High Plane Of Nutrition Research Articles

Effect of enhanced plane of nutrition in early life on the transcriptome and proteome of the anterior pituitary gland in Angus heifer calves

BackgroundEnhanced nutrition during the early calfhood period has been shown to lead to earlier pubertal development in heifer calves. This is of interest as earlier pubertal onset can subsequently facilitate earlier calving which can economically benefit production systems. Reproductive development in heifers is regulated by the hypothalamic-pituitary-ovarian signalling pathway. In particular the anterior pituitary gland is central to reproductive development, through the dynamics of gonadotropic pulsatility. However, despite clear knowledge of the influence of enhanced dietary intake on subsequent reproductive development, the molecular control governing this response in the pituitary gland within the hypothalamic-pituitary-ovarian signalling axis in heifer calves is not fully understood. The objective of this study was to examine the effect of an enhanced plane of nutrition during early life on the anterior pituitary gland of heifer calves through both transcriptomic and proteomic analyses. Between 3 and 21 weeks of age, heifer calves were offered either a high (HI, n = 14) or moderate (MOD, n = 14) plane of nutrition, designed to elicit target growth rates of 1.2 and 0.5 kg/d for HI and MOD groups, respectively. All calves were euthanised at 21 weeks of age and anterior pituitary tissue harvested for subsequent use in global transcriptomic and proteomic analyses.ResultsAverage daily gain was affected by diet (P < 0.001) and was 1.18 and 0.50 kg/day, for HI and MOD calves, respectively. RNAseq analysis resulted in the identification of 195 differentially expressed genes (Padj<0.05; fold change > 1.5), with 277 proteins identified as differentially abundant (Padj<0.05; fold change > 1.5) between contrasting dietary treatment groups. Biochemical pathway analysis of differentially affected genes and proteins revealed an enrichment for both growth hormone and GnRH signalling pathways (Padj.<0.05). Additionally, pathway analysis predicted an effect of enhanced dietary intake on endocrine function within the anterior pituitary gland as well as on reproductive system development and function (Padj.<0.05).ConclusionsResults from this study show that an enhanced dietary intake during early calfhood affected the molecular control of the anterior pituitary gland in heifer calves in early life.

The Effect of Colostrum Supplementation during the First 5 Days of Life on Calf Health, Enteric Pathogen Shedding, and Immunological Response.

The objective of this dairy farm study was to investigate the preweaning health, performance, immunity, and enteric pathogen shedding in calves supplemented with colostrum during five days after birth compared to calves not supplemented with colostrum. The colostrum supplementation was the previously frozen colostrum added to the milk replacer from day 2-5 given to 39 calves, and 36 Control calves received a milk-derived supplement. There was no significant difference in preweaning weight gain between the treatment groups. Serum samples collected on days 2, 7, 14, and 21 indicated that total and antigen-specific IgG levels against rotavirus, coronavirus, and E. coli F5 were not significantly different between the treatment groups. Fecal samples taken on days 7, 14, and 21 were all negative for coronavirus and E. coli F5, whereas there were low levels of Cryptosporidia and a trend for low levels of rotavirus on day 14 in colostrum-supplemented compared to Control calves. Respiratory clinical signs, depressed attitude and body temperature tended to be reduced in colostrum-supplemented compared to Control calves. This study shows that, even in calves with good colostrum status and high plane of nutrition, there can be benefits of post-closure colostrum supplementation including reduced Cryptosporidia and rotavirus shedding and reduced respiratory disease.

Influence of previous plane of nutrition on molecular mechanisms regulating the expression of urea and water metabolism related genes in the rumen and kidney of finishing crossbred Angus steers

This study aimed to understand how molecular mechanisms controlling water and urea metabolism at the finishing phase can be affected by previous plane of nutrition of crossbred Angus beef steers. Twenty-four (n = 24) animals were randomly distributed into either a moderate (MP) or high plane of nutrition during the background phase for 85 d. Animals were then blocked by their previous plane and were moved onto a 105-d finishing phase in a 2 × 2 factorial arrangement. The forage-finished group received only high-quality alfalfa hay, whereas the grain-fed group received a high grain diet (80% whole corn and 20% alfalfa hay). By the end of the finishing phase, animals were harvested and tissue samples from the rumen and kidney were collected. Changes in gene expression of aquaporins (AQP)-2, -3, -4, -7, ATP1A1, ATP1B1, SGK1, CLIC1 (kidney and rumen), UT-A1 (kidney only) and UT-B (rumen only), were assayed via real-time qPCR; 18S rRNA was used as an endogenous control. One-way ANOVA followed by Tukey's post hoc analysis was conducted. When animals were from MP, forage-finishing increased the relative abundance of AQP3 (P ≤ 0.05), AQP7 (P ≤ 0.05), ATP1B1 (P ≤ 0.05), and SGK1 (P ≤ 0.05) in the kidney when compared to grain-fed animals. In the rumen, for the MP group, AQP7 was differentially expressed in both treatments at the finishing phase (P ≤ 0.01), with forage-finished steers having the highest expression of AQP7. For the MP group, UT-B had a tendency of presenting a higher expression on grain-fed animals (P = 0.075). Overall, these results suggest that previous plane can impact expression of genes associated with water and urea metabolism during the finishing phase, namely AQP3, AQP7, ATP1B1, and SGK1 in the kidney, and AQP7 and UT-B in the rumen. The greatest impact observed on gene expression changes of investigated genes at the finishing phase was reflective of animals backgrounded on the moderate previous plane.

PSX-14 Effects of Forage and Grain-Based Finishing Diets on Fatty Acid Profile of Angus Steers Backgrounded Either in a Moderate Or in a High Plane of Nutrition

Abstract The objective of this study was to evaluate the fatty acid profile of beef backgrounded in two planes of nutrition and finished with forage-only or corn. Steers (n = 24) weighing approximately 298.63 ± 10.19 kg were randomly backgrounded in Triticale (100% DM; Moderate n = 12) and alfalfa (85% DM) and beardless wheat (15% DM; High, n = 12), blocked, and finished with forage-only (FORAGE – Alfalfa with 21% CP, 100% DM, n = 12) or with a grain-based diet (GRAIN - Alfalfa with 16% CP, 80% DM and Corn, 20% DM, n = 12). The feeding trial lasted 220 days (85 d backgrounding, 30 d finishing diet adaptation, and 105 d finishing). The fatty acid profile of strip loin steaks (m. longissimus lumborum) was assessed, and data were analyzed as a 2x2 factorial. Overall, no interaction effect between plane of nutrition and finishing diet was observed for individual or group of fatty acids. Minimal effects were observed for plane of nutrition. Steaks from steers backgrounded in Moderate had greater concentrations of C14:1T n-5 (P = 0.04) and C18:1TΔ n-9 (P = 0.04) when compared with steaks from steers backgrounded in High. Beef from steers finished with FORAGE showed higher concentrations of C10:0 (P = 0.01), C14:1T n-5 (P &amp;lt; 0.0001), C15:0 (P = 0.003), C16:0 (P = 0 .001), C16:1T n-7 (P &amp;lt; 0.0001), C17:0 (P = 0.001), C18:0 (P = 0.0002), C18:1TΔ n-9 (P = 0.0003), C18:2T n-6 (P = 0.005), C20:1 n-12 (P &amp;lt; 0.0001), C18:3 n-3 (P = 0.0003), 18:2 CLA t10c12 (P &amp;lt; 0.0001), C22:1 n-9 (P = 0.02), C22:2 n-6 (P = 0.001), and C22:5 n-3 (P = 0.02) when compared with beef from steers fed GRAIN. Beef fed GRAIN, had greater concentrations of C16:1 n-7 (P = 0.001), C18:1 n-9 (P = 0.004), C18:1Δ n-11 (P &amp;lt; 0.0001) and C18:2 n-6 (P = 0.02) when compared with beef fed FORAGE. Overall, backgrounding steers in moderate and high planes of nutrition does not affect the fatty acid profile of beef. Beef fed with FORAGE has higher total Omega 3 (P = 0.05), total Saturated (P &amp;lt; 0.0001), and total Trans fatty acids (P &amp;lt; 0.0001) when compared with beef fed GRAIN. GRAIN-fed beef has total Monounsaturated fatty acids (P = 0.0002) and higher Omega6:Omega3 (P = 0.0003). Regarding health indexes, based on its fatty acid profile, FORAGE-fed beef had Atherogenicity (P = 0.01) and Thrombogenicity indexes (P = 0.0001) when compared with beef fed GRAIN (Table 1).

37 Precision Feeding of Prolific Sheep in Highly Productive Management Systems

Abstract Globally lamb production is constrained by seasonal reproduction and flock productivity. There is potential to reduce both with improved reproductive and nutritional management in systems with a reduced interbirth interval. These accelerated systems can improve productivity &amp;gt;2 times compared with conventional systems. Successful adoption of these systems has been hampered; however, by low and variable reproductive efficiency during the suboptimal breeding period (February to July). We designed a series of studies to address this problem using an 8-month birth interval system with Polled Dorset x Polypay ewes without the use of exogenous hormone or photoperiod therapies. In study 1, we examined prebreeding nutrition combined with the male effect on reproductive outcomes in both long (April/May) and short-day (Dec./Jan.) breeding seasons. Ewes were randomly allocated to one of 3 nutritional treatments after weaning during a 21-day prebreeding period: 50%, 100% or 200% of maintenance energy intake. Ewes were exposed to vasectomized rams the last 14 days of treatment followed immediately with fertile rams for a 34-day breeding period (22 to 27 ewes per vasectomized or fertile ram). Both litter size (1.60 short vs. 1.34 long) and conception (96% short vs. 86% long) were greater in the short season (P &amp;lt; 0.001). Nutrition did not impact conception in either season; however, litter size was increased 15% in long and 25% in short day breeding season in ewes fed 200% compared the other treatments. These results suggest that litter size can be improved in these systems regardless of season by elevating energy intake above current recommendations. In study 2, we examined the impact of energy status during 2 preconception periods: lactation (last 30 days of previous lactation) and flushing (21 days pre-breeding plus 34-day breeding period). During lactation ewes received either 70% (L), 100% (C), and 150% (H) of energy requirements according to litter size. During flushing, ewes received 70%, 100% and 160% of maintenance energy with reproductive management as for study 1. Blood samples collected every 3 to 4 days were analyzed for plasma progesterone concentration via radioimmunoassay. Season had a great impact on return to estrus with 18% of ewes exhibiting luteal phases before teaser ram introduction during long as compared with 99% during short-day season. Nutrition during lactation also impacted return to estrus but only in long days with 40% of ewes on the H diet exhibiting luteal phases compared with 14% on the L diet before teaser ram introduction. Collectively, this indicates that an increased rate on conception is possible without the use of exogenous hormones or photoperiod manipulation in accelerated systems. Furthermore, a high plane of preconception nutrition improves litter size regardless of season and may hasten return to estrus during the suboptimal breeding period.

Optimization of Age at Maturity in Surti Buffalo Heifers with Dietary Supplementation of Bypass Protein and Bypass Fat

Surti buffaloes heifers reared under ideal feeding and managemental practices achieve puberty, sexual maturity and first calving at the optimum desired age and body weight. In growing heifers during first parity, requirement of high plane of nutrition is obvious to meet the demands of body growth of dam, growth of fetus, and galactopoetic functions. This study was aimed to find out the effect of feeding bypass protein and bypass fat right from the age of puberty up to the age of first successful conception, i.e. maturity in Surti buffalo heifers. Sixteen Surti buffalo heifers were allotted in four equal groups (n=4 in each group), viz., Control (T-1) fed basal diet following ICAR nutrient requirements, T-2 basal diet + 30 % protein of concentrate mixture replaced with formaldehyde treated guar meal (FTGM), T-3 basal diet + 100 gm bypass fat (BF), and T-4 basal diet + 30 % protein of concentrate mixture replaced with FTGM + 100 gm of BF. All the treatment diets were isonitrogenous. The results revealed that there was beneficial effect of feeding by pass protein and bypass fat along with routine feeding management on growth of heifers in terms of the body wt. gain and reduced age at first conception (maturity) and thereby age at first calving (AFC). AFC reduced to 37.25, 37.87 and 33.37 months, respectively, in T2, T3 and T4 groups respectively; compared to 43.75 months in Control group. Further, the net benefit over control, in the group of heifers fed with FTGM alone and FTGM plus BF groups were 22.90 % and 16.40 % respectively.

Effects of oral or parenteral iron supplementation on haematological parameters, blood iron status and growth in newborn calves fed milk replacer.

This study aimed to assess the influence of early life iron supplementation on the haematological parameters of calves fed milk replacer on a high plane of nutrition. Thirty calves were allocated to receive either a sham treatment (CON), injection of 1000mg Fe3+ (INJ) or oral administration of 1050mg Fe3+ (ORAL), all administered less than 1hour after birth. Blood was obtained before treatment, on days 1, 3, 5 and 7 of life and once weekly until week 9. Samples were analysed for haemoglobin (Hb), packed cell volume (PCV) and estimated transferrin saturation (%TSAT). The Hb and PCV of calves in the INJ and ORAL groups were above the values of those in the CON group throughout the study. Hb and PCV of the CON group remained within the reference range for calves. The %TSAT exceeded reported ranges in theORAL group in the first week. Values for the CON group were below the INJ and ORAL groups throughout the entire study. Average daily gain did not differ between treatments. The sample size was insufficient to assess the influence of iron supplementation on disease development. Furthermore, the study was set in a controlled environment and not performed under field conditions. Oral and subcutaneous iron administration had similar effects on haematological development but resulted in numerically different transferrin saturation. Control animals showed lower Hb and PCV but did not develop overt anaemia.

Early life nutrition affects the molecular ontogeny of testicular development in the young bull calf

Enhanced early life nutrition accelerates sexual development in the bull calf through neuroendocrine-signalling mediated via the hypothalamic–pituitary–testicular axis. Our aim was to assess the impact of contrasting feeding regimes in bull calves during the first 12 weeks of life on the testes transcriptome and proteome. Holstein–Friesian bull calves were offered either a high (HI) or moderate (MOD) plane of nutrition, designed to support target growth rates of 1.0 and 0.5 kg/day, respectively. At 12 weeks of age all calves were euthanized, testicular parenchyma sampled, and global transcriptome (miRNAseq and mRNAseq) and proteome analyses undertaken. Bioinformatic analyses revealed 7 differentially expressed (DE) miRNA and 20 DE mRNA. There were no differentially abundant proteins between the two dietary groups. Integration of omics results highlighted a potential role for the cadherin gene, CDH13, in earlier reproductive development. Furthermore, co-regulatory network analysis of the proteomic data revealed CDH13 as a hub protein within a network enriched for processes related to insulin, IGF-1, androgen and Sertoli cell junction signalling pathways as well as cholesterol biosynthesis. Overall, results highlight a potential role for CDH13 in mediating earlier reproductive development as a consequence of enhanced early life nutrition in the bull calf.

Finisher lamb growth and rumen fermentation responses to the plane of nutrition and naturally occurring coccidiosis.

The objective of the present study was to investigate the interaction of plane of nutrition and naturally occurring coccidiosis on finisher lamb growth performance, FAMACHA score, and rumen volatile fatty acid profile. The study included 30 Suffolk, Dorset or Suffolk x Dorset lambs and were divided into 2 groups based on their initial body weight and assigned to 2 feeding groups differing in dietary energy intake to create lambs representing divergent growth curves due to differing nutritional management. Lambs with naturally occurring coccidiosis and healthy lambs were present in both feeding groups making a 2 × 2 factorial arrangement of treatments, (a) high plane of nutrition (HPN) lambs with no clinical coccidiosis diagnosis (HPNH), (b) HPN lambs with clinical coccidiosis (HPNC), (c) low plane of nutrition (LPN) lambs with no clinical coccidiosis diagnosis (LPNH), (d) LPN lambs with clinical coccidiosis (LPNC). Body weight and FAMACHA scores were recorded once every 2 weeks. On d 65 of feeding, lambs were slaughtered, and rumen fluid samples were collected and analyzed for volatile fatty acid concentrations. All response variables were analyzed statistically using a linear mixed effects model with fixed effects for plane of nutrition, health status, and a random effect for initial body weight nested within the pen. The total and average weight gain were not associated with planes of nutrition, health status, or the interaction. Health status had an impact on FAMACHA© score (P = 0.047) and concentration of isobutyrate (P = 0.037) and tended to affect total VFA (P = 0.085) and acetate (P = 0.071) concentrations. The interaction between the plane of nutrition and the health status tended to affect butyrate concentration (P = 0.058). These data support the conclusion that coccidiosis infection impacted on rumen fermentation in a manner independent of the plane of nutrition; however, the translation of these rumen level impacts did not translate to the production responses.

Effects of starch content of calf starter on feed intake, growth performance, and fecal properties in dairy calves under a high plane of milk replacer feeding.

The objective of this study was to investigate the effects of different starch contents in calf starter on the growth, feed intake, and fecal characteristics in dairy calves fed under a high plane of nutrition. Twenty-seven Holstein calves were assigned equally to one of three calf starter treatment groups in a randomized block design: high (H) starch (41.8%); medium (M) starch (31.9%); and low (L) starch (22.0%). Milk replacer was fed up to 1.2kg/day as fed, gradually reduced from 6weeks of age; calves were weaned at 8weeks of age. Each starter (up to 3.5kg/day as fed) and chopped hay were provided ad libitum from 5days of age. Fecal samples, along with body measurements, were collected from 4 to 13 weeks of age. The average daily gain after weaning was greater in the H group than in the L group. The average starter intake for 3days before weaning was not different among treatments but was greater after weaning in the H group than in the L group. Starter starch content did not affect the number of days with diarrhea or fecal starch concentration. The high-starch starter had no adverse effects during the weaning transition.

324 Factors Affecting Growth, Efficiency, and Carcass Quality of Finishing Dairy x Beef Hybrids

Abstract Our objectives were to determine how pre-finishing plane of nutrition, season, and breed of beef sire affect performance, efficiency, and carcass attributes of dairy-beef hybrid calves. Dairy × beef hybrid steers (3 to 7 d of age) were maintained on either a moderate plane of nutrition or high plane of nutrition from 0 to 12 wk of age. Calves (n = 211, BW = 122 ± 16 kg) were then transported 689 km to the OSU Sparks Beef Research Center at an average age of 92 ± 1.6 d in four blocks. Calves from predominantly Holstein dairies in the Midwest were sired by Angus (n = 147) or Continental breed (n = 64) sires. Steers were processed on arrival and were sorted by BW within previous treatment into 4 to 5 head pens and fed receiving diets. Steers were transitioned to a grower diet from d 14 to 112. Steers were fed a 12% roughage finishing diet from d-112 to 224. A final 8% roughage finishing diet was fed from d 224 to slaughter with ractopamine hydrochloride (300 mg·steer-1·d -1) included the last 28-d before harvest. Increasing plane of nutrition during the milk replacer and starter feeding period increased (P ≤ 0.03) initial BW at arrival and through d 84, but was not affected (P ≥ 0.08) thereafter. Calves received during the winter and spring were heavier (P &amp;lt; 0.01) on arrival through d 168 and at harvest and gained BW faster during the growing phase and final finishing phase than steers received during the summer. Steers sired by Angus sires were heavier throughout finishing (P &amp;lt; 0.01) and gained BW more rapidly (P &amp;lt; 0.01) than steers sired by Continental breeds. Breed of sire and season have a large impact on performance of finishing dairy × beef hybrids.

Effect of pre-conceptional nutrition and season on fetal growth during early pregnancy in sheep

Gestational age in sheep can be closely predicted through ultrasonographic measurement of fetal bones when correlated to standardized fetal growth curves. However, these standardized curves do not account for factors that are known modulators of fetal growth, such as maternal nutrition or health status. Despite being seasonal breeders, and studies reporting an effect of season on birth weight, the influence of season on fetal growth has not been well characterized. In this study, we hypothesized that season of conception will affect fetal growth curves during mid-gestation and that pre-conceptional nutrition would have no effect. We investigated this by provisioning treatments of low, control, and high planes of nutrition during the lactation and flushing pre-conceptional periods to multiparous Dorset x Polypay and Dorset ewes over two seasons (the optimal breeding season [n = 97] and the suboptimal breeding season [n = 104]). Females were mated naturally with mating dates recorded, fetal biparietal diameter measured via ultrasound between gestational days 35–71, and newborn weights recorded at lambing. Pre-conceptional nutritional treatments did not affect fetal biparietal diameter. However, low vs. high nutrition in the pre-conceptional lactation (but not flushing) period resulted in reduced lamb birth weights (P < 0.001). Early fetal growth tended to be faster in the suboptimal breeding season than in the optimal breeding season (P < 0.061) with lambs being heavier at birth in the optimal breeding season (P < 0.001). There was no effect of fetal sex or litter size on fetal biparietal diameter during the first half of pregnancy, however both sex and litter size influenced lamb birth weight (P < 0.001) with males being heavier than females and singletons being heavier than twins and triplets. Mating date within the flushing period had a significant effect on lamb birth weight regardless of season and independent of treatment, with ewes that conceived later in the flushing period having heavier lambs at birth (P = 0.007). These findings suggest that pre-conceptional under- or overnutrition resulting in substantial changes in body condition does not affect fetal growth during the first half of pregnancy. However, the reduction in lamb birth weight indicates that pre-conceptional maternal nutrition during the previous lactation period may affect fetal growth later in pregnancy.

Macronutrient profile in milk replacer or a whole milk powder modulates growth performance, feeding behavior, and blood metabolites in ad libitum-fed calves

Milk replacers (MR) for calves usually contain more lactose and less fat than bovine whole milk (WM). There are insufficient data to determine whether these MR formulations are optimal for calves fed at high planes of nutrition. Thus, the effect of 3 MR formulations and a WM powder were evaluated on growth, feeding behavior, and blood metabolites in 96 male Holstein calves fed ad libitum and with 45.5 ± 4.30 kg (mean ± standard deviation) BW at arrival. Calves were blocked based on arrival sequence, and randomly assigned within block to one of the 4 treatments (n = 24 calves/group): a high-fat MR (25.0% fat, dry matter basis; 22.5% protein, 38.6% lactose; 21.3 MJ/kg; HF), a high lactose MR (44.6% lactose, 22.5% protein, 18.0% fat; 19.7 MJ/kg; HL), a high protein MR (26.0% protein, 18.0% fat, 41.5% lactose; 20.0 MJ/kg; HP), and a WM powder (26.0% fat; 24.5% protein, 38.0% lactose; 21.6 MJ/kg; WP). In the first 2 wk after arrival, calves were individually housed and were fed 3.0 L of their respective liquid feed 3 times daily at 135 g/L. They were then moved to group housing and fed ad libitum until d 42 after arrival. Weaning was gradual and took place between d 43 and 70 after arrival; thereafter, calves were fed solids only. Concentrates, chopped straw, and water were available ad libitum throughout the study. Body weight was measured, and blood was collected at arrival and then weekly thereafter from wk 1 to 12. Weight gain and height were greater in HL than WP calves. In the preweaning phase, HL and HP-fed calves consumed more milk than WP, and HL-fed calves consumed more milk than HF calves. In wk 10, starter feed intakes were lower in HF calves than in the other groups. In the preweaning phase, ME intakes were the same for all treatments. This suggests that milk intakes were regulated by the energy density of the milk supplied. The percentage of calves requiring therapeutic interventions related to diarrhea was greater in WP-fed calves (29%) than HF and HL calves (4%), whereas HP (13%) did not differ with other groups. This was coupled with lower blood acid-base, blood gas, and blood sodium in WP than in MR-fed calves. Calves fed HF had greater serum nonesterified fatty acids compared with other groups, and greater serum amyloid A compared with WP and HL calves. Among the serum parameters, insulin-like growth factor-1 and lactate dehydrogenase correlated positively with ME intake and average daily gain. The high lactose and protein intakes in HL and HP calves led to greater insulin-like growth factor-1 concentrations than in WP-fed calves. Although growth differences were limited among MR groups, the metabolic profile largely differed and these differences require further investigation.

Case-control study of behavior data from automated milk feeders in healthy or diseased dairy calves

Group housing of preweaning dairy calves is increasing in popularity throughout the dairy industry. However, it can be more difficult to individually monitor calves to identify disease in these group systems. Automated milk feeders (AMF) not only provide producers with the opportunity to increase the milk allowance offered to preweaning calves but they can also monitor individual feeding behaviors that could identify calves at increased risk of disease. The objective of this retrospective case-control study was to determine how feeding behaviors change in preweaning calves leading up to and during a disease bout. This study was conducted between fall 2015 and fall 2016 on 2 commercial dairy farms in Ontario, Canada. Producers' treatment records for respiratory or enteric illness were used to identify cases. Control calves were selected from calves not treated for disease and matched on the days on the AMF. Both farms housed calves in dynamic groups of 9 to 11 calves with an AMF and fed milk replacer. Differences in feeding behaviors, including milk consumption, drinking speed, rewarded visits, unrewarded visits, and total visits to the AMF per day, were analyzed by mixed models accounting for repeated measures. Data were analyzed for the 7 d before, the day of, and 7 d after treatment. A total of 28 cases and 28 control calves (n = 56) were analyzed. Calves with disease consumed significantly less milk than their healthy counterparts, beginning 5 d before disease and until 3 d after disease detection. Sick calves had fewer unrewarded visits starting 3 d before until 2 d after illness detection. Sick calves drank significantly more slowly starting 4 d before illness detection until the day after illness detection compared with healthy controls. No differences were found between cases and controls for rewarded visits. Calves on a high plane of milk nutrition significantly alter feeding behaviors before illness detection. Data from AMF on feeding behaviors may help to detect disease earlier in preweaning dairy calves.

A High Plane of Nutrition Is Associated with a Lower Risk for Neonatal Calf Diarrhea on Bavarian Dairy Farms

Simple SummaryCalf mortality and morbidity are still unacceptably high on many dairy farms worldwide. Neonatal calf diarrhea is the most common cause of disease and death in young calves. This study attempted to identify risk factors that are associated with the outbreak of this multifactorial disease on Bavarian dairy farms. For this purpose, farms with calf diarrhea as a herd problem were compared to farms without veterinarian treatment for calf diarrhea for one year before the study visit. The main factor that was associated with a lower risk of neonatal diarrhea was the provision of adequate amounts of milk as compared with lower milk feeding levels. In contrast, supplementation with iron soon after birth was associated with a higher risk for calf diarrhea as a herd problem. It is well known that poor colostrum management and restricted milk feeding compromise calf development and weaken the immune system. Therefore, it is not surprising that calves receiving more colostrum and more milk have a higher chance of remaining healthy. Ad libitum feeding of calves in the first three weeks of life is recommended. The observed association between an increased calf diarrhea risk and supplementation with iron after birth requires further investigation.In all bovine production systems, neonatal calf diarrhea remains worldwide an important issue of economic losses and animal welfare. The aim of the present study was to identify risk factors for neonatal calf diarrhea as a herd health problem on Bavarian dairy farms. For the purpose of this study, management factors related to calf health were retrospectively compared between 59 dairy farms with calf diarrhea as a herd problem with those of 18 control farms, where no veterinary treatment of calves for neonatal calf diarrhea took place for at least one year prior to the farm visit. A multivariable binary logistic regression analysis of management factors indicated that administration of 3 L or more of colostrum at the second feeding after birth (Odds ration [OR] = 0.21, 95% confidence interval [95% CI] = 0.05–0.89), ad libitum feeding of milk during the first week of life (OR = 0.06, 95% CI = 0.006–0.60), and administration of an iron containing preparation after birth (OR = 10.9, 95% CI = 1.25–95.6) were independently associated with the presence of a herd problem with neonatal diarrhea. Results of this study therefore suggest that a higher plane of nutrition is a protective factor with regard to the occurrence of neonatal diarrhea on Bavarian dairy farms. These findings support the establishment of ad libitum feeding programs in dairy calf rearing.

254 Effects of Nutrition on Bull Fertility

Abstract The greatest effects of nutrition on bull fertility occur by providing a relatively high plane of nutrition during calfhood when the seminiferous epithelium of the testes is developing. A high plane of nutrition from 5 to 25 weeks of age results in greater circulating gonadotropin concentrations, greater testicular volume, and greater sperm production at maturity. At this age, diet can be manipulated by creep feeding bull calves with both protein and energy supplements which could accelerate puberty and increase sperm production. Increased rate of gain in bull calves post-weaning can accelerate puberty a few weeks, but excess post-weaning gain and fat buildup in the neck of the scrotum can have detrimental effects on fertility. Considerable emphasis has been placed on specific micronutrient (especially minerals) effects on peripubertal bull fertility. Trace mineral supplementation is believed to be critical for optimal fertility and both copper (Cu) and zinc (Zn) supplementation have influenced male fertility in other species. However, there are no guidelines for recommended levels of these minerals to ensure fertility. Providing organic or complexed compared to inorganic mineral to peripubertal bulls have increased liver concentrations of mineral and in some cases, have accelerated puberty, but enhanced fertility-associated measures have not been realized. Because both Cu and Zn are present in the ejaculate, mineral needs during the breeding season may differ from the off-season. During the breeding season, bulls can lose 10 to 20% of their weight and need to re-gain this weight before the next breeding season. Divergent planes of nutrition provided to mature bulls during the off-season revealed enhanced sperm energy and stress-fighting potential with decreasing plane of nutrition. Specific mineral supplementation during the off-season in mature bulls provides no beneficial effect on fertility-associated measures. In summary, significant effects of nutrition post-weaning on bull fertility-associated measures have not been realized.

Bothersome Flies: How Free-Ranging Horses Reduce Harm While Maintaining Nutrition

The horses of Shackleford Banks, NC, United States are harassed by many species of biting flies. Apart from being a nuisance, their bites can lead to blood loss and transmit disease. As a result, these horses tend to avoid areas where fly abundances are high. Like other free-ranging horse populations, environmental factors such as low wind speeds and high temperatures increase fly loads per horse. Similarly, coat color matters since darker horses attract more flies than lighter ones, especially on hot sunny days. Many horse populations reduce per capita fly loads by living in large groups or by bunching tightly together. Shackleford horses do so, too, but also use wind speed differences among habitats to modulate fly numbers. By adopting a systematic pattern of moving between habitats such that they only visit a habitat when wind speed is high enough to keep fly harassment to a tolerable level, they can avoid being bitten while continuing to forage. Typically, they begin the day foraging on the salt marshes where fly abundance is inherently low and are lowered further by faint early morning breezes. Later in the morning, horses move to grassy patches (swales) when increasing wind speed reduces fly landings there to levels found on the marshes. Later still, when wind speeds peak, horses begin foraging among the sand dunes. At this point wind speeds are high enough so that horses using any habitat will be minimally harassed by flies, thus enabling them to freely choose where to feed based on which habitat meets particular dietary needs for protein, energy and nutrients on any particular day. Hence, Shackleford horses follow the breeze to solve a challenging dilemma of maintaining a high nutritional plane without succumbing to fly harassment. Other free-ranging horses populations appear to have a more limited “either-or” choice of “bite or be bitten,” thus limiting their decision-making options.

A high plane of nutrition during early life alters the hypothalamic transcriptome of heifer calves

The aim was to examine the effect of rapid body weight gain during early calfhood consistent with earlier sexual development on the transcriptional profile of the hypothalamus. Angus X Holstein–Friesian heifer calves (19 ± 5 days of age) were offered a high (HI, n = 14) or moderate (MOD, n = 15) plane of nutrition from 3 to 21 weeks of age to achieve a growth rate of 1.2 kg/d and 0.5 kg/d, respectively. Following euthanasia at 21 weeks, the arcuate nucleus (ARC) region was separated from the remainder of the hypothalamus and both were subjected to RNA-Seq. HI calves exhibited altered expression of 80 and 39 transcripts in the ARC and the remaining hypothalamus, respectively (P < 0.05) including downregulation of AGRP and NPY and upregulation of POMC, previously implicated in precocious sexual development. Stress-signaling pathways were amongst the most highly dysregulated. Organ morphology, reproductive system development and function, and developmental disorder were amongst the networks derived from differentially expressed genes (DEGs) in the ARC. Gene co-expression analysis revealed DEGs within the ARC (POMC, CBLN2, CHGA) and hypothalamus (PENK) as hub genes. In conclusion, enhanced nutrition during early calfhood alters the biochemical regulation of the hypothalamus consistent with advanced sexual development in the prepubertal heifer.

Effect of plane of nutrition during the first 12 weeks of life on growth, metabolic and reproductive hormone concentrations, and testicular relative mRNA abundance in preweaned Holstein Friesian bull calves.

The objective of this study was to examine the effect of nutrition during the first 12 wk of life on aspects of the physiological and transcriptional regulation of testicular and overall sexual development in the bull calf. Holstein Friesian bull calves with a mean (SD) age and bodyweight of 17.5 (2.85) d and 48.8 (5.30) kg, respectively, were assigned to either a high (HI; n = 15) or moderate (MOD; n = 15) plane of nutrition and were individually fed milk replacer and concentrate to achieve overall target growth rates of at least 1.0 and 0.5 kg/d, respectively. Throughout the trial, animal growth performance, feed intake, and systemic concentrations of metabolites, metabolic hormones, and reproductive hormones were assessed. Additionally, pulsatility of reproductive hormones (luteinizing hormone, follicle-stimulating hormone, and testosterone) was recorded at 15-min intervals during a 10-h period at 10 wk of age. At 87 ± 2.14 d of age, all calves were euthanized, testes were weighed, and testicular tissue was harvested. Differential expression of messenger ribonucleic acid (mRNA) candidate genes involved in testicular development was examined using quantitative polymerase chain reaction assays. All data were analyzed using the MIXED procedure in Statistical Analysis Software using terms for treatment as well as time for repeated measures. Blood metabolites and metabolic hormones generally reflected the improved metabolic status of the calves on the HI plane of nutrition though the concentrations of reproductive hormones were not affected by diet. Calves on the HI diet had greater mean (SED) slaughter weight (112.4 vs. 87.70 [2.98] kg; P < 0.0001) and testicular tissue weight (29.2 vs. 20.1 [2.21] g; P = 0.0003) than those on the MOD diet. Relative mRNA abundance data indicated advanced testicular development through upregulation of genes involved in cellular metabolism (SIRT1; P = 0.0282), cholesterol biosynthesis (EBP; P = 0.007), testicular function (INSL3; P = 0.0077), and Sertoli cell development (CLDN11; P = 0.0054) in HI compared with MOD calves. In conclusion, results demonstrate that offering dairy-bred male calves a high plane of nutrition during the first 3 mo of life not only improves growth performance and metabolic status but also advances testicular development consistent with more precocious sexual maturation.

263 Review of Current Nutrition Knowledge and Practices for Gilt Development

Abstract Nutrition for replacement gilts aims to support the development of prepubertal gilts towards their physiological maturity in terms of body weight, body tissue composition, structural soundness, and reproductive development. A key concept of gilt nutrition for lifetime productivity is to maintain a positive prepubertal growth rate and reach a target body weight of 115 to 140 kg at puberty. The application of this concept commonly presents a challenge with fast-growing and highly efficient contemporary gilt lines, particularly considering the proportion of gilts exceeding the target body weight at puberty and the negative impacts of overweight gilts on lactational performance, structural soundness, and longevity. Thus, nutritional decisions regarding dietary levels of energy, amino acids, and minerals in the pre- and peripubertal stage can be conflicting. Typically, gilts are fed ad libitum with moderate levels of energy and amino acids because restrictions below the requirements can have a negative effect on puberty onset. In addition, a high plane of nutrition is offered after the pubertal estrus to set ovulation rate for breeding at the next estrus. Moreover, gilts are fed levels of dietary calcium, phosphorus, and trace minerals above the requirements to improve bone mineral density in preparation for fetal development and lactation mobilization. Although these nutritional practices improve gilt performance, they also typically increase weight gain. Thus, there is a need to review nutritional strategies to manage body weight of replacement gilts while attaining optimum reproductive success and lifetime productivity.