2006
Bovine somatotropin and dietary fat enriched with omega-3 fatty acids in dairy cows: I. Lactation performance
M. Carriquiry1, W.J. Weber1, C.R. Dahlen2, G.C. Lamb3, and B.A. Crooker1
Multiparous cows (n=59) were blocked by expected calving date and previous 305ME and assigned randomly to a 2x2 factorial design to determine effects of bST (POSILAC ®) and dietary fat during 280 DIM. Diets (1.98 Mcal NEL1x, 184 g CP, and 185 g ADF per kg DM) included whole, high-oil sunflower seeds (10% of dietary DM, SS) or a mixture of Alifet-High Energy® and Alifet-Repro® (3.4 and 1.5% of dietary DM, AF) and were provided from calving. Cows received 0 or 500 mg bST (N,Y) every 10 d from 12 to 70 DIM and at 14 d-intervals thereafter. Blood was collected weekly through 150 DIM. Means from a repeated measures analysis differed when P<0.05. Daily 4%FCM yield was 4.7 kg/d greater after 23 d of bST but was not altered by diet. Peak milk was delayed (54.9 vs. 72.0 ± 3.9 DIM) and tended (P=0.07) to increase (48.9 vs. 51.1 ± 1.0 kg) with bST. Milk fat, protein, and lactose yields increased with bST but did not differ between diets. Daily DMI did not differ among treatments but BCS was reduced with bST (3.30 vs. 3.18 ± 0.06). Energy balance (EB) nadir (-11.2 ± 0.75 Mcal NEL/d) occurred at 15 DIM and did not differ among treatments. There was an interaction of bST and diet on EB as AF decreased the impact of bST on mean EB (2.04a, -2.75c, 2.00a, 0.13b ± 0.69 Mcal NEL/d for SSN, SSY, AFN, and AFY) and allowed AFY cows to reach positive EB earlier than SSY cows (70 for SSN, AFN, and AFY vs. 105 DIM for SSY). Adjusted gross efficiency was greater for bST cows (1.10 vs. 1.24 ± 0.02 kg FCM/Mcal NEL intake). Plasma NEFA and glucose were similar among treatments. The postpartum decrease in IGF-I did not differ among treatments but mean IGF-I during lactation was less for SS than AF (98.6 vs. 112.2 ± 6.7 ng/mL) and for non-bST than bST (85.7 vs. 126.1 ± 6.7 ng/mL) cows. Plasma IGF-I increased by 35 DIM for bST cows. Pre-calving concentrations of IGF-I were reached by 84 DIM for bST and after 168 DIM for non-bST cows. Initiation of bST at 12 DIM in cows fed AF increased FCM yield and plasma IGF-I by 35 DIM without detrimental effects on EB.
1University of Minnesota, St. Paul
2Northwest Research & Outreach Center, Crookston, MN
3North Central Research & Outreach Center, Grand Rapids, MN
Bovine somatotropin and dietary fat enriched with omega-3 fatty acids in dairy cows: II. Milk fatty acid composition
M. Carriquiry1, W.J. Weber1, C.R. Dahlen2, G.C. Lamb3, S.R. Sanders4,
L.H. Baumgard4, and B.A. Crooker1
Multiparous cows (n=32) were blocked by expected calving date and previous 305ME and assigned randomly to a 2x2 factorial design to determine effects of bST (POSILAC®) and dietary fat on milk fatty acid (FA) composition during the first 140 DIM. Isocaloric diets (1.98 Mcal NEL1x) that included whole, high-oil sunflower seeds (10% of dietary DM, SS) or a mixture of Alifet-High Energy® and Alifet-Repro® (3.4 and 1.5% of dietary DM, AF) were provided from calving. Alifet-Repro® contained protected omega-3 FA (15.7% 18:3, 1.3% 20:5, and 1.3% 22:6). Cows received 0 or 500 mg bST (N, Y) every 10 d from 12 to 70 DIM and at 14 d-intervals thereafter. Milk samples from wk 2, 8, and 20 of lactation were analyzed for FA composition. Means from a repeated measures analysis differed when P<0.05. Proportions of de novo synthesized FA (200 vs. 185 ± 6 mg/g FA) tended to decrease (P=0.06) and preformed FA (533 vs. 558 ± 5 mg/g FA) increased in milk with bST. Diet did not modify the proportions of de novo or preformed FA but 18:3, 20:5, and 22:6 FA were greater with AF. As lactation progressed, the proportion of de novo and mixed origin FA increased, while preformed FA decreased. The saturated to unsaturated FA ratio (S/U) did not differ among treatments and increased as lactation progressed. However, the increase in de novo FA, the decrease in preformed FA, and the increase in S/U ratio were detected later in lactation for bST cows (wk 8 vs. 20). The omega-6 to omega-3 FA ratio in milk was reduced in cows fed AF (8.80 vs. 7.39 ± 0.29) and increased by bST as lactation progressed. The cis-9, trans-11 CLA tended (P=0.07) to be reduced by AF and increased between wk 2 and 8 of lactation despite the decrease in trans-11 18:1. The 14:1/14:0 ratio increased with wk of lactation. Alifet-Repro® induced an increase in omega-3 FA in milk and bST prolonged the mobilization period in milk FA composition.
1University of Minnesota, St. Paul
2Northwest Research & Outreach Center, Crookston, MN
3North Central Research & Outreach Center, Grand Rapids, MN
4University of Arizona, Tucson
Bovine somatotropin and dietary fat enriched with omega-3 fatty acids in dairy cows: III. Postpartum ovarian activity
M. Carriquiry1, C.R. Dahlen2, W.J. Weber1, G.C. Lamb3, and B.A. Crooker1
Multiparous cows (n=59) were blocked by expected calving date and previous 305ME and assigned randomly to a 2x2 factorial design to determine effects of bST (POSILAC®) and dietary fat on ovarian activity during the first 90 DIM. Isocaloric diets (1.98 Mcal NEL1x) that included whole, high-oil sunflower seeds (10% of dietary DM,SS) or a mixture of Alifet-High Energy® and Alifet-Repro® (3.4 and 1.5% of dietary DM, AF) were provided from calving. Cows received 0 or 500 mg bST (N, Y) every 10 d from 12 to 70 DIM and at 14 d-intervals thereafter. Follicular dynamics, luteal growth and development (transrectal ultrasonography) and plasma P4 concentrations were evaluated (3X/wk) from 15 to 90 DIM. Breeding started after 90 DIM. Means differed when P<0.05. Days to first ovulation (33.6 ± 1.4) and incidence of anovulation at 45 or 70 DIM did not differ among treatments but time to first ovulation was less variable for AFY. Intraovulatory intervals were similar among treatments (22.1 ± 0.9 d). Incidence of 2-wave cycles was greater for SSY (71.0%) and AFN (80.0%) but more 3-wave cycles occurred with AFY (83.3%). Growth rate of the ovulatory follicle was greater for AF than SS (1.9 vs. 2.2 ± 0.11 mm/d) and diameter of ovulatory follicles was larger for AFN than the other treatments (17.9 vs 15.7 ± 0.7 mm). Multiple ovulations tended (P<0.10) to increase with bST. Maximal CL volume did not differ among treatments. Area under the P4 curve was reduced for SSY (63.2a, 48.1b, 55.5ab, and 61.4a ± 5.1 dxng/mL for SSN, SSY, AFN, and AFY). The number of class 1 (2 to 5 mm; decreased), class 2 (6 to 9 mm; increased), and class 3 (10 to 15 mm; tended to increase (P=0.07)) follicles were altered by bST. Class 2 follicles were reduced with AF. Neither diet nor bST affected the number of class 4 (>15 mm) or the mean size of class 2, class 3, and class 4 follicles. Initiation of bST at 12 DIM and dietary omega-3 fatty acids enhanced ovarian activity during the first 90 DIM and could benefit reproductive performance.
1University of Minnesota, St. Paul
2Northwest Research & Outreach Center, Crookston, MN
3North Central Research & Outreach Center, Grand Rapids, MN
Effect of feed barrier design on the behavior of loose-housed lactating dairy cows
M.I. Endres1, T.J. DeVries2, M.A.G. von Keyserlingk2, and D.M. Weary2
The objective of this study was to evaluate the effects of 2 feed barrier systems on feeding and social behavior of dairy cows. Forty-eight lactating Holstein cows were subjected to each of 2 treatments in a cross-over design. The treatments were 2 types of feed-line barriers: 1) post and rail, and 2) headlock. Time-lapse video was used to quantify the feeding behavior and incidence of aggressive displacements of the cows at the feed bunk. Average daily feeding time did not differ when cows used the headlock barrier compared with the post-and rail barrier. However, there were certain changes in feeding time during periods of peak feeding activity: cows that had lower feeding times relative to group mates when using the post-and-rail barrier showed more similar feeding times to group mates when using the headlock barrier. There were 21% fewer displacements at the feed bunk when cows accessed feed by the headlock barrier compared with the post-and-rail barrier. These results suggest that using a headlock barrier reduces aggression at the feed bunk and improves access to feed for socially subordinate cows during peak feeding periods.
1University of Minnesota, St. Paul
2Animal Welfare Program, The University of British Columbia, Vancouver
Management risk factors associated with clinical lameness in freestall housed Holstein cows
M.I. Endres and L.A. Espejo
University of Minnesota, St. Paul
The objective of this study was to investigate the association of some herd-level factors with the prevalence of lameness in 53 high-production groups of Holstein cows housed in 50 commercial dairy farms having freestall barns in Minnesota. Cows in the high-production group (n=5,626) were scored for locomotion (score of 1 to 5, where 1 = normal and 5 = severely lame) in order to estimate prevalence of lameness (locomotion score ≥ 3) in the group. Herd-level variables were used to explain the variation in prevalence among groups. Among the variables tested, herd size, pen space per cow, type and size of milking parlor, total mixed ration (TMR) content of crude protein and neutral detergent fiber (NDF), feeding frequency, linear feedbunk space per cow, type of feed barrier, and use of footbath did not show any association with the prevalence of lameness in the univariate analysis screening test and they were not included in the multivariate model. Pen stocking density (cows per 100 stalls), total daily distance between pen and milking parlor, number of cows per full time employee equivalent, cud chewing index, and pen type were eliminated from the multivariate model in the backwards stepwise procedure. Daily time away from the pen for milking was positively associated with the prevalence of lameness, whereas cow comfort quotient was negatively associated with prevalence of lameness. Prevalence of lameness was greater when farms performed hoof trimming only when the manager decided cows needed it because of hoof overgrowth or lameness compared with all cows in which feet were trimmed on a maintenance schedule once or twice annually. Brisket board height of more than 15.24 cm and presence of the area behind the brisket board filled with concrete were associated with greater prevalence of lameness. Most of these herd-level factors could possibly be managed in order to reduce lameness prevalence in commercial dairy farms.
1University of Minnesota, St. Paul
2University of Minnesota Extension Regional Center, St. Cloud
Prevalence of lameness in high-producing Holstein cows housed in freestall barns in Minnesota
L.A. Espejo1, M.I. Endres1, and J.A. Salfer2
A cross-sectional study was conducted to estimate the prevalence of clinical lameness in high-producing Holstein cows housed in 50 freestall barns in Minnesota during summer. Locomotion and body condition scoring were performed on a total of 5,626 cows in 53 high production groups. Cow records were collected from the nearest Dairy Herd Improvement Association test date, and herd characteristics were collected at the time of the visit. The mean prevalence of clinical lameness (proportion of cows with locomotion score ≥3 on a 1-to-5 scale, where 1 = normal and 5 = severely lame), and its association with lactation number, month of lactation, body condition score, and type of stall surface were evaluated. The mean prevalence of clinical lameness was 24.6%, which was 3.1 times greater, on average, than the prevalence estimated by the herd managers on each farm. The prevalence of lameness in first-lactation cows was 12.8% and prevalence increased on average at a rate of 8 percentage units per lactation. There was no association between the mean prevalence of clinical lameness and month of lactation (for months 1 to 10). Underconditioned cows had a higher prevalence of clinical lameness than normal or overconditioned cows. The prevalence of lameness was lower in freestall herds with sand stalls (17.1%) than in freestall herds with mattress stall surfaces (27.9%). Data indicate that the best 10th percentile of dairy farms had a mean prevalence of lameness of 5.4% with only 1.47% of cows with locomotion score = 4 and no cows with locomotion score = 5.
1University of Minnesota, St. Paul
2University of Minnesota Extension Regional Center, St. Cloud
Farmer-driven research for developing models of successful low input dairy farms of small to medium size in the American Midwest
D.G. Johnson1, M.V. Rudstrom1, R. Imdieke2, E. Ballinger3, and G.J. Cuomo1
The dairy industry in the upper Midwest continues to evolve with a drastic reduction in the numbers of moderate-sized, conventionally managed dairy farms that have been the backbone of dairying. Many of the farms that do remain are at a critical point where facilities require renovation or replacement that is not economic. Rural communities have fewer residents engaged in agriculture to participate in the local economy and the rural landscape includes many farm sites that are abandoned. Barns that have been used to stable cows may be renovated to provide a low cost but efficient milking center. Low input farms may include grazing, outdoor housing throughout the year, crossbreeding, group housing of calves, etc. The public investment in research to evaluate has been minimal, but farmers are eager to participate when they determine the direction of research. We will describe a research project designed to answer questions determined by farmers and next steps in designing effective reduced input dairy farms.
1West Central Research & Outreach Center, Morris, MN
2New London, MN
3University of Minnesota, St. Paul
Grazing dairies can be profitable
M.V. Rudstrom
West Central Research & Outreach Center, Morris, MN
Questions about the profitability of grazing dairies are a barrier to the adoption of management intensive rotational grazing (MIRG) systems in Minnesota and other Upper Midwest dairy states. Producers understand MIRG systems tend to have lower milk production and assume lower production will translate to lower net returns. Farm financial records from grazing dairies and non-grazing (confinement) dairies in Minnesota were queried with the purpose of assessing profitability of grazing dairies relative to confinement dairies over time. Production and financial performance summary statistics were reported for 2000-2002 for both groups. Because of the relatively small number of grazing dairy farms in the database, milk production comparisons of the Minnesota grazing dairy farms were made to a larger database of grazing dairy farms to validate production results. Farm financial records show grazing operations have about 25 percent lower production per cow than confinement dairies. Lower productivity did not translate to lower net returns per cow on the grazing dairies. Grazing dairies had similar direct costs but lower overhead costs than confinement dairies. For each year, net returns per cow and per hundredweight of milk sold were greater on the grazing dairies than confinement dairies in Minnesota.
2005
Relationship between type of stall surface and prevalence and severity of hock lesions in dairy cows housed in freestall barns
M.I. Endres1, L.A. Espejo1, and J.A. Salfer2
A total of 5,538 cows in 50 randomly selected dairy farms in Minnesota were scored for hock lesions using a standardized scoring system in a scale of 0 to 3 with 0 = no signs of hair loss or swelling on either hock region (no lesion), 1 = evidence of hair loss (mild lesion), 2 = one or more swollen hocks but no evidence of hair loss (moderate to severe lesion), 3 = one or more swollen hocks with evidence of hair loss (severe lesion). Free stall surface was either deep-bedded sand or rubber-filled mattresses. Thirty-four percent of the dairies used sand and 66% used mattresses. In each dairy, cows in one or more high producing pens were scored. On the average, 90% of cows in each group were scored. Number of cows per group varied from 34 to 304 with an average group size of 118. Number of milking cows in each herd varied from 104 to 1,250 with an average milking herd size of 423 cows. Lactation number, days in milk, and milk production per cow in the scored group averaged 2.6, 169.7 days, and 38.6 kg/d, respectively. Fifty-eight percent of the cows scored had hock lesions. Stall surface was associated with the prevalence of hock lesions (P ≤ 0.001) with 29.4% of cows in sand barns having lesions compared to 71.3% of cows in mattress barns. Severity of lesions was also greater (P ≤ 0.001) for cows in mattress herds than cows in sand herds. For the statistical analysis of severity of lesions, scores 2 and 3 were combined. In mattress herds, the percent of cows with hock lesion score of 1 was 57.2% and 2 or 3 was 14.1%. In sand herds, the percent of cows with hock lesion score of 1 was 27.6% and 2 or 3 was 1.8%. The association between lactation number (age) and DIM (stage of lactation) and the prevalence and severity of hock lesions was also investigated. Both prevalence and severity increased with age and DIM (P ≤ 0.05). There was no relationship between daily milk production and either prevalence or severity of lesions. In conclusion, the prevalence and severity of hock lesions were greater on dairy farms using mattress based stalls than on dairy farms using sand bedded stalls.
1University of Minnesota, St. Paul
2University of Minnesota Extension Regional Center, St. Cloud
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