Effect of genetic potential and level of feeding on milk protein composition

2001 ◽  
Vol 68 (4) ◽  
pp. 569-577 ◽  
Author(s):  
JEAN-BAPTISTE COULON ◽  
DIDIER DUPONT ◽  
SYLVIE POCHET ◽  
PHILIPPE PRADEL ◽  
HELENE DUPLOYER

Two groups of 15 multiparous cows in mid-lactation were used in a Latin square design experiment with 4-week experimental periods. The genetic milk protein concentration level was high in the first group and low in the second. Each group of cows was given in a random order three feeding levels that covered 85, 100 and 115% of energy requirements and 90, 110 and 125% of nitrogen requirements, respectively. In both groups, increasing level of feeding induced a significant increase in milk yield (+2·4 kg/d between lowest and highest levels) and in protein concentration (+1·7 g/kg). The proportion of paracasein in total proteins was not altered by either genetics or nutrition. The proportion of casein in total proteins was slightly increased by 0·5 percentage points (P<0·05) with the intermediate level of feeding. Plasmin and plasminogen activities were not significantly modified by the genetic milk concentration level. Plasmin activity significantly increased with nutrient supplementation, but only in animals of low genetic potential (+21% between low and high levels, P<0·01). Casein composition was not significantly altered by the genetics or level of nutrition. Over the whole range of individual measurements taken (n = 90), the relationships between casein or paracasein and total protein concentrations were linear and very narrow (R2 = 0·92 and 0·95, respectively). The proportion of casein or paracasein in total proteins significantly decreased as plasmin activity increased.

2008 ◽  
Vol 15 (3) ◽  
pp. 235 ◽  
Author(s):  
P. PURSIAINEN ◽  
M. TUORI

The effect of replacing wilted grass silage (GS) with pea-barley intercrop silage (PBS) on feed intake, diet digestibility and milk production was studied with 8 multiparous Ayrshire-cows in a replicated 4 × 4 Latin square experiment. Proportion of PBS was 0 (PBS0), 33 (PBS33), 67 (PBS67) or 100 (PBS100) % of silage dry matter (DM). The DM content was 559 and 255 g kg-1 for GS and PBS. Crude protein content was 131 and 170 g kg-1 DM, respectively. Pea-barley silage was more extensively fermented than GS with total fermentation acid content of 120 vs. 12 g kg-1 DM. Silage was fed for ad libitum intake and supplemented with on the average 13 kg concentrate per day. Silage DM intake was 9.2 (PBS0), 9.7 (PBS33), 9.0 (PBS67) and 7.1 (PBS100) kg per day (Pquadr. < 0.05). The energy corrected milk yield [30.3 (PBS0), 29.8 (PBS33), 30.3 (PBS67), 31.3 (PBS100) kg per day] was not significantly affected by the treatment. Milk protein concentration decreased linearly (P < 0.05) in response to feeding PBS. It is concluded that PBS can replace up to two thirds of wilted, moderate quality GS in the feeding of dairy cows because in this experiment pure pea-barley silage reduced silage intake.


1994 ◽  
Vol 61 (2) ◽  
pp. 179-189 ◽  
Author(s):  
John E. Hermansen ◽  
Steen Ostersen ◽  
Ole Aaes

SummaryIn a 2 × 2 × 3 factorial design grazing experiment we investigated the effect of fertilizer (none or 240 kg N/ha), amounts of clover grass available (low or high) and type and level of daily supplementary feed for each cow (3·5 kg barley, 3·5 kg concentrate mixture rich in protein and fat, or both, 7 kg) on the protein composition and renneting properties of their milk. The experiment was carried out in two successive grazing seasons (years) and included a total of 79 Danish Holstein cows. The effect on milk protein composition was determined in both years whereas the effect on renneting properties was determined only in the second year. Fertilization of the clover grass significantly decreased total milk protein concentration (− 1·4 g/kg; P < 0·01) and tended also to decrease the relative proportion of whey protein N. Fertilization had no effect on renneting properties. Increased availability of clover grass significantly increased milk protein concentration (1 g/kg; P < 0·05) and resulted in significantly poorer renneting properties, that is increased clotting time (P < 0·01) and decreased coagulum development. These effects seemed to be mediated through an effect on the pH of the milk (+ 0·05; P < 0·05) as the effect was markedly reduced when statistical correction was made for the actual pH. Use of the protein- and fat-rich concentrate mix (3·5 kg) significantly reduced the total protein content of the milk (P < 0·05) and increased the proportion of non-protein N (NPN) in total N compared with use of the other supplementary feeds (P < 0·05). We found no effect on renneting properties of the different supplementary feeds. Throughout the grazing season and independent of the main treatments, the NPN proportion of milk N increased at the expense of casein N. At the same time, renneting properties became poorer, especially with high clover grass availability.


2001 ◽  
Vol 73 (1) ◽  
pp. 137-147 ◽  
Author(s):  
J. D. Sutton ◽  
R. H. Phipps ◽  
S. B. Cammell ◽  
D. J. Humphries

AbstractThis paper reports the results of three experiments designed to attempt to improve the efficiency of milk production from diets based on a 1: 2 dry matter (DM) mixture of grass silage and whole-crop wheat (WCW) harvested at 550 to 600 g DM per kg and treated with 40 g urea per kg DM. In the first experiment a control diet of the forage mixture offered ad libitum with 9 kg fresh weight (FW) per day of a concentrate mix was compared with seven treatments in which the forage or the concentrates were varied. Eight multiparous cows were used in a four-period incomplete change-over design with 4-week periods. Caustic treatment of the WCW increased DM intake (P < 0·001) but tendencies for higher yields of milk and milk protein were not significant. Replacement of 2 kg FW concentrates per day by the same weight of molasses as a 24-h pre-soak of the forage (molasses pre-treatment) or added to the forage at feeding increased DM intake (P < 0·001) but did not increase milk yield or yield of milk solids. Molasses pre-treatment and molasses added to the concentrates reduced milk protein concentration (P < 0·05). Replacement of 2 kg FW concentrates per day by the same weight of ground wheat increased DM intake when added to the concentrates (P < 0·001) but not when added to the forage and milk yield was unaffected by either method of addition. The ground wheat tended to reult in higher milk protein concentrations than the molasses. Increasing the digestible undegradable protein content of the concentrates had no significant effect on food intake or milk production. In the second experiment diet digestibility and energy and nitrogen (N) balance were measured for the control diet and three of the treatments from experiment 1 in four multiparous cows in a 4 ✕ 4 Latin-square experiment with 5-week periods. There were no significant effects on food intake or milk yield. Caustic treatment reduced starch digestibility (P < 0·001) and increased neutral-detergent fibre (NDF) digestibility (P < 0·05) but had no effects on energy utilization. It also reduced N intake (P < 0·01) and urine N losses (P < 0·001) by reducing the ammonia concentration of the WCW. Molasses added to the forage or concentrates reduced milk protein concentration (P < 0·05) and digestibility of both starch and NDF (P < 0·05) but energy utilization was unaffected. In a further Latin-square experiment with the same treatments and four fistulated lactating cows, caustic treatment reduced daily mean ammonia concentration (P < 0·01) and increased daily mean pH (P < 0·01) in the rumen. It is concluded that these treatments did not generally improve the value of WCW although caustic treatment increased milk yield and milk protein yield consistently but not significantly. However practical problems may limit its use on the farm. Urea-treated WCW must be accepted as being a relatively low-energy food although with high intake characteristics, and future work should concentrate on evaluating WCW harvested at an earlier stage of maturity.


2005 ◽  
Vol 72 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Florian Leiber ◽  
Daniel Nigg ◽  
Carmen Kunz ◽  
Martin RL Scheeder ◽  
Hans-Rudolf Wettstein ◽  
...  

The influence of high altitude, alpine origin of the forage and roughage-only diets on milk protein content and composition, plasmin activity and cheesemaking properties was investigated. There were four treatment groups, each consisting of six dairy cows in early to mid-lactation. Two groups were fed only with hay ad libitum either at 2000 m or at 400 m a.s.l. One group, kept in the lowlands, was pair-fed to the alpine-site group and another group received a mixed diet of silages, hay and concentrates. Two hay types, harvested either at the alpine site or in the lowlands, were offered to all cows fed with hay alone, following a change-over design in three periods each of 3 weeks. In the respective third week, milk was sampled at every milking. Hay of alpine origin significantly reduced milk protein, in particular whey proteins, which is why the casein number increased. κ-Casein proportion in total casein was reduced and its glycosylation was increased by the alpine hay. The apparent plasminogen-derived activity was reduced when alpine hay was given, but apparent plasmin activity and rennet coagulation properties of the milk were not affected by hay type. Independent of hay type, the high altitude group showed a significantly reduced milk protein content, lower glycosylation of κ-casein and impaired rennet coagulation properties. For several of the traits, the trend was the same in the pair-fed group. There was no effect of altitude on apparent plasmin activity. Hay-alone v. the mixed diet resulted initially in marked declines in milk protein content but did not impair cheesemaking properties. Thus the extensive diet without concentrates, typical of high-alpine conditions, contributed less to the overall effect of extensive alpine v. intensive lowland feeding systems than hay quality and altitude did. In conclusion, certain positive influences of the alpine sojourn of cows on cheese processing quality are overruled by the major adverse impact of lower milk protein content.


2000 ◽  
Vol 25 ◽  
pp. 169-173
Author(s):  
M.J. Auldist ◽  
C.M. Menzies ◽  
R.J. Hooper ◽  
C.G. Prosser

AbstractThe objective of this study was to measure the effects of varying doses of atropine on the concentration and composition of milk protein and on blood α-amino N levels. Four treatments were administered to each of 12 cows over 12 days in a replicated Latin square experiment. There were at least 2 days between each of 4 treatment days. Treatments were: control (C; saline); low dose (L; 30mg atropine/kg LWT); medium dose (M; 40mg atropine/kg LWT); and 2 x low dose (2L). All treatments were administered via subcutaneous injection immediately after the morning milking; the second dose of the 2L treatment was given two hours later. Milk was sampled from each cow at the morning milking (time 0 h). Cows were then milked again 2, 6 and 10 h after treatment, and milk samples again collected. Blood samples were drawn from the coccygeal vein of each cow after each milking. Atropine decreased milk secretion at 6 h for the 2L treatment and 10 h for all treatments. Atropine reduced concentrations of milk protein and casein at 2 h and 6 h, but not at 10 h. Concentrations of whey proteins and of α-casein were depressed by atropine only at 6 h post-treatment, while a reduction in α-lactalbumin due to atropine was observed at 6 and 10 h post-treatment. In contrast, atropine increased concentrations of IgG and BSA at 6 h and 10 h post-treatment. Atropine also increased the ratio of casein:total protein at 6 h after injection. There was no difference between the effects of the low and medium doses of atropine, but the double low dose induced effects which were greater than for the single doses. Effects of a single dose of atropine were greatest for most milk proteins at 6 h post treatment; thus this would be the most useful milk sampling time for future experiments. Atropine did not significantly affect α-amino N concentrations in whole blood, although there was a trend for a reduction for all treatments at 2 h after treatment. Atropine may be useful for reducing milk protein concentrations and circulating levels of certain blood amino acids to base levels, during studies designed to elucidate the effects of perturbations in the blood amino acid profile on milk protein composition.


1996 ◽  
Vol 63 (1) ◽  
pp. 1-10 ◽  
Author(s):  
J. M. Moorby ◽  
R. J. Dewhurst ◽  
C. Thomas ◽  
S. Marsden

AbstractTo investigate the effects of energy source and protein level of diets on milk protein content, 12 multiparous Holstein-Friesian cows were used in a 4 × 4 Latin square change-over experiment with 4-week periods. Four diets were offered, with ad libitum silage as proportionately 0·40 of the diet, and the remaining 0·60 as one of four concentrates, two based on barley and two on molassed sugar-beet pulp. Two protein levels were achieved by altering the amounts of digestible undegraded protein in the concentrates, with all diets formulated to supply equal quantities of rumen degradable protein. There was no effect of diet on dry-matter intakes. Both starch and high dietary protein levels significantly increased milk protein concentration (P < 0·05), but had no effects on milk fat and lactose concentrations. Mean milk yields were significantly higher (P < 0·05) with increased dietary protein. Dietary protein significantly affected the yields of milk protein (P < 0·01) and lactose (P < 0·05) but not that of fat. Urinary allantoin excretion was significantly greater with both high protein (P < 0·05) and starch-based diets (P < 0·05). No significant interaction effects were found. It is concluded that dietary effects were due largely to differences in supply of rumen degradable protein; increases in milk protein concentration were therefore brought about by increasing the protein supply to the animal.


2001 ◽  
Vol 68 (1) ◽  
pp. 27-34 ◽  
Author(s):  
CHANG-HYUN KIM ◽  
TAE-GYU KIM ◽  
JAI-JUN CHOUNG ◽  
DAVID G. CHAMBERLAIN

To test the hypothesis that the availability of glucose or its precursors can influence the response of milk protein concentration to the intravenous infusion of amino acids, five cows were used in a 5 × 5 Latin square design with period lengths of 7 d. The five treatments were the basal diet of grass silage ad lib. plus 5 kg/d of a cereal-based supplement containing feather meal (Basal); Basal plus 4 g/d histidine, 8 g/d methionine and 26 g/d lysine (4H); Basal plus 8 g/d histidine, 8 g/d methionine and 26 g/d lysine (8H); and these two amino acid mixtures together with 600 g/d of glucose (4HG and 8HG respectively). Earlier experiments with this basal diet had shown that histidine was first-limiting for secretion of milk protein, followed by methionine and lysine. The yield of milk protein was increased progressively with the amount of histidine infused. The efficiency of transfer of histidine into milk protein was 0·42 for the 4H and 4HG and 0·35 for the 8H and 8HG treatments, and the concentration of milk protein was increased over Basal by all infusion treatments. However, milk protein concentrations were higher, and lactose concentrations in the milk were lower, in the absence of added glucose. Concentrations of insulin in blood plasma were not affected by treatment. It is concluded that, with the treatments without added glucose, a shortage of glucose prevented an increase in lactose secretion, and hence limited the increase in milk yield, leading to an increased concentration of protein in the milk.


2008 ◽  
Vol 15 (3) ◽  
pp. 252 ◽  
Author(s):  
A. VANHATALO ◽  
T. GÄDDNÄS ◽  
T. HEIKKILÄ

The study was conducted to evaluate effects of silage type (grass-red clover vs. pure grass) and grain supplement (oats vs. barley) on rumen fermentation, post-ruminal nutrient flows, diet digestion and milk production. Four primiparous Finnish Ayrshire cows fitted with cannulae in the rumen and duodenum were used in a 4 × 4 Latin square experiment with four 28-d experimental periods and 2 × 2 factorial arrangements of treatments. Using red clover-containing (40%) silage rather than pure grass silage had minor effects on rumen fermentation or diet digestion but increased non-ammonia nitrogen (N) flow in terms of increased flows of microbial and dietary N entering to the small intestine. This was reflected as a reduced ruminal N degradability on grass-red clover diets. Furthermore, grass-red clover diets in comparison to grass silage diets increased milk lactose concentration and yields of milk, protein and lactose. Feeding oats in replacement for barley had minor effects on rumen fermentation or post-ruminal non-ammonia N flows but reduced digestibility of organic matter and neutral detergent fibre in the diet. Using oats rather than barley increased yields of milk and lactose but reduced milk protein concentration. Oats also increased proportions of C18:0 and C18:1 in milk fat and reduced those of C10:0 to C16:0. It is concluded that inclusion of red clover and replacement of barley with oats in grass silage based diets have beneficial effects in dairy cow production.;


2021 ◽  
Vol 12 (6) ◽  
pp. 2605-2616
Author(s):  
Teresa Francis Wegrzyn ◽  
Alejandra Acevedo-Fani ◽  
Simon M. Loveday ◽  
Harjinder Singh

The gastric digestion behaviours of blended protein beverages containing different ratios of casein, whey protein and soya protein that were heat-treated at 60 °C or 80 °C were investigated using an in vitro dynamic human gastric simulator.


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