Introduction

With the forecasted expansion of Irish dairy cow number³, following the proposed changes of the milk quota regime, there will be greater number of dairy type claves available for beef production. Initially, at least, these extra male calves will be predominantly Holstein/Friesian (and some other dairy crossbreds). Finding the most suitable beef production systems for these male dairy calves is a challenge for the industry resulting in a renewed interest in bull beef production as an option for these calves. Before decoupling of support premia, bull beef production was generally less profitable than well managed steer beef, partly because of the higher premium earning capacity of the steers. However, rearing males as bulls has inherent efficiencies due mainly to their higher production potential arising from the natural presence of the male hormone testosterone. There are many systems of bull beef production, e.g. red veal, cereal beef, conventional rearing followed by silage/ concentrate finishing and conventional rearing followed by high concentrate finishing. The economics of production is, to a large extent dependent upon calf purchase price and concentrate costs. Irrespective of production system, it is imperative that a market outlet, and the approximate sale price, be established from the outset. Clarity is also needed on acceptable carcass weight and fat cover. Once bulls are ready for sale any delay or price discounting relative to steers can greatly reduce margins.

The breed mix used on the dairy herd is summarised in another paper at this conference (Beef production from the Dairy Herd). Currently, approximately sixty per cent of the 1.0 million dairy cows are mated to Holstein-Friesian sires (to produce replacement heifers). These matings result in the production of approximately 300,000 Holstein-Friesian male calves. The earliest born (late January to late February) are well suited to many systems of bull beef production because they will be well grown before turnout to pasture and can have a long first grazing season. Thus, they will be well developed, in both size and weight, in the autumn and can proceed directly to finishing. These early born bulls should then perform well during the high growth rate finishing phase, expressing some compensatory growth. Animals which are not well developed at the start of finishing, either because of later birth date or poorer performance at pasture, will require a longer and more costly finishing period. Animals that are not put to pasture but produced in a cereal beef system for slaughter at 11-13 months of age will reach slaughter in spring time when finished cattle are generally scarce and prices high.

Holstein-Friesian Bull Production Options

As indicated already, there are a range of production options using the early born Holstein-Friesian bulls. These can range from slaughtering at under 8-months of age (veal production), to 12 month cereal beef (barley beef), to 15, 18, 21 or 24 month slaughtering. Bull age can be a discriminating factor depending on the export market. High priced European markets tend towards bulls which are under 16 months. This paper summarises Holstein- Friesian dairy bull production systems at 12, 15 and 18 months of age. A steer beef production system, at 24 months of age, is also summarised.

Rearing and Feeding Friesian/Holstein Animals

12-13 month bull beef

The suitability of late winter-born Holstein/Friesian calves for bull production was examined in a series of experiments at Grange. Mean birth dates for calves used in these studies were typically mid-March. Currently, dairy herds are calving closer to mid-February (for Holstein/Friesian calves). The calves used in the studies reported here were purchased at livestock marts at about 7-14 days of age were reared indoors on a standard calf rearing regime and were approximately 12 weeks old when they moved to a high concentrate diet before starting the studies. Animals were housed on slatted floor sheds at a density of 2.5 m2/animal throughout.

Experiment 1 investigated the effect of feeding concentrate diets with differing energy densities on the performance of young bulls (Table 1). Starting at an initial weight of 110 kg, liveweight gains were approximately 1.1 to 1.2 kg/day over the 277 day feeding period. Over the first 140 days, gains were 1.2 to 1.3 kg/day and reduced 1.0 to 1.1 kg/day during the latter half of the feeding period. Concentrate consumption was 1500 to 1600 kg DM over the 277 days. Final liveweights were in the range 430- 450 kg, giving carcass weights of 230-235 kg. Overall conversion efficiency was approximately 9:1 (9 kg of concentrate DM/kg of carcass). Carcasses graded mainly O’s and had fat scores of 3 (1 to 5 scale). A barley (85 per cent), soyabean (13 per cent), plus mineral (2 per cent) mix proved to be an acceptable diet for this production system.

Effect of ration type on animal performance
	Treatment
	Barley / Soya	Low Energy	High Energy	Low then High	Sign
Initial Weight (kg)	110	110	110	109	NS
Concentrate intake (kg DM)
1 - 140d	747	717	744	734
141 - 277d	878	813	878	864
1 - 277d	1625	1530	1622	1598
Liveweight gain (g/d)
1 - 140d	1280	1260	1340	1330	NS
141 - 277d	1140	1010	1140	1120	NS
1 - 277d	1200	1140	1240	1220	NS
FCR (kg concentrate DM/kg gain)
1 - 140d	4.17	4.06	3.97	3.94
141 - 277d	5.62	5.88	5.62	5.30
1 - 277d	4.89	4.85	4.72	4.53
Final weight (kg)	445	424	452	447
Carcass weight (kg)	237	222	241	235	NS
FCR Carcass 1	9.1	9.3	8.9	9.1	NS
(kg conc. DM/kg carcass gai	6.4	4.5	8.9	9.1	NS
Kidney and channel fat (kg)	2.1	2.1	2.2	2.0	NS
Conformation2 Fat Score 3	3.3	2.6	2.9	3.0	NS
1 Calculated by assuming an initial killing-out rate of 480 g/kg 2 Based E = 5; U = 4; R = 3; O = 2 3 Based on fat score 1 (leanest) to 5 (fattest Source: Keane and Fallon, 2001

Experiment 2 investigated the effect of a 112 day period at pasture on the performance of spring-born Holstein/Friesian bull calves having access to either ad libitum or restricted concentrate feed. Starting at 125 kg liveweight, one group stayed indoors throughout on ad libitum concentrates, while another had access to ad libitum concentrates (same mix as Experiment 1) at pasture. A third group had access to grass only for the first 84 days, was then adapted to ad libitum concentrates over a 28 day period while still at grass and then moved indoors for the final 137 days. The full feeding period was 250 days (Table 2). Concentrate intake over the 250 day study was approximately 1600 kg DM for the both indoors, and outdoor ad libitum concentrate fed group. When given grass only for the first 84 days, total concentrate input (for the 250 days) was approximately 1150 kg DM. Having access to grass with ad libitum concentrates saved only 48 kg concentrates (during the first 112 days), while having no initial access to meal when at grass saves 447 kg concentrates. When subsequently moved indoors all groups had similar concentrate intakes over the final 137 days. However, performance was affected during the initial 112 days. Calves indoors full time and those at grass with ad libitum access to concentrates had similar liveweight gains of 1.4 kg/day, while a gain of 0.8 kg/day was achieved on grass only. When moved indoors for the final 137 days, calves from the grass only treatment grew at 1.4 kg/day, compared with 1.2 kg/day for the groups on ad libitum throughout. Over the full 250 days, daily gains of 1.3, 1.3 and 1.2 kg/day were measured on the indoor full time, grass plus ad libitum concentrates and grass only groups, respectively. Final liveweights were 442, 452 and 411 kg for these three, respective, feeding options. Carcass weights were 237, 237 and 215 kg, respectively. The concentrate savings of 450 kg (by having access to grass only for the first 84 days) resulted in the loss of 22 kg of carcass. Estimate DM concentrate feed conversion efficiency for both ad libitum groups was approximately 9:1, but was closer to 8:1 for those animals that had grass only at the start of the outdoor feeding period. The bulls killed out at 536g/kg for the indoor-full-time group and at 524g/kg for the other two groups. Conformation scores were mainly O’s and fat scores of 3 to 3.5.

Effect on outdoor period on the performance of bulls fed ad libitum or restricted amounts of concentrate
	Barley / Soya	Pasture + ad lib conc	Pasture +Restricted conc	Sign
Initial Weight (kg)	125	126	128	NS
Concentrate intake (kg DM)
1 - 112d	559	511	112
113 - 250d	1019	1051	1030
1 - 250d	1578	1562	1142
Liveweight gain (g/d)
1 - 112d	1390	1420	800	***
113 - 250d	1180	1220	1410	***
1 - 250d	1270	1310	1130	***
FCR (kg concentrate DM/kg gain)
1 - 112d	3.61	3.22	1.26
113 - 250d	6.31	6.26	5.33
1 - 250 d	4.98	4.78	4.05
Final liveweight (kg)	442	452	411	***
Carcass weight (kg)	237	237	215	***
KO %	53.6	52.4	52.4	***
Kidney and channel fat (kg)	8.47	8.49	8.46	**
Conformation score 1	1.89	1.97	1.94	NS
Fat Score 2	3.08	3.47	3.22	*
1 Based on E=5, U=4, R=3 and O=2 2 Based on fat score 1 (leanest) to 5 (fattest) Source: Keane and Fallon, 2001

Experiment 3 further examined the effects of an initial period (140 days) at grass, with different levels of concentrates on offer, on the subsequent performance indoors. Holstein/Friesian bull calves weighed 114 kg liveweight at the start of the study. The full study lasted 266 days. Calves were offered an adlibitum barley/soyabean ration (similar to earlier experiments), either indoors full-time, at pasture for 140 days or were offered 2 kg of this concentrate for 112 days at pasture and then gradually adapted to ad libitum concentrates (over 28 days) before the final finishing period of 125 days. For the first 140 days, the indoor calves consumed 711 kg DM in concentrate form, while those on ad ] libitum out doors consumed 640 kg DM (Table 3). Those on the 2 kg allowance consumed 384 kg concentrate DM. Over the final 125 days indoors, concentrate intakes of 872, 919, and 914 kg DM were recorded for the indoor full time, pasture plus ad libitum, and, pasture plus 2 kg groups, respectively. Total concentrate intakes were 1583, 1559 and 1298 kg DM for these three groups. The animals which were offered 2 kg concentrates (for the first 112 days) consumed 285 kg concentrates DM less than the ad libitum indoor group. Average daily liveweight gains for the initial 140 days were 1.26, 1.34 and 1.07 kg/day for the indoor full time, pasture plus ad libitum, and pasture plus 2 kg concentrate groups, respectively. For the final 125 days indoors, these groups grew at a similar growth rate (of approximately, 1.24-1.30 kg/day). Again for these groups, final liveweights were 447, 464, and 419 kg, giving carcass weights of 237, 244 and 216 kg. By allowing access to pasture and offering 2 kg of concentrates / day, a concentrate saving of 285 kg was made, but this was offset by the animals having 21 kg lower carcass weight. Kill out rates were highest for the ad libitum indoor group (at 531g/kg) and lowest for the grass plus 2 kg concentrate group (516g/kg). The other group was intermediate. Estimated concentrate feed conversion efficiencies for the ad libitum groups were approximately 8.5:1 (kg conc DM/kg carcass) but was better (8:1) for the animals which had access to pasture and restricted concentrates. Carcasses graded O’s and P’s and had fat scores were approximately 3. saving of 285 kg was made, but this was offset by the animals having 21 kg lower carcass weight. Kill out rates were highest for the ad libitum indoor group (at 531g/kg) and lowest for the grass plus 2 kg concentrate group (516g/kg). The other group was intermediate. Estimated concentrate feed conversion efficiencies for the ad libitum groups were approximately 8.5:1 (kg conc DM/kg carcass) but was better (8:1) for the animals which had access to pasture and restricted concentrates. Carcasses graded O’s and P’s and had fat scores were approximately 3.

Effect on outdoor period at pasture on the performance of spring- born bulls fed concentrates ad libitum
	Barley / Soya	Pasture + ad lib conc	Pasture + 2 kg conc	Sign
Initial Weight (kg)	114	114	114	NS
Concentrate intake (kg DM)
1 - 140d	711	640	384
141 - 266d	872	919	914
1 - 266d	1583	1559	1298
Concentrate intake (kg DM)
1 - 140d	1260	1340	1070
141 - 266d	1240	1300	1240	NS
1 - 266d	1250	1320	1150	***
FCR (kg concentrate DM/kg gain)
1 - 140d	4.04	3.40	2.56
141 - 266d	5.59	5.60	5.86
1 - 266 d	4.76	4.44	4.24
Final liveweight (kg)	4447	464	419	***
Carcass weight (kg)	237	244	216	***
KO %	53.1	52.5	51.6	***
Kidney and channel fat (kg)	6.88	6.76	5.10	**
Conformation score 1	1.85	1.79	1.67	*
Fat Score 2	3.18	2.94	2.85	NS
1 Based on E=5, U=4, R=3 and O=2 2 Based on fat score 1 (leanest) to 5 (fattest) Source: Keane and Fallon, 2001

15 and 18 month bull beef

The suitability of late winter-born Holstein/Friesian bull calves for beef production was examined in an experiment at Grange. The calves which were purchased at livestock marts were reared indoors initially and then went to pasture for a 223 day grazing season (April 10 to November 19). Average daily gain from arrival to the end of grazing (333 days) was 0.76 kg/day and mean liveweight at the end of the grazing season was 305 kg. They were then housed in a slatted shed and finished on grass silage plus concentrates fed at either 3 kg/day, 6 kg/day or ad libitum. Half of the animals on each treatment were slaughtered after 179 days (15 months) while the remainder were slaughtered 93 days later (18 month).

Growth rates

Mean daily gains for various sub-periods and for the total finishing period are shown in Table 4. Gains were higher in the period from 56 to 179 days than before or after. The lower gains in the first 56 days probably reflect the effects of adaptation to housing and the change of diet and also the fact that some of the animals may not have fully reached puberty and maximum testosterone production. The lower gains after 179 days, particularly in the better fed groups, are indicative of animals reaching maturity and having a higher level of fat deposition. It is noteworthy that after 179 days there was no reduction at all in the performance of the animals fed only 3 kg concentrates/day, whereas for those fed 6 kg concentrates/day there was a reduction of 142 g/day (10 per cent) and for those given concentrates ad libitum the reduction was 195 g/day (14 per cent). Mean liveweights after 179 days for the 3 kg/day, 6 kg/day and ad libitum concentrate groups were 467, 515 and 550 kg, respectively. Basically these data indicate that the daily growth rate of Holstein/Friesian young bulls, which have been fed to grow fairly rapidly over the previous 6 months, starts to decline after about 500 kg liveweight and the rate of decline increases with increasing weight and previous feeding level.

Overall mean weight gain for the 3 kg/day, 6 kg/day and ad libitum concentrate feeding levels was 908, 1164 and 1395 g/day, respectively up to 179 days and 961, 1022 and 1200 g/day afterwards. For the experiment as a whole mean performance was 914, 1141 and 1358 g/day, respectively for the treatments as listed.

Daily gains of young bulls during finishing
Concentrate level (kg/day)
Daily gain for (g):	3	6	ad libitum
Days 0 - 56	714	910	1228
56 - 112	866	1108	1429
112 - 179	1106	1425	1508
0 - 179	908	1164	1395
179 - 272	961	1022	1200
0 slaughter	914	1141	1358
Carcass gain (g)	598	741	895
Source: Keane and Fallon, 2001

Slaughter traits

Slaughter traits are shown in Table 5. Slaughter weight ranged from 467 kg for the animals fed 3 kg/day concentrates for 179 days to 670 kg for those fed concentrates ad libitum for 272 days. Corresponding carcass weights were 241 to 377 kg. Thus, the experimental treatments used here can be considered as a range of practical production options for the production of bull beef carcasses any desired weight within this range. Kill-out increased with increasing feeding level and slaughter weight. At the 3 kg/day feeding level, it averaged 531 g/kg. This increased to 541 g/kg at the 6 kg/day feeding level and to 554 g/kg at the ad libitum feeding level. It is likely that this increased kill-out was due more to increased slaughter weight than to higher feeding level per se. There was a big increase in kill-out due to the longer feeding period particularly for the lower feeding levels. The mean increase was 24 g/kg but this ranged from 29 g/kg for the 3 kg/day group down to 19 g/kg for the ad libitum group. Because of this increased kill-out in the animals retained for 272 days, the decrease in carcass gain after 179 days was relatively less than the decrease in liveweight gain. While the mean decrease in liveweight gain after 179 days was 169 g/day (13 per cent) for the 6 kg/day and ad libitum groups (there was no decrease for the 3 kg/ day group because they were still relatively light), the mean decrease in carcass gain was only 72 g/day (9 per cent). Thus, any economic assessment of various finishing periods and slaughter weights must offset the increasing kill-out against the decreasing liveweight gain which occurs as the length of finishing and slaughter weight increase.

Slaughter traits of young bulls finished on 3 feeding levels for 2 periods
Concentrate level (kg/day)	3		6		ad libitum
Age (months)	15	18	15	18	15	18
Finishing period (days)	179	272	179	272	179	272
Slaughter weight (kg)	467	562	515	607	550	670
Carcass weight (kg)	241	307	272	336	300	377
Kill-out (g/kg)	517	546	529	553	544	563
Conformation	2.0	2.3	2.2	2.9	2.6	3.1
Fat Score	2.9	2.9
3.2	3.1	3.2
Source: Keane and Fallon, 2001

Carcass grade improved with both increasing feeding level and length of finishing. Animals on the 3 kg/day concentrate level for 179 days averaged “O” whereas those on the ad libitum concentrate level for 272 days averaged “R”. Again the effect is likely to have been due to carcass weight more so than feeding level or feeding period. It can be estimated that conformation improved by one class per 120 kg increase in carcass weight. Fat score was relatively little affected by either feeding level of finishing period and averaged about 3.

Feed intakes and efficiency

Silage and concentrate intakes for the total finishing period are shown in Table 6. Concentrate intakes ranged from 0.5 tonne for animals fed 3 kg/ day for 179 days to 3.0 tonnes for animals fed ad libitum for 272 days. Silage intakes ranged from less than 1.0 tonne for animals fed ad libitum to almost 8 tonnes per animals fed 3 kg/day concentrates for 272 days. Since silage and concentrate intakes and liveweight gains varied with treatment, it is necessary to bring the feeds to some common denominator to get an estimate of efficiency. In all cases efficiency was poorer for those fed for 272 days than for those fed for 179 days, emphasising the importance of keeping the feeding period short. Otherwise the poorest efficiency occurred at the 3 kg/day concentrate feeding level with no difference between the 6 kg/day and ad libitum feeding levels.

While mean fat score did not differ greatly between the treatments, it is likely that in practice a high proportion of the animals fed on 3 kg/day concentrates for both the 179 and 272 day periods would be insufficiently finished.

Feed intakes of young bulls during finishing
Concentrate level (kg/day)	3		6		ad libitum
Age (months)	15	18	15	18	15	18
Finishing period (days)	179	272	179	272	179	272
Concentrates (kg)1	516	795	1032	1590	1763	2988
Silage (kg)1	4.52	7.82	3.06	5.62	0.90	1.36
Liveweight gain (kg)3	160	255	210	302	246	365
1 Fresh weight corrected to 860 g/kg dry matter (DM); 2 Fresh weight corrected to 200 g/kg DM; 3 Actual gains during finishing Source: Keane and Fallon, 2001

Therefore, the treatments of greatest relevance are 6 kg/day and ad libitum concentrates. If all animals were taken to a minimum slaughter weight of 550 kg giving a carcass of about 300 kg, the feed inputs necessary would be 1.3t concentrates plus 4.2t silage for animals fed 6 kg/day concentrates, and 1.8 tonnes concentrates plus 0.9t silage for animals fed ad libitum concentrates all animals were taken to a minimum slaughter weight of 550 kg giving a carcass of about 300 kg, the feed inputs necessary would be 1.3 tonnes concentrates plus 4.2 tonnes silage for animals fed 6 kg/day concentrates, and 1.8 tonnes concentrates plus 0.9 tonnes silage for animals fed ad libitum concentrates.

Steer beef from Holstein/Friesian steers at 24 months of age

Rearing Holstein/Friesian males as steers has been practiced widely in Ireland. The typical inputs and outputs from such a system are summarised in Tables 7 and 8. The typical system uses one tonne of concentrates per animal unit, 75 per cent of which is fed in the final finishing phase. Approximately 80, 60 and 110 kg of concentrates are fed during the indoor calf rearing stage, at grass in year one and during the first winter as weanlings, respectively. Winter forage (grass silage) requirement is 1.5t DM/animal unit, where 0.5 and 1.0t DM are fed in the first and second winter, respectively. Winter feed requirements are met by cutting approximately 55 per cent (or more) of the area for silage in late May, and, depending on stocking rate, a further 40 per cent in late July. Grazed grass requirement is approximately to 2.5t DM/calf plus yearling unit. Matching feed supply to herd demand for the full year, suggests that a stocking rate of 1.8 and 2.9 units (calf plus yearling)/ha can be carried within the 170 and 250 kg organic nitrogen limits.

Summary of inputs for spring-born Holstein-Friesian steers in a two-year system
Per head
Concentrates (kg)
Calf indoors	80	80
Calf at pasture	60	60
1st winter as weanlings	110	110
2nd winter as weanlings	750	750
Total	1000	1000
Grazed Grass (kg DM)
1st grazing season	660	660
2nd grazing season	1790	1790
Total	2450	2450
Silage (Kg DM)
1st Winter	500	500
2nd Winter	960	960
Total	1460	1460
Land Areas
ha/animal unit	0.55 (0.33 ha cut and 0.25 ha grazed)	0.35 (0.22 ha cut once, 0.2 ha cut twice)
Animal units/ha	1.8	2.9
Carcass output (kg/ha)	580	930

Typical target live weights for the system are 230 kg at first housing, 300 kg at turnout in spring and 490 kg at housing at the one and a half year-old stage. Lifetime daily gain (birth to slaughter) will be around 0.8 kg/day. Weanling normally grown at about 0.5-0.6 kg/day during their first winter and this is done to lower production cost and to optimise subsequent performance at pasture (compensatory growth). Managing calves and yearling at grass requires a balance between getting good daily gains and high grass utilisation. The practice of a leader-follower system, where calves graze ahead of the older animals, is often used. This system allows the calves the opportunity of unlimited access to quality pasture. Holstein/Friesian steers should be 620 kg liveweight at 24 month of age and yield a carcass of 320 kg. Typical carcasses will grade 80 per cent O’s and 20 per cent P’s and the fat scores will be 50:50 mix of 3’s and 4’s.

 

December 2010