The effect of different levels of spring grass supply and stocking rate on the performance and intake of cows in early lactation

End of project reportGrazed herbage can supply nutrients to dairy cows at a lower cost than alternative feeds (Shalloo et al., 2004). Therefore, the objective of pasture-based systems must be to maximize the proportion of grazed grass in the diet of the dairy cow (Dillon et al., 2005). The extension of the grazing season into the early spring period can be facilitated by ceasing grazing of pastures earlier in autumn which allows grass to accumulate, thereby ensuring an adequate herbage supply in early spring when animal demand exceeds grass growth/supply (O’Donovan, 2000). Grazing pastures in early spring has previously been shown to increase herbage utilization and condition swards for subsequent grazing rotations (O’Donovan et al., 2004; Kennedy et al., 2006)

A Comparison between Simulated Grazing, 2-Cut and 3-Cut Silage Management on the Performance of \u3cem\u3eLolium perenne\u3c/em\u3e L.

Internationally, the majority of grass cultivar evaluation protocols test the performance of cultivars under cutting managements with little or no exposure to animal stresses such as treading and plant pulling. In addition, the majority of these protocols test cultivars under 2 or 3 cut silage systems. Gilliland and Mann (2000) reported a difference in cultivar ranking between years and also between management systems when a severe (simulated grazing to 3 cm height) or lax (6 cm height) defoliation was applied to perennial ryegrass (Lolium perenne L.) cultivars in plot trials. Internationally, many evaluation protocols use only one management system within the protocol, whereby defoliation height is constant. If the protocol applied is not similar to the grazing manage-ment imposed at farm level, then it is unclear if the protocol can identify the cultivars which are most suitable to a particular production system

Effect of feed allowance at pasture on the lying behaviour of dairy cows

peer-reviewedIn temperate climates where cows are primarily managed at pasture shortages of grass could result in nutritional deficits for the cow and may have a variety of behavioural consequences. Lying behaviour is one of the most researched aspects of dairy cow behaviour, and can provide insights into cow welfare and physiological state. This study investigated the effect of daily herbage allowance (DHA) on the lying behaviour of dairy cow during early lactation. Ninety-six cows were randomly assigned to one of eight treatments in a 2 × 4 factorial design; experimental duration (2 week (2 W) or 6 week (6 W)), and nutritional levels (DHA) (60%, 80%, 100% or 120% of intake capacity). Cows were assigned to treatment at 28 ± 8.4 days in milk, and lying behaviour of cows in the 6 W treatments recorded using modified voltage data loggers on 4 occasions; the week prior to the start of the experiment, during week 3 (MID), and week 6 (LATE), and 7 weeks after the study concluded (POST), when the cows were all returned to a feed allowance of 100% intake capacity. Although there was an effect of treatment on daily lying time (P < 0.01), with the 60% cows spending less time lying than the 120% (P < 0.01), cows in all treatments spent at least 9 h lying per day throughout the experiment. Daily lying time increased as the grazing season progressed (P < 0.001). Feed allowance affected both lying bout duration (P < 0.01) and number (P < 0.05), with cows on the highest feed allowance having the highest values for both. There was an effect of feed allowance on the time that cows first lay down after both morning and afternoon milking (P < 0.001), with a similar pattern for both times; the lower the feed allowance, the longer it took. During the POST period, this pattern was no longer evident in the afternoon, but still present in the morning. None of the treatments imposed resulted in daily lying times lower than those reported in other studies at pasture. However, the significant differences in patterns of lying during the day could be reflective of satiety level; the patterns of lying in cows with a low feed allowance compared to those with an allowance aligned with intake capacity are in agreement with previous research. Herd level recording of lying behaviour, relative to time since milking and/or fresh feed allocation, has potential for use as an animal welfare indicator for cows at pasture

An observational study using blood gas analysis to assess neonatal calf diarrhea and subsequent recovery with a European Commission-compliant oral electrolyte solution

peer-reviewedAn observational study was conducted on dairy calves (51 healthy, 31 with neonatal diarrhea) during outbreaks of diarrhea on 4 dairy farms. Clinical assessment scores (CAS) were assigned to each healthy and diarrheic calf [from 0 (healthy) to 4 (marked illness)]. Blood gas analysis [pH, base excess (BE), Na+, K+, Ca2+, Cl−, glucose, total hemoglobin, standard HCO3−, strong ion difference (SID), and anion gap (AG)] was completed for each calf. Repeated measurements were taken in healthy animals, and pre- and postintervention measurements were taken for diarrheic calves. The mean CAS of diarrheic calves was 1.7, with 51, 30, 17, and 2% of calves scoring 1, 2, 3, and 4, respectively. The mean value for blood pH, BE, AG, and SID was 7.26, −4.93 mM, 16.3 mM, and 38.59 mM, respectively. Calves were administered an oral rehydration and buffering solution (ORBS; Vitalife for Calves, Epsilion Ltd., Cork, Ireland) and reassessed. The mean CAS decreased to 0.38 (65% of calves scored 0 and 35% scored 1) at 6 to 18 h posttreatment and to 0.03 (98% of calves scored 0 and 2% scored 1) within 24 to 48 h. Significant increases in mean value for pH, BE, HCO3−, Na+, and SID, and significant decreases in AG, K+, Ca2+, and total hemoglobin were recorded posttreatment. The correlation estimates indicated that pH, HCO3−, and BE were strongly correlated with CAS, with values exceeding 0.60 in all cases. Administration of an ORBS with a high SID and bicarbonate buffer demonstrated rapid recovery from a diarrheic episode in dairy calves

An investigation into the effects of different starts to the grazing season on sward structure and sward dynamics and dairy cow performance during the grazing season.

End of Project ReportSummary and Implications •Cows outdoors from mid February to early April offered an 80:20 grazed grass concentrate diet produced similar milk yield with higher protein yield and content compared to cows offered a 40:60 grass silage concentrate diet. •The improvement in animal performance is attributed to a higher energy, protein and total DM intake. •In the carryover period when both groups were grazing fulltime, the cows with early turnout had higher milk protein concentrations and higher grass DM intakes (1kg DM/cow/day) •An early grazed sward had a similar grass growth potential as a late grazed sward. •Herbage from early grazed swards have higher grass digestibility (OMD and UFL) value than late grazed swards •A lower daily herbage allowance can be tolerated with early grazed swards to achieve similar milk production performance as from late grazed swards. Up to 5-6 kg grass DM of late grazed swards will achieve the same level of milk production from early grazed swards. •With late turnout allocating high daily herbage allowance with large pre -grazing herbage mass is wasteful and compounds the effects of poor grass utilisation and undergrazing. •Early grazing is recommended when conditions allow even on heavy soil types. •From mid April onwards the optimum-stocking rate on early grazed swards is between 4.0 - 4.5 cows/ha. At this stocking rate a balance is found between feeding the cow adequately at pasture and achieving the correct post - grazing residuals. •Grass dry matter intake was significantly higher for the early grazed medium stocked cows in both studies, which clearly shows that the improvements in sward quality with early grazed swards can be converted to higher dairy cow performance. •Cows grazing the early grazed sward at a medium stocking rate had higher milk production performance which persisted in subsequent grazing rotations. This was due to the higher quality herbage available with the lower herbage mass swards. •When modelled to the whole farm system the reduced feed cost and higher performance achieved with early grazing, resulted in each extra day at grass increasing cow profitability by €2.70 cow/da

Comparison of rapid laboratory tests for failure of passive transfer in the bovine

peer-reviewedBackground Failure of passive transfer of maternal immunity via colostrum can occur in the bovine, and a number of blood tests have been developed to test calves for this failure. It is not clear which test is most suitable for this purpose. The objective was to examine the most commonly used tests for failure of passive transfer and to decide which is most suitable for routine laboratory use. 126 serum samples were taken from calves of dairy cows after birth but prior to colostrum feeding, and at 48 h of age. Five different tests were compared against radial immunodiffusion which is considered the appropriate reference method. These tests were serum gamma-glutamyltransferase levels, serum protein levels, serum globulin levels, an enzyme linked immunosorbent assay and the zinc sulphate turbidity test. Results The tests examined displayed high sensitivity but widely varying specificity. Examination of the use of different cut-off points allowed some improvement in specificity at the expense of sensitivity, but the tests which had performed best at the original cut-off points still displayed the best performance. Gamma-glutamyltransferase levels as a measure of colostrum absorption returned, in this study, the best balance between sensitivity and specificity. The ELISA used in this study and serum globulin levels displayed performance similar to the gamma-glutamyltransferase levels. Serum total protein was less successful than others examined at providing both sensitivity and specificity but may, when performed via refractometer, be useful for on-farm testing. As currently performed the poor sensitivity for which the zinc sulphate turbidity test is most often criticized is evident. Modification of the cut-off point to increase specificity is less successful at balancing these parameters than the ELISA, gamma-glutamyltransferase levels, and globulin levels. Conclusions Gamma-glutamyltransferase levels, ELISA testing and circulating globulin levels performed best in detecting failure of passive transfer in serum samples, although all three had some practical considerations

Effects of Diet during the First Winter on Replacement Heifer Weight Gain and Body Condition Score during the Subsequent Grazing Season

In seasonal calving dairy production systems it is important that heifers attain puberty in an appropriate timeframe especially when they are bred to calve at 2 years of age and in systems that impose restricted breeding periods (Ferrell, 1982). Achieving target weights at key time points is critical because, for example, the onset of puberty usually occurs in dairy heifers at 30-40% of their expected mature BW (Heinrichs 1993) which corresponds to approximately 240-320 kg in Holstein heifers. Furthermore, heifers should be managed to achieve 55% to 60% of mature bodyweight (BW) at mating start date (MSD; Patterson et al. 1992). Archbold et al. (2012) has shown that both heifer BW and body condition score (BCS) at MSD are positively associated with calving date and potential milk fat plus milk protein yield when they enter the lactating herd. Heifer rearing is the second largest expense in the dairy system, accounting for approximately 20% of total costs (Gabler et al. 2000). Therefore, it is necessary to focus on reducing costs of production, particularly feed costs, as they account for approximately 80% of total variable costs (Shalloo et al., 2004). One of the methods of reducing feed costs in particular, is by sourcing lower cost feeds. Finneran et al. (2010) reported that kale grazed in-situ ranked as the cheapest alternative to grazed grass and was considerably cheaper than grass silage. Kale has higher crude protein (CP) content than grass silage (Keogh et al. 2009) and may be suitable for inclusion in the diet of replacement dairy heifers. However, kale also tends to have a low neutral-detergent fibre (NDF) concentration (Keogh et al. 2009) suggesting that feeds with a higher NDF concentration (\u3e 500 g/kg DM), such as silage may need to be offered in order to avoid acidosis. The objectives of this study were to i) investigate five contrasting winter feeding regimes on heifer bodyweight (BW) gain and body condition score (BCS), ii) establish if similar BW gain is achieved from a kale only diet compared to a kale + grass silage diet and iii) determine if compensatory growth during the following grazing season exists in replacement heifer rearing systems

Identification of possible cow grazing behaviour indicators for restricted grass availability in a pasture-based spring calving dairy system

peer-reviewedPrecision livestock farming uses biosensors to measure different parameters of individual animals to support farmers in the decision making process. Although sensor development is advanced, there is still little implementation of sensor-based solutions on commercial farms. Especially on pasture-based dairy systems, the grazing management of cows is largely not supported by technology. A key factor in pasture-based milk production is the correct grass allocation to maximize the grass utilization per cow, while optimizing cow performance. Currently, grass allocation is mostly based on subjective eye measurements or calculations per herd. The aim of this study was to identify possible indicators of insufficient or sufficient grass allocation in the cow grazing behaviour measures. A total number of 30 cows were allocated a restricted pasture allowance of 60% of their intake capacity. Their behavioural characteristics were compared to those of 10 cows (control group) with pasture allowance of 100% of their intake capacity. Grazing behaviour and activity of cows were measured using the RumiWatchSystem for a complete experimental period of 10 weeks. The results demonstrated that the parameter of bite frequency was significantly different between the restricted and the control groups. There were also consistent differences observed between the groups for rumination time per day, rumination chews per bolus and frequency of cows standing or lying