The University of Minnesota SROC Calf and Heifer Research and Extension facility in Waseca contract raises over 800 dairy heifer calves annually for three commercial dairy operations. Calves are picked up twice weekly at 2 to 4 days of age and remain at SROC until they are 6 to 7 months of age. A partnership was established between the University of Minnesota and Ridley Inc. (including Hubbard Feeds Inc. and FeedRite, Canada) in 2003 to focus on applied nutrition and management research. Milk Products joined the partner team and more recently APC Inc. The SROC calf and heifer facilities were upgraded, and new facilities were completed in April 2004. This allowed for a sufficient number of calves to be raised to accommodate applied pre- and post-weaning studies developed by the partner team (up to 400 calves/year) and also have enough calves to be able to conduct studies with other university or allied industry collaborators. Contracts with each of the three dairies were finalized prior to moving to the new facilities. A close working relationship has developed between the University of Minnesota and management at each of the three dairies which has helped to maintain the quality of heifers raised at SROC. Since 2004, completed nursery (56 day) and post-weaning (up to 112 days) applied studies have involved over 3,000 heifer calves. This paper will provide a brief management overview of the facility and highlight the results of selected pre- and post-weaning applied research programs.
Calf and Facility Management
Nursery phase. Calves are picked up weekly by SROC staff from the respective dairies on Monday and Thursday and commingled in a well-bedded livestock trailer. During winter months, calf blankets are used at pick-up and remain on the calves at the discretion of SROC staff until the calves adjust to their new environment. In the nursery phase, calves are housed in one of two 200 ft x 30 ft curtain side-wall naturally ventilated calf barns. Each barn contains two 90 ft x 30 ft rooms with 40 individual pens (approximately 30 sq ft/calf) within each room. A 20 ft x 30 ft mixing and feed storage area is centrally located in each barn. The rooms are managed as an all-in, all-out system. All pen panels are removed and power-washed between calf groups. All bedding material is removed, and the remaining front gates and rear panel holders are also power-washed. Chopped straw is used for bedding calf pens in the winter and sawdust in the summer.
Calves remain in their respective pens for about 56 days unless a specific protocol requires a longer feeding period. Upon arrival, calves are weighed, hip heights taken, and two jugular blood samples drawn. One sample is used to check total serum proteins using a refractometer and a second sample for whole blood analyses by an outside laboratory to identify persistently infected BVD calves. Calves are administered an intranasal modified live IBR/PI3 and salmonella vaccine upon arrival. Calves between 75 and 110 lb at 2 to 4 days of age are assigned to applied nursery studies, if appropriate, across the resource location. Usually crossbred calves are not used in the studies (about 3% of total calves). An individual recording sheet is prepared for every calf regardless whether it is on trial or not. Daily records are kept for feed intake (milk and calf starter), fecal scores, and health treatments. Periodic growth parameters and management such as vaccinations, dehorning, and tail docking (one herd only) are also noted. All data from individual cards are transferred to an Excel worksheet for management and statistical analyses.
At approximately 2 and 6 weeks after arrival, calves are administered a bovine respiratory complex vaccine and a second dose of the salmonella vaccine. Dehorning and tail docking are completed about 30 days after arrival. The current standard feeding protocol is to offer a 20:20 all milk protein medicated milk replacer at 0.625 lb/feeding twice daily diluted with water to 12.5% solids for 35 days and once daily from day 36 to weaning at 42 days. An 18% CP complete texturized calf starter (including an ionophore) is offered from day 1. Fresh water is offered daily. This standard feeding protocol is included in as many nursery studies as possible to build a control database. Calves remain in their respective pens until 2 weeks after weaning and then are transferred to group pens of 6 heifers. Occasionally calves have remained in the nursery for up to 70 days. At least 20 to 25 calves are assigned for each treatment group for nursery studies. Prior to moving to group pens, all calves receive a second intranasal modified live IBR/PI3 vaccine.
Post-weaning group housing. Two post-weaning barns are used to house heifers until they attain 6 months of age. A new 65 ft x 150 ft curtain side-wall naturally ventilated facility completed in 2004 is located north of the calf nursery barns. This contains 20 12 ft x 25 ft pens and a scale with handling area. The front part of each pen is a scrape alley and the rear a manure pack. Heifers are fed through diagonal bars from a central feed alley. The front alley is scraped weekly and the manure pack cleaned out as often as deemed necessary. Pens are re-bedded once or twice weekly. A second post-weaning barn is an existing 80 ft x 160 ft manure pack pole barn. The barn contains 20 15 ft x 30 ft pens, each with 10 ft concrete feed bunks. There is a central scale and heifer handling area. This barn is cleaned out twice annually, but pens are re-bedded once or twice weekly. Both barns are used for studies alternating a complete study between each. Heifers are fed once daily, and both barns are managed as a continuous flow system.
Calves remain on their nursery calf starter for 7 to 10 days after moving to their respective group pens, then switch to a grain mix with access to long hay. The amount of feed offered by pen is recorded, and refusals are weighed as per study protocol. Body weights, body condition score, and hip heights are monitored. There have been a number of grain mixes evaluated, either offered free choice or limit-fed with or without access to long hay. A 16% whole corn and pellet grain mix fed at 6 lb/heifer daily for 28 days and 5 lb/day from 29 to 112 days with access to long hay has been established as a basis to which to compare performance. Heifers are transferred to other contract growers at 6 to 7 months of age, but often due to excess heifer numbers at SROC above capacity, additional facilities are used for 2 to 3 weeks prior to their transfer. Similarly, an existing inside calf room is used for overflow calves during the nursery phase. In between 4 and 5 months after arrival at SROC, heifers are vaccinated against leptospirosis and clostridium species.
Calf profiles. One of the key areas for raising dairy heifers is to start with a high-quality calf. The respective dairies are continually working to maintain calf quality. At least 3 feedings of colostrum are required before calves are picked up. The goal is to evaluate the profiles of total serum proteins on all calves upon arrival. In addition, minimizing other potential health issues such as navel infections is a priority for the dairies. The incidence of navel infections or related problems is 1.8%. There have been occasional leg problems (0.6%; contracted tendons, swollen, injured, etc.). Table 1 provides a heifer calf profile including total serum proteins and a summary of growth parameters at 6 months of age across the 3 dairy farms. Overall calf losses at SROC are < 2%. A recent addition to the overall project is to be able to use DHIA records to follow the heifers back to their respective dairy herds and document calving age and first lactation performance.
1. Calf nursery research studies. A target goal for calf performance in the nursery phase is to double the initial body weight by the end of the nursery phase and gain at least 4 inches of frame height in the same time period. These goals have been attained in a number of calf groups, but there are some variations by season of the year. Calves fed the standard SROC program during the 56-day nursery phase during studies from 2004 to 2007 have averaged 194% of their initial 2- to 4-day-old body weight (184 to 207%), almost 4
inches of frame gain (3 to 4.6 inches) and 1.50 lb daily gain (1.3 to 1.7 lb). Studies have been designed to provide options for both liquid and calf starter programs in relationship to calf performance, health, and potential changes in economic efficiencies. Performance summaries of nursery studies presented at national meetings have included Ziegler et al. (2005a); Ziegler et al. (2005b); Ziegler et al.(2006a); Ziegler et al. (2006 b); Braman et al. (2006), Chester-Jones et al. (2006b); Chester-Jones (2007), Hayes et al. (2007), and Ziegler et al. (2007a).
a. Liquid feeding programs. The premise of these programs has been to evaluate milk replacers (MR) containing varying protein levels, alternative proteins, energy sources, and nutritional supplements. In addition, MR feeding management strategies have been assessed in some studies in conjunction with varying calf starters (CS).
Conventional versus intensive MR programs. The initial MR study focused on conventional (C) versus modified intensive (MI) or intensive (I) programs (Table 2). Calves on the intensive program were weaned at 49 days and the remainder at 42 days. Gain advantages were apparent for the modified intensive and especially intensive programs versus more conventional system. Calf health was not affected by MR programs. Daily feed costs/calf (April 2008 feed prices) to 56 days averaged $1.57, $1.58, $2.18, $2.07, and $3.05 for calves fed non-acidified C, acidified C, MI high solids (HS), MI low solids (LS), and I, respectively. The calves remained in their pre-weaning treatments and were moved to group pens where they were limit-fed a 16 (conventional) versus 18% CP grain mix (modified intensive and intensive) with access to long hay. There were no differences in post-weaning performance from 9 to 25 weeks of age.
A complete analysis of raising costs would have to be undertaken to determine a viable cost:benefit ratio for each of the MR programs based on first calving age and lactation performance. The latter information will be forthcoming from DHIA tracking of heifers once they have entered the respective milking herds.
Alternative protein and energy sources in MR. The cost of milk proteins has remained high for sometime, and alternative proteins that do not compromise calf performance but result in lowering MR costs are worth pursuing. The standard SROC nursery feeding program (MR and calf starter) was compared to calves fed MR replacing 50% of the milk protein with hydrolyzed wheat gluten (WG) protein versus 50% of the milk protein with soybean protein concentrate (SPC) versus replacing 30% of the milk protein with WG versus 50% of the milk protein with 25% WG and 25% SPC (Table 3). All calves were fed the 18% CP calf starter. The MR were balanced for amino acids. Calves fed an all milk protein 20:20 MR had better overall performance than calves fed MR containing alternative protein sources. However, calf performance for those fed the standard SROC program exceeded that of the control calves from other SROC studies. Calves fed the alternative protein MR gained as well as control MR calves in other SROC studies. Current work at SROC is looking at other alternative protein sources and additives focusing on improving calf health during the pre-weaning period.
Animal fats (lard) are commonly used for MR formulations as energy sources. Interest in alternative energy sources has focused on all-vegetable fat sources or a combination of animal and vegetable fat. A study was undertaken to look at calf performance when offered varying energy sources using a 24:20 all milk protein medicated MR fed as per standard SROC protocol with a 18% CP CS. Fat treatments were animal fat (AF), vegetable blend of 80% palm oil and 20% coconut oil (VF), and AF plus a blend of medium chain triglycerides containing 1% caproic, 69% caprylic, 1% capric, and 29% lauric acids fed at 5 g/calf daily (AFVF). The study was conducted between January and March. Calves fed AF tended to have higher CS and total DMI than those fed AFVF, but overall calf performance was not influenced by fat source. The average frame growth exceeded 4 inches, and overall gain was within the range of other studies. Calf starter DMI, total DMI, daily gain, and feed/gain for the 56-day study were 127.52, 174.85, 1.60, 1.96; 118.46, 165.87, 1.52, 1.95; and 119.34, 166.92, 1.55, 1.93 for calves fed AF, VF, and AFVF, respectively.
Additives in MR and feeding strategies. Research at SROC has also included nutritional management to help calf health, intestinal health, and/or immune function during the nursery phase. An example involved incorporating mannan oligosaccharides (Bio-mos®, fed at 2 g/calf daily), fructooligosaccharides (inulin, fed at 5.67 g/calf daily), and a combination of Bio-mos® and inulin in non-medicated 20:20 MR. The additives did not affect pre- and immediate post-weaning calf performance versus non-medicated control MR. Other recently completed or ongoing studies are investigating non-medicated additives incorporated with different MR feeding rates. In addition, the implications on calf performance of varying the number of milk feedings a day are being documented.
b. Calf starter programs. Offering a high-quality CS and promoting optimal intake are integral to the success of all SROC nursery feeding programs. To evaluate CS options for calves, establishing some benchmarks for pre- and immediate post-weaning intake and expectations for calf performance under consistent management is indicated. Table 5 summarizes CS intake by season of the year at SROC. Under the SROC program, calves are weaned by days on feed rather than CS intake. However, it is apparent that good CS intake could allow for earlier weaning and reduce extra costs of extending the liquid feeding period. A number of nursery studies have investigated various CS fed with the standard SROC MR program.
Calf starter composition and physical form. In the initial SROC CS study, calves were fed the standard SROC MR program with texturized CS containing 6, 9, or 12% liquid molasses. Overall, when compared to calves fed 6% molasses, those fed the 12% molasses had 8.3% lower gains and utilized their feed 5.3% less efficiently. Calves fed the 9% molasses had similar performances to those fed the 6% level. A common question is why we do not feed complete pellets versus texturized CS for consistency of product. This was investigated when calves were offered free choice 18% CP CS as a complete texturized (T), complete pellet (P), or P with chocolate, whey, or sweet tart as intake-enhancing supplements. Calves fed the complete T CS had the highest feed efficiency and gained 7.1% faster than calves fed the complete P. Intake-enhancing supplements were not advantageous. Preliminary data suggest that corn processing and physical form do not improve calf performance when comparing CS based on steam flaked corn, pellet, and oats; whole corn and pellet; or roasted corn, pellet, and oats.
2. Post-weaning studies. Transitional nutrition and management of calves when moving from individual to group housing are challenges on many dairy operations. Ongoing SROC research is looking at ways of improving this adjustment period by management strategies in the nursery prior to moving or changes in feed formulations during the transition. Once calves have adjusted to the group pens, post-weaning studies have been implemented. Performance summaries of post-weaning studies presented at national meetings have included Linn et al. (2005); Larson et al. (2006); Chester-Jones et al. (2006a); Chester-Jones et al. (2007); and Ziegler et al. (2007b). An initial study in 2004 found that continually feeding a grain mix at 6 lb/heifer daily with access to long hay for 112 days resulted in good growth but higher than expected body condition. Follow-up studies then included variable grain feeding rates. Heifer performance on the SROC control limit-fed whole corn (WC) and pellet (P) 16% grain mix program across 4 studies is summarized in Table 5. Key points to note are average hay intake, average DM intake as a % of body weight, and heifer performance parameters.
Protein sources (dried distillers grains and urea), grain mix protein levels (13, 16, 19% CP), rumen fermentation enhancer (Fermenten®), fiber levels, and limit versus full-feeding grain mixes have been investigated. Regardless of feeding regimen, whether limit for full-feeding grain mixes with or without access to hay, heifer DM intake consistently represents close to 3% of body weight. Limit feeding to more precise target gains with improved feed efficiencies is a next logical step in the process.
Forage quality. The variability of hay quality offered to heifers is often related to market prices and current inventory on the farm. A SROC study investigated feeding hay of low quality (100 RFV) with or without a low-moisture molasses block (Crystalyx®; 30% CP); medium-quality (134 RFV) or high-quality (154 RFV) hay fed with a 16% CP cracked corn and pellet grain mix for 112 days (6 lb/day for days 1 to 14 and 4 lb/day from days 15 to 112).Using a low-moisture block supplement (B) with 100 RFV hay increased daily gain by 4% and feed efficiency by 3.3% compared to feeding 100 RFV without a block supplement. Average daily block consumption was 0.3 lb/heifer. Using a 130 RFV hay compared to 100 RFV hay increased daily gain by 9% and feed efficiency by 4%. Using a 154 RFV hay compared to a 130 RFV hay increased daily gain by 1.4% and feed efficiency by 5.7% over the 112-day study. Heifer performances were acceptable, and an economic comparison should be the criterion to select the hay of choice when limit feeding concentrates. Daily gain and feed/gain were 1.91, 4.73; 1.99, 4.62; 2.10, 4.59; and 2.13, 4.32 lb for heifers fed 100 RFV, 100 RFV + B, 130 RFV, and 154 RFV hay, respectively.
An overview of SROC calf management, facility management, and applied research programs has been presented. Options have been investigated to support an improvement in consistency of nutritional management for calf raising programs from 2 to 4 days up to 6 months of age. The information collected at SROC over the past 4 years also allows for future refinement of nutritional and management strategies to optimize the growth and health of dairy calves, especially in the early pre-weaning phase.
|Item||Farm A||Farm B||Farm C|
|A. Upon Arrival|
|Initial BW, lb||88.8||86.7||87.2|
|Initial serum protein, g/dl||5.4||5.4||5.2|
|Initial serum protein profiles|
|<4.0 g/dl, %||0.9||2.7||1.3|
|4.0-4.5 g/dl, %||8.2||12.2||13.7|
|4.6-5.0 g/dl, %||22.8||22.5||33.2|
|5.1-5.5 g/dl, %||24.8||20.5||23.4|
|5.6-6.0 g/dl, %||28.5||22.8||20.7|
|>6.0 g/dl, %||14.8||19.3||7.7|
|B. 6mth profile of 2,397 heifers|
|Final BW, lb||476||462||451|
|Final Hip Height, in||45.5||44.9||45.1|
|Total ADG, lb||1.92||1.91||1.91|
|Parameter||20:20 C Non-Acidified||20:20 C Acidified||28:16 MIHS||28:16 MILS||28:16 I|
|Feed rate lb/day MR1||1.25||1.25||1.5||1.5||2.25|
|CS CP %, as-fed||18%||18%||22%||22%||22%|
|Init. BW, lb||90.9||91.08||89.74||87.05||88.86|
|Init. HH, in||31.80||32.00||31.78||31.73||31.81|
|CS DM 42d, lb||43.38b||41.62b||43.49b||37.99b||23.61c|
|CS DM 42d, lb||73.50b||70.64b||74.82b||67.98b||43.85c|
|Milk DM, lb||47.76b||47.45b||57.51c||55.40c||94.89d|
|ADG 1-42 d, lb||1.25b||1.19b||1.47c||1.39c||1.74d|
|ADG 1-49 d, lb||1.34bc||1.28b||1.52d||1.45cd||1.78e|
|Overall 56 days|
|Final BW, lb||171.45b||167.55b||180.09c||169.42b||188.61d|
|CS DM 56d, lb||108.81b||105.09b||111.87b||102.63b||77.70c|
|Total DM, lb||156.57b||152.55b||169.38cd||158.03bc||172.59d|
|Total gain, lb||80.54b||76.47b||90.35c||82.37b||99.75c|
|Final HH, in||35.87bc||35.83b||35.91d||35.71cd||36.65e|
|HH gain, in||4.07||3.83||4.13||3.98||4.84|
|Total BW gain, %||189||184||201||195||212|
|Treatment costs/calf, $||1.54||1.15||1.41||2.33||1.11|
aAdapted from Ziegler et al. (2005b).
bcdMeans in the same row with different superscripts differ (P<0.05).
1All C, MIHS, and MILS calves fed the MR in 2 equal feedings twice daily for 35 days and 1/2 the amount x1 daily from day 36-42. Intensive calves were fed MR in 2 equal feedings twice daily for 42 days and 1/2 the amount x1 daily from day 43-49.
|Parameter||Standard SROC||50% WG||50% SPC||30% WG||25% SPC + 25% WG|
|Init BW2, lb||89.7||89.5||89.1||90.6||90.6|
|Init HH, in||31.6||32.1||31.9||32.0||31.8|
|BW 42d, lb||154.1a||146.2b||145.5b||146.6b||143.5b|
|MR, DM lb||48.2||47.8||48.0||48.1||47.8|
|CS DM, lb||57.2a||49.3b||52.6ab||48.9b||48.5b|
|BW 56d, lb||186.3a||177.5b||176.4b||176.0b||173.3b|
|CS DM, lb||68.7a||64.0ab||66.7ab||62.1b||62.4b|
|Final HH, in||36.2||35.8||35.7||35.7||35.6|
|HH gain, in||4.6||3.7||3.8||3.7||3.8|
|Total BW gain, %||208||198||198||194||191|
a,bMeans within a row without common superscripts are different at P<0.05.
1Adapted from Hayes et al. (2007).
2Initial BW included in the model as a covariate.
|Time of Year||No. Calves||20:20 MR lb/day||CS CP%||Day 1-14||Day 15-28||Day 29-42||Day 1-42||Day 43-56|
aAdapted from Chester-Jones (2007).
bIntake averaged across all milk replacer (MR) and calf starter treatments to obtain benchmarks for SROC dairy heifers.
cNon-medicated milk replacer.
|Mth study started||July 2004||December 2005||January 2007||July 2007|
|WCP, lb as-fed/d||112 d 6 lb||56 d 6 lb 56 d 5 lb||28 d 6 lb 84 d 5 lb||28 d 6 lb 84 d 5 lb|
|Init. BW, lb||187.7||208.0||194.3||187.8|
|Init. Hip Height, in||36.98||36.9||36.8||36.7|
|Period 1-112 d|
|BW 112d, lb||462.0||464.6||459.7||423.8|
|Daily gain, lb||2.45||2.29||2.37||2.11|
|WCP/d, lb DM||5.4||4.85||4.75||4.7|
|Hay/d, lb DM||3.9||5.27||4.83||4.6|
|DMI, % of BW||2.86||3.00||3.30||3.10|
|Final HH, in||45.12||45.01||45.0||44.4|
|HH gain, in||8.14||8.11||8.2||7.7|
|BW gain:hght ratio||33.7||31.6||32.4||30.7|
aAdapted from Chester-Jones (2007).
bIntake averaged across all milk replacer (MR) and calf starter treatments to obtain benchmarks for SROC dairy heifers.
cNon-medicated milk replacer.
Braman, B., S. Hayes, H. Chester-Jones, D. Ziegler, J. Linn,
and B. Ziegler. 2006. Performance of dairy heifer calves
fed milk replacers with equal protein and fat levels but
utilizing different fat sources. J. Dairy Sci. 89(Suppl
Chester-Jones, H., D. Ziegler, R. Larson, B. Ziegler, and J.
Linn. 2006a. Performance of Holstein dairy heifers full
vs. limit fed whole-shelled corn and protein pellet diets
differing in fiber levels. J. Dairy Sci. 89(Suppl 1.):366.
Chester-Jones, H. 2007. Calves tell us that all starters are
not created equal. Proc. 11th Annual Dairy Calf and
Heifer Conference Pre-Conference Calf Seminar, pp 6380,
March 20, Burlington, Vermont, PDHGA,
Chester-Jones, H., D. Ziegler, R. Larson, B. Ziegler, J. Linn,
M. Raeth-Knight, and G. Golombeski. 2007. Post-weaning performance of Holstein dairy heifers fed diets differing in forage quality and supplemented with a low
moisture block. J. Dairy Sci. 90 (Suppl.1):553. Abstract W282.
Hayes, S., B. Ziegler, R. Larson, H. Chester-Jones, D.
Ziegler, J. Linn, M. Raeth-Knight, and G. Golombeski.
2007. Pre- and post-weaning performance and health of
dairy heifer calves fed milk replacers with different
protein sources. J. Dairy Sci. 90 (Suppl.1):114. Abstract
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Jones. 2006. Performance of Holstein dairy heifers fed
concentrate diets containing dried distillers grains or
urea. J. Dairy Sci. 89(Suppl 1.):365.
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Soderholm, and S. Hayes. 2005b. The effect of milk
replacer protein, fat content, and feeding amount on
performance of Holstein heifer calves. J. Dairy Sci.
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and S. Hayes. 2006b. Pre- and post weaning
performance of dairy heifers fed texturized or pelleted
calf starters with or without intake enhancing flavors. J.
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Ziegler, B., R. Larson, S. Hayes, H. Chester-Jones, D.
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2007a. Pre- and post weaning performance and health of
dairy heifer calves fed milk replacers supplemented
with oligosaccharides. J. Dairy Sci. 90 (Suppl.1):113.
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Proceedings of the 2008 Four-State Dairy Nutrition and Management Conference,
July 10-12, Dubuque, IA
H. Chester-Jones1, D.M. Ziegler1, R.Larson2, B. Ziegler2, C. Soderholm2, S. Hayes3, J. G. Linn4, M. Raeth-Knight4, G. Golombeski4, and N. Broadwater5
1University of Minnesota SROC, Waseca, MN
2Hubbard Feeds Inc., Mankato, MN
3APC Inc., Ankeny, IA
4University of Minnesota Department of Animal Science, St. Paul, MN
5University of Minnesota Dairy Extension, Rochester, MN