Dry matter intake, body condition score, and grazing behavior of nonlactating, pregnant dairy cows fed on kale or grass once versus twice during winter

The objective of this study was to examine the effect of wintering pregnant, nonlactating dairy cows outdoors on either kale or grass, fed in 1 [11 kg of dry matter (DM) of kale or grass + 3 kg of DM of baled barley straw offered in the morning] or 2 allocations (5.5 kg of DM of kale or grass grazed + 1.5 kg of DM barley straw offered morning and afternoon) per day. The body condition score (BCS) gain over the 47-d winter feeding period was higher for grass-fed (0.5 BCS units) than kale-fed cows (0.3 BCS units), but was unaffected by feeding frequency. Forage DM utilization was higher for kale-fed (97%) than grass-fed cows (76%), leading to higher estimated dry matter intake (DMI) in kale-fed (10.7 kg of DM/cow per day) than grass-fed cows (7.7 kg of DM/cow per day). Forage DM utilization and estimated DMI were not affected by feeding frequency. Prehension bite rate was greater for grass-fed (37.3 bites/min) than kale-fed cows (7.6 bites/min), but more mastication bites were required for kale-fed cows. Cumulative DMI after 2, 3, and 6 h was greater in cows allocated forage once than twice a day and for kale than grass after 3 and 6 h. Mean eating time was greater for cows offered forage once (477 min) than twice (414 min) per day. In conclusion, increasing feeding frequency from once to twice per day decreased the intake rate within the first 6 h after allocation, but did not affect total daily DMI, DM utilization or BCS gain. Thus, moving cows more frequently would not have any significant advantage. It may increase labor requirements, thereby creating a more challenging wintering management than feeding once per day

Dry matter intake and body condition score gain of dairy cows offered kale and grass

An outdoor grazing study conducted with 45 pregnant, dry dairy cows for 47 days during the winter period measured dry matter (DM) utilisation, DM intake, forage disappearance, body condition score (BCS) and liveweight (LW) of cows fed 11 (K11) or 14 (K14) kg of kale DM per day or 11 (G11) kg DM Italian ryegrass per cow per day. Cows were offered 3 kg DM barley straw/cow/day at 0800 h and their daily forage allowance at 0900 h. Within 6 hours of being offered a fresh forage allocation, cows had consumed more than 86% of their apparent daily DM intake with cumulative DM intake of 10.4, 10.5 and 7.3 kg DM/cow for K11, K14 and G11, respectively. Daily percentage DM utilisation averaged over the 47 days of the trial was higher for K11 (96%) and K14 (88%) than for G11 (70%), leading to higher apparent daily DM intake for K14 (12.1 kg) and K11 (10.5 kg) than for G11 (7.9 kg DM). Liveweight and BCS gain during the 47 days were higher for K14 (45.4 kg LW and 0.3 BCS units) and G11 (46.8 kg LW and 0.3 BCS units) than for K11 (30.1 kg LW and 0.2 BCS units). This study indicates that compared with offering the common industry allowance of 11 kg kale DM/cow/day, increasing the allowance to 14 kg kale DM/cow/day or offering grass at 11 kg DM/cow/day may lead to higher BCS and LW gain, although all regimes failed to meet expectations of cows gaining 0.5 BCS units during the winter feeding period. © 2014 The Royal Society of New Zealand

Rumen function and foraging behaviour of non-lactating, pregnant dairy cows wintered on kale or grass

An outdoor grazing study conducted with 45 non-lactating, pregnant dairy cows during winter measured dry matter (DM) intake, grazing behaviour, rumen pH, ammonia (NH₃) and volatile fatty acids (VFAs) of cows fed 11 (K11) or 14 (K14) kg of kale DM/cow/day or 11 (G11) kg DM Italian ryegrass/cow/day. Cows in K14 spent more time grazing (441 min/day) than in K11 (9378 min/day) and G11 (326 min/day). Rumen ammonia concentrations ranged from 108 to 212 mg NH₃/L for K14, 91 to 306 mg NH₃/L for K11 and 57 to 269 mg NH₃/L for G11. Total VFAs concentration (mmol/L) was greatest for K14 (104), intermediate at G11 (96.7) and lowest for K11 (75.4). Rumen pH fell to reach its lowest values of 5.7 for G11, 6.2 for K11 and 6.1 for K14. Hence, there was little evidence of sub-acute rumen acidosis in kale-fed cows

Analysis of major fatty acids in milk produced from high-quality grazed pasture

In a survey of milk and pasture samples collected from commercial dairy farms in Canterbury, New Zealand, the results of pasture analysis indicated that levels of water soluble carbohydrates and crude protein were highest in spring and autumn, while the content of neutral detergent fibre was lowest during the same periods. The most notable features of milk fatty acid composition were the high levels of α-linolenic acid (C18:3) and conjugated linoleic acid and the low levels of linoleic acid (C18:2) in milk produced from cows consuming high-quality pasture. It seems likely that this is related to the high proportion of high-quality grazed pasture (mean crude protein = 23.9% of DM; mean water soluble carbohydrates = 16.2% of DM; mean neutral detergent fibre = 39.1% of DM) in the diet. The highest monthly mean value for milk C18:3 was 1.82% of total milk fatty acids for herds fed low levels of supplement in spring (October). This survey shows that there is variation in pasture quality over the season and this was reflected in milk fatty acid profiles

There is no relationship between plasma amino acid concentration and urinary nitrogen concentration in heifers fed plantain or ryegrass

The objective of this study was to investigate the relationship between plasma amino acid (AA) concentration and urinary nitrogen (N) concentration of dairy heifers offered cut plantain or perennial ryegrass-white clover pasture indoors. Twelve Jersey-Friesian heifers aged 9–10 months were equally assigned to two dietary treatments (plantain vs. perennial ryegrass-white clover pasture) in a completely randomised design. Urinary N concentration was lower in plantain fed heifers (1.4 g/kg) than in perennial ryegrass-white clover pasture fed heifers (3.4 g/kg). Feeding cut plantain or perennial ryegrass-white clover pasture did not have an effect on either plasma essential AA, non-essential AA or total AA. There was no association found between plasma AA concentration and urinary N concentration in the present study. Therefore, the urinary N concentration reduction in plantain fed heifers compared with perennial ryegrass-white clover pasture cannot be attributed by the differences in plasma AA

Effects of post-grazing herbage height and concentrate feeding on milk production and major milk fatty acids of dairy cows in mid-lactation

Milk fatty acids (FA) were compared in mid-lactation dairy cows in four feeding systems combining grazing management and supplementation. The four treatments were factorial combinations of compressed herbage grazed to 3·7 or 4·6 cm post-grazing height, with or without concentrate feeding (3·6 kg cow⁻¹ d⁻¹). Milk yield and composition were measured for four groups of eight Friesian × Jersey dairy cows over 3 weeks in mid-lactation for cows that had grazed treatments for 64 d from early spring. Milk yield was higher in cows fed concentrate plus herbage (23·9 kg d⁻¹ cow⁻¹) than cows fed herbage only (20·3 kg d⁻¹ cow⁻¹). Milk fat percentage was higher in cows fed herbage only (5·5%) than that fed herbage plus concentrate (5·1%). Milk protein percentage was higher in cows fed herbage plus concentrate (4·0%) than that fed herbage only (3·7%). The concentrations of conjugated linoleic acids c9, t11, C18:0, C18:1 t11 and C18:2 t9, c12 FA were lower where concentrate was fed. The concentrations of C18:1 t10, C18:1 t5, t8 and C18:2 c9, c12 FA were higher where concentrate was fed. The concentrations of C18:1 c6, C18:1 c9, C18:1 t9 and C18:3 c6,9,15 were unaffected by concentrate feeding. Post-grazing herbage height had no significant effect on milk yield or concentration of milk FA. Provided dairy cows are harvesting leafy material of similar nutrient and FA concentration, post-grazing herbage height does not appear to alter milk FA and the supply of high energy concentrates is more influential on milk FA profiles

Plasma amino acid profiles of dairy heifers grazing pasture, chicory and plantain

The objective of this study was to quantify amino acid (AA) profiles in plasma collected from dairy heifers grazing swards containing ryegrass/clover, chicory and plantain in autumn and spring. The study comprised a 28-day autumn trial and a 21-day spring trial using 56 Friesian x Jersey heifers. Total AA concentrations ranged from 2849 to 3165 μM in autumn and from 3195 to 3454 μM in spring, with no treatment effect. Season affected essential AA (EAA) and total AA concentrations. Total plasma AA concentrations were lower in autumn (2965 μM) than in spring (3303 μM). Based on these results, feeding dairy heifer’s either pure chicory, binary mixture or pure plantain does not affect EAA and total AA of Friesian x Jersey heifers. Further, no relationship was established between AA and weight gain of heifers in this study

Effect of a mixed silage of king grass (Cenchrus purpureus) and forage legumes (Leucaena leucocephala or Gliricidia sepium) on sheep intake, digestibility and nitrogen balance

Ensiled king grass (Cenchrus purpureus (Schumach.) Morrone) is commonly used as feed in tropical ruminant production. However, ruminant performance can be limited by low nitrogen (N) content in tropical grass silage. A mixed feed of legume–king grass silage may be an option to improve ruminant production. We investigated the effects of feeding an ensiled mixture of king grass forage and foliage of a browse tree legume, either leucaena (Leucaena leucocephala (Lam.) de Wit) or gliricidia (Gliricidia sepium (Jacq.) Walp), on dry matter (DM) intake, DM digestibility, organic matter (OM) digestibility and N balance of Pelibuey sheep. Twelve male lambs 9–11 months old were blocked by initial bodyweight (33 ± 3 kg, mean ± s.d.) into three groups of four lambs and randomly assigned to one of three feed treatments: king grass silage (KS); mixed king grass and leucaena silage (KLS); and mixed king grass and gliricidia silage (KGS). Results showed that DM and OM were similar among silages. The N content was higher (P < 0.001) in KLS and KGS than in KS. DM intake and DM digestibility were higher (P < 0.001) in KLS and KGS than in KS. OM digestibility was higher (P < 0.001) in KLS than in KS. Nitrogen intake, faecal N, urine volume, urinary N, digested N, N digestibility, N retention and retained N : N intake ratio from KLS and KGS treatments were higher (P < 0.05) than from KS. A lower (P < 0.01) urinary N : N intake ratio was detected from KGS and KLS than from KS. This study demonstrated that, compared with silage made from king grass alone, legume–king grass silage mixtures can improve intake and nutrient digestibility in Pelibuey lambs. Further, N retention can be enhanced when legume–king grass silages are used as feed compared with king grass silage alone

Effect of a mixed silage of king grass (Cenchrus purpureus) and forage legumes (Leucaena leucocephala or Gliricidia sepium) on sheep intake, digestibility and nitrogen balance

7 páginas, 4 tablas.Ensiled king grass (Cenchrus purpureus (Schumach.) Morrone) is commonly used as feed in tropical ruminant production. However, ruminant performance can be limited by low nitrogen (N) content in tropical grass silage. A mixed feed of legume–king grass silage may be an option to improve ruminant production. We investigated the effects of feeding an ensiled mixture of king grass forage and foliage of a browse tree legume, either leucaena (Leucaena leucocephala (Lam.) de Wit) or gliricidia (Gliricidia sepium (Jacq.) Walp), on dry matter (DM) intake, DM digestibility, organic matter (OM) digestibility and N balance of Pelibuey sheep. Twelve male lambs 9–11 months old were blocked by initial bodyweight (33 ± 3 kg, mean ± s.d.) into three groups of four lambs and randomly assigned to one of three feed treatments: king grass silage (KS); mixed king grass and leucaena silage (KLS); and mixed king grass and gliricidia silage (KGS). Results showed that DM and OM were similar among silages. The N content was higher (P < 0.001) in KLS and KGS than in KS. DM intake and DM digestibility were higher (P < 0.001) in KLS and KGS than in KS. OM digestibility was higher (P < 0.001) in KLS than in KS. Nitrogen intake, faecal N, urine volume, urinary N, digested N, N digestibility, N retention and retained N : N intake ratio from KLS and KGS treatments were higher (P < 0.05) than from KS. A lower (P < 0.01) urinary N : N intake ratio was detected from KGS and KLS than from KS. This study demonstrated that, compared with silage made from king grass alone, legume–king grass silage mixtures can improve intake and nutrient digestibility in Pelibuey lambs. Further, N retention can be enhanced when legume–king grass silages are used as feed compared with king grass silage alone.The Startup Research Fund offered by Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, to Long Cheng is acknowledged to support this international collaboration. We thank Miss Jiawen Li (Chengdu University of Information Technology) for useful discussion and help with formatting the manuscript for submission