• Comparison of a Calan gate and a conventional feed barrier system for dairy cows: feed intake and cow behaviour

      Ferris, C.P.; Keady, Tim; Gordon, F.J.; Kilpatrick, D.J. (Teagasc, Oak Park, Carlow, Ireland, 2006)
      There is little published information on comparisons of individual and group feeding systems for dairy cows. Twenty-four dairy cows were used in a three-period incompletely balanced, change-over design study, to examine food intake and feeding behaviour of dairy cows offered their food via group-access electronic Calan gates, or via a conventional feed-barrier system. The food offered was in the form of a complete diet, and comprised grass silage and concentrates (60:40 dry matter (DM) basis). With the conventional feed-barrier system a maximum of eight animals were able to feed at any one time, while the Calan-gate system allowed a maximum of three animals to feed at any one time. Method of offering the ration had no effect on daily DM intake. During the 8-h period after animals were given access to fresh food, the mean number of animals feeding at any one time was 5.4 and 3.0 for the conventional and Calan-gate systems, respectively, while total intake over this period was 11.0 and 9.2 kg DM per cow, respectively. When access to feed was restricted by the use of Calan gates, animals responded by increasing their intake rate. It is concluded that total DM intake was unaffected by the use of a group Calan-gate feeding system as animals modified their feeding behaviour to maintain food intake.
    • The effect of grazing pressure on rotationally grazed pastures in spring/early summer on the performance of dairy cows in the summer/autumn period

      Stakelum, G.; Dillon, Pat (Teagasc, Oak Park, Carlow, Ireland, 2007)
      Two 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.
    • Effect of suckler cow genotype on energy requirements and performance in winter and subsequently at pasture

      McGee, Mark; Drennan, Michael J; Caffrey, Patrick J. (Teagasc (Agriculture and Food Development Authority), Ireland, 2005)
      Three experiments using a total of 62 Charolais (C) and 110 Beef × Holstein-Friesian (BF) spring-calving cows were carried out to determine the relative energy requirements of the genotypes. Cows were individually offered a restricted allowance of grass silage daily during the last 85 and 107 days pre partum in Experiments 1 and 2, respectively, and ad libitum grass silage during the last 93 days pre partum in Experiment 3. In all 3 experiments grass silage was offered ad libitum during the first 34 days of lactation. In Experiments 1 and 2, cows and calves were grazed together during the subsequent grazing seasons. When fed to appetite, silage dry matter intake was similar for both cow genotypes but was higher for the BF cows when expressed relative to live weight. For Experiments 1 and 2 combined, initial live weights and live weight changes to post-partum, over the indoor period and at pasture were 720 (s.e. 14.1), 613 (s.e. 8.4), –74 (s.e. 4.0), –63 (s.e. 2.7), –106 (s.e. 6.0), –89 (s.e. 4.0) and 120 (s.e. 7.0), 88 (s.e. 5.3) kg for C and BF cows, respectively. In Experiment 3 the corresponding initial live weights and live weight changes to post partum were 759 (s.e. 12.3), 659 (s.e. 9.1) and –63 (s.e. 4.9) and –52 (s.e. 3.5) kg. There was no effect of genotype on body condition score or adipose cell diameter or their changes. Plasma creatinine concentrations were higher (P < 0.001) in C cows than BF cows. It is concluded that the energy requirements of a 660 kg C cow are approximately equivalent to a 600 kg BF cow during late pregnancy.
    • Effects of daily herbage allowance and stage of lactation on the intake and performance of dairy cows in early summer

      Stakelum, G.; Maher, J.; Rath, M. (Teagasc, Oak Park, Carlow, Ireland, 2007)
      The aim of this study was to investigate the relationship between daily herbage allowance (DHA) and the performance of dairy cows at two stages of lactation. Spring-calving (n=42, mean calving date 17 February) and autumn-calving (n=42, mean calving date 22 September) Friesian cows were divided into three equal groups and assigned to three levels of DHA (above a cutting height of 35 mm), 17 (L), 20 (M) and 23 (H) kg of dry matter (DM) per head, from late April to late June, 1996. The spring-calving cows grazed to sward heights (mm) of 47, 56 and 65 (s.e. 0.6) and residual herbage organic matter (OM) masses (above 35 mm) of 294, 408 and 528 (s.e. 12.1) kg/ha for L, M and H, respectively. The autumn-calving cows grazed to corresponding sward heights of 51, 60 and 69 (s.e. 1.1) mm and leftresidual herbage OM masses of 364, 445 and 555 (s.e. 12.9) kg/ha for L, M and H, respectively. Pastures were mechanically topped post grazing. Spring-calving cows consumed 13.3, 14.7 and 15.5 kg OM (s.e. 0.47) per day, and autumn-calving cows consumed 13.3, 13.8 and 14.9 kg OM (s.e. 0.43) per day for L, M and H, respectively. Mean daily solids-corrected milk yield was 23.1, 23.8 and 24.8 (s.e. 0.34) kg for the spring-calving cows, and 17.5, 18.4 and 18.7 (s.e. 0.35) kg for the autumncalving cows, for L, M and H, respectively. Milk yield could be predicted from preexperimental yield (PMY) and daily herbage organic matter allowance (DOMA, kg) according to the following equation: y = −1.13 + 0.76 (s.e. 0.030) PMY + 0.22 (s.e. 0.057) DOMA (r.s.d. 1.32, R2 0.89). The results indicate that high individual cow and herd production levels can be achieved from high quality herbage alone during early summer at a DHA of 23 kg DM for spring-calving cows and 20 kg DM for autumn-calving cows.
    • Effects of forage supplements on milk production and chemical properties, in vivo digestibility, rumen fermentation and N excretion in dairy cows offered red clover silage and corn silage or dry ground corn

      Salcedo, G.; Martinez-Suller, L.; Arriaga, H.; Merino, P. (Teagasc, Oak Park, Carlow, Ireland, 2010)
      This study concerned the effects of partial substitution of clover silage with high starch forages on milk production and chemical composition, in vivo digestibility, rumen fermentation pattern and nitrogen excretion of dairy cows. Sixteen dairy cows were separated into two groups and were assigned to treatments in a two-period crossover design. Two forage supplements were used: corn silage (CS) and dry ground corn (DG). All animals received 4.5 kg of concentrate dry matter per day. Results showed no significant difference between the forage supplements for milk production, while significant differences (P<0.01) were observed for milk fat, milk protein and nitrogen utilisation efficiency (42 v. 4.0 g/kg, 3.5 v. 3.3 g/kg and 222 v. 188 g/kg, respectively, for DG and CS). Faecal N excretion did not differ between forage supplements, but urinary N excretion was higher for CS (P<0.05). No significant differences were observed between treatments for rumen fluid pH or for rumen fluid concentrations of ammonium nitrogen or of acetic, propionic or butyric acids. Dry matter intake and the in vivo digestibility of dry matter, organic matter, acid detergent fibre and neutral detergent fibre were all higher for CS compared with DG.