John Foldager

High body weight gain and reduced bovine mammary growth: physiological basis and implications for milk yield potential

Available evidence concerning the relationship between growth rate, mammary growth and milk yield in heifers leads to these conclusions: 1) Increased growth rate due to high feeding level before puberty onset can lead to reduced pubertal mammary growth and reduced milk yield potential. 2) Increased growth rate due to high feeding level after puberty and during pregnancy have no effect on mammary growth and milk yield. 3) Higher body weight gain due to higher genetic potential for growth is positively related to milk yield. The negative effect of high feeding level before puberty occurs in all breeds, but the level of feeding causing reduced yield varies. Variation in responses between experiments suggests that feeding regimes that support high growth rates without negative effect on yield can be developed. A breakthrough most likely will originate from increased knowledge of the physiological relationship between nutrition and mammary development. Our investigations suggest that blood growth hormone (GH) is important for mammary development, and that the negative effect of high feeding level on mammary development may be due to reduced blood GH. GH, however, does not bind to mammary tissue. Experiments with exogenous GH suggest that GH acts on mammary tissue via IGF-I, but IGF-I is increased by high feeding level - not decreased as GH. This paradoxical relationship cannot be explained by changes in circulating IGF binding proteins. However, the sensitivity of mammary tissue to IGF-I is reduced by high feeding level, probably due to the action of locally produced binding proteins and/or growth factors.

Long-term Effect of Colostrum Feeding Methods on Behaviour in Female Dairy Calves

The experiment was carried out with 57 female dairy calves (Danish Holstein Friesian) divided into three groups and treated differently during the first four days of life (colostrum period). Treatments were: single box and no contact with the dam (group S0), cow and calf together in a maternity pen and no suckling (C0), and cow and calf together and suckling (C4). In the post-treatment period from day five until the end of their 24th week of lactation, all three groups received the same treatment (tie stalls in winter and pasture in summer). The results from the treatment period showed that calves, which were together with their dams (groups C0 and C4), grew about 100% more per day than calves in group S0. The calves in group S0 were licked less and had the highest duration of non-nutritive sucking on equipment. In the post-treatment period, non-nutritive sucking on equipment was lower in both duration and frequency for group C4 than for the two other groups during the observations on days 21, 42 and 70. ...

Effect of Sex and Pregnancy on Feed Intake Capacity of Growing Cattle

Abstract The effects of sex and pregnancy on feed intake capacity in growing cattle were studied in an experiment with fifteen bulls, steers and heifers, respectively, and designed with complete randomized blocks. All sexes were fed ad libitum with a complete diet based on chopped straw from three months of age to approximately 520 kg. At live weights below 250 kg heifers had higher feed intake capacities (IC) than bulls, and IC of steers was intermediary. Above 250 kg live weight sex differences in IC were small and not significant. The results support the hypothesis that early maturing animals (heifers and steers) have a higher IC than late maturing animals (bulls) at low live weight. Gestation decreases IC during the last 14 weeks of pregnancy and IC was depressed by 1.5% per week. During the last couple of weeks before calving the depression in IC may be even higher. The depression in IC is due to both physical limitation of the reticulorumen and gastrointestinal tract and hormonal regulation.

The Effect of Bovine Growth Hormone on Growth, Carcass Composition and Meat Quality of Dairy Heifers

Abstract Our objective was to examine the effects of bovine growth hormone (bGH) on growth, carcass composition and meat quality of dairy heifers. Nine monozygotic twin pairs of Friesian or Red Danish cattle were used, and pair-fed a diet consisting of grass silage, barley and soybean meal. Within each pair, one animal was given daily subcutaneous injections of 20 IU of pituitary-derived bGH (15–20 mg), while the other animal was injected with saline (excipient). Treatments started at 179±2 kg body weight and lasted for 15.6 weeks. At slaughter, carcass composition and meat quality were analyzed. bGH treatment increased gain by 8% (948 vs. 877 g/d; P <0.03). The amount of saleable meat in carcass and lean content of four main carcass cuts were on average increased by 2% (P <0.05). Concomitantly, carcass fat trim was reduced by 12% (P <0.001), fat trim of individual cuts by 4–21% (P <0.05), and kidney fat by 13% (P <0.01). Except for a 20% reduction of intramuscular fat content (P <0.001), meat quality ass...

Random Variation in Voluntary Dry Matter Intake and the Effect of Day Length on Feed Intake Capacity in Growing Cattle

Abstract The objective of this paper is to describe the random variation in voluntary dry matter intake (VDMI) and to discuss the application of the results for monitoring purposes. Furthermore, the objective is to review and quantify the influence of day length or photoperiod on VDMI. VDMI was recorded in fifteen bulls, steers and heifers, respectively, fed a complete diet ad libitum. The diet was based on chopped straw formulated to secure physical regulation of feed intake. Total random variation of recorded VDMI corresponded to a coefficient of variation (CV) of 24.6%. Two thirds of this variation was due to random day to day variation in VDMI. Random variation between weeks, random variation between animals and residual random variation corresponded to a CV of 3.6, 8.0 and 10.0%, respectively, and they explained 2.5, 12.2 and 18.8% of the total random variation. In the present experiment VDMI was increased by 0.32% per hour increase in day length. This is in agreement with the increase found in revie...

Long-term Effect of Housing Method during the First Three Months of Life on Human-Animal Relationship in Female Dairy Cattle

The effect of housing during the first three months of life till the end of the first lactation on the human-animal relationship and milk production was examined in an experiment with four treatments of 20 female dairy calves each. For the first 12 weeks of their lives, the calves were housed in either open single pens (SOpen) or closed single pens (SClosed), in groups of five calves (GCalf) or in groups of five cows and calves (GCow). Calves housed in a closed single pen approached humans more than calves housed in an open single pen. There was no difference in the ease of handling. The human-animal relationship was not affected by type of housing. Calves housed in groups of calves and cows sought less human contact, but were not difficult to handle. Milk production was not affected by housing method during early rearing. Therefore, group housing, which allows full socialization with other animals and involves better welfare than individual housing, can be recommended, as no negative effect was found on ...

Effect of Immunization against Somatostatin on Antibody Binding Capacity and Affinity, Hormone Concentrations, Performance and Carcass and Meat Quality in Young Friesian Bulls

Abstract Eight bull calves were immunized against somatostatin (SS) conjugated to human serum α-globulin (anti-SS), while another 8 were immunized against human serum α-globulin alone (placebo). All calves were tethered, individually fed concentrates ad libitum and slaughtered at an average live weight of 400 kg within each block. Only 5 of the 8 anti-SS calves formed significant amounts of antibodies, with an average binding capacity of 24–34 picomole SS per litre plasma and an antibody affinity (K D) of 0.20 ± 0.04 nM. No difference was found in daily gain (1454 vs. 1378 g, SEM = 71) although voluntary daily energy intake of concentrates was slightly higher (P = 0.17) in anti-SS calves (6.09 vs. 5.54 Scandinavian Feed Units, SEM = 0.27). Feed conversion was also higher (P = 0.08) in. anti-SS calves (4.20 vs. 4.01 SFU/kg gain, SEM = 0.7) and fat content (6.8 vs. 5.4 kg, SEM = 0.3) and amount of perirenal and mesenterial fat (8.45 vs. 6.26 kg, SEM = 0.44) was significantly increased (P < 0.01). Plasma lev...