Reducing post-partum anoestrous interval in first-calf Bos indicus crossbred beef heifers. 1. Effects of pre- and post-partum supplementation strategies

1993 ◽  
Vol 44 (5) ◽  
pp. 1063 ◽  
Author(s):  
CS McSweeney ◽  
LA Fitzpatrick ◽  
MJ D'Occhio ◽  
D Reid ◽  
KW Entwistle
Keyword(s):  
Milk Yield ◽  
Bos Taurus ◽  
Post Partum ◽  
Bos Indicus ◽  
Reproductive Function ◽  
Gravid Uterus ◽  
Treatment Groups ◽  
Ovarian Folliculogenesis ◽  
Plasma Gh ◽  
Dietary Treatments

The effects of pre-and post-partum (ppp) v. post-partum (pp ) supplementation on reproductive function were compared in Bos indicus x Bos taurus (5/8 x 3/8) first-calf heifers. Twenty-four pregnant heifers were allocated to three treatment groups all fed roughage hay ad libitum. The dietary treatments were: (1) nil supplement controls, (2) cracked maize (1 kg) plus formaldehyde treated sunflower seed meal (0.5 kg) daily for 60 days post-partum, (3) supplement 2 from 1-2 months pre-partum to 60 days post-partum. Supplementation did not affect hay intake prior to calving (6.5 kg/day), but significantly increased (P < 0.05) intake by approximately 50% after calving compared with a 20% increase in the controls. Maternal liveweight, adjusted for the weight of the foetus and gravid uterus, was 345 kg in all groups at 5 weeks before calving. This weight declined by 6 kg in unsupplemented animals and increased by 16 kg with supplementation before calving. During the 2 months after calving, ppp supplemented animals maintained weight, pp supplemented heifers gained 26 kg, and controls lost 39 kg. Birth weight of calves from heifers supplemented before parturition was 34.2 � 1.9 kg, 5.6 kg heavier than the other calves (28.64�0.7 kg). Milk yield and N secretion tended to be highest in ppp supplemented heifers in the peri-partum period. Two months after calving, milk yield and secretion of N, fat and lactose were not different in both supplemented groups, but were significantly higher (P < 0.05) than in the controls. Endogenous pulsatile release of LH and FSH was not detected in heifers from any group 50 days after calving. Following GnRH injection (100 8g, i/m), the LH response was not significantly different between groups, but the unsupplemented animals had greater ( P < 0.05) FSH responses than the supplemented heifers. Supplemented heifers had lower ( P = 0.07) plasma GH concentrations prior to calving; after calving, GH levels were in the order: ppp supplemented < pp supplemented < controls. There was no indication that supplementation affected ovarian folliculogenesis in animals treated with exogenous gonadotrophin, and all animals were in an anoestrous state at 60 days post-partum. In conclusion, the type of supplementation practiced here did not appear to improve reproductive performance in first-calf heifers weighing 340-360 kg in early lactation. However, ppp supplementation was the most effective treatment in reducing GH levels and maintaining liveweight in the peri-natal period, both of which have been associated previously with reducing post-partum anoestrous interval.

Reproductive function in average and high yielding dairy cows

2001 ◽  
Vol 26 (2) ◽  
pp. 495-498 ◽  
Author(s):  
Victoria J. Taylor ◽  
Andrew J. Hattan ◽  
Emma C.L. Bleach ◽  
David E. Beever ◽  
D. Claire Wathes
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Post Partum ◽  
Reproductive Function ◽  
Reproductive Activity ◽  
Corpora Lutea ◽  
Genetic Merit ◽  
Standard Management ◽  
Service Conception ◽  
The Difference

AbstractThe resumption of reproductive activity in the early post partum period and the subsequent fertility of dairy cows are of considerable practical and economic importance to the producer. Regular milk progesterone analysis was used in this study to monitor the re-establishment of reproductive cyclicity in animals of average (AGM, n=20) and high genetic merit (HGM, n=28) kept under standard management conditions. The profiles obtained were then characterised into normal and four different types of abnormal activity. Resumption of cycles occurred significantly later in the higher yielding cows than in those of average genetic merit (23 ±2.3 days in HGM cows and 15 ± 1.6 days in AGM cows; P=0.0089). There was a significant increase in the amount of abnormal cycles encountered in the high genetic merit animals compared with average yielding animals (61% and 30% respectively; χ2 test, P=0.045); in particular, the delayed occurrence of ovulation post partum (11% vs 0%) and an increased incidence of persistent corpora lutea (32% vs 20%). For high genetic merit animals, the incidence of abnormal cycles was associated with increased peak milkyields (abnormal cycles: peak milk yield 54.7 ± 1.11 kg/day; normal cycles: peak milk yield 46.4 ± 1.35 kg/day, P=0.002). This relationship was not apparent in average genetic merit animals. First service conception rates were 50% (9/18) for AGM cows and 38% (10/26) for HGM cows (χ2 test, n.s.). The calving to conception interval was 98 ± 9.7 days for AGM animals (n=l7) and 105 ± 9.1 days for HGMs (n=24) (t-test, n.s.). In conclusion, this study confirms that high genetic merit dairy cows have compromised reproductive function in terms of a delayed resumption of cyclicity and an increased incidence of abnormal progesterone cycles, which was associated with higher peak milk yields. There was also a reduced first service conception rate in high yielders although the difference was not significant with this group size.

39 EFFECT OF TIME OF FIXED-TIME AI ON PREGNANCY RATES IN ZEBU CROSS-BRED BEEF HEIFERS TREATED WITH PROGESTERONE RELEASING DEVICES AND ESTRADIOL CYPIONATE

2010 ◽  
Vol 22 (1) ◽  
pp. 177 ◽  
Author(s):  
M. Ramos ◽  
L. Cutaia ◽  
P. Chesta ◽  
G. A. Bó
Keyword(s):  
Bos Taurus ◽  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Beef Heifers ◽  
Treatment Groups ◽  
Condition Score ◽  
To Receive

Two experiments were designed to evaluate the effect of the timing of fixed-time AI (FTAI) in relation to the removal of an intravaginal progesterone-releasing device (1 g of progesterone, DIB, Syntex SA, Buenos Aires, Argentina) on pregnancy rates in Bos indicus × Bos taurus cross-bred heifers. In experiment 1, 285 Bonsmara × zebu cross-bred heifers, between 18 and 24 months of age and with a body condition score (BCS) between 3.0 and 3.5 (1-5 scale) were used. On the day of initiation of treatment (Day 0), the heifers’ ovaries were palpated (92% of them had a CL) and they received a new DIB plus 2 mg of estradiol benzoate (EB; Syntex SA) and 250 μg of cloprostenol (Ciclase DL, Syntex SA). On Day 8, DIB devices were removed and all heifers received 250 μg of Ciclase plus 0.5 mg of estradiol cypionate (ECP; Cipiosyn, Syntex SA). At that time the heifers were randomly divided to receive FTAI between 48 to 49 h, 53 to 54 h, or 58 to 59 h after DIB removal. The heifers underwent FTAI with semen from 4 bulls by 2 inseminators. In experiment 2, 260 heifers from the same group as those used in experiment 1 (87% with a CL) were treated exactly as those in experiment 1, except that previously used DIB was inserted on Day 0. Pregnancy diagnosis was performed 30 days post-fixed-time AI by ultrasonography. The data were analyzed by logistic regression, taking into account the effect of time of FTAI, semen, and inseminator on pregnancy rates. In experiment 1, pregnancy rates were lower (P = 0.04) in the heifers undergoing FTAI between 48 and 49 h after DIB removal (46/95, 48.4%) than those undergoing FTAI 53 to 54 h (61/99, 61.6%) or 58 to 60 h (57/91, 62.6%) after DIB removal. However, no differences in pregnancy rates were found (P = 0.72) in experiment 2 between the 3 treatment groups, with 39/91 (42.9%) for the 48 to 49 h group, 45/89 (50.6%) for the 53 to 54 h group, and 35/89 (43.8%) for the 58 to 59 h group. There was no effect of the semen or inseminator (P > 0.2) in either experiment. We conclude that when Bos indicus × Bos taurus beef heifers are synchronized with new DIB devices and ECP, higher pregnancy rates are obtained in heifers undergoing FTAI late (between 53 to 60 h after DIB removal) than in those undergoing FTAI early (48 to 49 h after DIB removal). However, time of insemination does not apparently affect pregnancy rates when Bos indicus × Bos taurus beef heifers are synchronized with previously used DIB devices and ECP.

Influence of shade on panting score and behavioural responses of Bos taurus and Bos indicus feedlot cattle to heat load

2020 ◽  
Vol 60 (2) ◽  
pp. 305 ◽  
Author(s):  
A. M. Lees ◽  
J. C. Lees ◽  
V. Sejian ◽  
M. L. Sullivan ◽  
J. B. Gaughan
Keyword(s):  
Treatment Group ◽  
Observational Data ◽  
Heat Load ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Observation Time ◽  
Feedlot Cattle ◽  
Night Time ◽  
Treatment Groups ◽  
Panting Score

Context Feedlot cattle can be negatively impacted by hot conditions, such that they have reduced performance and wellbeing. This study was conducted at the research feedlot located at The University of Queensland during a southern hemisphere summer (October to April). Aims The objective of this study was to evaluate the influence of shade on the behaviour and panting score of Bos taurus and Bos indicus feedlot cattle during summer. Methods Thirty-six steers (12 Angus, 12 Charolais and 12 Brahman) with an initial non-fasted liveweight of 318.5 ± 6.7 kg were used in a 154-day feedlot study consisting of two treatments: unshaded and shaded (3 m2/animal). Observational data were obtained for each steer at 2 h intervals between 0600 and 1800 hours daily from Day 1 to Day 154. Additional night time observational data were collected at 2-h intervals between 2000 and 0400 hours on 12 occasions. Data collected included activity (feeding, drinking, or ruminating), posture (standing or lying) and panting score. Panting scores were used to calculate a mean panting score for each breed × treatment group. Observational data were converted to a count for each breed × treatment group for each observation time point and were analysed using a binomial generalised linear model. Key results Maximum shade utilisation was the greatest at 1200 hours for Angus (85.5%), Charolais (32.7%) and Brahman (33.3%) steers. All breed × treatment groups exhibited a notable increase in mean panting score as heat load increased. Average increase in mean panting score was 0.36, where shaded Brahman exhibited the smallest increase (0.13) and unshaded Angus had the greatest increase (0.71). When heat load conditions were very hot (heat load index (HLI) ≥ 86) the mean panting score of all breed × treatment groups differed (P &lt; 0.05). Conclusions Overall these results emphasise the importance of providing shade to feedlot cattle, irrespective of genotype. Implications These results further highlight the importance of providing shade to feedlot cattle. These results challenge the general perception that Bos indicus feedlot cattle do not require access to heat load alleviation strategies.

Phenotypic and genetic parameters for milk yield in traditional Nublang cattle (Bos indicus) of Bhutan

2015 ◽  
Vol 57 ◽  
pp. 25-30
Author(s):  
Jigme Dorji ◽  
Dhendup ◽  
Iona M. MacLeod
Keyword(s):  
Milk Yield ◽  
Genetic Improvement ◽  
Genetic Parameters ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Sustainable Utilization ◽  
Dual Purpose ◽  
Lactation Length ◽  
Daily Milk Yield ◽  
Daily Milk

SummaryThe Nublang is a unique dual-purpose breed ofBos indicuscattle found in Bhutan. They have been crossed with Mithun (Bos frontalis) andBos taurusbreeds in an effort to improve milk production leading to a decline in the population of purebred Nublang. An alternative to crossbreeding would be the genetic improvement of milk yield within purebred Nublang, thus allowing conservation and sustainable utilization of the pure breed. It is important to measure the genetic variability (heritability) of milk yield to assess the potential for genetic improvement within Nublang. Therefore this study estimated phenotypic and genetic parameters of milk yield using 2 052 test day milk yields from 66 cows recorded from 1997 to 2013 in the National Nublang Farm, Tashiyangphu. The average daily milk yield (DMY) was 2.12 ± 0.7 litres (N 2 052, range: 0.3–5.0 L, CV: 34 percent). Parity, month in milk and year all had a significant effect on DMY (P&lt; 0.05). The average lactation milk yield (LMY) was 519.2 ± 151 L (N: 261, range: 115–881.7, CV: 29.1 percent) and average lactation length was 239 days. LMY was significantly influenced by parity (P&lt; 0.05) and season of calving. The heritability of DMY and LMY was 0.22 ± 0.16 and 0.13 ± 0.20, respectively. The repeatability estimates were 0.45 ± 0.05 and 0.49 ± 0.08 for DMY and LMY, respectively. Overall the heritability and repeatability estimates of milk yields indicate potential for genetic improvement of milk yield in Nublang cattle through selection. However, it is recommended that a larger dataset is generated to enable more precise estimates of genetic parameters.

scholarly journals 180EFFECT OF TIME OF ECG TREATMENT ON PREGNANCY RATES IN BOS INDICUS×BOS TAURUS RECIPIENTS SYNCHRONIZED WITH PROGESTERONE VAGINAL DEVICES AND TRANSFERRED WITHOUT ESTRUS DETECTION

2004 ◽  
Vol 16 (2) ◽  
pp. 212
Author(s):  
L.F. Nasser ◽  
E.L. Reis ◽  
A.M. Oliveira ◽  
G.A. Bo ◽  
P.S. Baruselli
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Bovine Embryo ◽  
Treatment Groups ◽  
Estrus Detection ◽  
Treatment Interaction

It has been shown recently that treatments with progesterone (P4)-releasing devices combined with estradiol benzoate (EB) plus P4 on Day 0, eCG and PGF on Day 5 and a second application of EB one day after device removal (Day 9) can be used successfully to transfer bovine embryos at a self-appointed time, without the necessity of estrus detection. Although the treatment solved one of the major problems in recipient management, estrus detection, it requires handling the recipients at least five times for treatments and embryo transfer. An experiment was designed to evaluate whether reducing one day of handling, by the administration of eCG and PGF at the time of removal of the P4 device (Day 8), results in comparable pregnancy rates than giving eCG on Day 5. A secondary objective was to determine the effect of injectable P4 at the time of device insertion plus EB treatment. Crossbred Bos taurus×Bos indicus beef heifers (n=301) were randomly assigned to 4 treatment groups in a 2 by 2 factorial design. All Heifers received a P4 device (DIB, Syntex, Argentina) plus 2mg EB i.m. (Syntex) at unknown stages of the estrous cycle (Day 0), with or without 50mg of P4 given i.m. at the same time. Heifers were further subdivided to receive PGF (0.150mg d-cloprostenol, Prolise, Tecnopec, Sao Paulo, Brazil) and 400IU of eCG (Novormon, Syntex) i.m. on Days 5 or 8. In all heifers, DIB devices were removed on Day 8 and 1 mg EB was administered i.m. on Day 9. Day 10 was arbitrarily considered as the day of estrus. On Day 17, heifers were bled for plasma P4 concentrations and examined by ultrasonography to determine the number of CL and their diameter. Heifers that had &gt;1 CL or a single CL with diameter ≥18mm received an in vitro-produced (IVP) embryo by nonsurgical transfer performed by the same veterinarian. Pregnancy rates were determined by ultrasonography 30 days later. The effects of Day of eCG administration (Day 5 or Day 8), P4 of treatment (E2 or E2+P4) and the day-by-P4 treatment interaction on the numbers of CL and plasma P4 were analyzed by ANOVA, and the proportion of recipients selected and pregnant were analyzed using non-parametric tests (NPAR1WAY, SAS). There was no significant effect of P4 treatment or the P4-by-day of eCG interaction in any of the parameters evaluated. However, there was a significant effect of day of eCG administration on plasma P4 concentrations (Day 5=2.4±0.3 v. Day 8=1.7±0.2; P=0.03) and the number of CL (Day 5=1.4±0.1 v. Day 8=1.1±0.0; P=0.02) on Day 17. Furthermore, the proportion of recipients pregnant/treated tended (P=0.1) to be higher in heifers in the Day 5 Group (71/151, 47.0%) than in those in the Day 8 Group (61/150, 40.7%). Although delaying the eCG and PGF administration from Day 5 to Day 8 saves one trip through the chute for treatments, it resulted in lower plasma P4 concentrations and tended to decrease pregnancy rates in bovine embryo recipients synchronized with DIB devices and EB and transferred at a fixed time. Furthermore, the administration of injectable P4 at the time of DIB insertion did not affect pregnancy rates.

scholarly journals Effect of supplementation of rumen protected choline and methionine on milk yield and composition of early lactating dairy cows

2021 ◽  
Vol 52 (2) ◽  
Author(s):  
Jayaraj Neelima ◽  
Purushothaman Sajith ◽  
K. Ally ◽  
Ananth Deepa ◽  
Simon Shibu
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Milk Fat ◽  
Milk Composition ◽  
Treatment Groups ◽  
Nitrogen Levels ◽  
Lactating Dairy Cows ◽  
Significant Difference ◽  
Milk Urea ◽  
Dietary Treatments

An experiment was conducted on early lactating dairy cows to study the effect of rumen protected choline (RPC) and methionine (RPM) on milk yield and composition. Fifteen crossbred dairy cows in early lactation (within 10 days of calving) were selected and randomly allotted to any one of the following three dietary treatments, T1 (Control)- with compound feed mixture containing CP- 20% and TDN- 68% , T2- T1+20g RPM and 20g RPC, T3- with compound fed mixture containing CP- 17%, TDN- 68% + 20g RPM and 20g RPC. All the experimental animals were fed as per ICAR feeding standards (ICAR, 2013). Results revealed no significant difference (p>0.05) in milk yield and 4 per cent fat corrected milk (FCM) yield between the three treatment groups. Among the milk constituents, animals in T3 had significantly higher milk fat (p<0.05), SNF (p<0.05), protein (p<0.05) and total solids (p<0.01) compared to those in T1 and T2. Milk urea nitrogen levels did not differ significantly among the three treatments and were within the normal range. The study showed that milk composition could be effectively improved by supplementing feed with rumen protected forms of choline and methionine in combination at lower dietary protein level without any reduction in milk yield.

The effect of supplements of formaldehyde-treated casein on the partitioning of nutrients between cow and calf in lactating Bos indicus × Bos taurus heifers fed a roughage diet

1988 ◽  
Vol 39 (6) ◽  
pp. 1151 ◽  
Author(s):  
RA Hunter ◽  
T Magner
Keyword(s):  
Growth Hormone ◽  
Milk Yield ◽  
Plasma Insulin ◽  
Bos Taurus ◽  
Physiological State ◽  
Bos Indicus ◽  
Plasma Insulin Concentration ◽  
The Mean ◽  
Milk Solids ◽  
Negative Growth

The effect of a supplement of formaldehyde-treated casein on partition of nutrients and productivity of Bos indicus x Bos taurus (50% x 50%) first-calf heifers was studied. Sixteen pregnant heifers were fed a long-chopped roughage diet (13 g N/kg organic matter) ad lib. for approximately 3 weeks before calving and for 16 weeks after calving. Half the animals were supplemented with formaldehyde-treated casein (300 g per day). There were also 8 non-pregnant, non-lactating controls, half of which were supplemented with formaldehyde-treated casein. Supplementation had no significant effect on intake, irrespective of the physiological state of the heifers. There was a significant (P < 0.05) positive multiple regression between peak intake during lactation and the weight change of both heifer and calf in the first 8 weeks of lactation. Milk yield was not significantly affected by supplementation for the first 8 weeks. In the second half of lactation supplemented heifers produced significantly (P < 0.05) less milk, but not less milk solids, than unsupplemented heifers. During the latter half of lactation there was a highly significant (P < 0.001) positive relationship between milk yield and lactose secretion. The mean (� s.e.m.) length of the period of anoestrus after calving was 17 � 2.5 and 12 � 1.7 weeks for unsupplemented and supplemented heifers respectively. The length of the period of anoestrus was positively related to milk production (P < 0.01) and peak intake during lactation (P < 0.05). Supplemented lactating heifers had significantly (P < 0.05) higher plasma insulin concentrations and significantly (P < 0.01) lower plasma growth hormone concentrations than unsupplemented lactating heifers. In supplemented heifers in the second 8 weeks of lactation plasma insulin concentration was significantly (P < 0.01) negatively correlated with milk yield and yield of milk constituents. Supplementation with formaldehyde-treated casein did not increase roughage intake but did affect the partition of nutrients via a positive insulin and negative growth hormone response. Nutrients were preferentially diverted into maternal body growth rather than milk synthesis in the second half of lactation.

The effects of forage type and level of concentrate supplementation on food intake, diet digestibility and milk production of crossbred cows (Bos taurus × Bos indicus)

1992 ◽  
Vol 54 (2) ◽  
pp. 183-189 ◽  
Author(s):  
H. Khalili ◽  
T. Varvikko ◽  
S. Crosse
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Milk Fat ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Daily Intake ◽  
Crossbred Cows ◽  
Concentrate Supplementation ◽  
Rumen Degradation ◽  
Forage Type

AbstractAn experiment was carried out to evaluate the effects of forage type and level of concentrate supplementation on forage intake, diet digestibility and milk production. Twenty-four crossbred cows (Bos taurus × Bos indicus), in early lactation, were allocated to the following six dietary treatments: native grass hay (H) or oat-vetch hay (OV), offered ad libitum, and supplemented with either 0, 2·5 or 5·0 kg per cow per day of a wheat-middling-based concentrate. A four-period, partially balanced, change-over design was used and the treatments were arranged as a 2 × 3 factorial.The daily dry-matter (DM) intake was 640 g (P < 0·001) higher with cows on (H) diets compared with those on OV diets. However, OV diets were more digestible (0·675 v. 0·566, P < 0·001) resulting in 800 g higher (P < 0·05) daily intake of digestible DM. The daily milk yield was 1·24 kg higher (P < 0·001) for cows on OV diets compared with H diets. Milk fat concentration was higher (P < 0·05), but milk protein concentration was lower (P < 0·001) with H diets. The rates of rumen degradation of DM and nitrogen of OV were higher than of H for all incubation periods; similarly the values of the rate constant of DM and nitrogen were greater for OV than for H.The daily DM intake increased by 3·72 kg/day (P < 0·001), when the amount of concentrate increased from 0 to 5·0 kg/day, indicating a minor substitution of basal forage by concentrate. The apparent DM digestibilities of the diets were higher when the diets were supplemented with concentrates. The milk yield increased linearly (P < 0·001), when the level of concentrate supplement increased from 0 to 5 kg, resulting in 0·52 kg more milk per day per kg additional concentrate given.

The effects of forage type (maize-lablab or oat-vetch) and level of supplementation (wheat-middlings) on food intake, diet apparent digestibility, purine excretion and milk production of crossbred (Bos taurus × Bos indicus) cows

1994 ◽  
Vol 58 (3) ◽  
pp. 321-328 ◽  
Author(s):  
H. Khalili ◽  
P. O. Osuji ◽  
N. Umunna ◽  
S. Crosse
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Milk Fat ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Apparent Digestibility ◽  
Concentrate Supplementation ◽  
Microbial Nitrogen ◽  
Wheat Middlings ◽  
Forage Type

AbstractAn experiment was carried out to evaluate the effects of forage type and level of concentrate supplementation on forage intake, diet apparent digestibility, purine excretion and milk production. Twelve crossbred cows (Bos taurus × Bos indicus), in early lactation, were allocated to the following six dietary treatments: maize-lablab forage (ML) or oat-vetch forage (OV), offered ad libitum, and supplemented with either 0, 2·5 or 5·0 kg per cow per day of a supplement (wheat middlings). A four-period, partially balanced, change-over design was used and the treatments were arranged as 2 × 3 factorial.Mean organic matter (OM) intake was 670 g higher with cows on ML-based diets compared with those on OV-based diets (P <0·02). The apparent digestibilities of crude protein (CP) and neutral detergent fibre (NDF) were similar for cows given ML- or OV-based diets but the apparent digestibility of OM was higher for ML diets (P <0·05). Values of the degradation parameters (a, b and c) of DM and NDF were greater for ML forage than for the OV forage. Forage type did not affect daily milk yield nor excretion of purine derivatives in urine used to estimate microbial-nitrogen supply (P >0·05). The concentration of milk fat and total solids in the milk were similar for the two forage types offered but the concentration of milk protein was slightly higher for the cows given ML-based diets (P <0·05).Daily OM intake increased by 3·75 and 2·70 kg per cow per day (P <0·001) respectively, when the amount of concentrate increased from 0 to 5·0 kg per cow per day for the ML- and OV-based diets. The CP apparent digestibilities of the diets were higher when the diets were supplemented with concentrates but there was no effect of supplementation on the apparent digestibilities of OM and NDF. The supply of microbial-nitrogen increased linearly with increasing level of concentrate supplementation (P <0·05). Milk yield increased linearly when the level of concentrate supplement increased from 0 to 5 kg (P <0·001), resulting in 0·39 and 0·29 kg more milk per day per kg additional concentrate given in cows on ML and OV, respectively. There was also a tendency for a quadratic effect (P <0·12), especially with ML diets, showing that when the level of concentrate increased from 0 to 2·5 or from 2·5 to 5·0 kg/day, the milk yield increased respectively by 0·62 and 0·15 kg/day per kg additional concentrate given.

Prepartum supplementation effects on growth and fertility in Bos indicus-cross cows

1997 ◽  
Vol 37 (2) ◽  
pp. 141 ◽  
Author(s):  
G. Fordyce ◽  
L. A. Fitzpatrick ◽  
T. J. Mullins ◽  
N. J. Cooper ◽  
D. J. Reid ◽  
...  
Keyword(s):  
Body Condition ◽  
Post Partum ◽  
Bos Indicus ◽  
Late Pregnancy ◽  
Dry Season ◽  
Pregnancy Rates ◽  
Wet Season ◽  
Calf Growth ◽  
Treatment Groups ◽  
Calving Season

Summary. Three experiments were conducted in the dry tropics of north Australia using Bos indicus-cross cows. Cows in mid–late pregnancy were either unsupplemented during the late dry season or offered ad libitum (2 kg/day) molasses with 7.4% urea (w/w) (M8U) or cottonseed meal (1 kg/day) for up to 54 days commencing 2 months before the start of the calving season. Supplementation reduced weight loss in experiments 1 and 2 (P<0.05), but had no significant effect on weight or body condition in experiment 3. Supplementation had no effect on subsequent calf growth or cow lactation yields. Following early wet season rains in experiment 1, 9 and 49% of cows were ovulating 40 and 80 days post-partum, respectively, with no effect of supplementation. In experiment 2, 10 and 100% of cows had ovulated by 60 and 200 days post-partum, respectively. At any time between 80 and 180 days post-partum, supplemented cows were more likely to be cycling (P<0.05), independent of supplementation effects on weight or body condition. The average post-partum interval to oestrus was 30 days less in cows supplemented for 42 days (P = 0.08). In experiment 3, pregnancy rates in 1/2 and 3/4 Brahmans supplemented with M8U for 54 days (MU54) or whose calves were weaned at 2–3 months of age (WEAN) were 14% higher in the latter 2 months of mating than in cows supplemented for less than 40 days. Good seasonal conditions resulted in high pregnancy rates in all mature 5/8 Brahmans; when not weaned early, their average calving to conception interval (CCI) was 54 days (s.e. = 8.5 days). Pregnancy rates of first-lactation 5/8 Brahmans (average CCI of 125 days) supplemented for 39 days or less and weaned when calves averaged 6 months of age were 14–32% lower between 2 and 9 months post-partum than in contemporaries in the MU54 or WEAN treatment groups. It was concluded that dry-season supplementation of mid- to late-pregnant Bos indicus-cross cows with an energy concentrate for 42–54 days (‘spike’ feeding) may reduce post-partum anoestrus intervals via a mechanism which is not dependent on the effects on weight or body condition.

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