scholarly journals Validation of protein evaluation systems by means of milk production experiments with dairy cows

1994 ◽  
Vol 42 (2) ◽  
pp. 89-104
Author(s):  
W.M. Van Straalen ◽  
C. Salaun ◽  
W.A.G. Veen ◽  
Y.S. Rijpkema ◽  
G. Hof ◽  
...  

Protein evaluation systems (crude protein (CP), digestible crude protein (DCP), protein digested in the intestine (PDI), amino acids truly absorbed in the small intestine (AAT), absorbed protein (AP), metabolizable protein (MP), crude protein flow at the duodenum (AAS) and digestible protein in intestine (DVE)) were validated using data from 15 production experiments with dairy cows, carried out in the Netherlands. Only treatments that were deficient in protein according to at least one system were selected. Average yield was 31.2 kg of fat and protein corrected milk daily and 989 g of milk protein daily. The observed milk protein production was compared with milk protein production predicted from the protein supply and requirements in each system. The difference between observed and predicted milk protein production expressed as the absolute and relative prediction error was smallest for the DVE-system (-2 g/day; 5.7%) and increased in the order CP (-22 g/day; 6.7%), PDI (-19 g/day; 7.8%), DCP (-44 g/day; 8.8%), AP(-37 g/day; 9.3%), AAS (100 g/day; 11.7%), AAT (112 g/day; 13.4%) and MP system (204 g/day; 22.9%). Predictions can be improved when a variable efficiency of milk protein production is used. In the DVE-system the observed efficiency decreased with increasing protein to energy ratio in the diet and milk production level. It was concluded that under Dutch conditions the prediction of milk protein production decreased in the order DVE, CP, PDI, DCP, AP, AAS, AAT and MP system.

2017 ◽  
Vol 84 (3) ◽  
pp. 240-247 ◽  
Author(s):  
Ruairi P McDonnell ◽  
Martin vH Staines

This research paper describes the effect of partially replacing wheat with maize grain and canola meal on milk production and body condition changes in early lactation Holstein-Friesian dairy cows consuming a grass silage-based diet over an 83-d period. Two groups of 39 cows were stratified for age, parity, historical milk yield and days in milk (DIM), and offered one of two treatment diets. The first treatment (CON) reflected a typical diet used by Western Australian dairy producers in summer and comprised (kg DM/cow per d); 8 kg of annual ryegrass silage, 6 kg of crushed wheat (provided once daily in a mixed ration), 3·6 kg of crushed lupins (provided in the milking parlour in two daily portions) and ad libitum lucerne haylage. The second treatment diet (COMP) was identical except the 6 kg of crushed wheat was replaced by 6 kg of a more complex concentrate mix (27% crushed wheat, 34% maize grain and 37% canola meal). Lucerne haylage was provided independently in the paddock to all cows, and no pasture was available throughout the experiment. The COMP group had a greater mean overall daily intake (22·5vs20·4 kg DM/cow) and a higher energy corrected milk (ECM) yield (29·2vs27·1 kg/cow;P= 0·047) than the CON cows. The difference in overall intake was caused by a higher daily intake of lucerne haylage in COMP cows (4·5vs2·3 kg DM/cow). The CON group had a higher concentration of milk fat (42·1vs39·3 g/kg;P= 0·029) than COMP cows. Milk protein yield was greater in COMP cows (P< 0·021); however, milk fat yield was unaffected by treatment. It is concluded that partially replacing wheat with canola meal and maize grain in a grass silage-based diet increases voluntary DMI of conserved forage and consequently yields of ECM and milk protein.


1998 ◽  
Vol 1998 ◽  
pp. 24-24 ◽  
Author(s):  
J.M. Moorby ◽  
P.R. Evans ◽  
N.E. Young

The efficiency of use of feed protein for milk protein production is very poor, particularly for animals offered conserved forages. Contributing to this is the inefficient capture of rumen degradable N in situations where a readily fermentable energy supply is not available for use by the rumen microbial population. The incorporation of a whole crop cereal into a conserved forage could increase rumen protein efficiency. This experiment was carried out to investigate the milk production of dairy cows offered a conserved forage of a whole crop barley and kale bicrop compared with grass silage, and a mixture of the two.


Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3545
Author(s):  
Layla King ◽  
Janaka Wickramasinghe ◽  
Brooke Dooley ◽  
Carrie McCarthy ◽  
Emily Branstad ◽  
...  

The study objective was to determine the effects of rumen-protected methionine (Met) by microencapsulation (RPM) on amino acid (AA) supply to the udder, milk production, and manure nitrogen (N) losses of dairy cows. A corn and soybean-based diet deficient in metabolizable Met (~10 g/d) was supplemented with RPM providing 0, 11.0, 19.3, and 27.5 g/d of Met. Dry matter intake (DMI), milk production, plasma essential AA (EAA), mammary plasma flow (MPF), and fecal (FN) and urinary N (UN) outputs (g/d) were determined. The RPM increased linearly milk yield, milk protein yield, and energy corrected milk yield (p < 0.040) without affecting DMI. Milk protein yield increased by 50 g/d for the 19.3 vs. 0 g/d dose (p = 0.006) but the rate of increment decreased for 27.5 g/d dose. Plasma Met, and MPF increased linearly with RPM dose (p < 0.050). Apparent total tract digestibility of crude protein (p = 0.020) and FN (p = 0.081) decreased linearly with RPM. The UN did not change but total manure N decreased linearly with RPM (p = 0.054). The RPM (19.3 g/d) seemed to help cows overcome the metabolizable Met deficiency while mitigating manure N excretions to the environment.


1998 ◽  
Vol 1998 ◽  
pp. 24-24
Author(s):  
J.M. Moorby ◽  
P.R. Evans ◽  
N.E. Young

The efficiency of use of feed protein for milk protein production is very poor, particularly for animals offered conserved forages. Contributing to this is the inefficient capture of rumen degradable N in situations where a readily fermentable energy supply is not available for use by the rumen microbial population. The incorporation of a whole crop cereal into a conserved forage could increase rumen protein efficiency. This experiment was carried out to investigate the milk production of dairy cows offered a conserved forage of a whole crop barley and kale bicrop compared with grass silage, and a mixture of the two.


1997 ◽  
Vol 1997 ◽  
pp. 83-83
Author(s):  
J A Metcalf ◽  
R J Mansbridge ◽  
J S Blake ◽  
J R Newbold ◽  
J D Oldham

Previous work at ADAS Bridgets aimed at evaluating the Metabolisable Protein (MP) system (AFRC 1992) has indicated that the efficiency of MP use for milk production may be too high, or that the amount of MP required for maintenance may be too low (Newbold et al 1994). This experiment was designed to indicate the true efficiency of MP use for milk protein production when metabolisable energy (ME) and MP supplies were balanced.


1998 ◽  
Vol 7 (2) ◽  
pp. 219-250 ◽  
Author(s):  
Pekka Huhtanen

The objective of this paper is to review research which has evaluated the feeding of dairy cows with diets containing large proportions of grass silage. In Finland, milk production systems evolved are based on the use of restrictively fermented silages. Higher potential yields, smaller production risks than with cereal grains, short grazing period and high digestibility of grasses grown in northern latitudes have facilitated this development. Factors affecting nutrient supply from these diets are discussed. Digestibility is determined mainly by the stage of maturity at harvesting and it is not markedly affected by the level of energy and protein supplementation. Intake of grass silage is influenced both by digestibility and fermentation characteristics. Efficiency of microbial synthesis is high in animals given diets based on restrictively fermented silage but rumen fermentation pattern is characterised by low molar proportions of propionate. Production responses to additional concentrate are relatively small, especially when the amount of concentrate exceeds 10 kg day-1. High substitution of silage dry matter (DM), negative associative effects on digestion and partitioning of energy towards body tissues account for small production responses. Protein supplementation has consistently increased milk protein yield but responses do not appear to be related to the level of milk production, silage crude protein content, amount of concentrate or stage of lactation. The new protein evaluation system provides an accurate prediction of protein yield with the typical Finnish dairy cow diets. The high slopes (ca. 0.5) between protein supply and milk protein yield within experiments suggest that protein supply is suboptimal and protein supplements are used with a high efficiency.


Author(s):  
D. Tristant ◽  
C. A. Moran

SummaryThe following trial was conducted to evaluate the impact of feeding Yea-Sacc® (YS; Alltech Inc, USA), a zootechnical feed additive based on a live probiotic strain of Saccharomyces cerevisiae, to lactating dairy cows over a 12 week period. Sixty-four primiparous and multiparous Holstein dairy cows, grouped to give similar range of parity, physiological and milk production stages, were selected for the study. Cows were equally allocated to either a control feed group or a diet supplemented with YS (32 cows per treatment). The test diet was formulated to include YS (Yea-Sacc® Farm Pak) incorporated in the total mixed ration (TMR), supplying a target dose of 5 × 107 CFU/kg feed dry matter (DM). This target dose delivered 1 × 109 CFU/cow/day, for a cow consuming 20 kg feed (DM basis) daily. Each cow was considered a replicate unit. Cows were fed a nutritionally adequate total TMR plus hay and a supplementary protein/energy concentrate (calculated according to milk yield) for 12 weeks, supplied once a day after the morning milking. Weigh backs of feed were recorded daily, with refusals being maintained at 3% of the total intake. During the 12 week study period, YS had significant beneficial effects on milk production (+0.8 kg/day; P = 0.003), energy corrected milk production (+1.4 kg/day; P < 0.0001), synthesis of milk protein (+36 g/day; P = 0.001), milk protein content (+0.3 g/kg; P = 0.009), and milk urea content (−0.09 mg/l; P = 0.004). The synthesis of milk fat was similar between treatments but milk fat content was lower for the YS group compared to the control group (−1.1 g/kg; P = 0.0002). Lactose content was always higher (+0.8 g/kg; P < 0.0001) for the YS group, indicating enhanced energy utilisation. In general, the effect of YS was higher during the first study period (one to seven weeks), when cows were in early lactation and the production potential was higher. YS cows produced significantly more milk during the study, and an additional 220 kg milk per cow was sold from this group from the output measured from the beginning of the study to two weeks post-trial. However, the statistical analysis including the post-study period did not show a significant effect. The 305-day simulated milk production was higher for the YS group (+400 kg/cow) but again the difference was not significant. In conclusion, YS at a target dose of 5 × 107 CFU/kg DM improved milk production and milk quality in healthy dairy cows. In addition, when the data were included in a whole-farm model, feeding YS reduced methane emissions by 4%, reduced the number of animals required for the desired milk production by 4% and increased overall farm margins by 1.4%.


Author(s):  
R.G. Wilkinson ◽  
C.M. Minter ◽  
G. Duffy ◽  
J. Celerier

Increasing the level of concentrate fed to lactating ruminants reduces forage intake, but increases the yield of milk and milk constituents (Aston et al. 1991). However, the proportion of the total response due to additional metabolisable energy (ME) or crude protein supply (CP) is unclear. Recent work with dairy cows (Aston et al. 1992) suggests that additional ME or CP fed as concentrate reduced and slightly increased silage intake respectively. Additional CP had twice the effect on milk and three times the effect on protein yield than additional ME. However, ME and CP were equally important in determining fat yield. The objective of the trial was to investigate whether dairy sheep respond to additional ME or CP supply as concentrate in a similar way to dairy cows.Three concentrate diets were formulated to contain 13.0 MJ/kg DM ME and either 100 (A), 200 (B) or 400 (C) g/kg DM CP. After weaning (6 weeks), 24 mature Freisland ewes were housed individually, and allocated by liveweight and initial milk yield to receive concentrate DM at daily rates of 0.8 kg, providing 10.4 MJ/day ME and 160 (B) or 320 (C) g/day CP (LLP, LHP), or 1.6 kg, providing 20.8 MJ/day ME and 160 (A) or 320 (B) g/day CP (HLP, HHP). The trial lasted 8 weeks and was analysed as a 2 X 2 factorial design.


Author(s):  
F.P. O'Mara ◽  
J.J. Murphy ◽  
M. Rath

Milk protein synthesis may be limited by amino acid (AA) flow to the duodenum. This can be increased by increasing the flow of microbial AA's or undegraded feed AA's. This experiment was carried out to determine the effect on milk production and nutrient flows at the duodenum of including fishmeal (120g/kg) in the supplement to grass silage at two levels of supplement feeding.The treatments, arranged in a 2x2 factorial, were 1.) 3.5 kg/day of 0% fishmeal supplement (L-UDP), 2.) 7 kg/day of L-UDP, 3.) 3.5 kg/day of 12% fishmeal supplement (H-UDP), and 4.) 7 kg/day of H-UDP. Supplements were fed to 3 6 Friesian cows in a 4x4 multiple Latin-square trial with three week periods to determine production responses, and to four ruminally and duodenally cannulated cows to determine rumen fermentation and nutrient flows. Flows were determined by the dual marker technique of Faichney (1975) using cobalt-EDTA and ytterbium acetate as liquid and solid phase markers respectively. Purines were used as the bacterial marker (Zinn and Owens, 1986). Degradability of the feeds was measured in 3 other cows using the small bag technique described by De Boer et al. (1987).


2001 ◽  
Vol 2001 ◽  
pp. 192-192
Author(s):  
R.E. Lawson ◽  
A.R. Moss ◽  
C. Rymer ◽  
J.S. Blake

Mansbridge (1995) reported that replacing ground wheat with a mix of ground wheat and maize grain increased milk protein concentration, which led the authors to speculate that increased inclusion of maize grain increased rumen by-pass starch. Indeed, de Visseret al(1990) reported that feeding less rapidly degradable starches has led to increased milk protein concentration.The objective of this study was to examine the effects of starch concentration and source on feed intake, milk yield and milk composition of dairy cows.


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