@conference {41937, title = {Supplementation with concentrates either pre- or post-partum does not affect milk production when diets are iso-energetic}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {416-422}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Dairy cow glucose requirements increase dramatically during the weeks preceding calving, suggesting that supplements that increase glucose supply (rapidly fermentable carbohydrates) would reduce precalving mobilisation of body tissue and improve subsequent milk production. Sixty-eight multiparous dairy cows were randomly allocated to one of two diets for 36 {\textpm} 8.7 days precalving. All cows were fed pasture and pasture-silage precalving, with one group also receiving 3kg DM of a barley-maize concentrate. Precalving diets were iso-energetic (114 MJ/cow/day). At calving, cows within each precalving feeding treatments were randomly allocated to two dietary treatments for 35 days in a 2x2 factorial arrangement. Postcalving, all cows received pasture and pasture silage with one group also receiving 5.0 kg DM of a barley-maize concentrate. Postcalving diets were also iso-energetic (179 MJ/cow/day). Milk yield and composition, and liveweight (LW) and body condition score (BCS) were assessed weekly for five weeks. Blood was sampled on day -21, -14, -7, 0, 1, 2, 3, 4, 7, 14, 21, 28 and 35 relative to calving, and plasma samples were analysed for indicators of energy status. Average milksolids yield (1.9 kg/cow/d) during the five weeks postcalving was not affected by either pre- or postcalving concentrate supplementation, although protein to fat ratio was higher in supplemented cows. Similarly, concentrate supplementation pre- or postcalving did not affect either LW or BCS change before or after calving. Cows receiving concentrates precalving had higher (P<0.001) plasma non-esterified fatty acid (NEFA) concentrations, but otherwise were not different to those receiving an equivalent energy intake from pasture and pasture silage. Postcalving concentrate supplementation increased (P<0.01) plasma glucose and NEFA and decreased (P<0.001) plasma B-OH butyrate. Results suggests little effect on milk production by replacing energy from structural carbohydrates in high quality pasture with energy from non-structural carbohydrate during the transition period. }, issn = {1176-5283}, author = {Roche JR and Lee JM and Aspin PW and Sheahan AJ and Burke CR and Kolver ES and Sugar B and Napper AR} } @conference {41570, title = {Effects of feeding level for four weeks precalving on milk production is small and dependent on level of feeding in early lactation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {215-220}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {The aim was to quantify the relationship between pre- and postcalving level of feeding and their effect on milk production. Sixty-eight multiparous dairy cows were randomly allocated to two levels of pasture feeding (Low and High; 4.8 and 11.9 kg DM/day) for 29 {\textpm} 7.7 days precalving. At calving, cows were randomly allocated (within precalving levels) to two levels of pasture feeding (Low and High; 8.6 and 13.5 kg DM/day) for 35 days postcalving. Daily milk yields were recorded and fat, protein and lactose concentrations determined on 2 days each week for 5 weeks postcalving, and once weekly for an additional 10 weeks post treatment. Body condition score (BCS) at calving was 4.2 and 4.7 for precalving Low and High treatment groups, respectively. Precalving restriction reduced milk fat production by 8.4\% during the first five weeks postcalving, but these differences were not evident subsequently. Postcalving feed restriction reduced yields of milk, fat and protein by 25, 21 and 28\%, respectively, during the first five weeks postcalving. Decreased (P < 0.05) yields of milk, fat and protein (12, 10 and 9\%, respectively) were also evident for ten weeks after the feed restriction finished. There was a trend towards a treatment interaction (P = 0.13) in milksolids (MS) production during the first five weeks of lactation between pre- and postcalving level of feeding. High- High cows produced 7.1 kg more MS than Low-High cows, but there was no effect of precalving level of feeding in cows that were restricted postcalving. Results confirm that level of feeding postcalving influences the milk production effect of precalving feeding. Nevertheless the effect of precalving energy intake on postcalving milk production is small. KEYWORDS: transition cow; pasture; dry matter intake. }, issn = {1176-5283}, author = {Roche JR and Kolver ES and Lee JM and Aspin PW and Burke CR and Taylor P and Napper AR} } @conference {41510, title = {Effect of precalving feeding level on the milk production of grazing dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {64}, year = {2004}, month = {Jan}, pages = {227-231}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Fifty-two multiparous dairy cows were allocated to four treatments with an apparent daily intake of 5.8, 8.9, 10.0 or 11.2 kg dry matter (DM)/cow/day of pasture for 27{\textpm}9.6 days precalving. This equated to 1.3, 2.0. 2.3 and 2.6\% of liveweight (not including the conceptus weight; LW). Following calving, all cows were fed generously on pasture. Daily milk yields were recorded postcalving and fat, protein and lactose concentrations determined on 2 days each week for 5 weeks. Blood was sampled 17 days precalving, on the day of calving and on days 1, 2, 3, 4, 7, 14, 28 and 35 postcalving. Precalving plasma concentrations of insulin-like growth factor-1 (IGF-1) increased (P<0.05) quadratically with increasing pasture intake. Concentrations of growth hormone declined (P<0.05) linearly and concentrations of non- esterified fatty acids declined (P<0.001) quadratically with increasing DM intake. Plasma concentrations of these metabolites postcalving showed no effect of precalving feeding. Level of feeding precalving did not affect milk yield or the yield of fat, protein or lactose in milk, but postcalving DM intake was negatively (P<0.1) related to precalving DMI. These results indicate that 0.93 MJ metabolisable energy/kg LW0.75 was required in the final three weeks of gestation to maintain cow energy balance. }, issn = {1176-5283}, author = {Roche JR and Kay JK and Kolver ES and Aspin PW and Lee J and Sugar B and Napper AR} } @conference {41359, title = {Concentrations of conjugated linoleic acid in milk from cows grazing pasture of fed a total mixed ration for an entire lactation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {240-241}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

Conjugated linoleic acid (CLA) is a collective term for the range of conjugated isomers of linoleic acid (C182). These fatty acids occur naturally in milkfat and have proven anticarcinogenic properties in laboratory rodents (Ip et al., 1999). Additionally, the various isomers have other reputed benefits for human health such as enhanced bone mineralisation, antidiabetic effects, reduced atherosclerosis and immune system modulation (Whigham et al., 2000). Such potential benefits for human health have focussed international research on enhancing concentrations of CLA in milk and dairy products. Overseas data show that one way to increase the concentrations of CLA in milk is to change the diet of cows from a typical total mixed ration (TMR) to pasture (Kelly et al., 1998; White et al., 2001). This points to a potential competitive advantage for the New Zealand dairy industry, in which pasture is already almost the sole source of feed. Despite this there are no data confirming the beneficial effects of pasture for enhancing CLA under New Zealand grazing conditions. The experiment described here used an existing experiment to compare the concentrations of CLA in milk from cows fed TMR or grazing pasture for an entire lactation under New Zealand conditions.

}, issn = {1176-5283}, author = {Audlist MJ and Kay JK and Thomson NA and Napper AR and Kolver ES} } @conference {41306, title = {Incidence of mastitis among cows of different genogtypes in differing nutritional environments}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {24-29}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {Over three seasons (1998, 1999 and 2000) groups of Holstein-Friesian cows of New Zealand (NZ) or overseas (OS) origin were monitored for mastitis when managed in two contrasting systems. Cows were fed either on pasture or total mixed ration (TMR) with cows on TMR confined to small loafing paddocks or a concrete feedpad. All quarters were sampled for bacteriology at calving, at dry off, in mid and late lactation and when clinical mastitis was detected. Individual cow somatic cell counts (SCC) were determined weekly throughout lactation. In 1998, there was no difference in incidence of clinical mastitis but in later seasons, cows on TMR experienced significantly more clinical, and sub-clinical mastitis, than cows on pasture, probably reflecting differences in bacterial challenge within the environment. Genotype differences were less evident compared to dietary effects. Compared to NZ cows, OS cows experienced more sub-clinical infections in 1998 and more clinical infections in 1999 whilst in 2000, genotype effects were confounded by diet. Seasonal SCC was higher for OS cows in 1999 and 2000, reflecting differences in incidence of sub-clinical mastitis among treatment groups. Despite the strong influence of environment on mastitis incidence, genotype differences were detectable between NZ and OS cows. }, issn = {1176-5283}, author = {Lacy-Hulbert SJ and Kolver ES and Williamson JH and Napper AR} } @conference {41362, title = {Pasture versus total mixed ration during the periparturient period}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {252-256}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

The effect of diet and genotype on metabolic indicators of energy status in the periparturient cow were investigated. Fifty-six dairy cows of two different genotypes (Overseas Holstein-Friesian (OSHF) and New Zealand Holstein-Friesian (NZHF)) were randomly allocated to two dietary regimens. Half of each genotype group received a pasture/pasture silage diet pre-calving and a pasture diet post-calving, while the other half received a total mixed ration (TMR) pre- and post-calving. Compared with NZHF, OSHF had higher concentrations of plasma non-esterified fatty acids (NEFA; P\<0.05) and glutamic acid dehydrogenase (GDH; P=0.09), an indicator of liver fat infiltration, 30 d post-calving. Genotype did not affect the concentration of either b-hydroxybutyrate (BHBA) or glucose in plasma. Cows grazing pasture pre-calving had greater (P\<0.05) BHBA concentrations, but plasma NEFA concentration and liveweight loss during the first 30 days of lactation were not different. In summary, a pre-calving TMR did not appear to improve the metabolic energy status of the cow pre-calving. These results suggest that provided sufficient nutrients are supplied in the diet, the homeorhetic mechanisms within the cow allow adaption to very different diets. This implies that an all-forage diet pre-calving is sufficient for dairy cows fed forage post-calving.

}, issn = {1176-5283}, author = {Roche JR and Kolver ES and Napper AR} } @conference {41361, title = {Total mixed rations versus pasture diets: Evidence for a genotype x diet on the concentration of amino acid-derived volatiles in milk}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {246-251}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

The performance of overseas (OS) and New Zealand (NZ) Holstein Friesian (HF) dairy cows were compared on an all-pasture diet (Grass) or a total mixed ration (TMR). Dietary treatments had been imposed for two years prior to the 2000/2001 season for which these results are reported. The four treatments were NZ Grass (n=14); OS Grass (n=13); NZ TMR (n=14); and OS TMR (n=14). Genotype x diet interactions were observed for annual milk yield, milksolids yield, efficiency of milksolids production, liveweight gain during lactation, and the proportion of cows not in calf. Measurement of individual cow intake using alkane markers during early, mid, and late lactation identified when these genotype x diet interactions occurred. When fed TMR, OS HF performed better than NZ HF, but on grass NZ HF performed better than OS HF. This has implications for the selection of sires for the national herd, and for the use of different dairy cow genotypes in different dairying systems.

}, issn = {1176-5283}, author = {Kolver ES and Roche JR and de Veth MJ and Thorne PL and Napper AR} } @conference {41212, title = {A comparison New Zealand and overseas Holstein Friesian heifers}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {265-269}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {The performance of overseas (OS) and New Zealand (NZ) Holstein Friesian (HF) dairy heifers was compared when fed an all-pasture diet (Grass) or a total mixed ration (TMR) throughout lactation. The four treatments were NZ Grass (n=14); OS Grass (n=9); NZ TMR (n=15); and OS TMR (n=10). Compared with NZ HF, OS HF had a higher live weight and produced more milk, but milksolids yield, efficiency of milksolids production, and persistency of lactation were not different. Compared with HF fed Grass, HF fed TMR produced more milk and milksolids, were more efficient, had a greater persistency of lactation, and ended lactation with a greater body weight. The OS HF genotype was unable to maintain acceptable body condition and live weight on an all-grass diet. This raises serious questions regarding the sustainability and suitability of these genetics for seasonal all-pasture dairying systems. }, issn = {1176-5283}, author = {Kolver ES and Napper AR and Copeman PJA and Muller LD} } @conference {41209, title = {The effect of pasture silage quality on milk production and liveweight gain of dairy cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {253-255}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Farmers in NZ have recently been encouraged to increase the quality of pasture silage they harvest. However, there was no New Zealand information available to ascertain the benefits of improved silage quality when it was offered as a supplement to grazing cows. Identical twin sets were divided into three groups in the winter, spring, summer and autumn during the 1998/99 season. Each group was offered a low pasture allowance and in addition, were offered 3 kg (winter) and 5 kg (spring, summer and autumn) DM/cow/day, of High, Medium and Low-quality pasture silage (nominally 10.4, 9.4 and 8.3 MJ ME/kg DM, respectively) as a supplement to pasture. In spring, summer and autumn offering a high quality silage increased milksolids yield from 1.57 to 1.78, 1.09 to 1.28 and 0.63 to 0.89 kg/cow/day, respectively (P<0.05) relative to cows offered Low-quality silage. There were no consistent live weight responses due to pasture silage quality. The spring, summer and autumn measured milksolids response can be calculated as having a net return (at $3.50/kg MS) of 6.7, 5.1 and 8.3 cents per MJME/kg DM increase. }, issn = {1176-5283}, author = {MacDonald KA and Nicholas PK and Kidd JM and Penno JW and Napper AR} } @conference {41006, title = {Use of {\textquoteright}Barkant{\textquoteright} turnips and {\textquoteright}Superchow{\textquoteright} sorghum crops to increase summer-autumn milk production}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {58}, year = {1998}, month = {Jan}, pages = {121-124}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {{\textquoteleft}Barkant{\textquoteleft} turnips and {\textquoteleft}Superchow{\textquoteleft} sorghum were compared as summer-autumn crops for lactating cows. Crops were fed at three levels (0, 4 and 8 kg DM/cow/d) to supplement pasture offered at a constant allowance. Sixty twin cows were used in two experimental periods in February and March 1997. Feeding 4 or 8 kg DM/cow/day increased milksolids (MS) yield/cow by 29\% or 36\% for turnips, and 26\% or 32\% for sorghum compared with pasture alone. Turnips gave responses of 58g and 45g MS/kg DM offered, at the lower allowance, in summer and autumn respectively, compared with 45g MS/kg DM in both seasons for sorghum. For both crops, increasing allowance from 4 to 8 kg further increased MS yield. Crop utilisation was lower on sorghum than turnips but substitution rates for turnips were higher than for sorghum at both allowances in both summer and autumn. This means that although both crops have a {\textquoteleft}pasture sparing{\textquoteleft} effect, sorghum contributed more to increased per cow intake. }, issn = {1176-5283}, author = {Harris SL and Clark DA and Waugh CD and Copeman PJA and Napper AR} } @conference {40913, title = {Effects of pasture intake and grain supplementation on milk nitrogen fractions}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {57}, year = {1997}, month = {Jan}, pages = {154-156}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Effects of underfeeding and supplementation on detailed milk components for 18 identical twin sets calving in July/August were assessed. Three treatments; 65\% ad libitum pasture (R), 65\% ad libitum pasture + 5.0 kg of cereal grain (S) and ad libitum pasture (F) were imposed in early (E), mid (M) and late (L) lactation. Milk was analysed for contents of fat, lactose and 12 nitrogen components. Treatment effects were generally greatest in E and M and often absent in L. Differences between F and R were significant by at least P>0.05, for 10, 7 and 2 of the 12 nitrogen components for E, M, L. Comparable differences for F-S were for E 6, M 5 and L 1. Changes were small in absolute terms and the extreme differences in type and level of feed suggest there is limited opportunity to manipulate nitrogen components in milk by feeding practices used in NZ. }, issn = {1176-5283}, author = {Petch SF and Bryant AM and Napper AR} } @conference {40826, title = {Effect of feeding turnips to dairy cows grazing limited amounts of pasture in mid to late lactation on milksolids production}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {242-244}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Three groups of 20 cows were allocated to one of three feeding treatments. A control group was offered only a restricted pasture allowance. Treatments groups were offered pasture and turnips at either 4 or 8 kg DM/cow/day. Cows offered 4 kg DM/cow and 8 kg DM/cow of turnips produced 265 g MS/c/day (}, issn = {1176-5283}, author = {Penno JW and Bryant AM and Napper AR and Copeman PJA} }