects of heat abatement during the pre-weaning phase on growth and reproductive performance of heifers and health, reproductive and productive performances of cows

Evaluation of heat stress abatement for pre-weaned dairy calves is a rare endeavor. We aimed to assess the impacts of cooling the environment of pre-weaned calves through ceiling fans on their performance after weaning and during their first lactation. We randomly assigned female Holstein calves to one of two treatment at birth (day 0): individual frame-wire hutches in a non-cooled barn ("SH", n = 125) and individual frame-wire hutches in a barn equipped with ceiling fans ("SHF", n = 101). Calves were housed under the same barn, with treatments applied in three alternating sections. Ceiling fans (2.1 m in diameter) were positioned 4.1 m from the ground and 7.6 m apart (center-to-center). Shade cloths were used to separate the sections designated for the SH and SHF treatments. Post-weaning, heifers were commingled. We recorded body weight (BW) and average daily gain (ADG) at weaning, 5, 7, and 10 mo of age. Pregnancy to first artificial insemination (P/1AI), hazard of pregnancy, and the hazard of commencing the first lactation are reported. Body weight at first calving, P/1AI, hazard of pregnancy, and milk yield in the first lactation are reported. No differences in BW (5 mo: SH = 162.9 ± 1.6 kg vs. SHF = 162.3 ± 1.6 kg; 7 mo: SH = 200.8 ± 2.2 kg vs. SHF = 201.1 ± 2.3 kg; 10 mo: SH = 300.5 ± 2.6 kg vs. SHF = 300.0 ± 2.8 kg) and ADG (SH = 0.94 ± 0.02 kg/d, SHF = 0.94 ± 0.02 kg/d) from 5 to 10 mo of age were detected. Treatment did not affect P/1AI (SH = 53.5 %, SHF = 45.9 %) and hazard of pregnancy [SH = referent, SHF – adjusted hazard ratio (AHR) = 0.87 (95 % CI = 0.65, 1.18)], but heifers in the SHF treatment were less likely to initiate the first lactation (76.2 % vs. 86.4 %). Body weight at calving (SH = 612.4 ± 5.3 kg, SHF = 618.2 ± 5.9 kg) and milk yield (SH = 39.0 ± 0.48 kg/d, SHF = 38.3 ± 0.57 kg/d) were not different, but the SHF treatment resulted in lower P/1AI (38.4 % vs. 51.4 %) and hazard of pregnancy (AHR = 0.68, 95 % CI = 0.49, 0.93) and fewer cows starting their second lactation (57.4 % vs. 72.8 %). In our experiment, providing cooling through ceiling fans during the pre-weaning phase had a negative impact on the reproductive performance of Holstein cows during their first lactation.

Weight Development and Growth Curves of Grazing Santa Inês Sheep Supplemented with Concentrate in the Pre-Weaning Phase.

Monitoring weight development is essential for decision-making and assessing the effectiveness of management strategies. However, this practice is often hindered by the lack of scales on farms. This study aimed to characterize the weight development and growth curves of male and female Santa Inês lambs from birth to weaning, managed on pasture with creep-fed concentrate supplementation. Data from 212 lambs during the pre-weaning phase were analyzed. The animals were weighed every seven days to evaluate total weight gain and average daily gain. Biometric measurements were taken every 28 days. Mixed models were used to assess the effects of sex and birth type on birth and weaning weights. Simple and multiple linear regression models were employed to estimate live weight using biometric measurements. The non-linear Gompertz model was utilized to describe weight development and formulate growth curves. Results were considered significant at p < 0.05. An interaction effect between birth type and sex (p < 0.05) was noted for birth weight, with the lowest weight observed in twin-birth females (2.96 kg) and the highest in single-birth males (3.73 kg) and females (3.65 kg) (p > 0.05). Birth type significantly influenced average daily gain, total weight gain, and weaning weight (p < 0.05). The Gompertz model accurately depicted the growth curves, effectively describing the weight development. Pearson's correlation coefficients between biometric measurements and weight were positive and significant (p < 0.05), ranging from 0.599 for hip height to 0.847 for heart girth. Consequently, the simple and multiple regression equations demonstrated high precision in predicting weaning weight. In conclusion, twin-birth lambs receiving concentrate supplementation via creep-feeding and managed on pasture showed different developmental patterns compared to single-birth lambs under the same conditions. The Gompertz model proved effective for monitoring development during the pre-weaning phase. All simple and multiple linear regression models were effective in predicting weaning weight through biometric measurements. However, for practical application, the model incorporating two measurements-body length and abdominal circumference-is recommended.

Serum insulin-like growth factor-1 and leptin concentrations in Black Bengal goats at different ages and gestation periods and their relationship to kid growth performance.

The impact of maternal hormone concentration on kid growth performance in relation to insulin-like growth factor 1 (IGF-1) and leptin is minimal. This study examined IGF-1 and leptin levels at varying ages and gestation periods for their correlation with Black Bengal goat kids' growth during the preweaning phase. Blood samples were collected from 43 dams with different reproductive cycles and 28 prepubertal goats to measure serum concentrations of IGF-1 and leptin. Among dams, both hormones were investigated in different age ranges (<2, 2-3, 3-4, and >4 years old) and reproductive cycles (non-pregnancy, early gestation (1-50 days), mid-gestation (51-100 days), late gestation (101-135 days), and the last 15 days before delivery). After delivery, 65 kids from 34 dams were weighted weekly for 8 weeks to calculate average daily weight gain (ADG) at 0-4 weeks (ADG0-4 W) and 4-8 weeks (ADG4-8 W) and growth performance, including weight (W), height (H), length (L), chest girth (C) measured at birth (W0, H0, L0, and C0) and at 10 weeks of age (W10, H10, L10, and C10) were related to hormone serum concentrations in their dams at different gestation periods including the last 15 days before delivery. Dams had higher mean serum IGF-1 (p < 0.001) and leptin (p < 0.05) than prepubertal goats. Dams at late gestation had higher IGF-1 concentrations than those at early and mid-gestation and during the last 15 days before delivery. However, it was consistent with non-pregnant goats. The kid's growth performance correlated positively with IGF-1 concentration, which was collected in the last 15 days before delivery. Multivariate analysis showed that ADG0-4 W was higher in kids born from dams with high IGF-1 than those with low IGF-1 measured during the last 15 days of delivery, whereas leptin tended to have a similar effect. Serum IGF-1 and leptin concentrations of dams measured during the last 15 days before delivery were associated with kid's growth during the preweaning period.

PSII-2 Effect of piglet processing and castration on growth performance in feeder pigs

Abstract Early in life castration in swine is a common practice to improve muscle and fat deposition and avoid “boar taint”, which is caused by production of androsterone and skatole within the intact male. The objective of this study was to evaluate the effect of performing piglet processing and castration on the same day compared with a 2-d protocol processing on d 1 and castrating on d 7. To determine the effect of processing protocol on subsequent growth in piglets, 42 piglets were randomly assigned at birth to one of two processing protocols: d 3 processing (“early”) or d 1 and d 7 processing (late). For both castration dates, males were castrated using the open method of castration. A sterile scalpel blade was used to make two vertical cuts posterior to each testicle before complete removal of each testicle. Both male and female piglets were assigned to a processing protocol, but only male piglets underwent castration as a sterility procedure. Females on the same processing protocol were subject to similar processing methods and vaccinations but were not sterilized. Body weights were collected on all piglets at d 1, 3, 7, 14, 21, 28 (weaning), and 56. For males, vocalization during the castration procedure was also recorded and analyzed along with growth and performance measures. At weaning (d 28), the early castrated barrows group weighed significantly more than the late castrated barrows; however, there were no significant differences in the body weight at weaning for the early group (males + females) as a whole compared with the late group (males + females) as a whole. This indicates that while males benefited from an early castration and were able to gain more body weight during the pre-weaning phase when processing occurred on d 3 rather than on d 1 and 7, females undergoing two processing dates gained less body weight between birth and weaning.

Influence of Jerusalem artichoke tuber as a prebiotic on the nutrient utilization, weaning stress indicators and immunocompetence of crossbred calves during the pre- and post-weaning phases

This study explored the potential prebiotic properties of pulverized Jerusalem artichoke tuber (JAP) in pre- and post-weaned calves. Accordingly, 24 fifteen-day-old calves were randomly assigned to four groups (n = 6). The groups received JAP supplementation at levels of 0 (CON), 1 (JAP1), 2 (JAP2), and 3 (JAP3) percent of dry matter intake (DMI) during the first 60 days of the 120-day experiment. Two 6-days digestion trials were conducted: one during the 4th week of the experiment (pre-wean), and the second during the tenth week (post-wean). Additionally, serum concentrations of cortisol and epinephrine were measured in both the pre- and post-weaning phases to assess the stress levels. Immunocompetence of the calves during both the stages was evaluated through lymphocyte proliferation response. In the pre-weaning phase, the calves supplemented with JAP had better (P < 0.05) protein intake and digestion compared to the control group. In the post-weaning phase, the JAP supplemented groups exhibited significantly (P < 0.05) improved digestibility coefficients for dry matter, organic matter, crude protein, ether extract, and neutral detergent fibre. Although cortisol levels didn't show significant differences (P > 0.05) between the groups during both pre-weaning and post-weaning stages, the post-weaning stage did reveal a significant reduction (P < 0.05) in epinephrine levels in JAP1 compared to the other groups. Additionally, JAP supplementation enhanced (P < 0.05) the calves' response to lymphocyte proliferation during the post-weaning phase. Considering the improved nutrient digestibility, enhanced systemic immunity, and reduced epinephrine levels observed in the JAP supplemented groups, our findings suggest that JAP may have promising potential as a prebiotic for calves.

Carryover effects of maternal late-gestation heat stress on granddaughters' growth and mammary gland development

Maternal (F0) exposure to late-gestation heat stress reduces their daughter's (F1) mammary gland fat pad mass (FP), parenchyma (PAR) mass, and epithelial cell proliferation when evaluated at birth and weaning, and go on to produce less milk in their first lactation. Herein, we investigated the effect of maternal late-gestation heat stress on whole-body growth and mammary development of their granddaughters (F2). Multiparous F0 cows had access to heat abatement (n = 41, shade, and active cooling via fans and water soakers) or not (n = 41, shade only) for the last 56 d of gestation during a subtropical summer. Consequently, the F1 daughters, born to F0 cows, were heat-stressed (HTF1, n = 36) or cooled (CLF1, n = 37) in utero during the last 2 mo of gestation. All F1 heifers were raised as an identically managed cohort until first calving. The F2 granddaughters, born to HTF1 (HTF2, n = 12) or CLF1 (CLF2, n = 17), were raised as an identically managed cohort until 70 d of age. Dry matter intake (DMI), body weight, hip height, wither height, chest girth, head circumference, mammary gland teat length, and left-right and front-rear teat distances were measured. Average daily gain (ADG) was calculated for the pre-weaned period (0-49 d). Mammary ultrasounds were performed on d 21, 49, and 70 (n = 9/group) on the rear left and right quarters to quantify PAR and FP areas. Mammary biopsies were collected for histological evaluation of epithelial structures (H&E staining), and to quantify cells positive for ERα (estrogen receptor, α subunit), cell proliferation (Ki67), and apoptosis (TUNEL). Heifer growth from birth to d 49 was similar between CLF2 and HTF2 for all parameters evaluated. Distances between teats and teat length were not different between groups. On d 70, CLF2 tended to have a greater average PAR (right and left quarters) relative to HTF2. Although the left FP was smaller in HTF2 relative to CLF2, the average FP was not different. The lumenal and non-lumenal epithelial structures in the PAR of HTF2 were significantly smaller than those of CLF2. In addition, HTF2 had a reduced percentage of proliferating cells in the epithelial and stromal compartments and a greater percentage of apoptotic cells, particularly in the stroma. The percentage of ERα positive cells was significantly reduced in HTF2. In summary, although HTF2 heifer's DMI was similar and they grew at the same rate as CLF2 heifers throughout the pre-weaning phase, their mammary glands had smaller PAR areas with fewer epithelial structures characterized by reduced cell turnover and lower ERα expression. These early changes in the microstructure and cellular turnover of the mammary gland may partly explain the reduction in lactation performance relative to CLF2 counterparts at maturity.

Effect of Creep Feeding Supplementation on Growth Performance and Metabolic Characteristics of Nellore Heifers

The objective of this paper is to evaluate the effects of creep feeding supplementation during the preweaning phase on the growth performance and metabolic characteristics of Nellore heifers. Forty-two female Nellore calves (age = 100 ± 25 d; initial body weight (BW) = 113.4 ± 16.6 kg) were randomly assigned to the following treatments: control, where calves received mineral mix supplementation (n = 21); supplemented in creep feeding, where calves received 6 g/kg BW of a concentrate supplement (n = 21) during a period of 140 d. In the postweaning phase, all heifers received 6 g/kg BW of a concentrate supplement during a period of 210 d. Supplemented heifers had a greater average daily gain (ADG) than control heifers during the preweaning phase and, consequently, were heavier at weaning and at the end of the growing phase (p &lt; 0.05). However, preweaning supplementation did not influence (p &gt; 0.05) the body measurements or BW at the end of the growing period. Greater (p &lt; 0.05) rib fat was observed in supplemented heifers. Concentrations of metabolites were not affected by preweaning supplementation (p &gt; 0.05). Thus, supplementing heifers in the preweaning phase improved growth performance of weaning and body adiposity.

Impacts of Individual and Pair Housing on Calves

Abstract Calf rearing is a large financial cost to farms, with particular importance for dairy heifer replacements where the forward investment does not receive any payback for 3–4 years. Ensuring the critical pre-weaning phase is carried out optimally and understanding the impact that housing has on this time is important. Historically, individual calf housing has been used to reduce disease transmission among calves, but there is limited evidence that pair housing has any detrimental impact on this. Instead, research over the past decade has served to highlight the range of benefits that pair housing can provide. Calves housed with others have increased play behaviours, which is a positive indicator of well-being. Pair-housed calves start to eat concentrates at an earlier age and in greater amounts, which can have positive impacts on growth rates, and longer-term improvements in reducing age at first calving and improving first lactation milk yields. Pair housing allows calves to start forming social relationships, which can have a calming effect in stressful situations such as group changes and can improve behaviours when heifers enter the milking herd. Pair-raised calves also have reduced food neophobia which can help adult cattle cope with diet changes that can occur frequently in the dairy herd. This growing body of evidence suggests that pair housing of calves results in overall better health and welfare compared to individual housing, therefore practitioners should help encourage farmers to move towards this housing type. Information © The Author 2023

Field Implementation of Forecasting Models for Predicting Nursery Mortality in a Midwestern US Swine Production System.

The performance of five forecasting models was investigated for predicting nursery mortality using the master table built for 3242 groups of pigs (~13 million animals) and 42 variables, which concerned the pre-weaning phase of production and conditions at placement in growing sites. After training and testing each model's performance through cross-validation, the model with the best overall prediction results was the Support Vector Machine model in terms of Root Mean Squared Error (RMSE = 0.406), Mean Absolute Error (MAE = 0.284), and Coefficient of Determination (R2 = 0.731). Subsequently, the forecasting performance of the SVM model was tested on a new dataset containing 72 new groups, simulating ongoing and near real-time forecasting analysis. Despite a decrease in R2 values on the new dataset (R2 = 0.554), the model demonstrated high accuracy (77.78%) for predicting groups with high (>5%) or low (<5%) nursery mortality. This study demonstrated the capability of forecasting models to predict the nursery mortality of commercial groups of pigs using pre-weaning information and stocking condition variables collected post-placement in nursery sites.

Comparing forecasting models for predicting nursery mortality under field conditions using regression and machine learning algorithms

Swine nursery mortality is one of the most important key performance indicators (KPIs) for commercial swine production systems and, for the purpose of this study, refers to the number of pigs that died during the first 60 days during the post-weaning phase (approximately 170-day period). Likewise, nursery mortality accounts for almost 50% of the mortality that occurs throughout the post-weaning phase. Despite being a metric concerning the post-weaning phase of production, previous studies have demonstrated that nursery mortality is highly correlated with the previous performance of the piglets in the pre-weaning phase and to stocking conditions at placement in nursery sites. However, there is no evidence of that predictive models are currently routinely utilized in the swine industry to predict the nursery performance of individual groups of pigs based on their previous performance in the pre-weaning phase. One obstacle to building such predictive models is that health and management data as well as production data for the pre and post-weaning phases are collected with separate record-keeping programs and stored in unconnected databases.Thus, the objective of this study was to measure and compare the performance of 5 forecasting models for predicting nursery mortality using a master table containing data collected from a single swine production system for 1,831 groups of pigs. An automated model was built to integrate information for 48 variables included in the master table that was previously disconnected within the production system. After the model and parameter tuning process, the model with the best overall prediction performance was the Support Vector Machine (SVM) in terms of Root Mean Squared Error (RMSE=0.3929), Mean Absolute Error (MAE=0.2956), and coefficient of determination (R2=0.7761). This study demonstrated the ability to use an integrated master table containing whole-herd information until the placement event of nursery groups to predict their downstream nursery mortality through the initial 60 days of the post-weaning phase.

Impacts of Individual and Pair Housing on Calves

Abstract Calf rearing is a large financial cost to farms, with particular importance for dairy heifer replacements where the forward investment does not receive any pay-back for 3 to 4 years. Ensuring the critical pre-weaning phase is carried out optimally and understanding the impact that housing has on this time are important. Historically, individual calf housing has been used to reduce disease transmission between calves, but there is limited evidence that pair housing has any detrimental impact on this. Instead, research over the past decade has served to highlight the range of benefits that pair housing can provide. Pair-housed calves start to eat concentrates at an earlier age and in greater amounts, although this does not always translate to increased growth rates during the pre-weaning period. Pair housing allows calves to start forming social relationships, which can have a calming effect in stressful situations and can improve behaviour when heifers enter the milking herd. Additionally, calves housed with others have increased play behaviours, which is a positive indicator of well-being. This growing body of evidence suggests that pair housing of calves results in overall better health and welfare compared to individual housing; therefore, practitioners should help encourage farmers to move towards this housing type. Information © The Author 2023

The Preservation of the Effects of Preweaning Nutrition on Growth, Immune Competence and Metabolic Characteristics of the Developing Heifer.

This experiment investigated the preservation effects of two preweaning milk feeding nutritional treatments (High: 8 L and Low: 4 L milk per day) on 20, 12-month-old Holstein-Friesian dairy heifers (Bos taurus). A vaccination immune challenge was initially implemented on these 20 heifers at 6 weeks of age and the findings indicated superior growth, immune competence and favorable metabolic characteristics from the calves that had been fed 8 L milk per day. Postweaning, all heifers were treated the same under non-experimental conditions, and the immune challenge was repeated at 12 months of age for the current experiment. Consistent with the first immune challenge, heifers from the High preweaning treatment group still had higher white cell count and neutrophil count, indicating superior immune competence. The differences found in metabolic biomarkers, including beta-hydroxybutyrate, glucose and insulin, in the preweaning phase had disappeared, suggesting these biomarkers were influenced directly by the nutritional input at the time. There were no differences in NEFA levels between treatments at either stage of development. Postweaning, the heifers from the Low preweaning treatment group experienced accelerated growth with slightly numerically higher ADG (0.83 kg/day vs. 0.89 kg/day), resulting in the initial differences in bodyweight recorded at weaning being eliminated by 13 months of age. These results are evidence of a form of immunological developmental programming as a result of accelerated preweaning nutrition and therefore, are not supportive of restricted milk feeding of calves.

Effects of propolis extract on growth performance and health condition of dairy calves

The aim of this study was to evaluate the effect of propolis ethanol extract, on performance, fecal structure, and general health status of calves during the preweaning phase. For this purpose, 24 Simmental calves that were given colostrum for the first 3days after birth were enrolled in the study. The study started when the calves were 4days old and finished when they were 60days old. These calves were divided into two groups as propolis and control groups according to their weight and gender. Both groups were given the same ration and housed in individual calf huts under the same environmental conditions. Differently from the control group, the calves in the propolis group were given 4mL of propolis extract (300mg/mL) with an oral feeding syringe for 56days after morning feeding. The amounts of feed intake and fecal scores of the calves were recorded daily. Health scores, rectal body temperature, fecal pH, body weight, and body measurements were recorded weekly. For the determination of the counts of Lactobacillus spp. and Bifidobacterium spp., fecal samples were collected at the beginning and at the end of the study. The results indicated that oral administration of propolis had positive effects in terms of some performance parameters, the number of days with diarrhea, and fecal scores. In this study, it was concluded that propolis extract had the potential to positively affect the growth performance and health status of preweaning calves.

Preweaning Nutrition and Its Effects on the Growth, Immune Competence and Metabolic Characteristics of the Dairy Calf

Feeding increased volumes of milk in the preweaning phase has been shown to improve growth, morbidity and mortality rates in calves (Bos Taurus). This experiment enlisted 20 Holstein-Friesian dairy replacement calves from birth until weaning (at 10 weeks of age) and assessed the effect of feeding either 4 L (Low) or 8 L (High) of milk per calf per day on their growth, immune competence and metabolic characteristics. The responsiveness of these systems was compared through a vaccination immune challenge. Calves in the High treatment group were significantly heavier from two weeks of age and were 19 kg heavier than calves in the Low treatment group at weaning. Calves in the High treatment group also exhibited greater immune responses, with significantly higher white cell counts and neutrophil counts than calves in the Low treatment group post-vaccination. Calves in the High treatment group also had lower beta-hydroxybutyrate both pre- and post-vaccination, and higher glucose and insulin levels post-vaccination, indicating superior metabolic characteristics. Calves had ad libitum access to lucerne hay (Medicago sativa) and a commercial concentrate. Solid feed intakes were mostly the same between treatments, with differences in hay intake only detected at 7 and 8 weeks of age. Results from this experiment are indicative of a positive influence of accelerated preweaning nutrition on growth, immune response and metabolic characteristics.

Growth rate and efficiency-related traits in Kermani lambs: estimations of (co)variance components and genetic parameters.

Using Kermani sheep, the current study estimated (co)variance components and genetic parameters for average daily gain, Kleiber's ratio, growth efficiency, and relative growth rate. Data were analyzed by the average information restricted maximum likelihood (AI-REML) method using six animal models with different combinations of direct and maternal effects. The best-fitting model was determined after testing for improvement in log-likelihood values. The estimates of h2 for average daily gain (ADG), Klieber's ratio (KR), growth efficiency (GE), and relative growth rate (RGR) in pre- and post-weaning phases were 0.13 ± 0.6 and 0.17 ± 0.02, 0.12 ± 0.04, and 0.16 ± 0.03; 0.05 ± 0.05 and 0.07 ± 0.03 and 0.06 ± 0.02 and 0.07 ± 0.01, respectively. Maternal heritabilities (m2) ranged from 0.03 ± 0.01 for relative growth rate in pre-weaning phase to 0.11 ± 0.04 for average daily gain in post-weaning period. The maternal permanent environmental component (Pe2) accounted for 3 to 13% to the phenotypic variance for all the studied traits. Estimated values of additive coefficient of variations (CVA) ranged from 2.79% for relative growth rate at 6 months of age to 23.74% for growth efficiency at yearling age. Genetic and phenotypic correlations among traits were ranged from -0.687 to 0.946 and -0.648 to 0.918, respectively. The result indicated that selection for growth rate and efficiency-related traits would also be less effective in achieving genetic change, because there was little additive genetic variation among Kermani lambs.