• Factors affecting body condition score, live weight and reproductive performance in spring-calving suckler cows

      Drennan, Michael J; Berry, Donagh (Teagasc, Oak Park, Carlow, Ireland, 2006)
      The objective was to identify factors affecting live weight (LW), body condition score (BCS), calving rate and calving interval in spring-calving suckler cows. A total of 925 records on 299 cows from the years 1987 to 1999 were used and the data were analyzed using mixed models and generalised estimating equations. Cows calving early in the year (< day 65 of the year) were significantly heavier at the start of winter, had greater BCS at the subsequent calving but lost most LW in winter. Despite having higher LW gain at pasture, annual LW gain of early-calving cows was lower than that of late-calving cows (> day 90 of the year). Trends in BCS were similar to LW but there was no effect of calving date on annual BCS change. Cows in parity 1, 2, 3 to 7 and >7 had initial LW of 523, 549, 614 and 623 kg, winter LW losses of 61, 52, 65 and 67 kg and LW gains at pasture of 81, 99, 94 and 75 kg, respectively. First parity animals had higher BCS at the start of winter but had greater BCS loss in winter and lower BCS gain at pasture than the other three parity groups. Overall pregnancy rate was 93.6% and was not affected by either previous calving date or cow parity. Mean calving interval was 367 days and was affected by previous calving date but there was no effect of either cow parity or previous calving difficulty. Mean calving interval for cows calving early, mid-season or late were 378, 364 and 353 days, respectively. The results show that good reproduction performance can be achieved in spring-calving suckler cows subjected to low feeding levels during the winter period but grazed on well-managed pasture in summer.
    • Quantification of cow milk yield and pre-weaning calf growth response in temperate pasture-based beef suckler systems: A meta-analysis

      Sapkota, D.; Kelly, A.K.; Crosson, Paul; White, R.R.; McGee, Mark; Teagasc Walsh Fellowship Programme (Elsevier, 2020-11)
      The objectives of this study were to quantitatively summarize factors associated with cow milk yield (MY) and calf growth response in pasture-based beef cow-calf suckler systems and to discern how cow genotype and parity influenced these responses. A dataset of 344 treatment mean observations was compiled from 69 studies that reported data on cow MY, and calf pre-weaning average daily live weight gain (ADG) and/or weaning weight (WW). Data were analysed using linear mixed effects models with study and region included as random effects. Models were developed for cow MY, calf ADG and WW response and each model was evaluated based on different model fit statistics. The final cow MY model included cow origin (Dairybeef or Beef), cow maturity (early-maturing (EM) or late-maturing (LM) genotypes) and parity. Dairybeef produced 35.4% more milk (8.64 vs. 6.38 kg/day) than Beef cows, and LM produced 20.9% more milk (8.20 vs. 6.78 kg/day) than EM genotypes (P < 0.001). Multiparous cows had a 14.8% higher MY (8.11 vs. 7.06 kg/day) compared to primiparous cows (P < 0.001). Lactation curve persistency was better (P < 0.05) for Beef and EM compared to Dairybeef and LM genotype cows, respectively. The final models of calf ADG and WW included cow origin, cow maturity and parity. Calves from Dairybeef and LM cows were 14 and 20 kg heavier (P < 0.001) at weaning (210-day adjusted) compared to those from Beef and EM genotype cows, respectively. Calves from multiparous cows were 13 kg heavier at weaning than those from primiparous cows (P < 0.001). The response in calf ADG associated with a 1 kg increase in cow daily MY was 47 and 53 g for Dairybeef and Beef cows, respectively (P < 0.001). Corresponding responses for EM and LM cows were 51 and 55 g (P < 0.001). In conclusion, the relationships between cow MY and calf pre-weaning growth, as well as the quantitative impact of cow genotype and parity were determined for pasture-based beef suckler systems; the coefficients generated can be used for improving beef cow-calf management strategies, beef cattle breeding programmes and bio-economic modelling purposes.
    • Quantification of cow milk yield and pre-weaning calf growth response in temperate pasture-based beef suckler systems: A meta-analysis

      Sapkota, D.; Kelly, A.K.; Crosson, P.; White, R.R.; McGee, M.; Teagasc Walsh Fellowship Programme (Elsevier BV, 2020-11)
      The objectives of this study were to quantitatively summarize factors associated with cow milk yield (MY) and calf growth response in pasture-based beef cow-calf suckler systems and to discern how cow genotype and parity influenced these responses. A dataset of 344 treatment mean observations was compiled from 69 studies that reported data on cow MY, and calf pre-weaning average daily live weight gain (ADG) and/or weaning weight (WW). Data were analysed using linear mixed effects models with study and region included as random effects. Models were developed for cow MY, calf ADG and WW response and each model was evaluated based on different model fit statistics. The final cow MY model included cow origin (Dairybeef or Beef), cow maturity (early-maturing (EM) or late-maturing (LM) genotypes) and parity. Dairybeef produced 35.4% more milk (8.64 vs. 6.38 kg/day) than Beef cows, and LM produced 20.9% more milk (8.20 vs. 6.78 kg/day) than EM genotypes (P < 0.001). Multiparous cows had a 14.8% higher MY (8.11 vs. 7.06 kg/day) compared to primiparous cows (P < 0.001). Lactation curve persistency was better (P < 0.05) for Beef and EM compared to Dairybeef and LM genotype cows, respectively. The final models of calf ADG and WW included cow origin, cow maturity and parity. Calves from Dairybeef and LM cows were 14 and 20 kg heavier (P < 0.001) at weaning (210-day adjusted) compared to those from Beef and EM genotype cows, respectively. Calves from multiparous cows were 13 kg heavier at weaning than those from primiparous cows (P < 0.001). The response in calf ADG associated with a 1 kg increase in cow daily MY was 47 and 53 g for Dairybeef and Beef cows, respectively (P < 0.001). Corresponding responses for EM and LM cows were 51 and 55 g (P < 0.001). In conclusion, the relationships between cow MY and calf pre-weaning growth, as well as the quantitative impact of cow genotype and parity were determined for pasture-based beef suckler systems; the coefficients generated can be used for improving beef cow-calf management strategies, beef cattle breeding programmes and bio-economic modelling purposes.