Impact of volume, immunoglobulin G concentration, and feeding method of colostrum product on neonatal nursing behavior and transfer of passive immunity in beef calves.

One-third of beef calves fail to achieve adequate transfer of passive immunity (TPI) through timely ingestion of colostrum, which substantially increases their risk of preweaning morbidity and mortality. Two randomized clinical trials were designed to assess the impact of volume, immunoglobulin G (IgG) concentration, and feeding method of colostrum product on neonatal nursing behavior and TPI. In Trial 1, 47 calves were randomly assigned to receive one of three colostrum interventions by oro-esophageal tube feeder (OET): 1 L with 100 g/L IgG, 1.4 L with 70 g/L IgG, or 2 L with 100 g/L IgG. In Trial 2, 29 calves were randomly assigned to be fed 1 L of colostrum product with 100 g/L IgG by either nipple bottle (NB) or OET. Colostrum intervention (i.e. feeding of colostrum product) occurred within 60 minutes of birth. Cow-calf pairs were monitored by video surveillance in individual stalls for 24 h. Dam colostrum was collected at 10 minutes and calf serum was collected at 24-36 h after birth to assess IgG concentration. Differences among colostrum intervention groups on latency to stand and nurse were analyzed using Kaplan-Meier survival curves and Cox proportional hazard models. The impact of colostrum intervention group on TPI was assessed using multivariable linear regression modeling. In Trial 1, calves fed 1.4 L with 70 g/L IgG by OET nursed from their dams statistically significantly earlier compared to calves fed 1 L with 100 g/L IgG (P = 0.003) and calves fed 2 L with 100 g/L IgG (P = 0.008). Six of the 15 calves in the NB group in Trial 2 refused to consume part of the colostrum feeding offered by bottle and required follow-up tube feeding of the remaining volume. These calves were analyzed as a separate group (NB + OET). Calves fed 1 L by NB stood and nursed statistically significantly earlier than calves fed by OET (P = 0.005) or a combination of NB + OET (P = 0.003). Calf serum IgG concentrations were not statistically significantly different among colostrum intervention groups (P > 0.1). Overall, the colostrum interventions assessed in this study led to only one calf with failed TPI. While statistically significant differences in serum IgG concentrations were not detected in this study, subsequent nursing behavior did vary and was improved by feeding a moderate volume (1.4 L with 70 g/L IgG) of colostrum when using an OET, and by using the NB when feeding a smaller volume (1 L with 100 g/L IgG).

Impact of restricting feed and probiotic supplementation on growth performance, mortality and carcass traits of meat-type quails.

The objective of this study was to evaluate the effects of quantitative feed restriction, along with dietary supplementation with a probiotic blend (Protexin) as a natural growth promoter, on the performance, water consumption, mortality rate and carcass traits of meat-type quails. A total of 250 1-day unsexed quails were randomly allocated to five equal groups in a completely randomized design. The first group (A) fed a basal diet without any restriction (24 hr/day); the second group (B1) fed the basal diet for 20 hr/day; the third group (B2) fed the basal diet enriched with probiotic (0.1 g/kg diet) for 20 hr/day; the fourth group (C1) fed the basal diet for 16 hr/day; and the fifth group (C2) fed the basal diet enriched with probiotic (0.1 g/kg diet) for 16 hr/day. Birds were fed ad-libitum from 0-14 days of age, and then the feed restriction regimes started from 14 till 28 days of age. Results showed that quails in the control-group consumed more feed and water than the other treatment groups (p < .01), however their body weights did not differ (p > .05) compared with the other treated groups. The best feed conversion values were achieved in quails supplemented with probiotic blend (B2 and C2) in comparison with the other groups (p < .01). Feeding probiotic had a positive effect on bird health which reduced the mortality rate. Further, mortality rate was significantly reduced (p < .05) by feed restriction, with or without probiotic supplementation. No carcass parameters were significantly affected (p > .05) by treatments. Our results show that quail could be reared under a feed restriction system, for 4-8 hr daily, along with dietary supplementation of probiotic as growth promoter for better growth performance.

Effects of supplemental fat concentration on feeding logistics, animal performance, and nutrient losses of heifers fed finishing diets based on steam-flaked corn and sorghum-based distiller's grains.

The use of distiller's grains (DG) in beef cattle finishing diets is a common practice. However, the effects of supplemental fat on performance and nutrient losses of cattle fed diets containing DG are not known. Therefore, we fed 398 crossbred yearling heifers (initial BW = 373.5 kg) for 106 d to determine the effects of dietary fat concentration and sorghum-based wet distiller's grains with solubles (SWDGS) on performance, carcass characteristics, and nutrient losses of finishing cattle. Treatments included two 92% concentrate, steam-flaked corn (SFC)-based diets with 0% or 3% added fat from yellow grease and 3 SFC-based diets with 15% SWDGS (DM basis) that contained either 0%, 1.5%, or 3% added fat (8 pens per treatment) in a randomized block design. Overall DMI and ADG were 5% to 6% greater (P < 0.01) for heifers fed 15% SWDGS than for those fed 0% SWDGS. Among heifers fed 15% SWDGS, DMI was greatest (P = 0.04; quadratic effect) and ADG tended (P = 0.12; quadratic effect) to be greatest for heifers fed 1.5% fat. The ADG:DMI did not differ between 0% SWDGS with 0% or 3% fat, and was not altered by replacing a portion of SFC with SWDGS (P > 0.36). However, ADG:DMI tended to increase as more fat was added to diets with 15% SWDGS (P = 0.06). Average hot carcass weight (HCW) was 5 kg greater (P = 0.05) when SWDGS was fed, but HCW tended to be greatest for heifers fed 15% SWDGS with 1.5% fat (P = 0.09, quadratic effect). Heifers fed 0% SWDGS with 0% fat tended to have a lower marbling score, less rib fat, lower average yield grade (P < 0.08), and more (P < 0.01) yield grade 1 carcasses than heifers fed 0% SWDGS with 3% fat. Averaged across fat levels, heifers fed 15% SWDGS had more rib fat and a higher yield grade (P < 0.03) than heifers fed 0% SWDGS. Feeding 15% SWDGS did not alter carcass quality grade distribution compared to feeding 0% SWDGS, but 15% SWDGS produced fewer yield grade 3 carcasses (P = 0.03) than 0% SWDGS. The calculated NEg of SWDGS (1.36 Mcal/kg) was 91% of the tabular value for dry rolled corn (1.50 Mcal/kg) and 84% of the tabular value for SFC (1.62 Mcal/kg). Nitrogen intake, and N excretion were greater (P < 0.05) in heifers fed 15% SWDGS than in heifers fed the 0% SWDGS diets, but N loss as a % of N intake was less (P < 0.05). Our results suggest adding 1.5% fat to diets containing 15% SWDGS may improve beef cattle performance; however, feeding logistics need to be considered when pricing wet DG.

The effect of tube versus bottle feeding colostrum on immunoglobulin G absorption, abomasal emptying, and plasma hormone concentrations in newborn calves.

The objective of this study was to determine if feeding colostrum to newborn calves through an esophageal tube, compared with a nipple bottle, would delay abomasal emptying, which would in turn decrease passive transfer of IgG and plasma glucose, insulin, and glucagon-like peptide (GLP) 1 and GLP-2 concentrations. Twenty newborn Holstein bull calves were fed 3 L of colostrum replacer (200 g of IgG) through either an esophageal tube or nipple bottle at 2 h after birth followed by feeding pooled whole milk every 12 h after birth. Acetaminophen was mixed into the colostrum meal as a marker for abomasal emptying. A jugular catheter was inserted 1 h after birth and blood was sampled frequently to analyze serum for IgG and acetaminophen and plasma for glucose, insulin, GLP-1, and GLP-2. Feeding method did not affect abomasal emptying, and as a result no treatment effect was present on serum IgG concentrations. Maximum concentration of serum IgG was 24.4 ± 0.40 mg/mL (± standard error), which was reached at 14.6 ± 1.88 h after the colostrum meal for both groups. Apparent efficiency of absorption at maximum concentration of IgG was 52.9%, indicating high efficiency of passive transfer of IgG for both treatments. Tube feeding increased glucose and insulin area under the curve before the first milk meal, most likely due to the decreased time to consume the colostrum meal. In addition, tube-fed calves consumed 0.5 ± 0.13 L more milk in their first milk meal than bottle-fed calves. No treatment effect on plasma concentrations of GLP-1 or GLP-2 was present, but both hormones increased after colostrum feeding. These findings confirm that there is no effect on absorption of IgG from colostrum when feeding good-quality colostrum at a volume of 3 L through either an esophageal tube or nipple bottle.

Associations between management practices and within-pen prevalence of calf diarrhea and respiratory disease on dairy farms using automated milk feeders.

Data on management practices used with automated milk feeders (AMF) are needed to identify factors associated with calf health in these systems. The objectives of this observational, longitudinal, cross-sectional study were to estimate the prevalence of calf diarrhea (CD) and bovine respiratory disease (BRD), and to identify factors associated with prevalence of these diseases at the pen level on dairy farms feeding milk to group-housed calves with AMF. Seventeen dairy farms with AMF in Ontario, Canada, were visited 4 times, seasonally, over 1 yr. The clinical health of all calves (n = 1,488) in pens (n = 35) with AMF was scored to identify the number of calves with CD and BRD. Data on calf, feeder, and pen management practices were analyzed using generalized linear mixed regression models for each disease. Overall calf-level prevalence of CD and BRD were 23 and 17%, respectively. Median (interquartile range, IQR) within-pen prevalence of CD and BRD were 17% (7 to 37%) and 11% (0 to 28%), respectively. Median age (IQR) for diarrheic calves was 25 d (16 to 42 d), and for calves with BRD was 43 d (29 to 60 d). Factors associated with lower within-pen prevalence of CD were the administration of vitamin E and selenium at birth [odds ratio (OR) = 0.56; 95% confidence interval (CI): 0.32 to 0.99], feeding of probiotics (OR = 0.44, 95% CI: 0.22 to 0.93), and adding fresh bedding every 2 to 3 d (OR = 0.43; 95% CI: 0.24 to 0.76) compared with every 7 or more days. In contrast, sharing air with older cattle (>9 mo old) was associated with increased within-pen prevalence of CD (OR = 4.54, 95% CI: 1.88 to 10.52). Additionally, total bacteria counts ≥100,000 cfu/mL in milk samples taken from the AMF mixing jar were associated with increased within-pen prevalence of CD during the summer visit (OR = 3.34; 95% CI: 1.31 to 8.54). Increased total solids in milk or milk replacer (OR = 0.48, 95% CI: 0.27 to 0.85) and feeding whole milk versus milk replacer (OR = 0.29, 95% CI: 0.11 to 0.75) were associated with lower within-pen prevalence of BRD. Factors associated with greater within-pen prevalence of BRD were sharing air with weaned cattle up to 8 mo old (OR = 3.21, 95% CI: 1.26 to 8.16), and greater depth of the wet bedding pack. The use of maternity pens for reasons other than just calving was associated with increased prevalence of both CD and BRD (OR = 1.85, 95% CI: 1.03 to 3.33; OR = 2.61, 95% CI: 1.21 to 5.58, respectively). These results suggest that isolation from older animals and frequent cleaning of the feeder and pen may help to reduce disease prevalence in group-housed calves fed with an AMF.

In ovo feeding of creatine pyruvate alters energy reserves, satellite cell mitotic activity and myogenic gene expression of breast muscle in embryos and neonatal broilers.

We investigated the effects of in ovo feeding (IOF) of creatine pyruvate (CrPyr) on energy reserves, satellite cell mitotic activity (SCMA) and myogenic gene expression in breast muscle of embryos and neonatal broilers. A total of 960 eggs were randomly allocated into three treatments: 1) non-injected control group, 2) saline group injected with 0.6 mL of physiological saline (0.75%), and 3) CrPyr group injected with 0.6 mL of physiological saline (0.75%) containing 12 mg CrPyr/egg at 17.5 d of incubation. After hatching, a total of 120 male chicks were randomly assigned to each treatment group, with eight replicate sets per group. Selected chicks had body BW close to the average of their pooled group. Our results showed that the total and relative breast muscle weights of broilers subjected to CrPyr treatment were higher than those in the control and saline groups on 19 d of incubation (19 E), the day of hatch, 3 and 7 d post-hatch (P < 0.05). The myofiber diameter and cross-sectional area of individuals in the CrPyr group were higher than those in other treatments on 3 and 7 d post-hatch (P < 0.05). Moreover, IOF of CrPyr increased (P < 0.05) creatine concentrations on 19 E, the day of hatch and 3 d post-hatch, the same treatment increased phosphocreatine concentrations on 19 E. Broilers in the CrPyr group showed higher expression of myogenic differentiation 1 (MyoD) (P < 0.05), myogenin and paired box 7 (Pax7), as well as higher index of SCMA on 3 d post-hatch. However, myostatin mRNA expression in CrPyr-treated broilers was down-regulated on 3 d post-hatch (P < 0.05). These results indicated that IOF of CrPyr increased energy reserves of embryos and SCMA of broilers on 3 d post-hatch, which led to enhanced muscle growth in the late embryos and neonatal broilers. Additionally, IOF of CrPyr increased the activity of satellite cells possibly through up-regulating MyoD, myogenin, and Pax7 mRNA expression and down-regulating myostatin mRNA expression.

Lying behaviour and IgG-levels of newborn calves after feeding colostrum via tube and nipple bottle feeding.

Oesophageal tube feeding colostrum is used to ensure sufficient colostrum intake in newborn calves but the impact of tube feeding on animal behaviour is unclear. Therefore the objective of this study was to compare lying behaviour of tube-fed or bottle-fed dairy calves. Calves (n = 37) in 3 groups were offered 3·5 l colostrum 2 h after birth. Calves of the bottle group were fed with a nipple bottle. Calves of the placebo tubing group were tubed for 4 min but no colostrum was given and they were then fed with a nipple bottle. Calves of the tubing group received 3·5 l colostrum via tube feeding. Consumed amount of bottle and placebo tubing calves was recorded. If they refused some of the offered 3·5 l the rest was offered in a second feeding 2 h later. Lying behaviour was measured by data loggers fitted to right hind leg for 3 d. Blood samples were taken 24 h after birth for determination of IgG concentration. The voluntary colostrum intake differed significantly between bottle-fed and placebo tubed calves at first feeding. Considering both colostrum feedings, bottle-fed calves consumed 3·44 ± 0·14 l and placebo tubed calves consumed 3·20 ± 0·38 l colostrum. ImmunoglobulinG intake (255·6 ± 77·5 g IgG), serum IgG concentration 24 h after birth (22·8 ± 6·7 g/l) and total serum protein concentration (6·1 ± 0·6 g/dl) did not differ between groups. None of the calves had a failure of passive transfer. There was no effect of tubing on lying behaviour.

Effect of stocking rate on milk and pasture productivity and supplementary feed use for spring calving pasture fed dairy systems.

The productivity of grazing systems is primarily limited by the scale and efficiency of systems applied to the grazable land platform adjacent to the milking parlor. The objective of this study was to compare forage production, utilization and quality, milk production, and requirement for supplementary feeds for 2 different grazing platform stocking rate (GPSR) treatments over 4 yr. Animals were randomly allocated to 1 of 2 GPSR treatments: high-closed (HC; 3.1 cows/ha) and high-open (HO; 4.5 cows/ha), which were designed to represent alternative GPSR in a post-European Union milk quota, spring calving, pasture-based milk production system. Animal production data were analyzed using Proc MIXED of SAS with GPSR, year, and parity included as fixed effects in the final model. Within a seasonal spring calving grazing system, at high GPSR and offering moderate amounts of additional supplements based on pasture supply deficits, both systems produced more milk and fat plus protein per hectare in comparison with Irish commercial dairy farms. Although requiring additional supplementation, increased GPSR resulted in increased milk production per hectare but also in an increased requirement for concentrate and forage supplementation during lactation. No significant influence of GPSR was found on body weight and body condition score or reproductive performance during the 4-yr study period. In addition, GPSR also had no effect on pasture production, utilization, or quality during the study period. The strategic use of additional supplements with restricted pasture availability at higher GPSR maintained milk production per cow and significantly increased milk production per hectare.

Creep-feeding to stimulate metabolic imprinting in nursing beef heifers: impacts on heifer growth, reproductive and physiological variables.

This experiment compared growth, physiological, and reproductive responses of beef heifers with (MI) or without (CON) access to a creep-feeder, as a manner to stimulate metabolic imprinting while nursing their dams. On day 0, 60 Angus × Hereford heifers were ranked by BW and age (140 ± 3 kg and 68±3 days), and assigned to pairs so all ranking criteria were similar between heifers within each pair. On day 1, pairs were randomly assigned to MI (n=15) or CON (n=15). From day 1 to 51, MI pairs and their dams were allocated to 15 drylot pens where heifers had ad libitum access to a corn-based supplement through a creep-feeder. The CON pairs and their dams were maintained in an adjacent single drylot pen. From day 52 to 111, treatments were managed as a single group on a semiarid range pasture. On day 111, heifers were weaned and allocated to two pastures (one pasture/treatment), receiving hay and a corn-based concentrate until day 326. Heifer BW was recorded before and at the end of the creep-feeding period (day 1 to 51), and on days 112 and 326. On days 0, 51, 111, 187, 261, and 325, jugular blood was collected and real-time ultrasonography for longissimus muscle depth and backfat thickness assessment was performed. Blood was also collected every 10 days from days 113 to 323 for puberty evaluation via plasma progesterone. Liver and subcutaneous fat biopsies were performed on days 51, 111, 261 and 325. Average daily gain was greater (P<0.01) for MI than CON from day 1 to 51, tended (P=0.09) to be greater for CON than MI from day 112 to 326, while BW on day 326 was similar between treatments. On day 51, MI had greater (P ⩽ 0.01) plasma IGF-I and glucose concentrations, as well as mRNA expression of hepatic pyruvate carboxylase and adipose fatty acid synthase than CON. On days 261 and 325, plasma insulin concentrations were greater (P ⩽ 0.03) in CON than MI. Mean mRNA expression of hepatic IGF-I and adipose peroxisome proliferator-activated receptor gamma were greater (P ⩽ 0.05) in MI than CON. No treatment effects were detected for puberty attainment rate. In conclusion, supplementing nursing heifers via creep-feeding for 50 days altered physiological and biochemical variables suggestive of a metabolic imprinting effect, but did not hasten their puberty attainment.

Effect of bovine colostrum feeding in comparison with milk replacer and natural feeding on the immune responses and colonisation of enterotoxigenic Escherichia coli in the intestinal tissue of piglets.

The present study investigated the effect of feeding bovine colostrum (BC) to piglets in comparison with feeding a milk replacer (MR) and conventional rearing by the sow on the intestinal immune system and number of enterotoxigenic Escherichia coli (ETEC) colonising the intestinal tissue. Piglets (23-d-old) were allocated to one of the following four groups: (1) killed at the beginning of the experiment (Base); (2) separated from the sow and fed BC (BC-fed); (3) separated from the sow and fed a MR (MR-fed); (4) kept with the sow (Sow-Milk). Blood was sampled on days 1 and 8, and faecal samples were collected on days 1, 3, 5 and 8. On day 8, piglets were killed and gastrointestinal digesta and intestinal segments were collected. The frequency of diarrhoea was found to be higher (P≤ 0·019) in MR-fed piglets than in BC-fed and Sow-Milk piglets. Piglets from the MR-fed group had the lowest lactic acid bacteria:haemolytic E. coli ratio (P(treat)= 0·064) in the faeces. The number of E. coli colonising the intestinal tissue was higher (P< 0·001) in piglets from the MR-fed group than in those from the BC-fed and Sow-Milk groups. Piglets from the Sow-Milk group had a higher (P= 0·020) mucosal IgG concentration than those from the MR-fed group, but did not exhibit any difference when compared with piglets from the Base and BC-fed groups. Piglets from the BC-fed group exhibited a reduced (P≤ 0·037) expression level of Toll-like receptor-4 in the intestinal mucosa when compared with those from the MR-fed and Sow-Milk groups. The expression level of IL-2 was higher (P≤ 0·051) in piglets from the MR-fed group than in those from the other treatment groups. In conclusion, feeding BC rather than MR to the piglets reduced the colonisation of intestine by ETEC and modulated the intestinal immune system, whereas no differences were observed in piglets fed BC and conventionally reared by the sows.

The impact of feeding growing-finishing pigs with daily tailored diets using precision feeding techniques on animal performance, nutrient utilization, and body and carcass composition.

The impact of moving from conventional to precision feeding systems in growing-finishing pig operations on animal performance, nutrient utilization, and body and carcass composition was studied. Fifteen animals per treatment for a total of 60 pigs of 41.2 (SE = 0.5) kg of BW were used in a performance trial (84 d) with 4 treatments: a 3-phase (3P) feeding program obtained by blending fixed proportions of feeds A (high nutrient density) and B (low nutrient density); a 3-phase commercial (COM) feeding program; and 2 daily-phase feeding programs in which the blended proportions of feeds A and B were adjusted daily to meet the estimated nutritional requirements of the group (multiphase-group feeding, MPG) or of each pig individually (multiphase-individual feeding, MPI). Daily feed intake was recorded each day and pigs were weighed weekly during the trial. Body composition was assessed at the beginning of the trial and every 28 d by dual-energy X-ray densitometry. Nitrogen and phosphorus excretion was estimated as the difference between retention and intake. Organ, carcass, and primal cut measurements were taken after slaughter. The COM feeding program reduced (P < 0.05) ADFI and improved G:F rate in relation to other treatments. The MPG and MPI programs showed values for ADFI, ADG, G:F, final BW, and nitrogen and phosphorus retention that were similar to those obtained for the 3P feeding program. However, compared with the 3P treatment, the MPI feeding program reduced the standardized ileal digestible lysine intake by 27%, the estimated nitrogen excretion by 22%, and the estimated phosphorus excretion by 27% (P < 0.05). Organs, carcass, and primal cut weights did not differ among treatments. Feeding growing-finishing pigs with daily tailored diets using precision feeding techniques is an effective approach to reduce nutrient excretion without compromising pig performance or carcass composition.

Effects of alternate-day feeding of dried distiller's grain plus solubles to forage-fed beef cows in mid- to late gestation.

Forty-six nonlactating beef cows were used to examine effects of dried distiller's grains plus solubles (DG) supplementation strategies to cows fed grass hay during mid- to late gestation on BW, ultrasound body composition characteristics, concentrations of serum NEFA and urea, feeding behavior, and calf birth weight. Cows were assigned to dietary treatments in a completely randomized design: 1) control, where hay was fed each day of the week (CON), 2) both hay and DG fed daily during the week (DG7), 3) hay fed daily but DG fed 3 d of the week (DG3), and 4) hay fed 4 d of the week alternating with DG fed on the remaining 3 d (DGA). Hay was offered ad libitum on days it was fed. The DG were fed at 0.40% of BW when offered daily and 0.93% of BW when offered 3 d per week (Monday, Wednesday, and Friday). Feed intake was monitored continuously over the 84-d feeding period. Hay intake and total DMI were reduced (P < 0.05) in DGA compared with DG7 and DG3. Gain and G:F were decreased (P < 0.05) for CON compared with other treatments. No differences (P > 0.05) were observed among treatments for change in BCS, intramuscular fat, rib fat, or rump fat from d 1 to 84. On a day when DG7, DG3, and DGA all received DG (Friday), DGA had reduced (P < 0.05) concentrations of urea compared with DG3 and DG7. On a day when only DG7 received DG (Saturday), urea was greater (P < 0.01) for DG3 and DGA compared with DG7, and concentrations of NEFA were greater (P < 0.01) in CON and DGA compared with DG7. On the second consecutive day when only DG7 received DG (Sunday), concentrations of NEFA were less (P < 0.001) for DG7 compared with other treatments. On days when all cows received hay, DGA spent more time eating (P < 0.05) compared with DG7 and DG3. Cows fed DGA had greater (P < 0.05) hay intake per meal and time per meal compared with other treatments. On days when DG7, DG3, and DGA all received DG, cows in the DG3 and DGA treatments had greater (P < 0.05) number of DG meals, time spent eating, intake per meal, and time per meal but a slower (P < 0.05) rate of DG intake compared with DG7. No differences (P > 0.05) were observed in calf birth weights among treatments. The alternate-day feeding strategy reduced hay and total intake, altered concentrations of serum urea and NEFA, and altered feeding behavior compared with other supplementation methods.

Influence of different systems for feeding supplements to grazing dairy cows on milk fatty acid composition.

This study investigated the effects of different strategies for feeding supplements to grazing dairy cows on the proportions of fatty acids in milk. Two hundred and sixteen cows were fed supplementary grain and forage according to one of 3 different strategies; (1) CONTROL: cows grazed perennial ryegrass pasture (14 kg dry matter/d) supplemented with milled barley grain fed in the milking parlour and pasture silage offered in the paddock; (2) Partial mixed ration 1 (PMR1): same pasture allotment and supplement as CONTROL strategy, but the supplements presented as a mixed ration after each milking in feedpad, and; (3) Partial mixed ration 2 (PMR2): same pasture allotment, supplemented with a mixed ration of milled barley grain, alfalfa hay, corn silage and crushed corn grain fed in a feedpad. Within each strategy, cows were assigned to receive either 6, 8, 10 or 12 kg dry matter supplement/cow per d. Milk fatty acid proportions from cows fed CONTROL and PMR1 strategies were similar and different from those fed PMR2, particularly at 10 to 12 kg dry matter supplement/cow per d. The reduction in milk fat yield and concentration in cows fed high amounts of supplement as CONTROL and PMR1 was coincident with 4 × increase in 10t-18:1 proportion. The composition of the partial mixed ration (PMR) and the amount offered affected milk fatty acid proportions and milk fat content, however, the method of supplementation did not.

Effect of different feeding strategies in intensive dairy farming systems on milk fatty acid profiles, and implications on feeding costs in Italy.

The aim of this work was to characterize the fatty acid (FA) profile of milk from intensive dairy farming systems in the Po Plain (Italy) to estimate the costs of the adopted feeding strategies and to simulate the effect of supplementary premiums on the basis of milk FA composition on milk income. Twenty dairy farms with 5 different feeding strategies were studied: 3 corn silage-based systems in which cows were supplemented with a great proportion (CCH), a medium proportion (CCM), or without commercial concentrate mix (CC0), and 2 systems in which part of corn silage was replaced with grass or legume silage (HF) or with fresh herbage (G), cut and fed indoors. Bulk milk was sampled and lactating cow performance, feeding strategies and forage characteristics were recorded through a survey, 3 times during a year. The milk FA supplementary premium was calculated considering C18:3n-3 and saturated FA (SFA) concentrations, and ratio of total cis C18:1 isomers to C16:0. The CCH, CCM, and CC0 systems bought most of their dairy cow feeds off farm, which allowed them to increase milk production to 35,000 L/yr per hectare. Their low dry matter and crude protein self-sufficiency led to higher feeding costs per liter of milk (from €0.158 to €0.184), and highest income over feed cost was achieved only for milk yield performance greater than 10,000 kg/cow per year. The use of homegrown forages in HF and G increased dry matter and crude protein self-sufficiency and reduced the feeding costs per liter of milk from 9 to 22%, compared with the other studied systems, making HF and G feeding economically competitive, even for a lower milk yield per cow. The studied systems highlighted a remarkable variation in FA profiles. The concentrations of C16:0 and SFA were the highest in CCH (31.53 and 67.84 g/100g of FA) and G (31.23 and 68.45 g/100g of FA), because of the larger proportion of commercial concentrate mix in the cow diet. The concentrations of C16:0 and SFA were the lowest in CCM (27.86 and 63.10 g/100g of FA), because of low roughage-to-concentrate ratio in the cow diet, which is known to favor milk fat depression, affecting particularly these FA. The calculated supplementary premium was the highest in the CCM system, based on milk FA profiles from those herds. The HF diet was rich in forages and resulted in greater concentration of C18:3n-3 in milk (0.57 g/100g of FA) than the other systems and thus led to an increase in milk FA supplementary premium. Milk from G and HF milk had the lowest ratio of Σn-6:Σn-3 FA compared with milk from the systems based on higher corn silage proportion in the cow diet (3.71, and 3.25, respectively, vs. 4.58 to 4.78), with the lower ratios being closer to recommendation for human nutrition.

Substitution rate and milk yield response to corn silage supplementation of late-lactation dairy cows grazing low-mass pastures at 2 daily allowances in autumn.

Feed costs in dairy production systems may be decreased by extending the grazing season to periods such as autumn when grazing low-mass pastures is highly probable. The aim of this autumn study was to determine the effect of corn silage supplementation [0 vs. 8 kg of dry matter (DM) of a mixture 7:1 of corn silage and soybean meal] on pasture intake (PI), milk production, and grazing behavior of dairy cows grazing low-mass ryegrass pastures at 2 daily pasture allowances (PA; low PA=18 vs. high PA=30 kg of DM/cow above 2.5 cm). Twelve multiparous Holstein cows were used in a 4 × 4 Latin square design with 14-d periods. Pre-grazing pasture mass and pre-grazing plate meter pasture height averaged 1.8 t of DM/ha (above 2.5 cm) and 6.3 cm, respectively. The quality of the offered pasture (above 2.5 cm) was low because of dry conditions before and during the experiment (crude protein=11.5% of DM; net energy for lactation=5.15 MJ/kg of DM; organic matter digestibility=61.9%). The interaction between PA and supplementation level was significant for PI but not for milk production. Supplementation decreased PI from 11.6 to 7.6 kg of DM/d at low PA and from 13.1 to 7.3 kg of DM/d at high PA. The substitution rate was, therefore, lower at low than at high PA (0.51 vs. 0.75). Pasture intake increased with increasing PA in unsupplemented treatments, and was not affected by PA in supplemented treatments. Milk production averaged 13.5 kg/d and was greater at high than at low PA (+1.4 kg/d) and in supplemented than unsupplemented treatments (+5.2 kg/d). Milk fat concentration averaged 4.39% and was similar between treatments. Milk protein concentration increased from 3.37 to 3.51% from unsupplemented to supplemented treatments, and did not vary according to PA. Grazing behavior parameters were only affected by supplementation. On average, daily grazing time decreased (539 vs. 436 min) and daily ruminating time increased (388 vs. 486 min) from 0 to 8 kg of supplement DM. The PI rate was 6g of DM/min lower in supplemented than in unsupplemented treatments (17 vs. 23 g of DM/min). The high milk yield response to supplementation may be related to a cumulative effect of the low-mass pasture (low PI) and the low quality of the pasture, which strongly limited energy supply in unsupplemented cows.

Short communication: Limit feeding dairy heifers: effect of feed bunk space and provision of a low-nutritive feedstuff.

The objectives of this study were to examine the behavioral effects of providing limit-fed dairy heifers an increased amount of feed bunk space compared with recommended feed bunk allowance, and to determine if the effects of provision of extra bunk space would be comparable to those seen when limit-fed heifers are provided a low-nutritive feedstuff. Twelve Holstein dairy heifers (381.1 ± 44.8 d of age, 417.3 ± 47.9 kg), divided into groups of 4, were exposed to each of 3 treatments using a 3 × 3 Latin square design with 7-d periods. The treatments were (1) 0.68 m of feed bunk space/heifer (TMR-0.68), (2) 0.34 m of feed bunk space/heifer (TMR-0.34), and (3) 0.34 m of feed bunk space/heifer with an additional 0.34 m of feed bunk space available for free-choice straw (TMR-S). The total mixed ration was fed once daily at a restricted level (1.83% of body weight) and contained (dry matter basis) 19.9% alfalfa/grass haylage, 20.1% corn silage, 49.6% high-moisture corn, and 10.4% protein supplement. Group dry matter intake (DMI) was recorded daily. Behavior at the feed bunk was recorded for the last 4 d of each treatment period. Due to the provision of straw, DMI was highest on the TMR-S treatment compared with the other treatments (9.4 vs. 7.8 kg/d). Heifers spent the most time feeding when on the TMR-S treatment (147.7 min/d), with no difference in feeding time between the limit-fed TMR treatments (64.5 min/d). Within the TMR-S treatment, feeding time on the straw was 76.9 min/d; thus, the rate of consumption of only the TMR was similar across all treatments. Unrewarded time at the feed bunk (when no feed was present) did not differ between treatments. Heifers did not differ in competitive behavior when on the limit-fed TMR treatments (13.1 displacements/heifer per day). However, while on the TMR-S treatment, heifers displaced each other more frequently (23.8 displacements/heifer per day) than while on the other 2 treatments. Overall, results suggest that neither increased feed bunk space nor provision of straw will reduce competition for, or slow consumption rates of, a limit-fed TMR. The provision of straw alongside a limit-fed TMR did increase DMI, which would contribute to further rumen fill, and allowed heifers to increase their time spent feeding throughout the day.

Effect of the provision of a low-nutritive feedstuff on the behavior of dairy heifers limit fed a high-concentrate ration.

The objective of this study was to examine the behavioral and growth responses of dairy heifers when a low-nutritive feedstuff was provided with (either within or alongside) a limit-fed ration. Twenty-four Holstein dairy heifers (187 ± 11.3 d of age, 231.1 ± 12.0kg), divided in groups of 4, were exposed to each of 3 treatments in a replicated Latin square design with 28-d periods. The treatment rations were (1) total mixed ration (TMR) in a limited amount (TMR-L), (2) TMR in a limited amount with straw (1.8 kg of DM/d per heifer) offered as a choice (TMR-SC), and (3) TMR in a limited amount with straw (1.8 kg of DM/d per heifer) mixed in (TMR-SM). The TMR was fed, once daily, at a restricted level (2.02% of body weight) and contained (on a DM basis) 19.0% alfalfa/grass haylage, 21% corn silage, 45% high moisture corn, and 15% protein supplement. Feeding behavior and unrewarded time at the feed bunk were recorded for the last 14 d of each period. Standing time was recorded for the last 7 d of each period. Rumination behavior was recorded twice weekly (during the fifth hour after feed delivery) in the last 14 d of each period. Body weight was recorded weekly and group DMI was recorded daily. Dry matter intake was lowest for the TMR treatment compared with the treatments with straw (5.7 vs. 7.3 kg/d). Heifer average daily gain tended to be lower on the TMR-SM treatment compared with the TMR-L and TMR-SC treatments (0.78 vs. 0.94 kg/d). Feed efficiency (DMI/ADG) was improved on the TMR-L (6.3) compared with TMR-SC (7.8) and TMR-SM (9.9) treatments. Daily feeding time differed between the TMR-L (76.1 min/d), TMR-SC (206.9 min/d), and TMR-SM (279.2 min/d) treatments. Unrewarded feeding time at the feed bunk differed between the TMR-L (38 min/d) compared with the TMR-SC (10.9 min/d) and TMR-SM (1.7 min/d) treatments. Inactive standing time differed among treatments, with TMR-L being the highest compared with TMR-SC and TMR-SM (556.4 vs. 409.9 vs. 340.1 min/d). There tended to be fewer heifers ruminating on the TMR-L compared with TMR-SM (14.0 vs. 21.9%). The results suggest that provision of straw as a choice alongside a limit-fed ration will allow heifer growth rates to be met, as well as provide a suitable foraging source that heifers can use to satisfy their natural feeding behavior patterns.

Effect of rumen-undegradable protein supplementation and fresh forage composition on nitrogen utilization of dairy ewes.

Previous trials with dairy ewes fed stored feeds indicate a positive effect of rumen-undegradable protein (RUP) supplementation on milk yield. However, dairy sheep production in the United States is primarily based on grazing mixed grass-legume pastures, which contain a high proportion of rumen-degradable protein. Two trials were conducted to evaluate the effects of high-RUP protein supplementation and fresh forage composition on milk yield and N utilization of lactating dairy ewes fed in confinement or on pasture. In a cut-and-carry trial, 16 multiparous dairy ewes in mid-lactation were randomly assigned to 8 pens of 2 ewes each. Pens were randomly assigned 1 of 2 protein supplementation treatments, receiving either 0.0 or 0.3 kg of a high-RUP protein supplement (Soy Pass, LignoTech USA Inc., Rothschild, WI) per day. Within supplementation treatment, pens were randomly assigned to 1 of 4 forage treatments, which were applied in a 4×4 Latin square design for 10-d periods. Forage treatments included the following percentages of orchardgrass:alfalfa dry matter: 25:75, 50:50, 75:25, and 100:0. No interactions were observed between supplement and forage treatments. Supplementation with a high-RUP source tended to increase milk yield by 9%. Milk yield, milk protein yield, milk urea N, and urinary urea N excretion increased linearly with increased percentage of alfalfa. Milk N efficiency was greatest on the 100% orchardgrass diet. In a grazing trial, 12 multiparous dairy ewes in mid lactation were randomly assigned to 3 groups of 4 ewes each. Within group, 2 ewes were randomly assigned to receive either 0.0 or 0.3 kg of a high-RUP protein supplement (SoyPlus, West Central Cooperative, Ralston, IA) per day. Grazing treatments were arranged in a 3×3 Latin square design and applied to groups for 10-d periods. Ewes grazed paddocks that contained the following percentages of surface area of pure stands of orchardgrass:alfalfa: 50:50, 75:25, and 100:0. No interactions were found between supplement and forage treatments. Milk yield, milk protein yield, and milk urea N increased linearly with increased percentage of alfalfa in the paddock. In conclusion, supplementing with high-RUP protein tended to increase milk yield and increasing the proportion of alfalfa in the diet increased dry matter intake, milk yield, and protein yield of lactating dairy ewes fed or grazing fresh forage.

Feed delivery method affects the learning of feeding and competitive behavior in dairy heifers.

The objective of this study was to determine how different feeding methods may affect the learning of feeding, sorting, and competitive behavior of growing dairy heifers. We hypothesized that heifers previously fed a total mixed ration (TMR) would distribute their feeding time more evenly throughout the day, sort the new ration less, compete less for feed, maintain a more solid fecal consistency, and continue to grow rapidly compared with heifers previously fed a top-dressed ration (TDR). Thirty-two Holstein heifers (237.2+/-21.9 d of age) were divided into 8 groups of 4 and exposed to 1 of 2 treatments for 13 wk: 1) TMR or 2) TDR, with each containing 65% grass/alfalfa haylage and 35% textured concentrate on a dry matter (DM) basis. Following this feeding period, all heifers were switched to an unfamiliar TMR containing 56.1% grass/alfalfa haylage, 21.0% corn silage, 21.0% high-moisture corn, and 1.9% mineral supplement (DM basis) for 7 wk. Group DM intakes were recorded daily throughout the experiment. Feeding behavior, recorded using time-lapse video, and sorting behavior were measured for 7 d during wk 1, 4, and 7 after the dietary change. Feeding competition was measured on d 2, 4, and 6 of each recording week. Sorting activity was determined through particle size analysis of the fresh feed and orts. The particle size separator separated feed into 4 fractions (long, medium, short, and fine). Sorting of each fraction was calculated as actual intake expressed as a percentage of predicted intake. Animals were scored for fecal consistency twice weekly, using a scale from 1 (liquid) to 4 (solid). Heifers were weighed every 2 wk. Neither DM intake (9.0 kg/d) nor average daily gain (1.2 kg/d) differed between treatments. Sorting also did not differ between treatments. Heifers tended to spend more time feeding if they had previously been fed a TDR (198.8 vs. 186.8 min/d). As they had done before the dietary change, heifers previously fed the TDR spent more time at the bunk in the 2h following feed delivery (40.6 vs. 25.9 min/d). Heifers previously fed the TDR were displaced from the feed bunk more frequently than heifers previously fed the TMR (23.0 vs. 13.1 times/d), particularly during the 2-h period following feed delivery. Fecal scores were lower (more fluid in consistency) for heifers originally fed the TDR (3.2 vs. 3.7). The continued difference in feed bunk competition suggests that heifers previously fed the TDR had learned these patterns in the past, retaining them even when switched to an unfamiliar ration. Furthermore, lower fecal scores for heifers previously fed the TDR suggest altered rumen fermentation, possibly because of altered diurnal consumption patterns. These results show that feeding a TMR to replacement dairy heifers from a young age promotes a more even diurnal feeding pattern, minimizes feed bunk competition, and promotes a more solid fecal consistency.

Feeding heat-treated colostrum to neonatal dairy heifers: effects on growth characteristics and blood parameters.

Newborn Holstein heifer calves were studied to compare absorption of immunoglobulin G (IgG(1) and IgG(2)), total serum protein concentration, lymphocyte counts, health scores, growth, and starter intake after receiving unheated or heat-treated colostrum. First-milking colostrum was collected from Holstein cows and frozen at -20 degrees C to accumulate a large batch. After thawing and mixing, half of the colostrum was transferred into 1.89-L plastic containers and frozen at -20 degrees C until needed for feeding. The remaining half was heated at 60 degrees C for 30 min, transferred into 1.89-L plastic containers, and then frozen at -20 degrees C until needed for feeding. Forty heifer calves weighing > or =32 kg at birth were enrolled into 1 of 2 treatment groups before suckling occurred. For the first feeding, 3.8 L of colostrum was bottle fed by 1.5 to 2 h of age. For the second and third feedings, pasteurized whole milk at 5% of birth body weight (BW) was fed. Subsequently, calves received milk replacer containing 20% crude protein and 20% fat at 10% of birth BW/d until wk 5. Milk replacer was reduced to 1 feeding of 5% birth BW until weaning at 6 wk of age. Blood samples and growth data were collected through wk 8. Batch heat-treatment of colostrum at 60 degrees C for 30 min lowered colostrum bacteria concentration while maintaining colostral IgG concentration and viscosity. Calves fed heat-treated colostrum had significantly greater IgG concentrations at 24 h and greater apparent efficiency of IgG absorption (IgG = 23.4 g/L; apparent efficiency of absorption = 33.2%) compared with calves fed unheated colostrum (IgG = 19.6 g/L; apparent efficiency of absorption = 27.7%). There was no difference between treatment groups in growth measurements, calf starter intake, lymphocyte counts, or health scores.