• Cow welfare in grass based milk production systems

      Boyle, Laura; Olmos, G.; Llamas Moya, S.; Palmer, M.A.; Gleeson, David E; O'Brien, Bernadette; Horan, Brendan; Berry, Donagh; Arkins, S.; Alonso Gómez, M.; et al. (Teagasc, 2008-08-01)
      Under this project, aspects of pasture based milk production systems, namely different milking frequency and feeding strategies as well as genetic selection for improved fitness using the Irish Economic Breeding Index (EBI) were evaluated in terms of dairy cow behaviour, health, immune function and reproductive performance. Additionally, a typical Irish pasture based system was compared to one in which cows were kept indoors in cubicles and fed a total mixed ration for the duration of lactation in order to elucidate the perceived benefits of pasture based systems for dairy cow welfare.
    • Effect of genetic group and feed system on locomotion score, clinical lameness and hoof disorders of pasture-based Holstein–Friesian cows

      Olmos, G.; Boyle, Laura; Horan, Brendan; Berry, Donagh; O'Connor, Paula M.; Mee, John F; Hanlon, A. (Cambridge University Press, 2009-01)
      The aim of the present study was to determine the effect of the genetic group of the Holstein–Friesian (HF) and pasture-based feeding system (3 × 2 factorial arrangement) on locomotion score (six gait aspects scored from one to five), clinical lameness and hoof disorders within a seasonal calving milk production system. The three genetic groups compared had an average Economic Breeding Index (EBI) value of 40, 70 and 80: representing the Irish national average genetic merit (LOW-NA), high EBI genetic merit of North American ancestry (HIGH-NA) and high EBI genetic merit of New Zealand ancestry (HIGH-NZ), respectively. Two feed systems were compared: a high grass allowance, low-concentrate system typical of spring-calving herds in Ireland (control) and a high-concentrate system. Data from 126 cows collected across a complete lactation period were analysed using generalised estimating equations and survival analysis. Genetic group of HF had a significant effect on locomotion score, clinical lameness and hoof disorders. Higher EBI cows (HIGH-NA and HIGH-NZ) had lower hazard of poor locomotion score in some gait aspects (e.g. spine curvature) and lower odds of clinical lameness in the first 200 days post-calving (Odds ratios 0.08 and 0.24, respectively, relative to the LOW-NA) and some hoof disorders (e.g. traumatic lesions) compared with LOW-NA cows. The high-concentrate feed system showed a higher incidence and severity of digital dermatitis (P < 0.01). Thus, high EBI cows have better locomotion, fewer cases of clinical lameness and less-severe hoof disorders (i.e. digital dermatitis, white line disease and traumatic lesions) than low EBI cows. These findings have important implications for cow welfare and productivity.
    • The effect of Holstein-Friesian genotype and feeding system on selected performance parameters of dairy cows on grass-based systems of milk production in Ireland

      Dillon, Pat; O’Connor, Paula M.; McCarthy, S.; Shalloo, Laurence; Linnane, M.; Berry, Donagh; Buckley, James F.; Mee, John F; Horan, Brendan (Teagasc, 2006-01-01)
      The overall objective of this project was to assess, the effect of strain of Holstein-Friesian dairy cow, pasture-based feed system (FS) and their interaction on animal performance in terms of milk productivity and lactation profile, body weight (BW), body condition score (BCS), feed intake and energy balance (EB), reproductive performance and overall economic profitability.
    • The effect of Holstein-Friesian genotype and feeding system on selected performance parameters of dairy cows on grass-based systems of milk production in Ireland.

      Dillon, Pat; O'Connor, Paula M.; McCarthy, Sean D.; Shalloo, Laurence; Linnane, M.; Berry, Donagh; Buckley, Frank; Mee, John F; Horan, Brendan (Teagasc, 2006-01-01)
      The overall objective of this project was to assess, the effect of strain of Holstein-Friesian dairy cow, pasture-based feed system (FS) and their interaction on animal performance in terms of milk productivity and lactation profile, body weight (BW), body condition score (BCS), feed intake and energy balance (EB), reproductive performance and overall economic profitability.
    • Effect of Holstein–Friesian genetic group on peripartum and early lactation haematological and acute phase proteins profiles, health and fertility

      Olmos, G.; Boyle, Laura; Horan, Brendan; Berry, Donagh; Sayers, Riona; Hanlon, A.; Mee, John F (Cambridge University Press, 2009-07)
      Pasture-based Holstein–Friesian cows from three genetic groups differing in the Irish ‘Economic Breeding Index’ (EBI) value and genetic background, namely North-American (NA) national average EBI genetic merit (LOW-NA, n542), North-American high EBI genetic merit (HIGH-NA, n542) and New Zealand (NZ) high EBI genetic merit (HIGH-NZ, n542), were studied. These genetic groups have been selected in different environments: pasture for NZ and confinement for NA. The objective was to determine the effect of genetic group on haematological and acute phase proteins profiles (white blood cell (WBC) counts, red blood cell (RBC) counts, acute phase proteins: serum amyloid A (SAA) and haptoglobin), health (rectal temperature (RT), clinical mastitis (CM) and somatic cell score), calving performance (stillbirth, calving assistance) and post-partum reproductive parameters (endometritis and ovarian cyclicity). Blood sampling and data recording took place 3 weeks pre-calving up to 7 weeks post-calving. Linear mixed models, logistic regression and generalised estimating equations were used for data analysis. HIGH-NZ animals had the highest ( P,0.05) RBC mean corpuscular volume (50.0 fl), exhibited a different WBC distribution pattern ( P,0.05) and had the lowest ( P,0.05) mean RT (38.48C) for the first 10 days post-calving. These findings suggest enhanced reticulocyte turnover, peripartum response mechanisms and thermoregulation in the HIGH-NZ compared to the other two genetic groups. LOW-NA animals had the highest SAA peak throughout the peripartum period (55.12 mg/l, P,0.05) and a tendency for higher somatic cell scores ( P,0.10) in early lactation. The HIGH-NA animals had the lowest incidence of udder quarter milk sample bacteria at calving, suggesting better udder health when commencing lactation. No differences were detected between genetic groups in calving performance, post-partum reproductive parameters or CM in the first 42 days post-calving. These results suggest that while inherited peripartum adaptation strategies have been developed by the different genetic groups selected in different environments (pasture5NZ v. confinement5NA), such differences have minimal impact on peripartum clinical health.
    • Effect of stocking rate and animal genotype on dry matter intake, milk production, body weight, and body condition score in spring-calving, grass-fed dairy cows

      Coffey, E. L.; Delaby, Luc; Fitzgerald, S.; Galvin, Norann; Pierce, K.M.; Horan, Brendan; Dairy Research Ireland (Elsevier, 2017-06-28)
      The objective of the experiment was to quantify the effect of stocking rate (SR) and animal genotype on milk production, dry matter intake (DMI), energy balance, and production efficiency across 2 consecutive grazing seasons (2014 and 2015). A total of 753 records from 177 dairy cows were available for analysis: 68 Holstein-Friesian and 71 Jersey × Holstein-Friesian (JxHF) cows each year of the experiment under a pasture-based seasonal production system. Animals within each breed group were randomly allocated to 1 of 3 whole-farm SR treatments defined in terms of body weight per hectare (kg of body weight/ha): low (1,200 kg of body weight/ha), medium (1,400 kg of body weight/ha), and high (1,600 kg of body weight/ha), and animals remained in the same SR treatments for the duration of the experiment. Individual animal DMI was estimated 3 times per year at grass using the n-alkane technique: March (spring), June (summer), and September (autumn), corresponding to 45, 111, and 209 d in milk, respectively. The effects of SR, animal genotype, season, and their interactions were analyzed using mixed models. Milk production, body weight, and production efficiency per cow decreased significantly as SR increased due to reduced herbage availability per cow and increased grazing severity. As a percentage of body weight, JxHF cows had higher feed conversion efficiency, higher DMI and milk solids (i.e., kg of fat + kg of protein) production, and also required less energy intake to produce 1 kg of milk solids. The increased production efficiency of JxHF cows at a similar body weight per hectare in the current analysis suggests that factors other than individual cow body weight contribute to the improved efficiency within intensive grazing systems. The results highlight the superior productive efficiency of high genetic potential crossbred dairy cows within intensive pasture-based milk production systems at higher SR where feed availability is restricted.
    • Factors associated with the financial performance of spring-calving, pasture-based dairy farms

      Ramsbottom, George; Horan, Brendan; Berry, Donagh; Roche, John R. (Elsevier for American Dairy Science Association, 2015-03)
      As land becomes a limiting resource for pasture-based dairy farming, the inclusion of purchased supplementary feeds to increase milk production per cow (through greater dry matter intake) and per hectare (through increased stocking rate) is often proposed as a strategy to increase profitability. Although a plausible proposition, virtually no analysis has been done on the effect of such intensification on the profitability of commercial pasture-based dairy farm businesses. The objective of this study was to characterize the average physical and financial performance of dairy systems differing in the proportion of the cow’s diet coming from grazed pasture versus purchased supplementary feeds over 4 yr, while accounting for any interaction with geographic region. Physical, genetic, and financial performance data from 1,561 seasonal-calving, pasture-based dairy farms in Ireland were available between the years 2008 and 2011; data from some herds were available for more than 1 yr of the 4-yr study period, providing data from 2,759 dairy farm-years. The data set was divided into geographic regions, based on latitude, rainfall, and soil characteristics that relate to drainage; these factors influence the length of the pasture growth season and the timing of turnout to pasture in spring and rehousing in autumn. Farms were also categorized by the quantity of feed purchased; farms in which cows received <10, 11–20, 21–30, or >30% of their annual feed requirements from purchased feed were considered to be categories representative of increasing levels of system intensification. Geographic region was associated with differences in grazing days, pasture harvested per hectare, milk production per cow and per hectare, and farm profitability. Farms in regions with longer grazing seasons harvested a greater amount of pasture [an additional 19 kg of dry matter (DM)/ha per grazing day per hectare], and greater pasture harvested was associated with increased milk component yield per hectare (58.4 kg of fat and 51.4 kg of protein more per tonne of DM pasture harvested/ha) and net profit per hectare (€268/ha more per tonne of DM harvested). Milk yield and yield of milk components per cow and per hectare increased linearly with increased use of purchased feed (additional 30.6 kg of milk fat and 26.7 kg of milk protein per tonne of DM purchased feed per hectare), but, on average, pasture harvested/hectare and net profit/hectare declined (−0.60 t of DM/ha and −€78.2/ha, respectively) with every tonne of DM supplementary feed purchased per hectare. The results indicate an effect of purchased feeds not usually accounted for in marginal economic analyses (e.g., milk to feed price ratio): the decline in pasture harvested/hectare, with the costs of producing the unutilized pasture in addition to the cost of feed resulting in a lower profit. In conclusion, greater milk component yields per cow were associated with increased profit per hectare, and a greater use of purchased feeds was associated with an increase in the yield of milk components. However, on average, increasing yield of milk components through the supply of purchased feeds to pasture-based cows was associated with a decline in pasture harvested per hectare and profitability. The decline in pasture harvested per hectare with increased use of purchased supplements per cow is probably the primary reason for the low milk production response and the failure to capitalize on the potential benefits of purchased supplements, with the associated costs of growing the unutilized pasture, in conjunction with increased nonfeed variable and fixed costs outweighing the increased milk production and revenue from supplementation. Farmers considering intensification through use of purchased supplements to increase the stock-carrying capacity of the farm (i.e., stocking rate) must ensure that they focus on management of pasture and total cost control to capture the potential benefits of supplementary feed use.
    • Milk production of Holstein-Friesian cows of divergent Economic Breeding Index evaluated under seasonal pasture-based management

      O'Sullivan, Margaret; Horan, Brendan; Pierce, Karina M.; McParland, Sinead; O'Sullivan, Kathleen; Buckley, Frank (Elsevier, 2019-01-03)
      The objective of this study was to validate the effect of genetic improvement using the Irish genetic merit index, the Economic Breeding Index (EBI), on total lactation performance and lactation profiles for milk yield, milk solids yield (fat plus protein; kg), and milk fat, protein, and lactose content within 3 pasture-based feeding treatments (FT) and to investigate whether an interaction exists between genetic group (GG) of Holstein-Friesian and pasture-based FT. The 2 GG were (1) extremely high EBI representative of the top 5% nationally (referred to as the elite group) and (2) representative of the national average EBI (referred to as the NA group). Cows from each GG were randomly allocated each year to 1 of 3 pasture-based FT: control, lower grass allowance, and high concentrate. The effects of GG, FT, year, parity, and the interaction between GG and FT adjusted for calving day of year on milk and milk solids (fat plus protein; kg) production across lactation were studied using mixed models. Cow was nested within GG to account for repeated cow records across years. The overall and stage of lactation-specific responses to concentrate supplementation (high concentrate vs. control) and reduced pasture allowance (lower grass allowance vs. control) were tested. Profiles of daily milk yield, milk solids yield, and milk fat, protein, and lactose content for each week of lactation for the elite and NA groups within each FT and for each parity group within the elite and NA groups were generated. Phenotypic performance was regressed against individual cow genetic potential based on predicted transmitting ability. The NA cows produced the highest milk yield. Milk fat and protein content was higher for the elite group and consequently yield of solids-corrected milk was similar, whereas yield of milk solids tended to be higher for the elite group compared with the NA group. Milk lactose content did not differ between GG. Responses to concentrate supplementation or reduced pasture allowance did not differ between GG. Milk production profiles illustrated that elite cows maintained higher production but with lower persistency than NA cows. Regression of phenotypic performance against predicted transmitting ability illustrated that performance was broadly in line with expectation. The results illustrate that the superiority of high-EBI cattle is consistent across diverse pasture-based FT. The results also highlight the success of the EBI to deliver production performance in line with the national breeding objective: lower milk volume with higher fat and protein content.
    • Relationship between dairy cow genetic merit and profit on commercial spring calving dairy farms

      Ramsbottom, George; Cromie, A. R.; Horan, Brendan; Berry, Donagh (Cambridge University Press, 2011-12)
      Because not all animal factors influencing profitability can be included in total merit breeding indices for profitability, the association between animal total merit index and true profitability, taking cognisance of all factors associated with costs and revenues, is generally not known. One method to estimate such associations is at the herd level, associating herd average genetic merit with herd profitability. The objective of this study was to primarily relate herd average genetic merit for a range of traits, including the Irish total merit index, with indicators of performance, including profitability, using correlation and multiple regression analyses. Physical, genetic and financial performance data from 1131 Irish seasonal calving pasture-based dairy farms were available following edits; data on some herds were available for more than 1 year of the 3-year study period (2007 to 2009). Herd average economic breeding index (EBI) was associated with reduced herd average phenotypic milk yield but with greater milk composition, resulting in higher milk prices. Moderate positive correlations (0.26 to 0.61) existed between genetic merit for an individual trait and average herd performance for that trait (e.g. genetic merit for milk yield and average per cow milk yield). Following adjustment for year, stocking rate, herd size and quantity of purchased feed in the multiple regression analysis, average herd EBI was positively and linearly associated with net margin per cow and per litre as well as gross revenue output per cow and per litre. The change in net margin per cow per unit change in the total merit index was h1.94 (s.e.50.42), which was not different from the expectation of h2. This study, based on a large data set of commercial herds with accurate information on profitability and genetic merit, confirms that, after accounting for confounding factors, the change in herd profitability per unit change in herd genetic merit for the total merit index is within expectations.