The effect of grazing pressure on rotationally grazed pastures in spring/early summer on subsequent sward characteristics

peer-reviewedTwo experiments (E1 and E2) were carried out to examine the effect of grazing pressure (GP) in the early part of the grazing season on subsequent sward composition. Three GP levels, equating to 6.35, 4.24 and 3.53 cows/ha in E1, and 6.06, 5.05 and 4.03 cows/ha in E2, were used. The GP treatments were applied between April and July in E1, and April and June in E2. As GP decreased different swards, termed high (HQ), medium (MQ) and low (LQ) quality, were created. The post-grazing sward heights at the end of the GP periods were 6.6, 10.5 and 14.6 (s.e. 0.78) cm in E1, and 5.9, 8.8 and 11.4 (s.e. 0.39) cm in E2, for HQ, MQ and low LQ, respectively. Organic matter digestibility coefficients for herbage from the HQ, MQ and LQ swards during the subsequent grazing cycles averaged 0.770, 0.729 and 0.702 (s.e. 0.0055) in E1, and 0.761, 0.731 and 0.711 (s.e. 0.0038) in E2, respectively. Average live leaf proportions of the HQ, MQ and LQ swards were 0.583, 0.427 and 0.329 (s.e. 0.0193) in E1, and 0.600, 0.474 and 0.362 (s.e. 0.0155) in E2, respectively. GP had a significant effect on the proportion of grass area categorised as short grass (SG). The proportions of SG area in HQ, MQ and LQ were 0.711, 0.579 and 0.445 (s.e. 0.0106), respectively, in E1, and 0.700, 0.556 and 0.441 (s.e. 0.0133), respectively, in E2. Pre-grazing herbage mass (dry matter above 45 mm) was 2,065, 2,736 and 3,700 (s.e. 144.1) kg/ha for HQ, MQ and LQ, respectively, in E1 and 2,688, 3,735 and 4,722 (s.e. 145.0) kg/ha for HQ, MQ and LQ, respectively, in E2. The results show the importance of early season grazing pressure in creating a leafy high-digestibility sward for the remainder of the grazing season

The effect of grazing pressure on rotationally grazed pastures in spring/early summer on the performance of dairy cows in the summer/autumn period

peer-reviewedTwo experiments (E1 and E2) were carried out to examine the effects of sward type (ST) on dairy cow performance. Applying grazing pressures (GP) in spring/early summer of 6.35, 4.24 and 3.53 cows/ha in E1, and 6.06, 5.05 and 4.03 cows/ha in E2, created the different ST. From summer to autumn, two stocking rates (SR) were applied to each sward, i.e., high (HR) and low (LR). As GP was reduced, the swards were characterised by progressively higher herbage mass of lower organic matter digestibility (OMD) and live leaf (LL) proportion, termed high (HQ), medium (MQ) and low (LQ) quality. There was no interaction between ST and SR for any animal performance variables except for grazing time. Mean diet OMD was 0.816, 0.803 and 0.794 (s.e. 0.0029) in E1, and 0.793, 0.780 and 0.772 (s.e. 0.0021) in E2, for HQ, MQ and LQ, respectively. The corresponding values for LL were 0.785, 0.740 and 0.709 (s.e. 0.0121) in E1, and 0.825, 0.790 and 0.759 (s.e. 0.0095) in E2. Milk yield per cow was 13.2, 12.2 and 10.6 (s.e. 0.55) kg in E1, and 18.4, 17.5 and 16.2 (s.e. 0.32) kg in E2, for HQ, MQ and LQ, respectively. Milk yields were 11.1 and 12.9 (s.e. 0.46) kg in E1, and 16.4 and 18.3 (s.e. 0.26) kg in E2, for HR and LR, respectively. There was no effect of ST or SR on milk composition or body weight gain. Herbage organic matter intake was 12.8, 12.5 and 11.1 (s.e. 0.28) kg in E2, for HQ, MQ and LQ, respectively. The corresponding values were 11.4 and 12.9 (s.e. 0.23) kg for HR and LR, respectively. The results show that milk yield of springcalving dairy cows is higher in summer when high rather than low stocking rates are applied in spring/early summer. The increased milk production is attributed to higher intake of herbage of higher nutritive value

The effect of herbage mass and allowance on herbage intake, diet composition and ingestive behaviour of dairy cows

peer-reviewedAn experiment was conducted to examine the effects of herbage mass [HM, based on regrowth intervals of 35 (T) and 21 (S) days] and herbage allowance [HA, 20.2 (H) and 12.7 (L) kg organic matter (OM)/cow] on herbage OM intake (OMI), dietary composition and ingestive behaviour of dairy cows. Four groups of three cows each were used in a 4 × 4 greco-latin square design along with four oesophageal-fistulated cows. The treatment periods were 7 days and the squares (SQ) were repeated three times in a balanced way. The experiment was conducted from 11 April to 3 July 1986. The HM (organic matter) above 3 cm was 3064, 3472 and 3515 kg/ha for T and 2395, 1113 and 2396 kg/ha (s.e. 94) for S, for SQ 1 to 3, respectively. Organic matter digestibility (OMD) was 842, 799 and 778 g/kg for T, and 851, 842 and 804 g/kg for S (s.e. 0.9), for SQ 1 to 3, respectively. Sward height (cm) after grazing was 8.5 and 7.6 for T and S, and 9.6 and 6.5 for H and L (s.e. 0.18), respectively. OMI was 15.2, 14.8 and 15.2 kg for TH, 12.3, 11.9 and 10.7 kg for TL, 15.8, 14.8 and 14.5 kg for SH and 11.9, 11.1 and 11.2kg for SL (s.e. 0.24), for SQ 1 to 3, respectively. The OMD of the diet was closely related to proportion of live leaf in the diet and sward OMD. Average biting rate increased with decreasing HM (R2 0.65). Grazing time was 8.93, 9.11 and 9.06 h for TH, 8.13, 7.96 and 7.91 h for TL, 8.96, 9.59 and 9.29 h for SH and 8.56, 9.36 and 8.52 h for SL (s.e. 0.155), for SQ 1 to 3, respectively. Multiple regression analysis showed that OMI was significantly related to HM (+0.48 kg/t), OMD of the sward (+0.18 kg per 10 g/kg) and pre-experimental milk yield (+0.37 kg/kg) (R2 0.89). The increase in OMI with potential milk yield, as indicated by pre-experimental yield, accounted for 0.80 of the supplementary energy requirements.National Development Plan 2000-200

Comparison of breed of dairy cow under grass-based spring milk production systems

End of project reportThe objective of this study was to investigate the potential differences among different dairy cow breeds across two feeding systems on milk production, udder health, milking characteristics, body weight, body condition score, hormone parameters, ovarian function, survival and overall reproductive efficiency. The breeds investigated included Holstein-Friesian (HF), Montbéliarde (MB), Normande (NM), Norwegian Red (NRF) and Holstein- Friesian × Montbéliarde (MBX) and Holstein- Friesian × Normande (NMX). Selection within the HF breed has, until recently, been predominantly for milk production with little or no direct selection for functional traits other than those correlated with superior type. The MB and the NM have been simultaneously selected for both milk and beef production in the past. The NRF were imported as calves and come from a more balanced total merit index incorporating production and cow functionality since the early 1970s. The dairy cow breeds were grouped into blocks of two within breed groups and randomized across two spring-calving grass-based feeding systems: low concentrate feeding system (LC) and high concentrate feeding system (HC). Those on LC feeding system were offered approximately 530 kg/cow over the total lactation, while those on HC feeding system were offered approximately 1030 kg/cow

Development of an efficient milk production profile of the Irish dairy Industry

End of project reportFluctuation around milk price will be the biggest factor that the dairy industry will experience over the next number of years. This fluctuation is being driven by fluctuation on the world dairy markets. In the past, when intervention was a much bigger feature of the CAP regime, the fluctuation in world markets had little effect on the EU price. This was because the Intervention system bought product from the market when prices were depressed and placed products on the world market when the price rose. This in effect meant that the CAP regime was having a regulatory effect on the world market as well as the EU markets. An example of the type of fluctuation observed on the world market can be gleamed from the Fonterra milk price in 2006-2007 ($4.50/kg (MS) milk solid) versus 2007-2008 ($7.90/kg MS). This corresponds to a 76% increase in price in 1 year. For the Dairy Industry in Ireland to prosper under these conditions all sectors will be required to be as efficient as possible from the farm, processing and marketing sectors. This report deals with; (1) Milk payment (2) Optimum milk production systems and (3) Seasonality of milk supply. (1) Milk payment systems in Ireland currently do not adequately reward high solids quality milk. Virtually all milk payment systems include a positive constant which reward the production of volume rather than the production of protein and fat kilograms. The A+B-C system of milk payment would adequately reward the production of protein and fat while at the same time correcting for the volume related processing costs. (2) Optimum systems of milk production will be built around the maximization of grass utilization in the future. Grazed grass is the cheapest feed that can be fed to dairy cows. Stocking rates nationally are 1.74cows/Ha around the milking platform and therefore when dairy farms are expanding they should do so by increasing stocking rate. The inclusion of supplementary feeds will reduce profitability for the vast majority of dairy farmers and could only possibly lead to increases in profitability when coupled increases in stocking rate. (3) Grass based systems while substantially reducing costs at farm level result in a seasonal milk supply profile. This results in a reduced capacity utilization of the milk processing facilities as well as restricted product port folio. However the production of Winter milk will lead to significant cost increases at farm level and should only be encouraged if the specific product produced would be sufficient to cover the additional costs associated with over winter production. Within spring calving systems milk payment systems should be used to encourage an efficient milk supply profile with a mean compact calving date of mid February.Teagasc acknowledges with gratitude the support of Dairy Levy Funds and EU Structural Funds (FEOGA) in financing the research programme

Major management factors associated with the variation in reproductive performance of Irish dairy herds

End of project reportThe results highlight the importance of BCS in achieving good reproductive performance. The likelihood of reproductive success was best predicted by BCS around the time of breeding and, for cows calving in good BCS (3.0 or greater) the level of BCS loss between calving and first service. A low BCS pre-calving (3.5) results in excessive BCS loss (>0.5) post-calving. On the basis of these findings a pre-calving BCS of no greater than 3.25 is a sensible target for pasture-based spring calving systems in Ireland. It is necessary to maintain BCS at 2.75 or greater during the breeding season, and loss of body condition between calving and first service should be restricted to 0.5 BCS units.National Development Plan (NDP

An Evaluation of High Genetic Merit Cows Using Forage and Pasture-based Systems.

End of Project ReportThe rate of genetic improvement in Ireland up until the mid-80’s was low (approx. 0.5% per year) compared to North America where genetic merit for milk production was increasing by 1.5% per year (Funk, 1993). Since 1985 the rate of genetic improvement increased markedly to about 1.5% per year in 1992 (Coffey, 1992). This high rate of genetic progress has mostly been achieved through the importation of North American and European genetics. The relative merit of these sires has been obtained from the performance of their progeny in systems of milk production which differ greatly from those operated in Ireland. The term “high genetic index” (HGI) is used to describe a cow, which as a result of selection, is generally predisposed to produce significantly more milk than a cow of lower merit status. Studies from New Zealand have shown that cows of high “genetic index” at pasture, produce more milk (20 to 40%), consume more herbage (5 to 20%), were more efficient convertors of food into milk (10 to 15%) than lower merit cows (Holmes, 1988). However, these “high” genetic index cows would be considered “low” when compared to present-day genetics. Recent results from Langhill (Veerkamp et al., 1994) have shown that increasing genetic index results in major increases in feed efficiency, reflecting increases in milk yield with cows fed indoors on silage/concentrate diets. There is little information available on the performance of present-day HGI dairy cows, on seasonal calving, grass-based systems of milk productio

Measurement of Grassland Management Practice on Commercial Dairy Farms

End of Project ReportVisual assessment (>4 cm) was found to be the preferred method of pasture mass estimation. Grass budgeting with the use of grass cover measurement, was found to be the most effective aid to good grazing management. Closing farm grass cover in late November/early December should be 350 to 450 kg DM/ha with a range in covers of 200 to 900. Target farm grass covers of 550 to 600 kg DM/ha at turnout at stocking rate of 2.75 cow/ha. Pre-grazing yields at turnout should not be less than 1000 kg DM/ha, giving daily grass allowance of not less than 5 kg DM/cow. The available grass supply in Spring should be budgeted so as to finish the first grazing rotation between the 10th-20th April (grass supply equal grass demand). During the main grazing season (May to August), grazing grass cover should be maintained at 900 to 1000 kg DM/ha or 200 to 240 kg DM/cow. Pre-grazing yield should be maintained at 1800 to 2000 kg DM/ha, with post-grazing residuals at 150 to 200 kg DM/ha (5.5 to 6.5 cm post-grazing height). Stocking rates of greater than 4.5 cow/ha on the grazing area in May/June mostly resulted in inadequate grass supply at some periods over that time. Rotation length can be increased from 21 days in mid/late August to 35 days in late September, allowing grass cover to increase to 1100 to 1300 kg DM/ha. Last rotation should be 25 to 35 days, with first paddocks rested from the 10th to 15th October. Greater use of grass measurements at farm level will allow dairy farmers to obtain a greater proportion of the dairy herd’s feed demand from grazed grass, and higher cow performance.Teagasc acknowledge with gratitude the support of Irish Fertiliser Industries, FBD Trust and Dairy Levy Farmer Funds in the financing of this research project

Implementing biosecurity measures on dairy farms in Ireland

peer-reviewedDairy farms in Ireland are expanding in preparation for a new era of unrestricted milk production with the elimination of the European Union (EU) production quotas in 2015. Countries experiencing a changing agricultural demographic, including farm expansion, can benefit from documenting the implementation of on-farm biosecurity. The objectives of this study were to document and describe influences on biosecurity practices and related opinions on dairy farms. A representative response rate of 64% was achieved to a nationwide telesurvey of farmers. A 20% discrepancy was found between self-declared and truly ‘closed’ herds indicating a lack of understanding of the closed herd concept. Although >72% of farmers surveyed considered biosecurity to be important, 53% stated that a lack of information might prevent them from improving their biosecurity. Logistic regression highlighted regional, age, and farm-size related differences in biosecurity practices and opinions towards its implementation. Farmers in the most dairy cattle dense region were three times more likely to quarantine purchased stock than were their equivalents in regions where dairy production was less intense (P = 0.012). Younger farmers in general were over twice as likely as middle-aged farmers to implement biosecurity guidelines (P = 0.026). The owners of large enterprises were almost five times more likely to join a voluntary animal health scheme (P = 0.003), and were over three times more likely to pay a premium price for health accredited animals (P = 0.02) than were those farming small holdings. The baseline data recorded in this survey will form the basis for more detailed sociological and demographic research which will facilitate the targeting of future training of the farming community in biosecurity

Accuracy of predicting milk yield from alternative milk recording schemes

peer-reviewedThe effect of reducing the frequency of official milk recording and the number of recorded samples per test-day on the accuracy of predicting daily yield and cumulative 305-day yield was investigated. A control data set consisting of 58 210 primiparous cows with milk test-day records every 4 weeks was used to investigate the influence of reduced milk recording frequencies. The accuracy of prediction of daily yield with one milk sample per test-day was investigated using 41 874 testday records from 683 cows. Results show that five or more test-day records taken at 8-weekly intervals (A8) predicted 305-day yield with a high level of accuracy. Correlations between 305-day yield predicted from 4-weekly recording intervals (A4) and from 8-weekly intervals were 0.99, 0.98 and 0.98 for milk, fat and protein, respectively. The mean error in estimating 305-day yield from the A8 scheme was 6.8 kg (s.d. 191 kg) for milk yield, 0.3 kg (s.d. 10 kg) for fat yield, and −0.3 kg (s.d. 7 kg) for protein yield, compared with the A4 scheme. Milk yield and composition taken during either morning (AM) or evening (PM) milking predicted 24-h yield with a high degree of accuracy. Alternating between AM and PM sampling every 4 weeks predicted 305-day yield with a higher degree of accuracy than either all AM or all PM sampling. Alternate AM-PM recording every 4 weeks and AM + PM recording every 8 weeks produced very similar accuracies in predicting 305-day yield compared with the official AM + PM recording every 4 weeks