scholarly journals THE INFLUENCE OF GENOTYPIC FACTORS ON LONGEVITY AND LIFETIME PRODUCTION OF DAIRY COWS

2021 ◽  
Vol 61 ◽  
pp. 90-106
Author(s):  
Yu. P. Polupan ◽  
R. V. Stavetska ◽  
V. A. Siriak
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Fat ◽  
Milk Protein ◽  
Holstein Cows ◽  
Paternal Inheritance ◽  
Lactation Length ◽  
Related Group ◽  
Dairy Breed ◽  
Daily Milk

The influence of genotypic factors (breed, Holstein share heredity, line or related group, sire) on the longevity and lifetime production of dairy cows has been investigated. The study was carried out in a retrospective statistical experiment on the commercial dairy farm “Terezyne”, which located in Kyiv region. The formed matrix of observations in the sta format generally contained information about 5703 cows for 458 variables. Holstein cows were characterized by higher longevity (1489 ± 27.8 days) and higher lifetime milk production (21940 ± 500.9 kg), the lowest longevity and lifetime milk production had cows of Ukrainian Red-and-White dairy breed. Holstein cows compared to animals of Ukrainian Red-and-White dairy breed had in average more lactations (+0.57 ± 0.187) and higher number of total calves (+0.59 ± 0.244). They had an advantage in lifespan by 218 ± 80.1 days, productive lifespan – by 326 ± 82.0 days, total lactation length – by 282 ± 62.2 days. During the lifetime, they produced 4119 ± 1398.4 kg more milk and 549.3 ± 99.62 kg more milk fat and milk protein. Lifetime daily milk yield of Holstein cows was on average 2.6 ± 0.37 kg higher, lifetime daily milk fat and milk protein – 208 ± 26.7 g more compared to animals of the Ukrainian Red-and-White dairy breed. Cows of Ukrainian Black-and-White dairy breed in most traits were intermediate between Holstein and Ukrainian Red-and-White dairy breed. While increasing Holstein share heredity the longevity and lifetime production of cows tended for curvilinear growing. Lifetime of Holstein cows (100%) in the herd was 0.16 ± 0.405 lactations and 325 ± 170.7 days (P < 0.1) longer compared to animals with Holstein share heredity less than 75%. Their lifetime milk production was 8969 ± 2351.6 kg (P < 0.001) higher, lifetime milk fat and milk protein production by 709.9 ± 164.73 kg (P < 0.001) higher, lifetime daily yield by 3.0 ± 0.62 kg (P < 0.001) and 250 ± 43.5 g (P < 0.001), respectively, higher. The cows of Starbuck 352790, Valiant 1650414 and Elevation 1491007 lines and daughter of V. Astronomer 2160438 and H. R. Artist 6284191 sires showed the best longevity and lifetime production. The advantage of cows of the related group of Starbuck 352790 in comparison to animals of other lines in total number of lactations was 0.28–1.29, number of total calves – 0.16–1.20, lifespan – 90–508 days, productive lifespan – 116–603 days, total lactation length – 98–500 days, lifetime milk production – 1402–12161 kg, lifetime milk fat and milk protein production – 115–892 kg. Daughters of bull V. Astronomer 2160438 characterized by 0.96–2.72 more total number of lactations than daughters of other bulls; they had 0.80–2.33 higher average number of total calves. In terms of lifespan, productive lifespan and total lactation length, daughters of this bull were predominated the daughters of other bulls by 392–1037, 297–1143 and 278–971 days, respectively. One-way analysis of variance showed that the greatest influence on longevity and lifetime production of dairy cows had a paternal inheritance, the lowest – breed, it means there is a tendency of increasing the influence of genotypic factors on the researched traits while reducing the level of selection group in the system hierarchy. The strength of breed influence (higher level of intraspecific selection system hierarchy) on the traits of longevity and lifetime production of cows ranged from 1.1 to 12.5%, Holstein share heredity – 3.9 to 19.5%, line or related group – 4.0–19.8% and paternal inheritance – 25.0–47.6%. Greater degree of influence of paternal inheritance is explained both by the lowest (basic) level of intrabreed system hierarchy (the closest level of intragroup kinship) and (partially) by a much higher number of gradations of the organized factor.

Replacing wheat with canola meal and maize grain in the diet of lactating dairy cows: Feed intake, milk production and cow condition responses

2017 ◽  
Vol 84 (3) ◽  
pp. 240-247 ◽  
Author(s):  
Ruairi P McDonnell ◽  
Martin vH Staines
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Fat ◽  
Milk Protein ◽  
Daily Intake ◽  
Canola Meal ◽  
Grass Silage ◽  
Holstein Friesian ◽  
Maize Grain ◽  
The Difference

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.

The efficacy of feeding a live probiotic yeast, Yea-Sacc®, on the performance of lactating dairy cows

2015 ◽  
Vol 3 ◽  
Author(s):  
D. Tristant ◽  
C. A. Moran
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Fat ◽  
Milk Protein ◽  
Feed Additive ◽  
Control Group ◽  
Target Dose ◽  
Lactating Dairy Cows ◽  
Farm Model ◽  
The Impact

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%.

scholarly journals Betaine Improves Milk Yield in Grazing Dairy Cows Supplemented with Concentrates at High Temperatures

Animals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 57 ◽  
Author(s):  
Frank Dunshea ◽  
Kehinde Oluboyede ◽  
Kristy DiGiacomo ◽  
Brian Leury ◽  
Jeremy Cottrell
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Milk Fat ◽  
Milk Protein ◽  
The Mean ◽  
Fat Yield ◽  
Grazing Dairy Cows ◽  
Daily Milk Yield ◽  
Betaine Supplementation ◽  
Daily Milk

Betaine is an organic osmolyte sourced from sugar beet that accumulates in plant cells undergoing osmotic stress. Since the accumulation of betaine lowers the energy requirements of animals and, therefore, metabolic heat production, the aim of this experiment was to investigate if betaine supplementation improved milk yield in grazing dairy cows in summer. One hundred and eighteen Friesian × Holstein cows were paired on days in milk and, within each pair, randomly allocated to a containing treatment of either 0 or 2 g/kg natural betaine in their concentrate ration for approximately 3 weeks during February/March 2015 (summer in Australia). The mean maximum February temperature was 30 °C. Cows were allocated approximately 14 kg dry matter pasture and 7.5 kg of concentrate pellets (fed in the milking shed) per cow per day and were milked through an automatic milking system three times per day. Betaine supplementation increased average daily milk yield by over 6% (22.0 vs. 23.4 kg/day, p < 0.001) with the response increasing as the study progressed as indicated by the interaction (p < 0.001) between betaine and day. Milk fat % (p = 0.87), milk protein % (p = 0.90), and milk somatic cell count (p = 0.81) were unchanged by dietary betaine. However, betaine supplementation increased milk protein yield (677 vs. 719 g/day, p < 0.001) and fat yield (874 vs. 922 g/day, p < 0.001) with responses again being more pronounced as the study progressed. In conclusion, dietary betaine supplementation increased milk and component yield during summer in grazing dairy cows.

PSVIII-14 Effect of Certillus, a direct-fed microbial, on milk yield, milk components, and feed intake in primi- and multiparous lactating Holstein cows

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 426-427
Author(s):  
Excel Rio S Maylem ◽  
Martina Vargiu ◽  
Caleb Melton ◽  
Jesse Thompson ◽  
John O’Neill ◽  
...  
Keyword(s):  
Milk Production ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Repeated Measures ◽  
Milk Fat ◽  
Holstein Cows ◽  
Fat Percentage ◽  
Milk Components ◽  
Daily Milk Production ◽  
Daily Milk

Abstract To determine the effect of Certillus on milk production, milk components and feed efficiency, primiparous (n = 13) and multiparous (n = 12) Holstein cows were assigned to one of two dietary groups starting from 8 to 120 days of lactation. The controls (n = 13) received regular TMR ration, and treated cows (n =12) received control TMR plus 2 x 109 cfu/head of Certillus (Church & Dwight Co., Inc., Waukesha, WI). Cows were housed in an open-air free-stall barn with 16 Insentec electronic feeders (8 feeders/group) to record daily feed events and intake (DMI). Cows were provided with ad libitum TMR fed twice daily and were milked twice daily. Milk samples were taken weekly during successive a.m./p.m. milkings and analyzed for percentage milk fat, protein, lactose, and milk urea nitrogen (MUN). Data were analyzed using a repeated-measures 2 x 2 factorial ANOVA. Daily milk production (4%FCM) was influenced (P &lt; 0.05) by treatment x parity, week and parity, averaging 11% greater (P &lt; 0.05) in Certillus-fed than control cows. Milk fat percentage increased (P &lt; 0.005) from 4.02 to 4.41 + 0.09% with Certillus feeding. Milk lactose was influenced (P &lt; 0.05) by week and treatment x parity. Milk protein was affected by week (P &lt; 0.001) only. Certillus decreased (P &lt; 0.05) MUN levels such that MUN was 1.0 mg/dL greater (P &lt; 0.001) in Certillus-fed than control cows. Feed intake was reduced by 9% (P &lt; 0.01) and feed efficiency (kg 4%FCM/kg DMI) was improved by 14% (P &lt; 0.05) in Certillus-fed versus control cows. We conclude that Certillus may hold potential as an effective direct-fed microbial to increase feed efficiency and milk production.

scholarly journals Effects of mammae hand massages on oxytocin release, milk yield, and milk quality in dairy cows

2021 ◽  
Vol 19 (3) ◽  
pp. 311
Author(s):  
Inggit Kentjonowaty ◽  
Achmad Bagus Adhiluhung Mardhotillah ◽  
Trinil Susilawati ◽  
Puguh Surjowardojo
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Yield ◽  
Milk Fat ◽  
Milk Protein ◽  
Block Design ◽  
Fat Content ◽  
Milk Quality ◽  
Randomized Block Design ◽  
Oxytocin Release

<p class="MDPI17abstract"><strong>Objective: </strong><span lang="EN-GB">The objective of this study was conducted to evaluate the effects of Mammae Hand Massages (MHM) on oxytocin release, milk yield, and milk quality in dairy cows.</span></p><p class="MDPI17abstract"><strong>Methods: </strong><span lang="EN">Twelve dairy cows with the following criterion: 5-yr-old, 1st to 9th month of lactation, and average body weight of 390 ± 5.55 kg were used. Cows were assigned in a randomized block design with 4 treatments, i.e T0 (without massage), T1 (MHM for 20 s), T2 (MHM for 50 s), and T3 (MHM for 80 s). Oxytocin release, milk yield, and milk quality were measured accordingly</span><span lang="EN-GB">.</span><strong></strong></p><p class="MDPI17abstract"><strong>Results: </strong><span lang="EN">The data obtained were analyzed using analysis of variance (ANOVA). The results showed that MHM had a very significant effect on milk production (P &lt;0.01) as evidenced by the MHM 50 s treatment obtained the highest average milk production (13.08 ± 3.38 liters/head/day) compared to the MHM 20 s, MHM 80 s and control. MHM (1-1.6 volts) for 50 s resulted in the highest release of oxytocin (0.22955 pcg/0.1mL) at 240 seconds compared to control, MHM 20 s and 80 s. Likewise, the percentage of milk protein content (2.96 ± 0.03) and milk fat content (4.27 ± 0.70) was highest at MHM 50 s</span><span lang="EN-GB">.</span><strong></strong></p><strong><span>Conclusions: </span></strong><span lang="EN">It can be concluded that MHM (1-1.6 volts) for 50 seconds increases the release of oxytocin, milk production, and milk quality in terms of the percentage of milk protein and fat content</span><span lang="EN-GB">.</span>

scholarly journals Production response in dairy cows milked two or three times a day: A meta-analysis

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Juan Isidro Sanchez-Duarte ◽  
Alvaro Garcia ◽  
Karla Rodríguez-Hernández ◽  
David G. Reta-Sánchez ◽  
Homero Salinas-Gonzalez ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Fat ◽  
Dry Matter ◽  
Milk Protein ◽  
Meta Analysis ◽  
Milk Composition ◽  
Fat Percentage ◽  
Milking Frequency ◽  
Production Response

The objective was to evaluate the effects of two (2×) vs three (3×) times per day milking on milk production and milk composition in dairy cows. Fourteen scientific papers, containing production data from 16 trials, where dairy cows were milked 2× or 3×, were analysed using meta-analysis with fixed and random-effects with the R statistical program. The degree of heterogeneity and publication bias were measured with the I2 statistic and Begg’s test, respectively. In addition, the meta-regression analysis explored other sources of heterogeneity for the response. The estimated effect size of 2× and 3× milkings was calculated for dry matter intake (DMI), milk production, and milk composition. Dry matter intake, milk production, and milk fat and protein yields showed substantial heterogeneity (I2>50%). Whereas milk fat-percentage had moderate heterogeneity (I2<50%), and milk protein had no (I2=0%)heterogeneity. The year of publication, trial duration, and cattle breed did not influence production response parameters to milking frequency. We found no evidence of publication bias for the parameters evaluated (Begg’s test; P>.05). Cows milked 2× produced less milk (2.23 kg/d), less milk fat (0.06kg/d), and less milk protein (0.05 kg/d). In contrast, the fat percentage was lower (0.07 units) in 3×, compared with 2× milking frequency. There was no effect of milking frequency on DMI and milk protein percentage. In conclusion, milk production and milk fat and protein yields improves as milking frequency increase from 2× to 3× daily, without affecting DMI. The implementation of 3× milking frequency must consider dairy cow management, labor, and milking parlour infrastructure, particular to each dairy farm.

Predicting milk responses to cereal-based supplements in grazing dairy cows

2017 ◽  
Vol 57 (4) ◽  
pp. 746 ◽  
Author(s):  
J. W. Heard ◽  
M. Hannah ◽  
C. K. M. Ho ◽  
E. Kennedy ◽  
P. T. Doyle ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Yield ◽  
Correction Factor ◽  
Bias Correction ◽  
Milk Fat ◽  
Milk Protein ◽  
Prediction Models ◽  
Dairy Industry ◽  
Fat Yield

The feeding of cereal-based supplements is common in the Australian dairy industry, as it allows cows to increase intakes of total dry matter (DM) and metabolisable energy (ME), while achieving greater stocking rates, greater pasture utilisation and greater milk production per hectare than occurs when cows are fed pasture-only diets. However, for this practice to be profitable, it is important to know how much extra milk, milk protein and milk fat are produced for each kilogram DM consumed. This is difficult to determine in such a complex biological system. We combined information from 24 concentrate-feeding experiments using meta-analysis techniques, so as to develop improved prediction models of the milk, milk protein and milk fat produced when cereal-based concentrates are fed to grazing, lactating dairy cows. Model terms, consistent with biological processes, linear, quadratic and factorial, were selected according to statistical significance. The models were then tested in two ways, namely, their goodness of fit to the data, and their ability to predict novel production data from a further six, unrelated, experiments. A sensitivity analysis was also undertaken to determine how sensitive these predictions are to changes in key inputs. The predictive model for milk yield was shown to very closely reflect milk yield (kg/cow.day) measured under the experimental conditions in unrelated experiments (r = 0.96), with very little bias (Lin’s bias correction factor = 0.98) and high concordance (Lin’s concordance coefficient = 0.95). Predictions generated by multiplying predicted milk protein concentration by predicted milk yield closely matched observed milk protein yield (kg/cow.day) (r = 0.96, Lin’s bias correction factor = 0.98, Lin’s concordance coefficient = 0.95), and predictions found by multiplying predicted milk fat concentration by predicted milk yield closely matched observed milk fat yield (kg/cow.day) (r = 0.94, Lin’s bias correction factor = 0.99, Lin’s concordance coefficient = 0.93). Factors included in the new models for milk, milk protein and milk fat yield reported here have been identified previously as elements that can influence milk production. The value to the dairy industry from being able to predict profitable amounts of concentrates to feed at various stages throughout lactation is considerable. For farmers and their advisers, being able to apply these models to estimate the immediate marginal milk protein and milk fat responses to supplementary feeds should lead to more robust, efficient and profitable milk production systems.

Duration of a severe feed restriction required to reversibly decrease milk production in the high-producing dairy cow

2007 ◽  
Vol 87 (3) ◽  
pp. 455-458 ◽  
Author(s):  
Chanelle A. Toerien ◽  
John P. Cant
Keyword(s):  
Dairy Cows ◽  
Key Words ◽  
Milk Production ◽  
Milk Yield ◽  
Dairy Cow ◽  
Milk Protein ◽  
Holstein Cows ◽  
Plasma Metabolites ◽  
Feed Restriction ◽  
Post Trial

To establish the duration of a severe feed restriction necessary to reversibly decrease milk production in high-producing Holstein cows, milk, plasma and urine parameters were assessed every 6 h during a 24-h restriction and 18-h refeed period. The 24-h restriction decreased yields of milk, protein and lactose by more than 30% without inducing ketosis or impairing milk production post-trial. Key words: Feed restriction, dairy cows, milk yield, plasma metabolites

Effect of grazing intensity in spring on pasture growth, composition and digestibility, and on milk production by dairy cows

1987 ◽  
Vol 27 (1) ◽  
pp. 35 ◽  
Author(s):  
P Michell ◽  
WJ Fulkerson ◽  
PJ Michell
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Fat ◽  
Milk Protein ◽  
Grazing Intensity ◽  
Accumulation Rates ◽  
Grazing Intensities ◽  
Dead Material ◽  
Similar Quantity ◽  
Stocking Rates

Two 20-block farmlets, each of 6.5 ha, were rotationally grazed by milking cows in spring at stocking rates of 1.9 and 3.4 cows/ha to give a low (LGI) or high (HGI) grazing intensity. These grazing intensities were designed to simulate dairy farms with low or high levels of pasture conservation, and resulted in post-grazing residues of2.6 (LGI) and 1.7 (HGI) t/ha DM by late spring. Over summer, the 2 groups of cows continued to graze their respective areas, but spare cows were re-allocated between the groups so that stocking rates were the same at 1.7 cows/ha. The HGI cows produced 1 kg less milk fat (0.79 v. 0.81 kg/day.cow, P> 0.05) in spring (15 October-30 November), but produced significantly (P < 0.05) more milk fat (0.63 v. 0.59 kg/day.cow) and 1.3 kg milk protein (0.44 v. 0.42 kg/day.cow) in summer (1 December-1 February). Despite the higher grazing intensity in spring. there was no difference in intake of pasture or in digestibility of herbage selected by the cows in the two herds. In summer the HGI swards contained less dead herbage (P<0.05) but a similar quantity of green herbage compared with the LGI swards, and, compared with LGI cows, the HGI cows removed a higher proportion of this green herbage during grazing. Digestibility of the LGI swards was lower because of the higher content of dead herbage but cows in both groups rejected this dead material and selected a diet of similar digestibility. The presence of dead herbage in the LGI swards appeared to reduce animal production by reducing availability and intake of green herbage rather than by reducing the digestibility of the diet selected by the cows. The high grazing intensity increased daily net accumulation of grass leaf in spring (1 7 v. 6 kg/ha of DM, P< 0.05) but reduced that of true stem (-4 v. 28 kg/ha, P < 0.10) and of total herbage (43 v. 54 kg/ha, P<0.10). The HGI swards had higher ryegrass tiller densities in summer and higher (P<0.05) net accumulation rates of herbage in summer through to winter). Increased grazing intensity in spring above normally accepted levels increased pasture utilisation in spring and summer, and milk production in summer, and increased the quantity of spring herbage available for conservation.

A comparison of the effects of cracked wheat and sodium hydroxide-treated wheat on food intake, milk production and rumen digestion in dairy cows given maize silage diets

2001 ◽  
Vol 72 (3) ◽  
pp. 585-594 ◽  
Author(s):  
R. H. Phipps ◽  
J. D. Sutton ◽  
D. J. Humphries ◽  
A. K. Jones
Keyword(s):  
Food Intake ◽  
Dairy Cows ◽  
Sodium Hydroxide ◽  
Milk Production ◽  
Milk Fat ◽  
Milk Protein ◽  
Volatile Fatty Acids ◽  
Ammonia Nitrogen ◽  
Maize Silage ◽  
Dietary Regimen

AbstractTo examine the effects of manipulating the amount and ruminal degradability of starch on food intake, milk production and digestion in the rumen of lactating dairy cows, cracked wheat (CW) and sodium hydroxide-treated wheat (SW) were compared when offered with either immature (IM) or mature (MM) maize silage given in a 3: 1 dry matter (DM) ratio with grass silage. The total mixed ration (TMR) contained (kg/t DM basis) forage 600, wheat (CW or SW) 170, rapeseed meal 100, soya-bean meal 100, molasses/urea supplement 30 and minerals and vitamins were added at 20 kg/t diet DM. In experiments 1 and 2 respectively, 16 multiparous Holstein-Friesian cows and four similar cows with duodenal and ruminal cannulas were offered four diets (IMCW, IMSW, MMCW, MMSW) in 4 ✕ 4 Latin-square designs. In experiment 3, the in sacco degradability of CW and SW was measured in the rumen of three lactating fistulated cows. In experiment 1 total DM intake was 0·7 kg/day higher and milk yield was 0·5 kg/day higher with MM than IM silage but the increases were not significant and type of wheat had no effect. Milk fat content was reduced by MM silage (P < 0·05) but was unaffected by type of wheat. For milk protein content SW caused a non-significant increase with IM but a decrease (P < 0·05) with MM silage (interaction P < 0·05). There were no significant effects on yield of fat or protein. Neutral-detergent fibre digestibility in the rumen was unaffected by the treatments. Starch intake increased (P < 0·05) with MM silage when compared with IM silage and was accompanied by an increase (P < 0·01) in starch flow to the duodenum and in the amount (P < 0·001) digested in the rumen, although there was no significant change in rumen digestibility. Replacing CW with SW increased starch flow to the duodenum (P < 0·05) and reduced rumen digestibility (P < 0·05). Although the amount of total nitrogen (TN) digested in the rumen and rumen digestibility decreased (P < 0·01) with crop maturity, the flow of TN and non-ammonia nitrogen to the duodenum was unaffected. Total tract digestibility of DM was unaffected by treatments. Although the amount of starch digested in the total tract increased for MM compared with IM silage, reflecting the higher starch intake, total tract starch digestibility was unaffected by treatment and averaged 0·972. There were no main treatment effects on daily mean pH, concentration of ammonia or concentration or molar proportions of volatile fatty acids in the rumen. With SW, effective degradability (outflow rate of 0·08 per h) for both DM and starch was reduced when compared with CW. In conclusion the studies confirm that SW is more slowly fermented than CW and can increase the supply of starch to the duodenum. However the concept that increasing starch supply to the duodenum by a combination of MM silage and SW is likely to be beneficial to milk protein yield or concentration is not established under the present dietary regimen.

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