Pasture is considered one of our most important agricultural crops, contributing more than one third of all feed consumed by livestock in the United States. High quality pasture has been recognized to be highly important in efficient milk production. It has been shown, however, that good pasture must be supplemented by concentrates if' milk production is to be maintained at a high level.

The objectives of this study were to evaluate the effect of rumen-protected fish oil (RPFO) and rumen-protected marine algae (RPMA) supplements on ovarian function of lactating dairy cows on pasture or in confinement during the estrus and ovulation synchronization period. Thirty-six Holstein cows were assigned to one of the two feeding systems and fed with lipid supplements from 30d before to 100d after calving. The resumption of cyclicity and onset of estrus were not influenced by LS. Mean daily number of the large follicles was similar across the treatments. During the Ovsynch period, RPFO treated cows had larger follicles (?10mm; P<0.05). Ovulation was delayed in RPFO and RPMA group but the number of ovulation was not altered. The number and diameter of CL were greater in the RPMA group. Progesterone concentrations were greater in the RPMA group on pasture (P<0.05). These findings indicate that RPMA supplementation improves the ovarian function.

Master of Science / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / Lactating dairy cows from 2 Kansas farms were used to determine the effectiveness of exogenous progesterone in the form of an intravaginal insert (controlled internal drug release; CIDR) in conjunction with an ovulation-synchronization protocol. Cows were enrolled in a Presynch + Ovsynch protocol after parturition, where they received 2 injections of PGF[subscript]2[alpha], 14 d apart (Presynch) beginning between 30 and 36 DIM. Cows (n = 155) detected in estrus after the second PGF[subscript]2[alpha] injection of Presynch were inseminated (early AI). Remaining cows were assigned randomly to be treated with the Cosynch-72 protocol (GnRH 12 d after last Presynch PGF[subscript]2[alpha] injection, PGF[subscript]2[alpha] 7 d after GnRH, and timed AI + GnRH injection 72 h later) and served as controls (n = 159), or to be treated with the Cosynch-72 protocol and receive a progesterone insert (Ovsynch + CIDR; n = 175) for 7 d between GnRH and PGF[subscript]2[alpha]. Blood was collected at d −22 and −10 (relative to TAI at d 0) to determine cycling status based on progesterone concentrations and again at d 11 post AI to determine luteal competency. Treated cows were assigned body condition scores (BCS) on d −22 and −10. Pregnancy status was confirmed by palpation of the uterus per rectum and its contents on d 38 post-timed AI and verified again 4 wk later. Treatment with the progesterone insert increased timed AI pregnancies per AI in Cosynch- 72 + CIDR-treated cows when compared with controls (38 vs. 24%), but did not differ from early AI cows (38%). Pregnancy loss was numerically less in progesterone-treated cows than in controls (4.4 vs. 11.8%). Our study shows that increased pregnancies per AI can be achieved by the use of a progesterone insert in a reduced population of cows not yet inseminated, but treated with a progesterone insert.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The dry matter (DM) production and chemical composition of whole crop faba beans (Vicia faba) and oats (Avena sativa) were determined according to fresh material harvested at weekly intervals. From 75 to 166 days after planting whole plants of faba beans and oats were harvested at a height of ca. 10 cm above the ground on five randomly selected areas of 0.25 m² each. The freshly harvested material was weighed “as is” and ovendried to determine the DM content of each sample. The fresh and DM forage production per hectare was then calculated. The crude protein (CP), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), nitrogen free extract (NFE), fat (EE), calcium (Ca) and phosphorus (P) contents were determined according to standard laboratory techniques. The change in chemical composition of fresh whole crop material was regressed on days after planting using simple linear regressions. The fresh and DM production of whole crop faba beans and oats increased with advancing growth stage. During the 2002 production year fresh yield production of both whole crop faba beans and oats peaked at 131 days (44.7±6.9 and 28.4±7.1 ton/ha respectively). DM yield peaked at 159 and 152 days for whole crop faba beans and oats being 9.4±1.3 and 8.8±0.7 tons DM/ha respectively. The chemical composition of both forage crops decreased with advancing growth stage. The CP content of whole crop faba beans decreased (P<0.05) from 25.3% at 82 days after planting to 18.4 % at 166 days after planting in the 2002 production year, while during the 2003 production year the CP content of whole crop faba beans decreased (P<0.05) from 28.2 to 19.5 % from 75 to 159 days after planting. During 2002 the CF % of faba beans increased from 20.2 to 22.6%, while during 2003 CF % similarly increased from 21.8 to 26.5%. The CF % for oats during 2003 increased from 25.6 to 36.9%. During the same time the EE, Ca and P contents also decreased (P<0.05), while the NDF, CF and ADF contents increased (P<0.05). Two milk production studies were conducted to compare the feed intake, milk yield and milk composition of Holstein cows receiving either whole plant faba bean silage or oats as a hay or silage. Faba bean (Vicia faba) silage (FBS) was compared to that of cows receiving either oat (Avena sativa) hay (OH) or oat silage (OS) and in a 50:50 combination with FBS. Faba beans (cv. Ascot) and oats (cv. Sederberg) were planted on a Glenrosa soil. Whole crop faba beans were ensiled 145 days after planting in an above ground concrete bunker using a commercial bacterial inoculant after being wilted for one day. In the first experiment, total mixed rations (TMR) containing FBS, OH or a 50:50 mixture of FBS and OH as forage, together with a concentrate, were fed to three groups of seven lactating Holstein cows each. The experiment was conducted according to a randomized block design. Cows were on average 112±44 days post calving producing 24.0±6.2 kg milk/day. Milk production parameters of cows receiving diets containing different forages were compared by analysis of variance. The DM intake and milk yield of cows receiving TMR’s containing FBS, OH or a mixture of 50:50 FBS and OH as forages did not differ (P>0.05), milk yields being 18.9±1.9, 20.6±1.3 and 20.5±1.4 kg/cow/day respectively. With the exception of MUN, milk composition parameters did not differ among treatments (P>0.10). Cows fed OH as roughage source had a higher (P=0.06) MUN level in the milk. Results from this study indicate that FBS could effectively replace OH in lactating dairy cow diets. In the second experiment, total mixed rations (TMR) containing FBS, oat silage (OS) or a 50:50 mixture of FBS and OS as forages, together with a concentrate, were fed to six Holstein cows according to a double 3 x 3 Latin Square cross-over experimental design. Each cow received 13 kg DM either FBS, OS or a 50:50 mixture of FBS and OS were fed as forages, together with three different concentrates at nine kg “as is” each, to each cow. Cows were on average 108±30 days post calving producing 22.0±2.0 kg milk/day. DM intake, body weight, milk yield and milk composition parameters of cows receiving diets containing different forages were compared statistically. The DM intake and body weight of cows receiving TMR’s containing FBS, OH or a mixture of 50:50 FBS and OS as forages did not differ (P>0.10), although body weight changes differed significantly (P<0.10), i.e. 4.0±3.2, 8.8±3.2 and -6.0±3.2 kg respectively. The milk yield of cows receiving TMR’s containing FBS, OS or a mixture of 50:50 FBS and OS as forages did not differ (P>0.10), milk yields being 22.8±0.4, 21.4±0.4 and 21.9±0.4 kg/cow/day respectively. Of the milk composition parameters, the milk CP(%) of cows fed TMR’s containing FBS differed (P<0.05) from the cows fed the 50:50 mixture of FBS and OS, as well as cows fed the OS, being 2.82±0.02, 2.93±0.02 and 2.96±0.02% respectively. Results from this study indicate that FBS could effectively replace OS in lactating dairy cow diets. The South African database on in situ protein and fiber degradability values for whole crop faba beans and oats is limited. The chemical composition of whole crop faba beans and oats constantly change as plants mature. For optimal stage of ensiling and feed formulation it would be useful to have CP, NDF and ADF degradability values available for whole crop faba beans and oats harvested at different growth stages. The objective of this study was to determine the ruminal nutrient degradabilities of whole crop faba beans (Vicia faba) and oats (Avena sativa). Whole crop faba beans and oats were cut at weekly intervals from 75 to 159 days after planting. Effective DM, CP, NDF and ADF degradability values of faba beans and oats harvested at 117, 131, 145 and 159 days after planting were determined by using the in situ nylon bag technique. Three non-lactating Holstein cows fitted with ruminal fistulae were used. Plant material put into Dacron bags was incubated in the rumen for 4, 8, 12, 24, 48, 72 and 96 hours. The degradability of DM, CP, NDF and ADF fractions of whole plant faba beans and oats in four different growth stages (117, 131, 145 and 159 days from planting) did not differ (P<0.05) among cows. The degradability of different fractions for both roughages were affected (P<0.05) by growth stage and incubation hours. DM, CP, NDF and ADF disappearance of whole crop faba beans and oats at 117 and 159 days after planting differed (P<0.05) at 4, 8, 12, 24, 48, 72 and 96 hours of incubation time. The DM, CP, NDF and ADF disappearance values were fitted to the non-linear model p = a + b (1- e-ct). The effective degradabilities (P) could be calculated using a fractional outflow rate of k = 0.05. For whole crop faba beans, parameter b (potentially degradable fraction) and parameter c (the rate at which b is degraded) all differed different forages were compared by analysis of variance. The DM intake and milk yield of cows receiving TMR’s containing FBS, OH or a mixture of 50:50 FBS and OH as forages did not differ (P>0.05), milk yields being 18.9±1.9, 20.6±1.3 and 20.5±1.4 kg/cow/day respectively. With the exception of MUN, milk composition parameters did not differ among treatments (P>0.10). Cows fed OH as roughage source had a higher (P=0.06) MUN level in the milk. Results from this study indicate that FBS could effectively replace OH in lactating dairy cow diets. In the second experiment, total mixed rations (TMR) containing FBS, oat silage (OS) or a 50:50 mixture of FBS and OS as forages, together with a concentrate, were fed to six Holstein cows according to a double 3 x 3 Latin Square cross-over experimental design. Each cow received 13 kg DM either FBS, OS or a 50:50 mixture of FBS and OS were fed as forages, together with three different concentrates at nine kg “as is” each, to each cow. Cows were on average 108±30 days post calving producing 22.0±2.0 kg milk/day. DM intake, body weight, milk yield and milk composition parameters of cows receiving diets containing different forages were compared statistically. The DM intake and body weight of cows receiving TMR’s containing FBS, OH or a mixture of 50:50 FBS and OS as forages did not differ (P>0.10), although body weight changes differed significantly (P<0.10), i.e. 4.0±3.2, 8.8±3.2 and -6.0±3.2 kg respectively. The milk yield of cows receiving TMR’s containing FBS, OS or a mixture of 50:50 FBS and OS as forages did not differ (P>0.10), milk yields being 22.8±0.4, 21.4±0.4 and 21.9±0.4 kg/cow/day respectively. Of the milk composition parameters, the milk CP(%) of cows fed TMR’s containing FBS differed (P<0.05) from the cows fed the 50:50 mixture of FBS and OS, as well as cows fed the OS, being 2.82±0.02, 2.93±0.02 and 2.96±0.02% respectively. Results from this study indicate that FBS could effectively replace OS in lactating dairy cow diets. The South African database on in situ protein and fiber degradability values for whole crop faba beans and oats is limited. The chemical composition of whole crop faba beans and oats constantly change as plants mature. For optimal stage of ensiling and feed formulation it would be useful to have CP, NDF and ADF degradability values available for whole crop faba beans and oats harvested at different growth stages. The objective of this study was to determine the ruminal nutrient degradabilities of whole crop faba beans (Vicia faba) and oats (Avena sativa). Whole crop faba beans and oats were cut at weekly intervals from 75 to 159 days after planting. Effective DM, CP, NDF and ADF degradability values of faba beans and oats harvested at 117, 131, 145 and 159 days after planting were determined by using the in situ nylon bag technique. Three non-lactating Holstein cows fitted with ruminal fistulae were used. Plant material put into Dacron bags was incubated in the rumen for 4, 8, 12, 24, 48, 72 and 96 hours. The degradability of DM, CP, NDF and ADF fractions of whole plant faba beans and oats in four different growth stages (117, 131, 145 and 159 days from planting) did not differ (P<0.05) among cows. The degradability of different fractions for both roughages were affected (P<0.05) by growth stage and incubation hours. DM, CP, NDF and ADF disappearance of whole crop faba beans and oats at 117 and 159 days after planting differed (P<0.05) at 4, 8, 12, 24, 48, 72 and 96 hours of incubation time. The DM, CP, NDF and ADF disappearance values were fitted to the non-linear model p = a + b (1- e-ct). The effective degradabilities (P) could be calculated using a fractional outflow rate of k = 0.05. For whole crop faba beans, parameter b (potentially degradable fraction) and parameter c (the rate at which b is degraded) all differed v significantly (P<0.05) between four different growth stages (117, 131, 145 and 159 days from planting) of plant maturity for CP, NDF and ADF. In oats, parameter b and parameter c did not differ (P>0.05) between the four different growth stages (117, 131, 145 and 159 days from planting) of plant maturity. Results from this study could make a valuable contribution towards the South African databases on faba bean and oats nutrient values and can be used in dynamic feed formulation. Faba beans cut as fresh crop or silage may in the foreseeable future play an increasingly larger role in the feeding of dairy cattle in the Winter Rainfall Region of South Africa. As in the case of lupin silage, though with much higher protein content, farmers will be able to produce their own quality and high protein roughage. The nutritive properties of faba bean silage holds great promise as a forage in lactating dairy cows. / AFRIKAANSE OPSOMMING: Die droëmateriaal (DM) produksie en chemiese samestelling van heelplant fababone (Vicia faba) en hawer (Avena sativa) is bepaal deur vars plantmateriaal op ‘n weeklikse basis te sny. Plantmonsters van beide fababoon en hawerplante is gesny vanaf 75 tot 166 dae na plant op ‘n hoogte van ca. 10 cm bo die grond. Plantmonsters is weekliks gesny op vyf ewekansige persele met ‘n oppervlak van 0.25 m² elk. Die vars gesnyde plantmateriaal is geweeg en daarna ge-oonddroog om die DM inhoud van elke monster te bepaal. Die varsmateriaal en DM opbrengs per hektaar is bereken. Die ruproteïen (RP), ruvesel (RV), neutraal bestande vesel (NBV), suur bestande vesel (SBV), stikstof vrye ekstrak (NVE), eterekstrak (EE), kalsium (Ca) en fosfor (P) inhoud is bepaal volgens standaardlaboratorium metodes. Lineêre regressie is gebruik om die verandering in chemiese samestelling van heelplant fababone en hawer te kwantifiseer. Vars en DM produksie van heelplant fababone en hawer het toegeneem met toename in groeistadium. Gedurende die 2002 produksiejaar het varsmateriaal opbrengs vir beide fababone en hawer gepiek op 131 dae (44.7±6.9 en 28.4±7.1 ton/ha respektiewelik). Heelplant fababoon en hawer DM opbrengs het gepiek op 159 en 152 dae na plant op 9.4±1.3 en 8.8±0.7 ton DM/ha, respektiewelik. Die chemiese samestelling van beide gewasse het afgeneem met toename in groeistadium. Die RP inhoud van heelplant fababone het verminder (P<0.05) van 25.3% op 82 dae na plant tot 18.4% op 166 dae na plant vir die 2002 produksiejaar, terwyl gedurende die 2003 produksiejaar die RP inhoud verminder (P<0.05) het vanaf 28.2 tot 19.5% vanaf 75 tot 159 dae na plant. Gedurende die 2002 produksiejaar het die ruvesel % van fababone toegeneem vanaf 20.2 tot 22.6%, terwyl gedurende die 2003 produksiejaar het die ruvesel toegeneem vanaf 21.8 tot 26.5%. Die ruvesel % vir heelplant hawer het vir die 2003 produksiejaar toegeneem vanaf 25.6 tot 36.9%. Vir dieselfde tyd, het EE, Ca en P inhoud ook verminder (P<0.05), terwyl NBV, RV en SBV inhoud toegeneem (P<0.05) het. Twee melkproduksiestudies is uitgevoer om die effek van fababoonkuilvoer op voerinname, melkopbrengs en melksamestelling van Holsteinkoeie te bepaal. Fababoonkuilvoer (FBKV) is vergelyk met behulp van koeie wat hawerhooi (HH) of hawerkuilvoer (HKV) en in ‘n 50:50 kombinasie met FBKV as ruvoere ontvang het. Fababone (cv. Ascot) en hawer (cv. Sederberg) is gevestig op ‘n Glenrosa grond. Heelplant fababone is gesny en ingekuil op 145 dae na plant. Gesnyde materiaal is toegelaat om vir ‘n dag te verlep, waarna dit in ‘n bogrondse kuilvoersloot ingekuil is met behulp van ‘n kommersiële bakteriële entstof. In die eerste eksperiment is volvoere met FBKV, HH en ‘n 50:50 mengsel van FBKV en HH as ruvoer, saam met ‘n konsentraat, gevoer aan drie groepe koeie wat bestaan het uit sewe Holsteinkoeie elk. Die eksperiment is uitgevoer volgens ‘n ewekansige blokontwerp. Koeie was gemiddeld 112±44 dae in melk en het 24.0±6.2 kg melk/dag geproduseer. Melkproduksie-veranderlikes van koeie wat diëte ontvang het met verskillende ruvoere is met ‘n variansie-analise vergelyk. Die DM inname en melkopbrengs van koeie op volvoere bevattende vii FBKV, HH of ‘n 50:50 mengsel van FBKV en HH, het nie betekenisvol verskil (P>0.05) nie. Melkopbrengs was 18.9±1.9, 20.6±1.3 en 20.5±1.4 kg/koei/dag, respektiewelik. Met die uitsondering van melkureumstikstof (MUN), het melksamestelling-veranderlikes nie betekenisvol (P>0.10) verskil tussen behandelings nie. Koeie wat HH as ruvoer ontvang het, het ‘n hoër (P=0.06) MUN vlak in die melk gehad. Resultate van hierdie studie dui daarop dat FBKV effektief HH in lakterende melkkoeidiëte kan vervang. In die tweede eksperiment is volvoere, betsaande uit FBKV, hawerkuilvoer (HKV) of ‘n 50:50 mengsel van FBKV en HKV as ruvoer, saam met ‘n konsentraat aan ses Holsteinkoeie gevoer volgens ‘n dubbel 3 x 3 Latynse Vierkant omskakel proefontwerp. Elke koei het 13 kg DM van FBKV, HKV of ‘n 50:50 mengsel van FBKV en HKV ontvang as ruvoere, saam met drie verskillende konsentrate van 9 kg op ‘n natuurlike vogbasis elk. Koeie was gemiddeld 108±30 dae in melk en het 22.0±2.0 kg melk/dag geproduseer. DM inname, liggaamsmassa, melkopbrengs- en melksamestelling- veranderlikes van koeie op verskillende diëte wat verskillende ruvoere ingesluit het, is statisties vergelyk. Die DM inname en liggaamsmassa van koeie op volvoere bevattende FBKV, HKV of ‘n 50:50 mengsel van FBKV en HKV, het nie betekenisvol (P>0.10) verskil nie. Verandering in liggaamsmassa het betekenisvol (P<0.10) verskil, te wete 4.0±3.2, 8.8±3.2 en -6.0±3.2 kg, respektiewelik. Die melkopbrengs van koeie op volvoere bevattende FBKV, HKV of ‘n 50:50 mengsel van FBKV en HKV as ruvoer, het nie verskil (P>0.10) nie. Melkopbrengs was 22.8±0.4, 21.4±0.4 en 21.9±0.4 kg/koei/dag, respektiewelik. Ten opsigte van die melksamestelling-veranderlikes van die koeie op die onderskeie volvoere, was dit slegs melk RP(%) van koeie wat volvoere met FBKV ontvang het, wat betekenisvol (P<0.05) verskil het van die koeie wat HKV en die 50:50 mengsel van FBKV en HKV as ruvoer ontvang het. Melk RP(%) was 2.82±0.02, 2.93±0.02 en 2.96±0.02%, respektiewelik. Resultate van hierdie studie dui daarop dat FBKV effektief HKV in lakterende melkkoei diëte kan vervang. Die Suid-Afrikaanse databasis van in situ proteïen- en veseldegradeerbaarheidswaardes vir heelplant fababone en hawer is beperk. Die chemiese samestelling van heelplant fababone en hawer verander gedurig soos plante toeneem in ouderdom en groeistadium. Vir optimale stadium van inkuiling en voerformulering sou dit belangrik wees om DM, RP, NBV en SBV degradeerbaarheidswaardes van heelplant fababone en hawer ge-oes op verskillende groeistadiums te hê. Die doel van die studie was om die ruminale degradeerbaarheidswaardes vir heelplant fababone en hawer te bepaal. Effektiewe DM, RP, NBV en SBV degradeerbaarheidswaardes is vir fababone en hawer bepaal vir groeistadiums 117, 131, 145 en 159 dae na plant deur gebruik te maak van die in situ nylon sakkie tegniek. Drie nie-lakterende Holsteinkoeie elk toegerus met ‘n rumen- kannula is gebruik om ruminale degradeerbaarheidswaardes te bepaal. Plantmateriaal wat in Dacron sakkies afgeweeg is, is in die rumen geplaas vir 4, 8, 12, 24, 48, 72 en 96 ure. Die degradeerbaarheid van DM, RP, NBV en SBV fraksies van heelplant fababone en hawer vir vier verskillende groeistadiums (117, 131, 145 en 159 dae na plant) het nie betekenisvol (P<0.05) tussen koeie verskil nie. Die degradeerbaarheid van verskillende fraksies van beide ruvoere het verskil (P<0.05) tussen groeistadiums en inkubasie-ure. DM, RP, NBV en SBV verdwyning van heelplant fababone en hawer op 117 en 159 dae na plant het betekenisvol (P<0.05) verskil by 4, 8, 12, 24, 48, 72 en 96 inkubasie-ure. Die DM, RP, NBV en SBV verdwyningswaardes is gepas op ‘n nie-lineêre model p = a + b (1- e-ct). Die effektiewe degradeerbaarheid (P) kon bereken word met ‘n fraksionele uitvloeitempo van k = viii 0.05 vanuit die rumen. Vir heelplant fababone het parameter b (potensieel degradeerbare fraksie) en parameter c (die tempo waarteen b degradeer word) betekenisvol verskil (P<0.05) vir alle groeistadiums (117, 131, 145 en 159 dae na plant) vir degradeerbaarheidswaardes van RP, NBV en SBV. Vir hawer het parameter b en parameter c nie betekenisvol (P>0.05) tussen die vier verskillende groeistadiums (117, 131, 145 and 159 dae na plant) verskil nie. Die resultate van hierdie studie kan ‘n belangrike bydrae maak tot die Suid-Afrikaanse databasis van fababoon en hawer voedingswaardes, en kan aangewend word in dinamiese voerformulering. Die gebruik van varsgesnyde of ingekuilde heeplant fababone kan in die toekoms ‘n al groter rol speel in melkkoeivoeding in die Winterreënstreek van Suid-Afrika. Soos in die geval met lupiene, maar met ‘n hoër proteïen inhoud, sal produsente hul eie kwaliteit en hoë proteïen ruvoer kan verbou. Die voedingswaarde van fababoonkuilvoer hou groot belofte in as ruvoer vir lakterende melkkoeie.

Forty-eight Holstein cows at Utah State Dairy Farm were blocked statistically according to date of calving, previous milk production, and numbers of lactation at parturition. The cattle were assigned randomly to one of four treatments within blocks. The four treatments included a base ration (control, treatment #1), base ration plus .8% of sodium bicarbonate (treatment #2), base ration plus .4% of magnesium oxide (treatment #3), and base ration plus both .8% of sodium bicarbonate and .4% of magnesium oxide (treatment #4). The research was conducted from February 1983 to November 1984. A formagraph was used to measure milk coagulation parameters and pH was determined. There was no significant difference in milk coagulation parameters or pH between the control and the buffer treatments. Milk parameters were significantly different in individual cow, week, and milk pH. Milk parameters did not appear to be dependent upon season. Curd firmness was significant in interaction of season and treatment. Significant variations in milk pH were observed in relation to week, season, and individual cow. Overall treatments, the clotting time, K20, and pH value increased each week, and A30 decreased each week. The milk parameters and pH in each treatment were significant between weeks except K20 and A30 in treatment #3, and A30 in treatment #2 (p>0.05). The clotting time and K20 were negatively correlated with firmness, and there was positive correlation between Ct and K20 as expected. Somatic cell count was positively correlated with clotting time, K20, and pH and negatively correlated with A30. Milk pH was the most significant and had positive correlation coefficient with clotting time and firming rate and negative correlation coefficient with curd firmness.

Oil seeds are natural sources of fat and protein in diets for lactating cows, and are usually fed whole or crushed. A recently released variety of safflower seed, 'Nutrasaff,' contains high fat (47% crude fat) and low fiber (26% NDF), and has a potential to be effectively used as a fat supplement for lactating dairy cows. Therefore, a lactating dairy cow trial was conducted to assess production performance of dairy cows when fed graded levels of whole Nutrasaff safflower seed (NSS), to determine the optimum level of NSS supplementation in the diet and to identify its impact on milk fat content and milk fatty acid (FA) profiles. Fifteen Holstein dairy cows in midlactation (118 ± 39 days in milk) were assigned into 5 groups of 3 cows each according to previous milk yield. The experimental design was a triple 5 × 5 Latin square with each period lasting 21 d (14 d of treatment adaptation and 7 d of data collection). The animals were fed a basal diet containing 56% forage (69% alfalfa hay and 31% corn silage) and 44% concentrate mix. The diet was supplemented with 0 (control), 1, 2, 3, or 4% (DM basis) whole NSS. The NSS was added to the diet by replacing whole linted-cottonseed. Intake of DM ranged from 26.4 to 27.5 kg/d across all treatments, and did not differ due to NSS inclusion. Yield of milk and ECM averaged 33.7 and 31.6 kg/d, respectively, and they were similar in response to NSS inclusion. Milk fat percentage decreased with increasing NSS inclusion, while milk protein and lactose concentrations did not differ among treatment diets. Milk fat concentration was reduced by 11% when NSS was included at 4% of the dietary DM. Feeding NSS at 1, 2, or 3% resulted in a similar milk fat concentration, and these diets also had similar milk fat percentage compared with the control diet. Concentration of milk urea N decreased by NSS inclusion regardless of level of NSS inclusion, implying that NSS supplementation improved dietary N use for milk production. Digestibilities of DM (P = 0.12) tended to increase when NSS was supplemented at 1, 2, or 3%. Cis-9, trans-11 conjugated linoleic acid (CLA) linearly increased as the NSS inclusion increased. Total concentration of n-3 FA increased by feeding NSS at 1 and 2%, whereas total concentration of n-6 FA linearly increased with increasing inclusion level of NSS. This study clearly demonstrates that it is highly possible to use NSS as a means of fat supplementation to lactating dairy cows without negative impact on lactational performance if added less than 3% of dietary DM. The enhanced milk quality with increased cis-9, trans-11 CLA concentration due to the addition of NSS could have positive implications to human health.

No presente estudo foram efetuados três ensaios. No primeiro, foram comparados os efeitos de teores crescentes de proteína metabolizável (PM), de acordo com o NRC (2001) para vacas lactantes mantidas em pastagens de capim Elefante. Os aumentos em PM foram obtidos com o aumento da proporção de farelo de soja na ração. Foram utilizadas 12 vacas, delineadas em quadrado latino 3 x 3 com quatro repetições, durante 60 dias de avaliação. Não foi observado efeito (P>0,05) sobre a produção de leite e leite corrigido para 3,5% de gordura, teores e produção de gordura, proteína e sólidos totais. Houve aumento linear (P<0,05) nos teores de nitrogênio uréico no leite (11,17; 13,17; 15,63 mg dL-1) e no plasma (18,57; 19,93; 21,99 mg dL-1). No segundo ensaio, foram avaliados os efeitos de dois diferentes intervalos entre desfolhas (95% de interceptação de luz pelo dossel - T1 e 27 dias fixos - T2) das pastagens de capim Elefante sobre o desempenho lactacional de vacas leiteiras. Foram utilizadas oito vacas lactantes, delineadas em cross-over, durante 80 dias. Os dados das pastagens foram analisados através de delineamento inteiramente casualizado com medidas repetidas no tempo. Foi observado maior (P<0,05) altura do dossel em pré (1,03 e 1,21m) e pós-pastejo (0,62 e 0,71m), interceptação de luz pelo dossel (95,47 e 97,91%), teor de fibra em detergente ácido (35,88 e 37,05%) e fibra em detergente neutro (65,08 e 66,99%). Não houve efeito dos tratamentos (P>0,05) sobre a massa de forragem em pré (6.270 e 6.310 kg de MS ha-1) e pós-pastejo (3.580 e 3.850 kg de MS ha-1). Houve tendência de maior produção de leite (16,72 e 14,09 kg dia-1), produção de gordura (0,64 e 0,54 kg dia-1), lactose (0,72 e 0,58 kg dia-1) e de sólidos totais (2,04 e 1,70 kg dia-1) para o T1 em comparação com o T2. No terceiro estudo, foram avaliados os efeitos de três estratégias de suplementação protéica nas rações (isoprotéicas) com cana-de-açúcar para vacas em lactação, em dois níveis de produção, 18 kg dia-1 (T1, T2 e T3) e 10 kg dia-1 (T4, T5 e T6). No T1 e T4, foi usado o teor de 1 kg de uréia para cada 100 kg de cana-de-açúcar in natura, no T2 e T5 as rações foram formuladas com teores ajustados de PM, enquanto no T3 e T6 havia teores excessivos de PM, conforme o NRC (2001), através do aumento em farelo de soja e redução na uréia. Para a análise dos dados foi utilizado o delineamento em quadrado latino 3 x 3 com três replicações. Não houve efeito dos tratamentos (P>0,05) sobre o consumo de matéria seca, produção de leite, teor de gordura, proteína e sólidos totais. Também não houve efeito dos tratamentos (P>0,05) sobre os teores de nitrogênio uréico no leite (13,42; 13,26; 14,03 e 13,62; 13,48; 14,12 mg dL-1) e no plasma (19,03; 19,22; 20,02 e 19,23; 19,32 e 20,12 mg dL-1), para ambos os grupos avaliados. / In the present study three trials were conducted. Trial 1: Three concentrates with increasing metabolizable protein (MP) contents were fed to lactating dairy cows grazing Elephant grass. Extra soybean meal was fed to increase MP in the diet beyond NRC (2001) recommendation. Twelve cows were used in a 3 x 3 latin square design, replicated four times, for 60 days. There were no effects (P>0.05) of treatments on milk yield, 3,5% fat corrected milk, on fat, protein and total solids contents and yields. Milk urea nitrogen and plasma urea nitrogen concentrations increased linearly (P<0.05)(11.17; 13.17; 15.63 and 18.57; 19.93; 21.99 mg dL-1) with increasing concentrate crude protein content. Trial 2: Two different intervals between defoliation (95% of light interception - T1 and 27 days fixed - T2) of Elephant grass pasture were compared for lactating dairy cows. Eight cows were used in a cross-over design during 80 days. The pasture data were analyzed in a complete random design with time repeated measurements. The sward heights pre-grazing (1.03 and 1.21m), and post-grazing (0.62 and 0.71m), light interception (95.47 and 97.91%), acid detergent fiber (35.88 and 37.05%) and neutral detergent fiber (65.08 and 66.99%) were higher for T2 compared to T1. Forage mass pre-grazing (6270 and 6310 kg DM ha-1) and post-grazing (3580 and 3850 kg DM ha-1) were not affected by treatments (P>0.05). There were tendencies for higher milk yield (16.72 and 14.09 kg day-1), fat yield (0.64 and 0.54 kg day-1), lactose yield (0.72 and 0.58 kg day-1) and total solids yield (2.04 and 1.70 kg day-1) for T1 in comparison with T2. Trial 3: Three strategies for protein adequacy in sugarcane based diets were compared for lactating dairy cows producing 18 kg milk day-1 (T1, T2 and T3), or 10 kg of milk day-1 (T4, T5 and T6). In treatment 1 (T1 and T4) urea was added to the diets in the dose of 1% of sugarcane (as fed), as traditionally done in Brazil. In treatment 2 (T2 and T5), diets were formulated according to NRC (2001) to be adequate in MP. In treatment 3 (T3 and T6), MP was fed in excess of NRC (2001) recommendation. All the three diets were isonitrogenous. Increasing soybean meal and decreasing urea in the diets was done to increase MP. Eighteen dairy cows, separated in two groups (10 and 18 kg milk-1 day-1) with nine cows each, were used during sixty days, in a 3 x 3 latin square design replicated three times. There were not effects of treatments (P>0.05) on DMI, milk yield, fat contents and yields, protein contents and yields and total solids contents and yields. There were not effects of treatments (P>0.05) on milk urea nitrogen (13,42; 13,26; 14,03 e 13,62; 13,48; 14,12 mg dL-1) and plasma urea nitrogen (19.03; 19.22; 20.02 and 19.23; 19.32 e 20.02 mg dL-1).

No presente estudo foram efetuados três ensaios. No primeiro, foram comparados os efeitos de teores crescentes de proteína metabolizável (PM), de acordo com o NRC (2001) para vacas lactantes mantidas em pastagens de capim Elefante. Os aumentos em PM foram obtidos com o aumento da proporção de farelo de soja na ração. Foram utilizadas 12 vacas, delineadas em quadrado latino 3 x 3 com quatro repetições, durante 60 dias de avaliação. Não foi observado efeito (P>0,05) sobre a produção de leite e leite corrigido para 3,5% de gordura, teores e produção de gordura, proteína e sólidos totais. Houve aumento linear (P<0,05) nos teores de nitrogênio uréico no leite (11,17; 13,17; 15,63 mg dL-1) e no plasma (18,57; 19,93; 21,99 mg dL-1). No segundo ensaio, foram avaliados os efeitos de dois diferentes intervalos entre desfolhas (95% de interceptação de luz pelo dossel – T1 e 27 dias fixos – T2) das pastagens de capim Elefante sobre o desempenho lactacional de vacas leiteiras. Foram utilizadas oito vacas lactantes, delineadas em cross-over, durante 80 dias. Os dados das pastagens foram analisados através de delineamento inteiramente casualizado com medidas repetidas no tempo. Foi observado maior (P<0,05) altura do dossel em pré (1,03 e 1,21m) e pós-pastejo (0,62 e 0,71m), interceptação de luz pelo dossel (95,47 e 97,91%), teor de fibra em detergente ácido (35,88 e 37,05%) e fibra em detergente neutro (65,08 e 66,99%). Não houve efeito dos tratamentos (P>0,05) sobre a massa de forragem em pré (6.270 e 6.310 kg de MS ha-1) e pós-pastejo (3.580 e 3.850 kg de MS ha-1). Houve tendência de maior produção de leite (16,72 e 14,09 kg dia-1), produção de gordura (0,64 e 0,54 kg dia-1), lactose (0,72 e 0,58 kg dia-1) e de sólidos totais (2,04 e 1,70 kg dia-1) para o T1 em comparação com o T2. No terceiro estudo, foram avaliados os efeitos de três estratégias de suplementação protéica nas rações (isoprotéicas) com cana-de-açúcar para vacas em lactação, em dois níveis de produção, 18 kg dia-1 (T1, T2 e T3) e 10 kg dia-1 (T4, T5 e T6). No T1 e T4, foi usado o teor de 1 kg de uréia para cada 100 kg de cana-de-açúcar in natura, no T2 e T5 as rações foram formuladas com teores ajustados de PM, enquanto no T3 e T6 havia teores excessivos de PM, conforme o NRC (2001), através do aumento em farelo de soja e redução na uréia. Para a análise dos dados foi utilizado o delineamento em quadrado latino 3 x 3 com três replicações. Não houve efeito dos tratamentos (P>0,05) sobre o consumo de matéria seca, produção de leite, teor de gordura, proteína e sólidos totais. Também não houve efeito dos tratamentos (P>0,05) sobre os teores de nitrogênio uréico no leite (13,42; 13,26; 14,03 e 13,62; 13,48; 14,12 mg dL-1) e no plasma (19,03; 19,22; 20,02 e 19,23; 19,32 e 20,12 mg dL-1), para ambos os grupos avaliados. / In the present study three trials were conducted. Trial 1: Three concentrates with increasing metabolizable protein (MP) contents were fed to lactating dairy cows grazing Elephant grass. Extra soybean meal was fed to increase MP in the diet beyond NRC (2001) recommendation. Twelve cows were used in a 3 x 3 latin square design, replicated four times, for 60 days. There were no effects (P>0.05) of treatments on milk yield, 3,5% fat corrected milk, on fat, protein and total solids contents and yields. Milk urea nitrogen and plasma urea nitrogen concentrations increased linearly (P<0.05)(11.17; 13.17; 15.63 and 18.57; 19.93; 21.99 mg dL-1) with increasing concentrate crude protein content. Trial 2: Two different intervals between defoliation (95% of light interception – T1 and 27 days fixed – T2) of Elephant grass pasture were compared for lactating dairy cows. Eight cows were used in a cross-over design during 80 days. The pasture data were analyzed in a complete random design with time repeated measurements. The sward heights pre-grazing (1.03 and 1.21m), and post-grazing (0.62 and 0.71m), light interception (95.47 and 97.91%), acid detergent fiber (35.88 and 37.05%) and neutral detergent fiber (65.08 and 66.99%) were higher for T2 compared to T1. Forage mass pre-grazing (6270 and 6310 kg DM ha-1) and post-grazing (3580 and 3850 kg DM ha-1) were not affected by treatments (P>0.05). There were tendencies for higher milk yield (16.72 and 14.09 kg day-1), fat yield (0.64 and 0.54 kg day-1), lactose yield (0.72 and 0.58 kg day-1) and total solids yield (2.04 and 1.70 kg day-1) for T1 in comparison with T2. Trial 3: Three strategies for protein adequacy in sugarcane based diets were compared for lactating dairy cows producing 18 kg milk day-1 (T1, T2 and T3), or 10 kg of milk day-1 (T4, T5 and T6). In treatment 1 (T1 and T4) urea was added to the diets in the dose of 1% of sugarcane (as fed), as traditionally done in Brazil. In treatment 2 (T2 and T5), diets were formulated according to NRC (2001) to be adequate in MP. In treatment 3 (T3 and T6), MP was fed in excess of NRC (2001) recommendation. All the three diets were isonitrogenous. Increasing soybean meal and decreasing urea in the diets was done to increase MP. Eighteen dairy cows, separated in two groups (10 and 18 kg milk-1 day-1) with nine cows each, were used during sixty days, in a 3 x 3 latin square design replicated three times. There were not effects of treatments (P>0.05) on DMI, milk yield, fat contents and yields, protein contents and yields and total solids contents and yields. There were not effects of treatments (P>0.05) on milk urea nitrogen (13,42; 13,26; 14,03 e 13,62; 13,48; 14,12 mg dL-1) and plasma urea nitrogen (19.03; 19.22; 20.02 and 19.23; 19.32 e 20.02 mg dL-1).