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Comparison of milk and grass composition from grazing Irish dairy herds with and without milk fat depression. Ir Vet J 2023; 76:5. [PMID: 36843021 PMCID: PMC9969643 DOI: 10.1186/s13620-023-00230-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 01/05/2023] [Indexed: 02/28/2023] Open
Abstract
BACKGROUND This study investigated the factors relating to pasture chemical and fatty acid (FA) composition that influence the milk fat percentage of spring calving, grazing dairy cows. The relationship between milk fat percentage and FA composition of the milk in these herds was also investigated. RESULTS Milk protein percentage, milk casein percentage and cheddar cheese yield were increased in milk from HMF herds. Cows from LMF herds did not have negatively altered milk processability including rennet coagulation time (RCT), pH and ethanol stability. Crude protein, NDF, ADF, ether extract and total FA content of pasture was not different between LMF and HMF herds. Milk fat concentration of conjugated linoleic acid (CLA) t10, c12 was not different between HMF and LMF herds. Pre-grazing herbage mass and pasture content of crude protein, neutral detergent fibre (NDF) and total FA were similar between HMF and LMF herds. Pasture offered to LMF herds had a higher concentration of monounsaturated fatty acids (MUFA). A strong negative relationship (r = -0.40) was evident between milk fat percentage and pasture crude protein content for MMF herds (3.31-3.94% milk fat). CONCLUSIONS This research reports improved milk protein percentage, milk casein percentage and cheddar cheese yield from HMF herds compared to LMF herds. Milk processability was not impacted by low milk fat percentage. Pasture NDF and total fatty acid content was similar in HMF herds and LMF herds. Milk fat percentage had a strong negative association (r = -0.40) with pasture crude protein content in MMF herds (MF 3.31-3.94%). Correlation values between pasture chemical and FA composition and milk fat percentage in LMF herds and HMF herds were low, indicating that diet is not the only causative factor for variation in milk fat of grazing dairy cows. Comparison of milk fatty acid composition from herds with and without milk fat depression suggests that there may be other fatty acids apart from CLA t10, c12 that contribute to the inhibition of milk fat synthesis during milk fat depression in grazing herds.
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Doran MJ, Mulligan FJ, Lynch MB, Fahey AG, Markiewicz-Keszycka M, Rajauria G, Pierce KM. Effects of Protein Supplementation Strategy and Genotype on Milk Production and Nitrogen Utilisation Efficiency in Late-Lactation, Spring-Calving Grazing Dairy Cows. Animals (Basel) 2023; 13:ani13040570. [PMID: 36830357 PMCID: PMC9951762 DOI: 10.3390/ani13040570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/30/2023] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
The objectives of this study were to evaluate the effects of (1) protein supplementation strategy, (2) cow genotype and (3) an interaction between protein supplementation strategy and cow genotype on milk production and nitrogen (N) utilisation efficiency (milk N output/ total dietary N intake × 100; NUE) in late-lactation, spring-calving grazing dairy cows. A 2 × 2 factorial arrangement experiment, with two feeding strategies [13% (lower crude protein; LCP) and 18% CP (higher CP; HCP) supplements with equal metabolisable protein supply] offered at 3.6 kg dry matter/cow perday, and two cow genotype groups [lower milk genotype (LM) and higher milk genotype (HM)], was conducted over 53 days. Cows were offered 15 kg dry matter of grazed herbage/cow/day. Herbage intake was controlled using electric strip wires which allowed cows to graze their daily allocation-only. There was an interaction for herbage dry matter intake within cows offered HCP, where higher milk genotype (HM) cows had increased herbage dry matter intake (+0.58 kg) compared to lower milk genotype (LM) cows. Offering cows LCP decreased fat + protein yield (-110 g) compared to offering cows HCP. Offering cows LCP decreased the total feed N proportion that was recovered in the urine (-0.007 proportion units) and increased the total feed N proportion that was recovered in the faeces (+0.008 proportion units) compared to offering cows HCP. In conclusion, our study shows that reducing the supplementary CP concentration from 18% to 13% resulted in decreased milk production (-9.8%), reduced partitioning of total feed N to urine (-0.9%) and increased partitioning of total feed N to faeces (+14%) in late lactation, grazing dairy cows.
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Affiliation(s)
- M. J. Doran
- School of Agriculture and Food Science, University College Dublin Lyons Farm, W23 ENY2 Naas, Ireland
- Correspondence:
| | - Finbar J. Mulligan
- School of Veterinary Medicine, University College Dublin, Belfield, DO4 V1W8 Dublin, Ireland
| | - Mary B. Lynch
- School of Agriculture and Food Science, University College Dublin Lyons Farm, W23 ENY2 Naas, Ireland
- Teagasc Environment Research Centre, Johnstown Castle, Y35 Y521 Wexford, Ireland
| | - Alan G. Fahey
- School of Agriculture and Food Science, University College Dublin Lyons Farm, W23 ENY2 Naas, Ireland
| | - Maria Markiewicz-Keszycka
- School of Agriculture and Food Science, University College Dublin Lyons Farm, W23 ENY2 Naas, Ireland
| | - Gaurav Rajauria
- School of Agriculture and Food Science, University College Dublin Lyons Farm, W23 ENY2 Naas, Ireland
| | - Karina M. Pierce
- School of Agriculture and Food Science, University College Dublin Lyons Farm, W23 ENY2 Naas, Ireland
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Serra E, Lynch M, Gaffey J, Sanders J, Koopmans S, Markiewicz-Keszycka M, Bock M, McKay Z, Pierce K. Biorefined press cake silage as feed source for dairy cows: effect on milk production and composition, rumen fermentation, nitrogen and phosphorus excretion and in vitro methane production. Livest Sci 2022. [DOI: 10.1016/j.livsci.2022.105135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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4
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Doran M, Mulligan F, Lynch M, Fahey A, Rajauria G, Brady E, Pierce K. Effects of concentrate supplementation and genotype on milk production and nitrogen utilisation efficiency in late-lactation, spring-calving grazing dairy cows. Livest Sci 2022. [DOI: 10.1016/j.livsci.2022.104962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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5
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The effect of concentrate feeding strategy and dairy cow genotype on milk production, pasture intake, body condition score and metabolic status under restricted grazing conditions. Livest Sci 2022. [DOI: 10.1016/j.livsci.2021.104815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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6
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Doran MJ, Mulligan FJ, Lynch MB, Fahey AG, Ryan NJ, McDonnell C, McCabe S, Pierce KM. Effect of supplement crude protein concentration on milk production over the main grazing season and on nitrogen excretion in late-lactation grazing dairy cows. J Dairy Sci 2021; 105:347-360. [PMID: 34635358 DOI: 10.3168/jds.2021-20743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/24/2021] [Indexed: 11/19/2022]
Abstract
The objectives of this study are to evaluate the effects of (1) a potential interaction between supplement crude protein (CP) concentration and differing cow genotypes on milk production, (2) differing cow genotypes on milk production, and (3) decreasing the supplement CP concentration on milk production and N excretion during the main grazing season within a spring-calving herd. A 2 × 2 factorial arrangement experiment, with 2 feeding strategies [14%; n = 30 (lower CP; LCP) and 18%; n = 28 (higher CP; HCP) CP concentrate supplements] offered at varying levels according to pasture availability and days in milk (DIM) was conducted over the main grazing season from April 3 to September 3, 2019, at University College Dublin Lyons Farm. Cows were also grouped into 2 genotype groups: lower milk genotype; n = 30 [LM; milk kg predicted transmitting ability (PTA): 45 ± 68.6 (mean ± SD); fat kg PTA: 10 ± 4.9; and protein kg PTA: 7 ± 2.3] and higher milk genotype; n = 28 [HM; milk kg PTA: 203 ± 55.0; fat kg PTA: 13 ± 3.8; and protein kg PTA: 10 ± 2.4]. A total of 46 multiparous and 12 primiparous (total; 58) Holstein Friesian dairy cows were blocked on parity and balanced on DIM, body condition score, and Economic Breeding Index. Cows were offered a basal diet of grazed perennial ryegrass pasture. The N partitioning study took place from August 25 to 30, 2019 (187 ± 15.2 DIM). No interactions were observed for any milk production or milk composition parameter. No effect of supplement CP concentration was observed for any total accumulated milk production, daily milk production, or milk composition parameter measured. The HM cows had increased daily milk yield (+1.9 kg), fat and protein (+0.15 kg), and energy-corrected milk (+1.7 kg), compared with the LM cows. Furthermore, HM cows had decreased milk protein concentration (-0.1%) compared with LM cows. For the N partitioning study, cows offered LCP had increased pasture dry matter intake (PDMI; +0.9 kg/d), dietary N intake (+0.022 kg/d), feces N excretion (+0.016 kg/d), and decreased N partitioning to milk (-2%), and N utilization efficiency (-2.3%). In conclusion, offering cows LCP had no negative influence on milk production or milk composition over the main grazing season where high pasture quality was maintained. However, any potential negative effects of offering LCP on milk production may have been offset by the increased PDMI. Furthermore, offering cows LCP decreased N utilization efficiency due to the higher PDMI and feed N intake associated with cows on this treatment in our study.s.
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Affiliation(s)
- M J Doran
- School of Agriculture and Food Science, University College Dublin Lyons Research Farm, Celbridge, Naas, Co. Kildare, Ireland, W23 ENY2.
| | - F J Mulligan
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland, D04 V1W8
| | - M B Lynch
- School of Agriculture and Food Science, University College Dublin Lyons Research Farm, Celbridge, Naas, Co. Kildare, Ireland, W23 ENY2; Teagasc Environment Research Centre, Johnstown Castle, Wexford, Ireland, Y35 Y521
| | - A G Fahey
- School of Agriculture and Food Science, University College Dublin Lyons Research Farm, Celbridge, Naas, Co. Kildare, Ireland, W23 ENY2
| | - N J Ryan
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland, D04 V1W8
| | - C McDonnell
- School of Agriculture and Food Science, University College Dublin Lyons Research Farm, Celbridge, Naas, Co. Kildare, Ireland, W23 ENY2
| | - S McCabe
- School of Agriculture and Food Science, University College Dublin Lyons Research Farm, Celbridge, Naas, Co. Kildare, Ireland, W23 ENY2
| | - K M Pierce
- School of Agriculture and Food Science, University College Dublin Lyons Research Farm, Celbridge, Naas, Co. Kildare, Ireland, W23 ENY2
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7
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Doran M, O'Sullivan M, Mulligan F, Lynch M, Fahey A, McKay Z, Ryan H, Pierce K. Effects of protein supplementation strategy and genotype on milk composition and selected milk processability parameters in late-lactation spring-calving grazing dairy cows. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2021.105050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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8
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Brady EL, Pierce KM, Lynch MB, Fahey AG, Mulligan FJ. The effect of nutritional management in early lactation and dairy cow genotype on milk production, metabolic status, and uterine recovery in a pasture-based system. J Dairy Sci 2021; 104:5522-5538. [PMID: 33663864 DOI: 10.3168/jds.2020-19329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/27/2020] [Indexed: 11/19/2022]
Abstract
High levels of milk production coupled with low feed intake cause negative energy balance in early lactation, especially in the first month postpartum (PP). Therefore, specific nutritional management at this time may improve nutritional and metabolic status with the possibility of contrasting genotypes responding differently. Thus, the objective of this study was to compare the effects of nutritional management strategies and dairy cow genotype on milk production, metabolic status, and some fertility parameters during early lactation in a pasture-based system. Sixty Holstein Friesian cows were blocked on parity and genotype [low-fertility high-milk (LFHM) and high-fertility low-milk (HFLM)] and were randomly assigned to 1 of 2 treatments in a 2 × 2 factorial arrangement, in a randomized complete block design based on calving date, previous 305-d milk yield, and precalving body condition score (BCS). The nutritional management treatments were: (1) ad libitum access to fresh pasture plus an allowance of 3 kg of concentrates per day (CTR, n = 30); and (2) ab libitum access to a tailored total mixed ration (TMR, n = 30). These diets were offered for the first 30 d PP. Following the first 30 d PP, cows fed TMR joined the CTR treatment and were managed similarly until 100 d PP. Blood samples were taken at d 7, 14, 21, and 28 PP to determine metabolic status. Milk samples for composition analysis were collected weekly and BCS assessed every 2 wk. Genotype had a significant effect on milk output, whereas LFHM had increased fat (+0.28 kg/d) and fat-plus-protein (+0.17 kg/d) yield in the first 30 d PP compared with HFLM cows. The LFHM group also exhibited higher protein and lactose yields over the first 100 d PP. Nutritional management did create significant differences in milk composition in the first 30 d: TMR cows had lower protein, milk urea nitrogen, and casein concentration and higher lactose concentration than CTR cows. Over the first 100 d PP, TMR cows had higher fat-plus-protein and lactose yields. Feeding TMR reduced concentrations of nonesterified fatty acids (-0.12 mmol/L) and β-hydroxybutyric acid (-0.10 mmol/L) compared with the CTR group. Cows fed TMR had smaller BCS losses from calving to 60 d PP. There was no effect of any treatment on uterine recovery. Cows in the LFHM group demonstrated greater milk production in the first 30 and 100 d in milk. These results demonstrate that feeding cows a TMR for the first month of lactation has positive effects on milk output, metabolic status, and BCS profile.
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Affiliation(s)
- E L Brady
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
| | - K M Pierce
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - M B Lynch
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - A G Fahey
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - F J Mulligan
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
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9
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Doran M, Mulligan F, Lynch M, O'Sullivan M, Fahey A, McKay Z, Brady E, Grace C, O'Rourke M, Pierce K. Effects of genotype and concentrate supplementation on milk composition and selected milk processability parameters in late-lactation spring-calving grazing dairy cows. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2020.104942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Boland TM, Pierce KM, Kelly AK, Kenny DA, Lynch MB, Waters SM, Whelan SJ, McKay ZC. Feed Intake, Methane Emissions, Milk Production and Rumen Methanogen Populations of Grazing Dairy Cows Supplemented with Various C 18 Fatty Acid Sources. Animals (Basel) 2020; 10:E2380. [PMID: 33322624 PMCID: PMC7764364 DOI: 10.3390/ani10122380] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 01/05/2023] Open
Abstract
Emissions of methane (CH4) from dairy production systems are environmentally detrimental and represent an energy cost to the cow. This study evaluated the effect of varying C18 fatty acid sources on CH4 emissions, milk production and rumen methanogen populations in grazing lactating dairy cows. Forty-five Holstein Friesian cows were randomly allocated to one of three treatments (n = 15). Cows were offered 15 kg dry matter (DM)/d of grazed pasture plus supplementary concentrates (4 kg DM/d) containing either stearic acid (SA), linseed oil (LO), or soy oil (SO). Cows offered LO and SO had lower pasture DM intake (DMI) than those offered SA (11.3, 11.5 vs. 12.6 kg/d). Cows offered LO and SO had higher milk yield (21.0, 21.3 vs. 19.7 kg/d) and milk protein yield (0.74, 0.73 vs. 0.67 kg/d) than those offered SA. Emissions of CH4 (245 vs. 293, 289 g/d, 12.4 vs. 15.7, 14.8 g/kg of milk and 165 vs. 207, 195 g/kg of milk solids) were lower for cows offered LO than those offered SA or SO. Methanobrevibacter ruminantium abundance was reduced in cows offered LO compared to SA. Offering supplementary concentrates containing LO can reduce enteric CH4 emissions from pasture fed dairy cows.
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Affiliation(s)
- Tommy M. Boland
- School of Agriculture and Food Science, University College Dublin, Dublin 4 D04 V1W8, Ireland; (K.M.P.); (A.K.K.); (M.B.L.); (Z.C.M.)
| | - Karina M. Pierce
- School of Agriculture and Food Science, University College Dublin, Dublin 4 D04 V1W8, Ireland; (K.M.P.); (A.K.K.); (M.B.L.); (Z.C.M.)
| | - Alan K. Kelly
- School of Agriculture and Food Science, University College Dublin, Dublin 4 D04 V1W8, Ireland; (K.M.P.); (A.K.K.); (M.B.L.); (Z.C.M.)
| | - David A. Kenny
- Teagasc Animal and Bioscience Department, Animal & Grassland Research and Innovation Centre, Grange, Dunsany, Co. Meath, C15 PW93, Ireland; (D.A.K.); (S.M.W.)
| | - Mary B. Lynch
- School of Agriculture and Food Science, University College Dublin, Dublin 4 D04 V1W8, Ireland; (K.M.P.); (A.K.K.); (M.B.L.); (Z.C.M.)
| | - Sinéad M. Waters
- Teagasc Animal and Bioscience Department, Animal & Grassland Research and Innovation Centre, Grange, Dunsany, Co. Meath, C15 PW93, Ireland; (D.A.K.); (S.M.W.)
| | | | - Zoe C. McKay
- School of Agriculture and Food Science, University College Dublin, Dublin 4 D04 V1W8, Ireland; (K.M.P.); (A.K.K.); (M.B.L.); (Z.C.M.)
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11
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Sheehy MR, Mulligan FJ, Taylor ST, Fahey AG. Effects of a novel heat-treated protein and carbohydrate supplement on feed consumption, milk production, and cheese yield in early-lactation dairy cows. J Dairy Sci 2020; 103:4315-4326. [PMID: 32113775 DOI: 10.3168/jds.2019-17468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 12/20/2019] [Indexed: 01/20/2023]
Abstract
Protein is an expensive component of the dairy cow diet, and overfeeding protein can have adverse economic and environmental impacts. Our objective was to maintain milk production and components while decreasing dietary crude protein (CP) through use of a heat-treated, rumen-resistant sugar amino acid complex (SAAC) as the Schiff base, as an addition to low-protein diets. Dietary treatments included a negative control [NC, 146 g of CP/kg of dry matter (DM)], a positive control (PC, 163 g of CP/kg of DM), and the NC supplemented with SAAC in lieu of some barley grain (SAAD, 151 g of CP/kg of DM). Diets were fed to 30 multiparous Holstein-Friesian dairy cows for the first 50 d postpartum. Dry matter intake (DMI) was determined daily. Milk yield and content of fat, protein, lactose, and casein were recorded weekly from wk 2 to 7 of lactation. The fixed effects of treatment, week, treatment × week, month of calving, and BCS at calving, and a random effect of cow, were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC). The SAAD treatment had greater energy-corrected milk yield than did NC. The PC treatment had greater DMI than did NC, and SAAD tended to have greater DMI than did NC. We found significant treatment effects for fat percentage and yield. The NC and SAAD treatments had higher fat percentages than did PC, and SAAD had a higher fat yield than did the NC and PC treatments. Treatment effects were found for casein yield and percentage. We discovered a treatment effect for protein percentage and yield. The PC treatment had higher protein percentage than did NC and SAAD. The PC treatment had a higher protein yield than did NC, and analysis revealed no difference in protein yield between PC and SAAD. The SAAD treatment had higher total milk solids than did the NC treatment. Lactose yield tended to be higher in PC than in NC, and no differences were found between PC and NC and SAAD treatments. The PC treatment had a higher casein percentage than did NC and SAAD; however, the SAAD and PC treatments had higher casein yields than did NC. The PC treatment had a higher casein:fat ratio than did the NC and SAAD treatments. The NC and SAAD treatments had higher Cheddar cheese yields than did PC. We found no treatment × week interactions for any parameter. Supplementing low-protein dairy cow diets with a heat-treated, rumen-resistant SAAC caused beneficial effects by improving milk components and increasing cheese yield to levels similar to those found when feeding expensive and environmentally damaging high-protein diets.
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Affiliation(s)
- M R Sheehy
- School of Veterinary Medicine, University College Dublin, D04 V1W8, Ireland; Devenish Nutrition Ltd., Belfast, BT1 3 BG, Northern Ireland
| | - F J Mulligan
- School of Veterinary Medicine, University College Dublin, D04 V1W8, Ireland.
| | - S T Taylor
- Devenish Nutrition Ltd., Belfast, BT1 3 BG, Northern Ireland
| | - A G Fahey
- School of Agriculture and Food Science, University College Dublin, D04 V1W8, Ireland
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Beltrán IE, Al-Marashdeh O, Burgos AR, Gregorini P, Balocchi OA, Wittwer F, Pulido RG. The Order of Grass and Maize Silage Supplementation Modifies Milk Yield, Grazing Behavior and Nitrogen Partitioning of Lactating Dairy Cows. Animals (Basel) 2019; 9:ani9060373. [PMID: 31248163 PMCID: PMC6617380 DOI: 10.3390/ani9060373] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/17/2019] [Accepted: 06/16/2019] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to evaluate the effects of the order of grass silage (GS) and maize silage (MS) supplementation on milk yield, grazing behavior and nitrogen (N) partitioning of lactating dairy cows during autumn. Thirty-six Holstein-Friesian dairy cows were randomly assigned to one of three treatments, and cows remained on these treatments for a 62 days period: (1) MIX; cows supplemented with 3 kg of dry matter (DM) of silage containing 1.5 kg DM of MS and 1.5 kg DM of GS in both the morning and afternoon; (2) GS-MS; cows supplemented with 3 kg DM of GS in the morning and 3 kg DM of MS in the afternoon; (3) MS-GS; cows supplemented with 3 kg DM of MS in the morning and 3 kg DM of GS in the afternoon. All cows received a pasture allowance of 17 kg DM/cow/d and 3 kg DM of concentrate. Grazing time and pasture intake were unaffected by treatment; however, milk production was greater for MS-GS, while milk protein was greater for GS-MS. Urinary N excretion was greater for MS-GS than MIX. In conclusion, MS-GS resulted in high milk yield but also high urinary N excretion, while MIX resulted in low urinary N excretion but also decreased milk yield.
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Affiliation(s)
- Ignacio E Beltrán
- Graduate School, Faculty of Veterinary Sciences, Universidad Austral de Chile, P.O. Box 567, Valdivia, Chile.
- Instituto de Investigaciones Agropecuarias, INIA Remehue, Ruta 5 Norte, km 8, Osorno 5290000, Chile.
| | - Omar Al-Marashdeh
- Department of Agricultural Sciences, Lincoln University, P.O. Box 7647, Lincoln, New Zealand.
| | - Ana R Burgos
- Graduate School, Faculty of Veterinary Sciences, Universidad Austral de Chile, P.O. Box 567, Valdivia, Chile.
| | - Pablo Gregorini
- Department of Agricultural Sciences, Lincoln University, P.O. Box 7647, Lincoln, New Zealand.
| | - Oscar A Balocchi
- Animal Production Institute, Faculty of Agricultural Sciences, Universidad Austral de Chile, P.O. Box 567, Valdivia, Chile.
| | - Fernando Wittwer
- Veterinary Clinical Sciences Institute, Faculty of Veterinary Sciences, Universidad Austral de Chile, P.O. Box 567, Valdivia, Chile.
| | - Rubén G Pulido
- Animal Science Institute, Faculty of Veterinary Sciences, Universidad Austral de Chile, P.O. Box 567, Valdivia, Chile.
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13
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McKay ZC, Mulligan FJ, Lynch MB, Rajauria G, Miller C, Pierce KM. The effects of cereal type and α-tocopherol level on milk production, milk composition, rumen fermentation, and nitrogen excretion of spring-calving dairy cows in late lactation. J Dairy Sci 2019; 102:7118-7133. [PMID: 31155249 DOI: 10.3168/jds.2019-16270] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/08/2019] [Indexed: 12/21/2022]
Abstract
Grass-based production systems use concentrate supplementation primarily when pasture quality and availability have declined. Barley is a common concentrate ingredient; however, oat grain grows well in Ireland, is a source of lipids and fiber, and may provide an alternative to barley. The antioxidant α-tocopherol (α-TOC) plays a role in cell membrane structure, and it has the potential to improve tight junction structures of the mammary gland that deteriorate in late lactation. The objective of this research was to investigate the effect of cereal type and α-TOC level on milk yield, milk composition, rumen fermentation, and N excretion in late-lactation dairy cows at pasture and when housed indoors on grass silage. Forty-eight Holstein Friesian dairy cows were blocked on days in milk (+185 d in milk) and balanced for parity, pre-experimental milk yield, milk composition, and body condition score and assigned to 1 of 4 dietary treatments in a randomized complete block design (n = 12). The dietary treatments were control (C) base diet; base diet + barley-based concentrate + low α-TOC (350 IU/kg) (B); base diet + oat-based concentrate + low α-TOC (350 IU/kg) (O); and base diet + oat-based concentrate + high α-TOC (1,050 IU/kg) (O+T). Following a 14-d acclimation period, diets were offered for a 49-d experimental period at pasture (P1) and a 21-d experimental period indoors (P2). The base diet was grazed grass in P1 and grass silage in P2. In P2, cows on C also received 2.65 kg (dry matter) of a standard concentrate. In P1, supplementation increased milk and milk solids yield (B: 20.7 kg/d, 1.74 kg/d; O: 20.6 kg/d, 1.81 kg/d; O+T: 20.5 kg/d, 1.77 kg/d, respectively) compared with C (17.8 kg/d, 1.60 kg/d). Cows offered B had a lower milk fat (4.60%) concentration than C (5.00%) and O (4.90%). In P2, cereal type and α-TOC level did not alter milk production. In conclusion, concentrate supplementation increased milk and milk solids yield and cows offered O had a higher milk fat concentration than cows offered B. Increasing the level of α-TOC had no major effect on production parameters measured in P1 or in P2.
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Affiliation(s)
- Z C McKay
- School of Agriculture and Food Science, University College Dublin, Lyons Research Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, Ireland W23 ENY2
| | - F J Mulligan
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland D04 W6F6
| | - M B Lynch
- School of Agriculture and Food Science, University College Dublin, Lyons Research Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, Ireland W23 ENY2
| | - G Rajauria
- School of Agriculture and Food Science, University College Dublin, Lyons Research Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, Ireland W23 ENY2
| | - C Miller
- Gain Feeds, Glanbia Plc, Bridge Street, Portlaoise, Ireland R32 ND7A
| | - K M Pierce
- School of Agriculture and Food Science, University College Dublin, Lyons Research Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, Ireland W23 ENY2.
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McKay ZC, Lynch MB, Mulligan FJ, Rajauria G, Miller C, Pierce KM. The effect of concentrate supplementation type on milk production, dry matter intake, rumen fermentation, and nitrogen excretion in late-lactation, spring-calving grazing dairy cows. J Dairy Sci 2019; 102:5042-5053. [PMID: 30981482 DOI: 10.3168/jds.2018-15796] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 02/20/2019] [Indexed: 11/19/2022]
Abstract
In Ireland, milk is primarily produced using a spring-calving grass-based system, with the use of concentrate supplementation mainly when pasture availability and quality are reduced. In the autumn, when cows are in late lactation, reduced pasture productivity results in reduced milk yield and altered milk composition. Nitrogen utilization efficiency also reduces as lactation progresses. Concentrate supplementation has been found to increase milk production and reduce nitrogen (N) excretion, as high-N grass is usually replaced by a lower-N supplement; however, there is a paucity of information with regard to the optimum type of supplementation in late lactation. Therefore, the objective of this research is to investigate the effect of different concentrate supplementation types, based on barley or maize, on milk production, dry matter intake (DMI), rumen fermentation, and N excretion in late-lactation, spring-calving, grazing dairy cows. Thirty-six Holstein Friesian dairy cows were blocked on days in milk (185 DIM) and balanced for parity, pre-experimental milk yield, milk composition, and body condition score. Cows were randomly assigned to 1 of 3 dietary treatments in a randomized complete block design (n = 12). The 3 treatments consisted of a perennial ryegrass-based pasture-only (PO) treatment and pasture plus either of 2 supplementary concentrates, based on barley (PB) or maize (PM). The diets were fed for a 14-d acclimatization period and then for a further 63-d experimental period. Cows offered PO had a lower daily milk yield (15.1 kg) than PB (18.2 kg) or PM (16.8 kg). Similarly, PO had lower daily milk solids yield (1.46 kg) than PB or PM (1.68 and 1.53 kg, respectively). Cows offered PB had a greater milk yield and higher fat and protein yields than those offered PM. Offering PB increased total DMI (19.5 kg) compared with PO (17.7 kg), and milk response to concentrates was also greater for PB compared with PM (1.21 vs. 0.71 kg of milk per kg of concentrate). Cows offered PB had increased N in milk compared with PO. In conclusion, concentrate supplementation based on barley or maize resulted in increased milk and milk solids yield compared with offering PO. Cows offered barley had a greater response to concentrates and increased milk and milk solids yield in comparison to maize and showed increased N partitioning in milk compared with PO. A barley-based concentrate increased total DMI compared with PO.
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Affiliation(s)
- Z C McKay
- School of Agriculture and Food Science, University College Dublin, Lyons Research Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, Ireland W23 ENY2
| | - M B Lynch
- School of Agriculture and Food Science, University College Dublin, Lyons Research Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, Ireland W23 ENY2
| | - F J Mulligan
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland D04 W6F6
| | - G Rajauria
- School of Agriculture and Food Science, University College Dublin, Lyons Research Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, Ireland W23 ENY2
| | - C Miller
- Gain Feeds, Glanbia Plc., Bridge Street, Portlaoise, Ireland R32 ND7A
| | - K M Pierce
- School of Agriculture and Food Science, University College Dublin, Lyons Research Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, Ireland W23 ENY2.
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Beltrán IE, Gregorini P, Morales A, Balocchi OA, Pulido RG. Interaction between herbage mass and time of herbage allocation modifies milk production, grazing behaviour and nitrogen partitioning of dairy cows. ANIMAL PRODUCTION SCIENCE 2019. [DOI: 10.1071/an18183] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The objective of the present study was to evaluate the interaction effects between herbage mass and time of herbage allocation on milk production, grazing behaviour and nitrogen partitioning in lactating dairy cows. Forty-four Holstein Friesian cows were grouped according to milk production (24.7 ± 2.8 kg), bodyweight (580.6 ± 51.7 kg), days in milk (74 ± 17.1) and body condition score (3.1 ± 0.3), and then assigned randomly to one of four treatments: (1) L-AM: access to new herbage allocation after morning milking with herbage mass of 2000 kg DM/ha, (2) L-PM: access to new herbage allocation after afternoon milking with herbage mass of 2000 kg DM/ha, (3) M-AM: access to new herbage allocation after morning milking with herbage mass of 3000 kg DM/ha, and (4) M-PM: access to new herbage allocation after afternoon milking with herbage mass of 3000 kg DM/ha. All cows received a daily low herbage allowance of 21 kg DM measured above ground level, 3.0 kg DM of grass silage and 3.5 kg DM of concentrate. Herbage intake was similar between treatments, averaging 8.3 kg DM/day (P > 0.05). Total grazing time was lower for M-PM compared with other treatments (P < 0.01). Milk production was greater for M-AM and M-PM compared with L-PM (P < 0.05). Urea in milk and plasma were greater for L-AM than L-PM and M-PM (P < 0.01). Similarly, rumen ammonia was greater for L-AM compared with M-PM and M-AM (P < 0.05). Nitrogen intake was 13.6% greater for L-AM than L-PM, and 17.5% greater for L-AM than M-PM (P < 0.05). Nitrogen use efficiency was 22.1% greater for M-PM than L-AM, and 11.8% greater for M-PM than L-PM (P < 0.01). In conclusion, the best management combination was observed when a medium herbage mass was delivered in the afternoon, maintaining a low nitrogen intake, low urinary nitrogen excretion and high milk production.
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Condren SA, Kelly AK, Lynch MB, Boland TM, Whelan SJ, Grace C, Rajauria G, Pierce KM. The effect of by-product inclusion and concentrate feeding rate on milk production and composition, pasture dry matter intake, and nitrogen excretion of mid-late lactation spring-calving cows grazing a perennial ryegrass-based pasture. J Dairy Sci 2018; 102:1247-1256. [PMID: 30580955 DOI: 10.3168/jds.2018-14970] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/18/2018] [Indexed: 11/19/2022]
Abstract
Interest is growing in the use of by-products as economical sources of nutrients that complement grazed grass, particularly at times when grass supply is insufficient to meet the nutritional demands of lactating dairy cattle. The objective of this research was to assess the effect of the amount of by-product inclusion and concentrate feeding rate on pasture dry matter intake, milk production and composition, and N excretion from spring-calving cows grazing summer pasture during mid-late lactation. Forty-eight Holstein Friesian dairy cows were randomly assigned to 1 of 4 dietary treatments in a 2 × 2 factorial design. Cows were grazed in one group on a perennial ryegrass-based sward, with pelleted concentrates offered twice daily during milking over a 63-d experimental period. The dietary treatments were 3 kg of concentrate containing 35% by-products; 6 kg of concentrate containing 35% by-products; 3 kg of concentrate containing 95% by-products; and 6 kg of concentrate containing 95% by-products on a fresh matter basis. The by-products used were soybean hulls, palm kernel expeller, and maize dried distillers grains with solubles, included in equal proportions on a dry matter basis. Pasture dry matter intake (14.5 kg/d) was not affected by the amount of by-product inclusion or feeding rate. By-product inclusion had no effect on milk yield (27.1 kg/d) or milk solids (MS) yield (2.0 kg/d). Cows offered 6 kg of concentrate had a greater milk (+1.6 kg/d) and MS (+0.13 kg/d) yield, consumed more N (+0.08 kg/d), and excreted a lower proportion of N in the milk (0.25 vs. 0.27) and feces (0.39 vs. 0.41) and a higher proportion in the urine (0.39 vs. 0.32) compared with cows offered 3 kg of by-product-based concentrate. In conclusion, by-products can be included at up to 95% of the concentrate fed to cows grazing pasture without affecting pasture dry matter intake, milk production or composition, or N excretion. Cows offered 6 kg of concentrates produced more milk and MS than cows offered 3 kg but had higher urinary N excretion. Economics of this yield response will depend on milk and concentrate prices.
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Affiliation(s)
- S A Condren
- School of Agriculture and Food Science, University College Dublin Lyons Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, W23 ENY2, Ireland
| | - A K Kelly
- School of Agriculture and Food Science, University College Dublin Lyons Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, W23 ENY2, Ireland.
| | - M B Lynch
- School of Agriculture and Food Science, University College Dublin Lyons Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, W23 ENY2, Ireland
| | - T M Boland
- School of Agriculture and Food Science, University College Dublin Lyons Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, W23 ENY2, Ireland
| | - S J Whelan
- Institute of Technology Carlow, Wexford Campus, Summerhill, Wexford, Y35 KA07, Ireland
| | - C Grace
- School of Agriculture and Food Science, University College Dublin Lyons Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, W23 ENY2, Ireland
| | - G Rajauria
- School of Agriculture and Food Science, University College Dublin Lyons Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, W23 ENY2, Ireland
| | - K M Pierce
- School of Agriculture and Food Science, University College Dublin Lyons Farm, Lyons Estate, Celbridge, Naas, Co. Kildare, W23 ENY2, Ireland
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Sheehy MR, Fahey AG, Aungier SPM, Carter F, Crowe MA, Mulligan FJ. A comparison of serum metabolic and production profiles of dairy cows that maintained or lost body condition 15 days before calving. J Dairy Sci 2016; 100:536-547. [PMID: 27837975 DOI: 10.3168/jds.2016-11206] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 09/14/2016] [Indexed: 11/19/2022]
Abstract
Body condition score (BCS) change is an indirect measure of energy balance. Energy balance before calving may affect production and health in the following lactation. It is likely that cows may experience BCS loss before calving due to negative energy balance. The objective of this study was to determine if loss of BCS 15d before calving affected milk production, BCS profile, and metabolic status during the transition period and early lactation. On d -15 to d 0 relative to calving, BCS was assessed (1=emaciated, 5=obese) for 98 Holstein-Friesian cows. The cows were divided into 2groups: those that did not lose BCS between d -15 and d 0 (maintained, BCS-M, n=55) and those that lost BCS from d -15 to d 0 (lost, BCS-L, n=43, average loss of 0.29±0.11 BCS). The fixed effects of BCS group, parity, week (day when analyzing milk production records), their interactions, and a random effect of cow were analyzed using PROC MIXED of SAS (SAS Institute Inc., Cary, NC). Before calving, BCS-L cows tended to have higher concentrations of nonesterified fatty acids than BCS-M cows (0.88 vs. 0.78mmol/L). After calving, BCS-L cows had higher nonesterified fatty acid concentrations in wk 1 (0.93 vs. 0.71mmol/L), wk 2 (0.84 vs. 0.69mmol/L), and wk 4 (0.81 vs. 0.63mmol/L) than BCS-M cows. The BCS-L cows had higher concentrations of β-hydroxybutyrate (BHB) in wk 1 (0.72 vs. 0.57mmol/L), wk 2 (0.97 vs. 0.70mmol/L), and wk 4 (0.94 vs. 0.67mmol/L) compared with BCS-M cows. We detected significant reductions in insulin concentrations in BCS-L cows from wk -1 (2.23 vs. 1.37 µIU/mL) to wk 2 (1.68 vs. 0.89 µIU/mL) and wk 4 (2.21 vs 1.59 µIU/mL) compared with BCS-M cows. Prevalence of subclinical ketosis increased in BCS-L cows in wk 3 and 4 when BHB was ≥1.4mmol/L and in wk 1, 3, and 4 when BHB was ≥1.2mmol/L. In wk 1, BCS-L cows tended to have lower levels of calcium than BCS-M cows (2.33 vs. 2.27mmol/L). We found no differences between the groups of cows for milk yield and energy-corrected milk. The BCS-L cows had lower BCS up to 75d in lactation. Overall, BCS-L cows had higher somatic cell scores with an elevated somatic cell score on d 45, d 60, and d 75. There was an overall tendency for BCS-L cows to have higher fat yield and an overall significant increase in fat percentage. Overall, BCS-L cows had lower lactose percentage, with a reduction on d 60. This work shows that BCS loss before calving may have significant consequences for metabolic status, milk composition, somatic cell score, and BCS profile in dairy cows.
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Affiliation(s)
- M R Sheehy
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Devenish Nutrition Ltd., Belfast BT1 3BG, United Kingdom
| | - A G Fahey
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - S P M Aungier
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - F Carter
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - M A Crowe
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - F J Mulligan
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
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Hynes D, Stergiadis S, Gordon A, Yan T. Effects of crude protein level in concentrate supplements on animal performance and nitrogen utilization of lactating dairy cows fed fresh-cut perennial grass. J Dairy Sci 2016; 99:8111-8120. [DOI: 10.3168/jds.2016-11110] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/27/2016] [Indexed: 11/19/2022]
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Hynes DN, Stergiadis S, Gordon A, Yan T. Effects of concentrate crude protein content on nutrient digestibility, energy utilization, and methane emissions in lactating dairy cows fed fresh-cut perennial grass. J Dairy Sci 2016; 99:8858-8866. [PMID: 27592423 DOI: 10.3168/jds.2016-11509] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/27/2016] [Indexed: 11/19/2022]
Abstract
Although many studies have investigated mitigation strategies for methane (CH4) output from dairy cows fed a wide variety of diets, research on the effects of concentrate crude protein (CP) content on CH4 emissions from dairy cows offered fresh grass is limited. The present study was designed to evaluate the effects of cow genotype and concentrate CP level on nutrient digestibility, energy utilization, and CH4 emissions in dairy cows offered fresh-grass diets. Twelve multiparous lactating dairy cows (6 Holstein and 6 Holstein × Swedish Red) were blocked into 3 groups for each breed and assigned to a low-, medium-, or high-CP concentrate diet [14.1, 16.1, and 18.1% CP on a dry matter (DM) basis, respectively], in a 3-period changeover study (25d per period). Total diets contained (DM basis) 32.8% concentrates and 67.2% perennial ryegrass, which was harvested daily. All measurements were undertaken during the final 6d of each period: digestibility measurements for 6d and calorimetric measurements in respiration chambers for 3d. Feed intake and milk production data were reported in a previous paper. We observed no significant interaction between concentrate CP level and cow genotype on any parameter. Concentrate CP level had no significant effect on any energy utilization parameter, except for urinary energy output, which was positively related to concentrate CP level. Similarly, concentrate CP content had no effect on CH4 emission (g/d), CH4 per kg feed intake, or nutrient digestibility. Cross breeding of Holstein cows significantly reduced gross energy, digestible energy, and metabolizable energy intake, heat production, and milk energy output. However, cow genotype had no significant effect on energy utilization efficiency or CH4 parameters. Furthermore, the present study yielded a value for gross energy lost as CH4 (5.6%) on fresh grass-based diets that was lower than the widely accepted value of 6.5%. The present findings indicate that reducing concentrate CP content from 18.1 to 14.1% may not be a successful way of alleviating CH4 emissions from lactating dairy cows offered good-quality fresh grass, but grazing cows could be offered a low-CP concentrate without compromising energy utilization efficiency. Further research is needed to investigate whether larger differences in dietary CP content may yield positive results.
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Affiliation(s)
- D N Hynes
- Sustainable Agri-Food Sciences Division, Agriculture Branch, Agri-Food and Biosciences Institute, Large Park, Hillsborough, BT26 6DR, United Kingdom; Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, University Road, Belfast, BT7 1NN, United Kingdom
| | - S Stergiadis
- Animal, Dairy and Food Chain Sciences Division, Centre for Dairy Research, University of Reading, School of Agriculture, Policy and Development, Earley Gate, PO Box 237, Reading, RG6 6AR, United Kingdom
| | - A Gordon
- Finance and Corporate Affairs Division, Biometrics and Information Systems Branch, Agri-Food and Biosciences Institute, 18a Newforge Lane, Belfast, BT9 5PX, United Kingdom
| | - T Yan
- Sustainable Agri-Food Sciences Division, Agriculture Branch, Agri-Food and Biosciences Institute, Large Park, Hillsborough, BT26 6DR, United Kingdom.
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Campion FP, McGovern FM, Lott S, Fahey AG, Creighton P, Boland TM. Comparison of energy rationing systems for late gestation ewes: Impacts on ewe and lamb performance1. J Anim Sci 2016; 94:3441-3456. [DOI: 10.2527/jas.2016-0522] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Reid M, O’Donovan M, Murphy J, Fleming C, Kennedy E, Lewis E. The effect of high and low levels of supplementation on milk production, nitrogen utilization efficiency, and milk protein fractions in late-lactation dairy cows. J Dairy Sci 2015; 98:5529-44. [DOI: 10.3168/jds.2014-9016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 04/12/2015] [Indexed: 11/19/2022]
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Reid M, O’Donovan M, Elliott C, Bailey J, Watson C, Lalor S, Corrigan B, Fenelon M, Lewis E. The effect of dietary crude protein and phosphorus on grass-fed dairy cow production, nutrient status, and milk heat stability. J Dairy Sci 2015; 98:517-31. [DOI: 10.3168/jds.2014-8437] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 09/24/2014] [Indexed: 11/19/2022]
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Benchaar C, Hassanat F, Gervais R, Chouinard P, Petit H, Massé D. Methane production, digestion, ruminal fermentation, nitrogen balance, and milk production of cows fed corn silage- or barley silage-based diets. J Dairy Sci 2014; 97:961-74. [DOI: 10.3168/jds.2013-7122] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 11/02/2013] [Indexed: 11/19/2022]
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